[CLAUDE] Drastic refactor: flat workflow Phòng × Cấp + Migration 21 (Chunk A)

User chốt drastic refactor — bỏ phase enum hoàn toàn, dùng ChoDuyet=10
đơn nhất + currentStepIndex tracking. Workflow flat list (Phòng × Cấp ×
Approvers). Mỗi PE/HĐ pin WorkflowDefinitionId chạy hết quy trình đó.

Schema (Migration 21 `RefactorWorkflowToFlatModel`):
- Phase enum +ChoDuyet=10 (PE + Contract). Legacy 2-9 + 98 deprecated.
- WorkflowStep + DepartmentId Guid? (FK Restrict) + PositionLevel int?
  (PE + Contract — mirror).
- PE/Contract + CurrentWorkflowStepIndex int? + RejectedAtStepIndex int?
- DROP table PurchaseEvaluationWorkflowStepInnerSteps (Mig 18)
- DROP table WorkflowStepInnerSteps (Mig 20)
- DROP column ContractDeptApproval.InnerStepId (Mig 20)
- DROP column PEDeptApproval.InnerStepId (Mig 18)
- DROP filtered indexes (Mig 19/20) + restore simple unique
  (TargetId, Phase, Dept, Stage) non-filtered

Service rewrite (PE + Contract WorkflowService.TransitionAsync):
- Phase transitions: DangSoanThao → ChoDuyet (Drafter trình, init idx=0)
- ChoDuyet → ChoDuyet (advance idx per approve)
- ChoDuyet → DaDuyet/DaPhatHanh (idx >= steps.Count → terminal)
- ChoDuyet → DangSoanThao (Trả lại — save RejectedAtStepIndex)
- ChoDuyet → TuChoi (Từ chối — khoá vĩnh viễn)
- DangSoanThao + RejectedAtStepIndex → ChoDuyet jump-back to saved idx
- Approver match: actor.Dept == step.Dept AND actor.PositionLevel >=
  step.PositionLevel (OR-of-many cùng cấp/dept = pass) OR
  Approvers.Any(Kind=User AND id match) OR
  Approvers.Any(Kind=Role AND actorRoles contains)
- Admin role bypass policy. Last step done → gen mã HĐ (Contract only)

App CQRS:
- WorkflowStepDto + WorkflowStepInput drop InnerStep, add DepartmentId
  + PositionLevel fields. PE + Contract mirror.

Tests rewrite:
- DROP PeNStageApprovalTests.cs (6 test) + ContractNStageApprovalTests.cs
  (6 test) + PeTwoStageApprovalTests.cs (7 test) — legacy N-stage/2-stage
  no longer applicable
- UPDATE PeWorkflowAdminTests signature to new flat input
- 96 → 77 test pass (drop 19 legacy)

Reference Domain entities removed:
- WorkflowStepInnerStep (Contract)
- PurchaseEvaluationWorkflowStepInnerStep (PE)
- DTOs WorkflowStepInnerStepDto / CreateWorkflowStepInnerStepInput per module

Memory `feedback_drastic_refactor_scope.md` validated: drastic refactor
done in dedicated session với context fresh, scope ~5h actual (planned ~8-10h
with 2x buffer).

Verify:
- dotnet build SolutionErp.slnx 0 error
- dotnet ef database update Mig 21 LocalDB applied OK
- dotnet test 77 pass (54 Domain + 23 Infra)
- 3-file rule: Migration .cs + Designer.cs + Snapshot updated

Pending Chunk B: FE Designer flat UI (PeWorkflowsPage + WorkflowsPage).
Pending Chunk C: FE PeWorkflowPanel + workflow timeline display.
Pending Chunk D: Docs + Skill + Memory + session log.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/Backend/SolutionErp.Application/Contracts/WorkflowAdminFeatures.cs

@@ -17,26 +17,19 @@ public record WorkflowStepApproverDto(
     string AssignmentValue,
     string? DisplayName);   // resolved role label or user fullName
 
-// Mig 20 — N-stage approval inner step level con (mirror PE Mig 18)
+// Mig 21 — flat workflow step. Mỗi step = 1 (Phòng × Cấp + Approvers users)
-public record WorkflowStepInnerStepDto(
+// sequential. Service iterate theo Order, advance Contract.CurrentWorkflowStepIndex.
-    Guid Id,
-    int Order,
-    Guid DepartmentId,
-    string? DepartmentName,
-    int PositionLevel,        // 1=NV, 2=PP, 3=TP
-    string? Name,
-    int? SlaDays,
-    bool IsRequired);
-
 public record WorkflowStepDto(
     Guid Id,
     int Order,
-    int Phase,
+    int Phase,                  // [DEPRECATED post-Mig 21] dùng ChoDuyet=10 cho new
     string PhaseLabel,
-    string Name,
+    string Name,                // "Phòng A — Cấp 1"
     int? SlaDays,
-    List<WorkflowStepApproverDto> Approvers,
+    Guid? DepartmentId,         // Mig 21
-    List<WorkflowStepInnerStepDto> InnerSteps);
+    string? DepartmentName,     // resolved display
+    int? PositionLevel,         // Mig 21 — 1=NV, 2=PP, 3=TP
+    List<WorkflowStepApproverDto> Approvers);
 
 public record WorkflowDefinitionDto(
     Guid Id,
@@ -96,15 +89,15 @@ public class GetWorkflowAdminOverviewQueryHandler(
         var definitions = await db.WorkflowDefinitions.AsNoTracking()
             .Include(d => d.Steps.OrderBy(s => s.Order))
                 .ThenInclude(s => s.Approvers)
-            .Include(d => d.Steps)
-                .ThenInclude(s => s.InnerSteps.OrderBy(i => i.Order))
             .OrderByDescending(d => d.Version)
             .ToListAsync(ct);
 
-        // Resolve dept names cho InnerStep.DepartmentName display (Mig 20)
+        // Resolve dept names cho step.DepartmentId display (Mig 21)
         var deptIds = definitions
-            .SelectMany(d => d.Steps).SelectMany(s => s.InnerSteps)
+            .SelectMany(d => d.Steps)
-            .Select(i => i.DepartmentId).Distinct().ToList();
+            .Where(s => s.DepartmentId != null)
+            .Select(s => s.DepartmentId!.Value)
+            .Distinct().ToList();
         var deptNames = deptIds.Count == 0
             ? new Dictionary<Guid, string>()
             : await db.Departments.AsNoTracking()
@@ -151,19 +144,13 @@ public class GetWorkflowAdminOverviewQueryHandler(
                 PhaseLabels.GetValueOrDefault(s.Phase, s.Phase.ToString()),
                 s.Name,
                 s.SlaDays,
+                s.DepartmentId,
+                s.DepartmentId != null ? deptNames.GetValueOrDefault(s.DepartmentId.Value) : null,
+                s.PositionLevel != null ? (int?)s.PositionLevel : null,
                 s.Approvers.Select(a => new WorkflowStepApproverDto(
                     (int)a.Kind,
                     a.AssignmentValue,
-                    ResolveDisplay(a, userNames))).ToList(),
+                    ResolveDisplay(a, userNames))).ToList()
-                s.InnerSteps.OrderBy(i => i.Order).Select(i => new WorkflowStepInnerStepDto(
-                    i.Id,
-                    i.Order,
-                    i.DepartmentId,
-                    deptNames.GetValueOrDefault(i.DepartmentId),
-                    (int)i.PositionLevel,
-                    i.Name,
-                    i.SlaDays,
-                    i.IsRequired)).ToList()
             )).ToList());
 
         var types = Enum.GetValues<ContractType>()
@@ -193,23 +180,16 @@ public class GetWorkflowAdminOverviewQueryHandler(
 
 public record CreateWorkflowStepApproverInput(int Kind, string AssignmentValue);
 
-// Mig 20 — Inner step input cho designer N-stage. InnerSteps optional empty
+// Mig 21 — flat workflow step input. DeptId + PositionLevel = Phòng × Cấp.
-// list → service fallback 2-stage Review/Confirm logic legacy Mig 16.
+// Phase auto-assign ChoDuyet=10 cho new definitions (legacy phase-specific deprecated).
-public record CreateWorkflowStepInnerStepInput(
-    int Order,
-    Guid DepartmentId,
-    int PositionLevel,        // 1=NV, 2=PP, 3=TP
-    string? Name,
-    int? SlaDays,
-    bool IsRequired);
-
 public record CreateWorkflowStepInput(
     int Order,
-    int Phase,
+    int Phase,                  // [DEPRECATED] caller có thể truyền 10=ChoDuyet hoặc legacy enum value
     string Name,
     int? SlaDays,
-    List<CreateWorkflowStepApproverInput> Approvers,
+    Guid? DepartmentId,         // Mig 21
-    List<CreateWorkflowStepInnerStepInput>? InnerSteps = null);
+    int? PositionLevel,         // Mig 21 — 1=NV, 2=PP, 3=TP
+    List<CreateWorkflowStepApproverInput> Approvers);
 
 public record CreateWorkflowDefinitionCommand(
     ContractType ContractType,
@@ -233,25 +213,18 @@ public class CreateWorkflowDefinitionCommandValidator : AbstractValidator<Create
         RuleForEach(x => x.Steps).ChildRules(step =>
         {
             step.RuleFor(s => s.Order).GreaterThanOrEqualTo(1);
-            step.RuleFor(s => s.Phase).InclusiveBetween(1, 9);
+            step.RuleFor(s => s.Phase).InclusiveBetween(1, 99);   // Mig 21 accept ChoDuyet=10
             step.RuleFor(s => s.Name).NotEmpty().MaximumLength(200);
             step.RuleFor(s => s.SlaDays).GreaterThanOrEqualTo(0)
                 .When(s => s.SlaDays != null);
+            step.RuleFor(s => s.PositionLevel).InclusiveBetween(1, 3)
+                .When(s => s.PositionLevel != null)
+                .WithMessage("PositionLevel: 1=NV, 2=PP, 3=TP.");
             step.RuleForEach(s => s.Approvers).ChildRules(app =>
             {
                 app.RuleFor(a => a.Kind).InclusiveBetween(1, 2);
                 app.RuleFor(a => a.AssignmentValue).NotEmpty().MaximumLength(100);
             });
-            step.RuleForEach(s => s.InnerSteps!).ChildRules(inner =>
-            {
-                inner.RuleFor(i => i.Order).GreaterThanOrEqualTo(1);
-                inner.RuleFor(i => i.DepartmentId).NotEmpty();
-                inner.RuleFor(i => i.PositionLevel).InclusiveBetween(1, 3)
-                    .WithMessage("PositionLevel: 1=NV, 2=PP, 3=TP.");
-                inner.RuleFor(i => i.Name).MaximumLength(200);
-                inner.RuleFor(i => i.SlaDays).GreaterThanOrEqualTo(0)
-                    .When(i => i.SlaDays != null);
-            }).When(s => s.InnerSteps != null);
         });
     }
 }
@@ -291,20 +264,13 @@ public class CreateWorkflowDefinitionCommandHandler(IApplicationDbContext db)
                     Phase = (ContractPhase)s.Phase,
                     Name = s.Name,
                     SlaDays = s.SlaDays,
+                    DepartmentId = s.DepartmentId,
+                    PositionLevel = s.PositionLevel != null ? (PositionLevel)s.PositionLevel : null,
                     Approvers = s.Approvers.Select(a => new WorkflowStepApprover
                     {
                         Kind = (WorkflowApproverKind)a.Kind,
                         AssignmentValue = a.AssignmentValue,
                     }).ToList(),
-                    InnerSteps = (s.InnerSteps ?? new()).OrderBy(i => i.Order).Select(i => new WorkflowStepInnerStep
-                    {
-                        Order = i.Order,
-                        DepartmentId = i.DepartmentId,
-                        PositionLevel = (PositionLevel)i.PositionLevel,
-                        Name = i.Name,
-                        SlaDays = i.SlaDays,
-                        IsRequired = i.IsRequired,
-                    }).ToList(),
                 })
                 .ToList(),
         };

src/Backend/SolutionErp.Application/PurchaseEvaluations/PeWorkflowAdminFeatures.cs

@@ -18,27 +18,18 @@ public record PeWorkflowStepApproverDto(
     string AssignmentValue,
     string? DisplayName);
 
-// Mig 18 — N-stage approval inner step level con. Cấu hình động trong cùng
+// Mig 21 — flat workflow step. Mỗi step = 1 (Phòng × Cấp + Approvers users).
-// 1 phase: NV.A → PP.A → TP.A → NV.B → ... theo Order asc.
-public record PeWorkflowStepInnerStepDto(
-    Guid Id,
-    int Order,
-    Guid DepartmentId,
-    string? DepartmentName,
-    int PositionLevel,        // 1=NV, 2=PP, 3=TP
-    string? Name,
-    int? SlaDays,
-    bool IsRequired);
-
 public record PeWorkflowStepDto(
     Guid Id,
     int Order,
-    int Phase,
+    int Phase,                  // [DEPRECATED post-Mig 21] dùng ChoDuyet=10
     string PhaseLabel,
-    string Name,
+    string Name,                // "Phòng A — Cấp 1"
     int? SlaDays,
-    List<PeWorkflowStepApproverDto> Approvers,
+    Guid? DepartmentId,         // Mig 21
-    List<PeWorkflowStepInnerStepDto> InnerSteps);
+    string? DepartmentName,
+    int? PositionLevel,         // Mig 21 — 1=NV, 2=PP, 3=TP
+    List<PeWorkflowStepApproverDto> Approvers);
 
 public record PeWorkflowDefinitionDto(
     Guid Id,
@@ -92,15 +83,15 @@ public class GetPeWorkflowAdminOverviewQueryHandler(
         var definitions = await db.PurchaseEvaluationWorkflowDefinitions.AsNoTracking()
             .Include(d => d.Steps.OrderBy(s => s.Order))
                 .ThenInclude(s => s.Approvers)
-            .Include(d => d.Steps)
-                .ThenInclude(s => s.InnerSteps.OrderBy(i => i.Order))
             .OrderByDescending(d => d.Version)
             .ToListAsync(ct);
 
-        // Resolve dept names cho InnerStep.DepartmentName display
+        // Resolve dept names cho step.DepartmentId display (Mig 21 flat)
         var deptIds = definitions
-            .SelectMany(d => d.Steps).SelectMany(s => s.InnerSteps)
+            .SelectMany(d => d.Steps)
-            .Select(i => i.DepartmentId).Distinct().ToList();
+            .Where(s => s.DepartmentId != null)
+            .Select(s => s.DepartmentId!.Value)
+            .Distinct().ToList();
         var deptNames = deptIds.Count == 0
             ? new Dictionary<Guid, string>()
             : await db.Departments.AsNoTracking()
@@ -147,19 +138,13 @@ public class GetPeWorkflowAdminOverviewQueryHandler(
                 PhaseLabels.GetValueOrDefault(s.Phase, s.Phase.ToString()),
                 s.Name,
                 s.SlaDays,
+                s.DepartmentId,
+                s.DepartmentId != null ? deptNames.GetValueOrDefault(s.DepartmentId.Value) : null,
+                s.PositionLevel != null ? (int?)s.PositionLevel : null,
                 s.Approvers.Select(a => new PeWorkflowStepApproverDto(
                     (int)a.Kind,
                     a.AssignmentValue,
-                    ResolveDisplay(a, userNames))).ToList(),
+                    ResolveDisplay(a, userNames))).ToList()
-                s.InnerSteps.OrderBy(i => i.Order).Select(i => new PeWorkflowStepInnerStepDto(
-                    i.Id,
-                    i.Order,
-                    i.DepartmentId,
-                    deptNames.GetValueOrDefault(i.DepartmentId),
-                    (int)i.PositionLevel,
-                    i.Name,
-                    i.SlaDays,
-                    i.IsRequired)).ToList()
             )).ToList());
 
         var types = Enum.GetValues<PurchaseEvaluationType>()
@@ -189,23 +174,15 @@ public class GetPeWorkflowAdminOverviewQueryHandler(
 
 public record CreatePeWorkflowStepApproverInput(int Kind, string AssignmentValue);
 
-// Mig 18 — Inner step input cho designer N-stage. InnerSteps optional empty
+// Mig 21 — flat workflow step input. DeptId + PositionLevel = Phòng × Cấp.
-// list → service fallback 2-stage Review/Confirm logic legacy Mig 16.
-public record CreatePeWorkflowStepInnerStepInput(
-    int Order,
-    Guid DepartmentId,
-    int PositionLevel,        // 1=NV, 2=PP, 3=TP
-    string? Name,
-    int? SlaDays,
-    bool IsRequired);
-
 public record CreatePeWorkflowStepInput(
     int Order,
-    int Phase,
+    int Phase,                  // [DEPRECATED] caller có thể truyền 10=ChoDuyet hoặc legacy
     string Name,
     int? SlaDays,
-    List<CreatePeWorkflowStepApproverInput> Approvers,
+    Guid? DepartmentId,         // Mig 21
-    List<CreatePeWorkflowStepInnerStepInput>? InnerSteps = null);
+    int? PositionLevel,         // Mig 21 — 1=NV, 2=PP, 3=TP
+    List<CreatePeWorkflowStepApproverInput> Approvers);
 
 public record CreatePeWorkflowDefinitionCommand(
     PurchaseEvaluationType EvaluationType,
@@ -240,16 +217,9 @@ public class CreatePeWorkflowDefinitionCommandValidator : AbstractValidator<Crea
                 app.RuleFor(a => a.Kind).InclusiveBetween(1, 2);
                 app.RuleFor(a => a.AssignmentValue).NotEmpty().MaximumLength(100);
             });
-            step.RuleForEach(s => s.InnerSteps!).ChildRules(inner =>
+            step.RuleFor(s => s.PositionLevel).InclusiveBetween(1, 3)
-            {
+                .When(s => s.PositionLevel != null)
-                inner.RuleFor(i => i.Order).GreaterThanOrEqualTo(1);
-                inner.RuleFor(i => i.DepartmentId).NotEmpty();
-                inner.RuleFor(i => i.PositionLevel).InclusiveBetween(1, 3)
                 .WithMessage("PositionLevel: 1=NV, 2=PP, 3=TP.");
-                inner.RuleFor(i => i.Name).MaximumLength(200);
-                inner.RuleFor(i => i.SlaDays).GreaterThanOrEqualTo(0)
-                    .When(i => i.SlaDays != null);
-            }).When(s => s.InnerSteps != null);
         });
     }
 }
@@ -287,20 +257,13 @@ public class CreatePeWorkflowDefinitionCommandHandler(IApplicationDbContext db)
                     Phase = (PurchaseEvaluationPhase)s.Phase,
                     Name = s.Name,
                     SlaDays = s.SlaDays,
+                    DepartmentId = s.DepartmentId,
+                    PositionLevel = s.PositionLevel != null ? (PositionLevel)s.PositionLevel : null,
                     Approvers = s.Approvers.Select(a => new PurchaseEvaluationWorkflowStepApprover
                     {
                         Kind = (WorkflowApproverKind)a.Kind,
                         AssignmentValue = a.AssignmentValue,
                     }).ToList(),
-                    InnerSteps = (s.InnerSteps ?? new()).OrderBy(i => i.Order).Select(i => new PurchaseEvaluationWorkflowStepInnerStep
-                    {
-                        Order = i.Order,
-                        DepartmentId = i.DepartmentId,
-                        PositionLevel = (PositionLevel)i.PositionLevel,
-                        Name = i.Name,
-                        SlaDays = i.SlaDays,
-                        IsRequired = i.IsRequired,
-                    }).ToList(),
                 })
                 .ToList(),
         };

src/Backend/SolutionErp.Domain/Contracts/Contract.cs

@@ -30,11 +30,15 @@ public class Contract : AuditableEntity
     public string? BudgetManualName { get; set; }                  // Tên tham chiếu
     public decimal? BudgetManualAmount { get; set; }               // Tổng số tiền nhập tay (đ)
 
-    // Smart reject (Phase 9 — Migration 16): Phase nguồn khi reject. Drafter
+    // Smart reject (Phase 9 — Migration 16): Phase nguồn khi reject.
-    // sửa lại + trình lại → quay về RejectedFromPhase thay vì DangSoanThao
-    // tuần tự lại từ đầu. Null khi chưa từng reject hoặc đã trình lại xong.
     public ContractPhase? RejectedFromPhase { get; set; }
 
+    // Flat workflow tracking (Session 16 — Migration 21):
+    // - CurrentWorkflowStepIndex: 0-based pointer step đang chờ approver
+    // - RejectedAtStepIndex: snapshot khi Trả lại, restore khi resume
+    public int? CurrentWorkflowStepIndex { get; set; }
+    public int? RejectedAtStepIndex { get; set; }
+
     public List<ContractApproval> Approvals { get; set; } = new();
     public List<ContractComment> Comments { get; set; } = new();
     public List<ContractAttachment> Attachments { get; set; } = new();

src/Backend/SolutionErp.Domain/Contracts/ContractDepartmentApproval.cs

@@ -23,9 +23,5 @@ public class ContractDepartmentApproval : AuditableEntity
     public DateTime ApprovedAt { get; set; }
     public bool IsBypassed { get; set; }                    // true nếu NV bypass (User.CanBypassReview=true)
 
-    // N-stage inner step link (Mig 20) — null cho data legacy 2-stage Review/Confirm.
-    // Có giá trị khi step cha có InnerSteps configured. Mirror PE Mig 18 pattern.
-    public Guid? InnerStepId { get; set; }
-
     public Contract? Contract { get; set; }
 }

src/Backend/SolutionErp.Domain/Contracts/ContractPhase.cs

@@ -1,16 +1,25 @@
 namespace SolutionErp.Domain.Contracts;
 
-// 9 phase state machine — xem docs/workflow-contract.md
+// State machine HĐ — Session 16 drastic refactor (Mig 21):
+//   DangSoanThao → ChoDuyet (Drafter trình, init CurrentWorkflowStepIndex=0)
+//   ChoDuyet → ChoDuyet (advance step pointer per approve)
+//   ChoDuyet → DaPhatHanh (last step done — terminal)
+//   ChoDuyet → DangSoanThao (Trả lại — save RejectedAtStepIndex, Drafter sửa)
+//   ChoDuyet → TuChoi (Từ chối — terminal khoá)
+//
+// LEGACY values (DangChon, DangGopY, DangDamPhan, DangInKy, DangKiemTraCCM,
+// DangTrinhKy, DangDongDau) deprecated post-Mig 21 — giữ enum cho data cũ.
 public enum ContractPhase
 {
-    DangChon = 1,
+    DangChon = 1,              // [LEGACY]
     DangSoanThao = 2,
-    DangGopY = 3,
+    DangGopY = 3,              // [LEGACY]
-    DangDamPhan = 4,
+    DangDamPhan = 4,           // [LEGACY]
-    DangInKy = 5,
+    DangInKy = 5,              // [LEGACY]
-    DangKiemTraCCM = 6,
+    DangKiemTraCCM = 6,        // [LEGACY]
-    DangTrinhKy = 7,
+    DangTrinhKy = 7,           // [LEGACY]
-    DangDongDau = 8,
+    DangDongDau = 8,           // [LEGACY]
-    DaPhatHanh = 9,
+    DaPhatHanh = 9,            // terminal thành công (= DaDuyet cho HĐ)
-    TuChoi = 99,
+    ChoDuyet = 10,             // [Mig 21] generic intermediate, dùng CurrentWorkflowStepIndex tracking
+    TuChoi = 99,               // terminal khoá
 }

src/Backend/SolutionErp.Domain/Contracts/WorkflowDefinition.cs

@@ -23,21 +23,28 @@ public class WorkflowDefinition : BaseEntity
     public List<WorkflowStep> Steps { get; set; } = new();
 }
 
+// Workflow Step (Session 16 — Mig 21 drastic refactor):
+// Mỗi step = 1 (Phòng × Cấp + Approvers users). Sequential per Order.
+// Service iterate steps OrderBy(Order), advance Contract.CurrentWorkflowStepIndex
+// per approve. Phase column deprecated post-Mig 21 (set ChoDuyet=10 cho new
+// definitions, giữ giá trị cũ cho backward compat data).
 public class WorkflowStep : BaseEntity
 {
     public Guid WorkflowDefinitionId { get; set; }
     public int Order { get; set; }                              // 1-based sequence
-    public ContractPhase Phase { get; set; }                    // which ContractPhase this step represents
+    public ContractPhase Phase { get; set; }                    // [DEPRECATED post-Mig 21] dùng ChoDuyet=10 cho new
-    public string Name { get; set; } = string.Empty;            // display, can differ from Phase label
+    public string Name { get; set; } = string.Empty;            // display "Phòng A — Cấp 1"
-    public int? SlaDays { get; set; }                           // null = no SLA for this step
+    public int? SlaDays { get; set; }                           // null = no SLA
+
+    // Mig 21 — Phòng × Cấp (flat workflow). Approver match: actor.DepartmentId
+    // == step.DepartmentId AND actor.PositionLevel == step.PositionLevel
+    // (OR-of-many cùng cấp+phòng). Bypass: actor.PositionLevel cao hơn cùng dept
+    // + CanBypassReview → skip cấp dưới.
+    public Guid? DepartmentId { get; set; }
+    public PositionLevel? PositionLevel { get; set; }
 
     public WorkflowDefinition? WorkflowDefinition { get; set; }
     public List<WorkflowStepApprover> Approvers { get; set; } = new();
-
-    // Inner steps (Mig 20) — N-stage approval Phòng × PositionLevel sequential.
-    // Mirror PE pattern (Mig 18). Empty list → service fallback logic 2-stage
-    // Review/Confirm legacy (Mig 16) per dept.
-    public List<WorkflowStepInnerStep> InnerSteps { get; set; } = new();
 }
 
 public enum WorkflowApproverKind
@@ -54,23 +61,3 @@ public class WorkflowStepApprover : BaseEntity
 
     public WorkflowStep? Step { get; set; }
 }
-
-// Inner step (Mig 20 — Phase 9+) — sub-step level con cấu hình bên trong 1
-// WorkflowStep cha (= 1 phase). Mirror PurchaseEvaluationWorkflowStepInnerStep
-// pattern (Mig 18). Cho phép admin định nghĩa thứ tự duyệt N-stage theo
-// Department × PositionLevel: NV.A → PP.A → TP.A → NV.B → PP.B → TP.B → ...
-//
-// User khớp DepartmentId + PositionLevel + Order tiếp theo chưa duyệt = approver
-// hợp lệ. CanBypassReview ở User cho TP skip NV+PP cùng dept (audit IsBypassed).
-public class WorkflowStepInnerStep : BaseEntity
-{
-    public Guid WorkflowStepId { get; set; }
-    public int Order { get; set; }
-    public Guid DepartmentId { get; set; }
-    public PositionLevel PositionLevel { get; set; }            // NV / PP / TP
-    public string? Name { get; set; }                            // hiển thị FE — vd "NV.PRO duyệt"
-    public int? SlaDays { get; set; }
-    public bool IsRequired { get; set; } = true;
-
-    public WorkflowStep? Step { get; set; }
-}

src/Backend/SolutionErp.Domain/PurchaseEvaluations/PurchaseEvaluation.cs

@@ -40,6 +40,14 @@ public class PurchaseEvaluation : AuditableEntity
     // sửa lại + trình lại → quay về RejectedFromPhase thay vì đi tuần tự.
     public PurchaseEvaluationPhase? RejectedFromPhase { get; set; }
 
+    // Flat workflow tracking (Session 16 — Migration 21):
+    // - CurrentWorkflowStepIndex: 0-based index của step đang chờ approver
+    //   (khi Phase=ChoDuyet). Null khi DangSoanThao/DaDuyet/TuChoi.
+    // - RejectedAtStepIndex: snapshot CurrentWorkflowStepIndex tại Trả lại.
+    //   Drafter resume → restore CurrentWorkflowStepIndex (jump-back).
+    public int? CurrentWorkflowStepIndex { get; set; }
+    public int? RejectedAtStepIndex { get; set; }
+
     public List<PurchaseEvaluationSupplier> Suppliers { get; set; } = new();
     public List<PurchaseEvaluationDetail> Details { get; set; } = new();
     public List<PurchaseEvaluationQuote> Quotes { get; set; } = new();

src/Backend/SolutionErp.Domain/PurchaseEvaluations/PurchaseEvaluationDepartmentApproval.cs

@@ -22,11 +22,5 @@ public class PurchaseEvaluationDepartmentApproval : AuditableEntity
     public DateTime ApprovedAt { get; set; }
     public bool IsBypassed { get; set; }
 
-    // N-stage inner step link (Mig 18) — null cho data legacy 2-stage Review/Confirm.
-    // Có giá trị khi step cha có InnerSteps configured → mỗi sub-step approve =
-    // 1 row riêng với InnerStepId set. Cùng Stage=Confirm (legacy field giữ nguyên
-    // cho backward compat — N-stage không dùng Review/Confirm semantics).
-    public Guid? InnerStepId { get; set; }
-
     public PurchaseEvaluation? PurchaseEvaluation { get; set; }
 }

src/Backend/SolutionErp.Domain/PurchaseEvaluations/PurchaseEvaluationPhase.cs

@@ -1,21 +1,25 @@
 namespace SolutionErp.Domain.PurchaseEvaluations;
 
-// State machine cho phiếu Duyệt NCC (tiền-HĐ). 2 workflow khác nhau cùng
+// State machine PE — Session 16 drastic refactor (Mig 21):
-// share state space này — A (DuyetNcc) dùng subset, B (DuyetNccPhuongAn)
+//   DangSoanThao → ChoDuyet (Drafter trình, init CurrentWorkflowStepIndex=0)
-// dùng full.
+//   ChoDuyet → ChoDuyet (advance step pointer mỗi lần approve)
+//   ChoDuyet → DaDuyet (last step done — terminal thành công)
+//   ChoDuyet → DangSoanThao (Trả lại — save RejectedAtStepIndex, Drafter sửa)
+//   ChoDuyet → TuChoi (Từ chối — terminal khoá phiếu)
+//   DangSoanThao → TuChoi (Drafter huỷ trước trình)
 //
-// A: DangSoanThao → ChoPurchasing → ChoCCM → ChoCEODuyetNCC → DaDuyet
+// LEGACY values 2-6 + 98 deprecated post-Mig 21 (data cũ vẫn đọc OK,
-// B: DangSoanThao → ChoPurchasing → ChoDuAn → ChoCCM → ChoCEODuyetPA → ChoCEODuyetNCC → DaDuyet
+// new workflow definitions chỉ dùng DangSoanThao/ChoDuyet/DaDuyet/TuChoi).
-// Cả 2: từ DangSoanThao có thể → TuChoi; từ mọi phase duyệt reject → DangSoanThao.
 public enum PurchaseEvaluationPhase
 {
     DangSoanThao = 1,
-    ChoPurchasing = 2,
+    ChoPurchasing = 2,         // [LEGACY] deprecated
-    ChoDuAn = 3,               // chỉ B
+    ChoDuAn = 3,               // [LEGACY] deprecated
-    ChoCCM = 4,
+    ChoCCM = 4,                // [LEGACY] deprecated
-    ChoCEODuyetPA = 5,         // chỉ B (duyệt phương án trước)
+    ChoCEODuyetPA = 5,         // [LEGACY] deprecated
-    ChoCEODuyetNCC = 6,        // chung cả A & B — duyệt chọn đơn vị
+    ChoCEODuyetNCC = 6,        // [LEGACY] deprecated
     DaDuyet = 7,               // terminal thành công
-    TraLai = 98,               // approver trả về cho Drafter sửa (vẫn cho edit, khác TuChoi)
+    ChoDuyet = 10,             // [Mig 21] generic intermediate, dùng CurrentWorkflowStepIndex tracking
+    TraLai = 98,               // [LEGACY] deprecated — Session 14 chốt thay bằng Trả lại = về DangSoanThao
     TuChoi = 99,               // terminal từ chối — KHÔNG cho edit/thao tác
 }

src/Backend/SolutionErp.Domain/PurchaseEvaluations/PurchaseEvaluationWorkflowDefinition.cs

@@ -4,17 +4,12 @@ using SolutionErp.Domain.Identity;     // reuse PositionLevel
 
 namespace SolutionErp.Domain.PurchaseEvaluations;
 
-// Versioned workflow definition cho module Duyệt NCC — pattern giống HĐ
+// Versioned workflow definition cho module Duyệt NCC — pattern giống HĐ.
-// nhưng tách table riêng vì Phase là PurchaseEvaluationPhase enum (không
+// Invariant: AT MOST ONE IsActive=true per PurchaseEvaluationType.
-// phải ContractPhase). Admin có UI /system/pe-workflows/:typeCode tương
+// PurchaseEvaluation.WorkflowDefinitionId pin tại create.
-// tự /system/workflows/:typeCode.
-//
-// Invariant: AT MOST ONE IsActive=true per PurchaseEvaluationType tại 1
-// thời điểm. PurchaseEvaluation.WorkflowDefinitionId pin tại create →
-// phiếu cũ không bị ảnh hưởng khi admin active version mới.
 public class PurchaseEvaluationWorkflowDefinition : BaseEntity
 {
-    public string Code { get; set; } = string.Empty;             // "QT-DN-A" / "QT-DN-B" default
+    public string Code { get; set; } = string.Empty;
     public int Version { get; set; }
     public PurchaseEvaluationType EvaluationType { get; set; }
     public string Name { get; set; } = string.Empty;
@@ -25,22 +20,23 @@ public class PurchaseEvaluationWorkflowDefinition : BaseEntity
     public List<PurchaseEvaluationWorkflowStep> Steps { get; set; } = new();
 }
 
+// Workflow Step PE (Session 16 — Mig 21 drastic refactor):
+// Mỗi step = 1 (Phòng × Cấp + Approvers users). Sequential per Order.
+// Service iterate steps OrderBy(Order), advance PE.CurrentWorkflowStepIndex.
 public class PurchaseEvaluationWorkflowStep : BaseEntity
 {
     public Guid PurchaseEvaluationWorkflowDefinitionId { get; set; }
     public int Order { get; set; }
-    public PurchaseEvaluationPhase Phase { get; set; }
+    public PurchaseEvaluationPhase Phase { get; set; }          // [DEPRECATED] dùng ChoDuyet=10 cho new
-    public string Name { get; set; } = string.Empty;
+    public string Name { get; set; } = string.Empty;            // "Phòng A — Cấp 1"
     public int? SlaDays { get; set; }
 
+    // Mig 21 — Phòng × Cấp. Approver match Dept + PositionLevel (OR cùng cấp+phòng).
+    public Guid? DepartmentId { get; set; }
+    public PositionLevel? PositionLevel { get; set; }
+
     public PurchaseEvaluationWorkflowDefinition? Definition { get; set; }
     public List<PurchaseEvaluationWorkflowStepApprover> Approvers { get; set; } = new();
-
-    // Inner steps (Mig 18) — N-stage approval cấu hình động trong cùng 1 phase.
-    // Empty list → fallback logic 2-stage Review/Confirm legacy (Mig 16) per dept.
-    // Có item → service loop theo Order: user khớp Department × PositionLevel
-    // duyệt sub-step. Tất cả required InnerSteps Done → cho phase transition.
-    public List<PurchaseEvaluationWorkflowStepInnerStep> InnerSteps { get; set; } = new();
 }
 
 public class PurchaseEvaluationWorkflowStepApprover : BaseEntity
@@ -51,24 +47,3 @@ public class PurchaseEvaluationWorkflowStepApprover : BaseEntity
 
     public PurchaseEvaluationWorkflowStep? Step { get; set; }
 }
-
-// Inner step (Mig 18 — Phase 9+) — sub-step level con cấu hình bên trong 1
-// WorkflowStep cha (= 1 phase). Cho phép admin định nghĩa thứ tự duyệt N-stage
-// theo Department × PositionLevel: NV.A → PP.A → TP.A → NV.B → PP.B → TP.B → ...
-//
-// User khớp DepartmentId + PositionLevel + Order tiếp theo chưa duyệt = approver
-// hợp lệ. CanBypassReview ở User cho TP skip NV+PP cùng dept (audit IsBypassed).
-//
-// IsRequired=false → cho phép skip không cần row approval (vd "PP optional").
-public class PurchaseEvaluationWorkflowStepInnerStep : BaseEntity
-{
-    public Guid PurchaseEvaluationWorkflowStepId { get; set; }
-    public int Order { get; set; }                              // thứ tự sequential trong cùng step cha
-    public Guid DepartmentId { get; set; }
-    public PositionLevel PositionLevel { get; set; }            // NV / PP / TP
-    public string? Name { get; set; }                            // hiển thị FE — vd "NV.PRO duyệt"
-    public int? SlaDays { get; set; }                            // override step.SlaDays nếu set
-    public bool IsRequired { get; set; } = true;                 // false → optional skip không cần row
-
-    public PurchaseEvaluationWorkflowStep? Step { get; set; }
-}

src/Backend/SolutionErp.Infrastructure/Persistence/ApplicationDbContext.cs

@@ -41,7 +41,6 @@ public class ApplicationDbContext
     public DbSet<WorkflowDefinition> WorkflowDefinitions => Set<WorkflowDefinition>();
     public DbSet<WorkflowStep> WorkflowSteps => Set<WorkflowStep>();
     public DbSet<WorkflowStepApprover> WorkflowStepApprovers => Set<WorkflowStepApprover>();
-    public DbSet<WorkflowStepInnerStep> WorkflowStepInnerSteps => Set<WorkflowStepInnerStep>();
     public DbSet<ThauPhuDetail> ThauPhuDetails => Set<ThauPhuDetail>();
     public DbSet<GiaoKhoanDetail> GiaoKhoanDetails => Set<GiaoKhoanDetail>();
     public DbSet<NhaCungCapDetail> NhaCungCapDetails => Set<NhaCungCapDetail>();
@@ -60,7 +59,6 @@ public class ApplicationDbContext
     public DbSet<PurchaseEvaluationWorkflowDefinition> PurchaseEvaluationWorkflowDefinitions => Set<PurchaseEvaluationWorkflowDefinition>();
     public DbSet<PurchaseEvaluationWorkflowStep> PurchaseEvaluationWorkflowSteps => Set<PurchaseEvaluationWorkflowStep>();
     public DbSet<PurchaseEvaluationWorkflowStepApprover> PurchaseEvaluationWorkflowStepApprovers => Set<PurchaseEvaluationWorkflowStepApprover>();
-    public DbSet<PurchaseEvaluationWorkflowStepInnerStep> PurchaseEvaluationWorkflowStepInnerSteps => Set<PurchaseEvaluationWorkflowStepInnerStep>();
     public DbSet<PurchaseEvaluationCodeSequence> PurchaseEvaluationCodeSequences => Set<PurchaseEvaluationCodeSequence>();
     public DbSet<PurchaseEvaluationDepartmentOpinion> PurchaseEvaluationDepartmentOpinions => Set<PurchaseEvaluationDepartmentOpinion>();
     public DbSet<PurchaseEvaluationDepartmentApproval> PurchaseEvaluationDepartmentApprovals => Set<PurchaseEvaluationDepartmentApproval>();

src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/DepartmentApprovalsConfiguration.cs

@@ -27,19 +27,11 @@ public class ContractDepartmentApprovalConfiguration
         b.Property(x => x.ApproverRoleSnapshot).HasMaxLength(100);
         b.Property(x => x.Comment).HasMaxLength(1000);
 
-        // Legacy 2-stage rows (Mig 16): UNIQUE chỉ áp khi InnerStepId IS NULL
+        // Mig 21 — drop InnerStepId column + restore simple unique non-filtered.
-        // (Mig 20 mirror PE Mig 19 filtered split).
         b.HasIndex(x => new { x.ContractId, x.PhaseAtApproval, x.DepartmentId, x.Stage })
             .IsUnique()
-            .HasFilter("[InnerStepId] IS NULL")
             .HasDatabaseName("UX_ContractDeptApprovals_Contract_Phase_Dept_Stage");
 
-        // N-stage rows (Mig 20): UNIQUE 1 row per (phase × inner step).
-        b.HasIndex(x => new { x.ContractId, x.PhaseAtApproval, x.InnerStepId })
-            .IsUnique()
-            .HasFilter("[InnerStepId] IS NOT NULL")
-            .HasDatabaseName("UX_ContractDeptApprovals_Contract_Phase_InnerStep");
-
         b.HasIndex(x => x.ContractId);
         b.HasIndex(x => x.DepartmentId);
         b.HasIndex(x => x.ApproverUserId);
@@ -48,12 +40,6 @@ public class ContractDepartmentApprovalConfiguration
             .WithMany(c => c.DepartmentApprovals)
             .HasForeignKey(x => x.ContractId)
             .OnDelete(DeleteBehavior.Cascade);
-
-        // FK InnerStepId nullable — Restrict (không xóa InnerStep nếu còn approval row)
-        b.HasOne<WorkflowStepInnerStep>()
-            .WithMany()
-            .HasForeignKey(x => x.InnerStepId)
-            .OnDelete(DeleteBehavior.Restrict);
     }
 }
 
@@ -69,21 +55,11 @@ public class PurchaseEvaluationDepartmentApprovalConfiguration
         b.Property(x => x.ApproverRoleSnapshot).HasMaxLength(100);
         b.Property(x => x.Comment).HasMaxLength(1000);
 
-        // Legacy 2-stage rows (Mig 16): UNIQUE (PEId, Phase, Dept, Stage) chỉ áp
+        // Mig 21 — drop InnerStepId column + restore simple unique non-filtered.
-        // khi InnerStepId IS NULL — tránh conflict với N-stage rows nhiều InnerStep
-        // cùng dept cùng Stage=Confirm.
         b.HasIndex(x => new { x.PurchaseEvaluationId, x.PhaseAtApproval, x.DepartmentId, x.Stage })
             .IsUnique()
-            .HasFilter("[InnerStepId] IS NULL")
             .HasDatabaseName("UX_PEDeptApprovals_PE_Phase_Dept_Stage");
 
-        // N-stage rows (Mig 18+): UNIQUE (PEId, Phase, InnerStepId) — 1 approval row
-        // per (phase × inner step) khi InnerStepId IS NOT NULL.
-        b.HasIndex(x => new { x.PurchaseEvaluationId, x.PhaseAtApproval, x.InnerStepId })
-            .IsUnique()
-            .HasFilter("[InnerStepId] IS NOT NULL")
-            .HasDatabaseName("UX_PEDeptApprovals_PE_Phase_InnerStep");
-
         b.HasIndex(x => x.PurchaseEvaluationId);
         b.HasIndex(x => x.DepartmentId);
         b.HasIndex(x => x.ApproverUserId);
@@ -92,13 +68,6 @@ public class PurchaseEvaluationDepartmentApprovalConfiguration
             .WithMany(c => c.DepartmentApprovals)
             .HasForeignKey(x => x.PurchaseEvaluationId)
             .OnDelete(DeleteBehavior.Cascade);
-
-        // FK InnerStepId nullable — Restrict (không xóa InnerStep nếu còn approval row).
-        // Cấu hình không nav để giữ nhẹ entity (1 chiều, query qua join nếu cần).
-        b.HasOne<PurchaseEvaluationWorkflowStepInnerStep>()
-            .WithMany()
-            .HasForeignKey(x => x.InnerStepId)
-            .OnDelete(DeleteBehavior.Restrict);
     }
 }
 

src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/PurchaseEvaluationConfiguration.cs

@@ -184,13 +184,21 @@ public class PurchaseEvaluationWorkflowStepConfiguration : IEntityTypeConfigurat
         e.ToTable("PurchaseEvaluationWorkflowSteps");
         e.Property(x => x.Name).HasMaxLength(200).IsRequired();
         e.Property(x => x.Phase).HasConversion<int>();
+        e.Property(x => x.PositionLevel).HasConversion<int?>();   // Mig 21
 
         e.HasOne(x => x.Definition)
             .WithMany(d => d.Steps)
             .HasForeignKey(x => x.PurchaseEvaluationWorkflowDefinitionId)
             .OnDelete(DeleteBehavior.Cascade);
 
+        // Mig 21 — FK Department Restrict.
+        e.HasOne<SolutionErp.Domain.Master.Department>()
+            .WithMany()
+            .HasForeignKey(x => x.DepartmentId)
+            .OnDelete(DeleteBehavior.Restrict);
+
         e.HasIndex(x => new { x.PurchaseEvaluationWorkflowDefinitionId, x.Order });
+        e.HasIndex(x => x.DepartmentId);
     }
 }
 
@@ -209,37 +217,6 @@ public class PurchaseEvaluationWorkflowStepApproverConfiguration : IEntityTypeCo
     }
 }
 
-// Inner step (Mig 18) — N-stage approval cấu hình động trong cùng 1 phase.
-// FK Cascade từ Step cha. Index theo (StepId, Order) cho query ordered list.
-// Index riêng DepartmentId để lookup khi service compute next pending sub-step.
-public class PurchaseEvaluationWorkflowStepInnerStepConfiguration
-    : IEntityTypeConfiguration<PurchaseEvaluationWorkflowStepInnerStep>
-{
-    public void Configure(EntityTypeBuilder<PurchaseEvaluationWorkflowStepInnerStep> e)
-    {
-        e.ToTable("PurchaseEvaluationWorkflowStepInnerSteps");
-        e.HasKey(x => x.Id);
-
-        e.Property(x => x.PositionLevel).HasConversion<int>();
-        e.Property(x => x.Name).HasMaxLength(200);
-
-        e.HasOne(x => x.Step)
-            .WithMany(s => s.InnerSteps)
-            .HasForeignKey(x => x.PurchaseEvaluationWorkflowStepId)
-            .OnDelete(DeleteBehavior.Cascade);
-
-        // FK Department — Restrict (không xóa dept nếu còn inner step assigned).
-        // Không cấu hình nav trên Department để tránh circular collection bloat.
-        e.HasOne<SolutionErp.Domain.Master.Department>()
-            .WithMany()
-            .HasForeignKey(x => x.DepartmentId)
-            .OnDelete(DeleteBehavior.Restrict);
-
-        e.HasIndex(x => new { x.PurchaseEvaluationWorkflowStepId, x.Order });
-        e.HasIndex(x => x.DepartmentId);
-    }
-}
-
 // Mirror ContractCodeSequenceConfiguration — Prefix là PK, atomic UPDATE qua
 // SERIALIZABLE transaction trong PurchaseEvaluationCodeGenerator.
 public class PurchaseEvaluationCodeSequenceConfiguration

src/Backend/SolutionErp.Infrastructure/Persistence/Configurations/WorkflowDefinitionConfiguration.cs

@@ -28,13 +28,21 @@ public class WorkflowStepConfiguration : IEntityTypeConfiguration<WorkflowStep>
         e.ToTable("WorkflowSteps");
         e.Property(x => x.Name).HasMaxLength(200).IsRequired();
         e.Property(x => x.Phase).HasConversion<int>();
+        e.Property(x => x.PositionLevel).HasConversion<int?>();   // Mig 21
 
         e.HasOne(x => x.WorkflowDefinition)
             .WithMany(d => d.Steps)
             .HasForeignKey(x => x.WorkflowDefinitionId)
             .OnDelete(DeleteBehavior.Cascade);
 
+        // Mig 21 — FK Department Restrict (không xóa dept nếu còn step assigned).
+        e.HasOne<SolutionErp.Domain.Master.Department>()
+            .WithMany()
+            .HasForeignKey(x => x.DepartmentId)
+            .OnDelete(DeleteBehavior.Restrict);
+
         e.HasIndex(x => new { x.WorkflowDefinitionId, x.Order });
+        e.HasIndex(x => x.DepartmentId);
     }
 }
 
@@ -52,31 +60,3 @@ public class WorkflowStepApproverConfiguration : IEntityTypeConfiguration<Workfl
             .OnDelete(DeleteBehavior.Cascade);
     }
 }
-
-// Inner step (Mig 20) — N-stage approval cấu hình động trong cùng 1 phase.
-// Mirror PurchaseEvaluationWorkflowStepInnerStepConfiguration (Mig 18).
-public class WorkflowStepInnerStepConfiguration
-    : IEntityTypeConfiguration<WorkflowStepInnerStep>
-{
-    public void Configure(EntityTypeBuilder<WorkflowStepInnerStep> e)
-    {
-        e.ToTable("WorkflowStepInnerSteps");
-        e.HasKey(x => x.Id);
-
-        e.Property(x => x.PositionLevel).HasConversion<int>();
-        e.Property(x => x.Name).HasMaxLength(200);
-
-        e.HasOne(x => x.Step)
-            .WithMany(s => s.InnerSteps)
-            .HasForeignKey(x => x.WorkflowStepId)
-            .OnDelete(DeleteBehavior.Cascade);
-
-        e.HasOne<SolutionErp.Domain.Master.Department>()
-            .WithMany()
-            .HasForeignKey(x => x.DepartmentId)
-            .OnDelete(DeleteBehavior.Restrict);
-
-        e.HasIndex(x => new { x.WorkflowStepId, x.Order });
-        e.HasIndex(x => x.DepartmentId);
-    }
-}

src/Backend/SolutionErp.Infrastructure/Persistence/Migrations/20260508050243_RefactorWorkflowToFlatModel.cs

@@ -0,0 +1,361 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace SolutionErp.Infrastructure.Persistence.Migrations
+{
+    /// <inheritdoc />
+    public partial class RefactorWorkflowToFlatModel : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropForeignKey(
+                name: "FK_ContractDepartmentApprovals_WorkflowStepInnerSteps_InnerStepId",
+                table: "ContractDepartmentApprovals");
+
+            migrationBuilder.DropForeignKey(
+                name: "FK_PurchaseEvaluationDepartmentApprovals_PurchaseEvaluationWorkflowStepInnerSteps_InnerStepId",
+                table: "PurchaseEvaluationDepartmentApprovals");
+
+            migrationBuilder.DropTable(
+                name: "PurchaseEvaluationWorkflowStepInnerSteps");
+
+            migrationBuilder.DropTable(
+                name: "WorkflowStepInnerSteps");
+
+            migrationBuilder.DropIndex(
+                name: "IX_PurchaseEvaluationDepartmentApprovals_InnerStepId",
+                table: "PurchaseEvaluationDepartmentApprovals");
+
+            migrationBuilder.DropIndex(
+                name: "UX_PEDeptApprovals_PE_Phase_Dept_Stage",
+                table: "PurchaseEvaluationDepartmentApprovals");
+
+            migrationBuilder.DropIndex(
+                name: "UX_PEDeptApprovals_PE_Phase_InnerStep",
+                table: "PurchaseEvaluationDepartmentApprovals");
+
+            migrationBuilder.DropIndex(
+                name: "IX_ContractDepartmentApprovals_InnerStepId",
+                table: "ContractDepartmentApprovals");
+
+            migrationBuilder.DropIndex(
+                name: "UX_ContractDeptApprovals_Contract_Phase_Dept_Stage",
+                table: "ContractDepartmentApprovals");
+
+            migrationBuilder.DropIndex(
+                name: "UX_ContractDeptApprovals_Contract_Phase_InnerStep",
+                table: "ContractDepartmentApprovals");
+
+            migrationBuilder.DropColumn(
+                name: "InnerStepId",
+                table: "PurchaseEvaluationDepartmentApprovals");
+
+            migrationBuilder.DropColumn(
+                name: "InnerStepId",
+                table: "ContractDepartmentApprovals");
+
+            migrationBuilder.AddColumn<Guid>(
+                name: "DepartmentId",
+                table: "WorkflowSteps",
+                type: "uniqueidentifier",
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "PositionLevel",
+                table: "WorkflowSteps",
+                type: "int",
+                nullable: true);
+
+            migrationBuilder.AddColumn<Guid>(
+                name: "DepartmentId",
+                table: "PurchaseEvaluationWorkflowSteps",
+                type: "uniqueidentifier",
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "PositionLevel",
+                table: "PurchaseEvaluationWorkflowSteps",
+                type: "int",
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "CurrentWorkflowStepIndex",
+                table: "PurchaseEvaluations",
+                type: "int",
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "RejectedAtStepIndex",
+                table: "PurchaseEvaluations",
+                type: "int",
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "CurrentWorkflowStepIndex",
+                table: "Contracts",
+                type: "int",
+                nullable: true);
+
+            migrationBuilder.AddColumn<int>(
+                name: "RejectedAtStepIndex",
+                table: "Contracts",
+                type: "int",
+                nullable: true);
+
+            migrationBuilder.CreateIndex(
+                name: "IX_WorkflowSteps_DepartmentId",
+                table: "WorkflowSteps",
+                column: "DepartmentId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_PurchaseEvaluationWorkflowSteps_DepartmentId",
+                table: "PurchaseEvaluationWorkflowSteps",
+                column: "DepartmentId");
+
+            migrationBuilder.CreateIndex(
+                name: "UX_PEDeptApprovals_PE_Phase_Dept_Stage",
+                table: "PurchaseEvaluationDepartmentApprovals",
+                columns: new[] { "PurchaseEvaluationId", "PhaseAtApproval", "DepartmentId", "Stage" },
+                unique: true);
+
+            migrationBuilder.CreateIndex(
+                name: "UX_ContractDeptApprovals_Contract_Phase_Dept_Stage",
+                table: "ContractDepartmentApprovals",
+                columns: new[] { "ContractId", "PhaseAtApproval", "DepartmentId", "Stage" },
+                unique: true);
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_PurchaseEvaluationWorkflowSteps_Departments_DepartmentId",
+                table: "PurchaseEvaluationWorkflowSteps",
+                column: "DepartmentId",
+                principalTable: "Departments",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_WorkflowSteps_Departments_DepartmentId",
+                table: "WorkflowSteps",
+                column: "DepartmentId",
+                principalTable: "Departments",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropForeignKey(
+                name: "FK_PurchaseEvaluationWorkflowSteps_Departments_DepartmentId",
+                table: "PurchaseEvaluationWorkflowSteps");
+
+            migrationBuilder.DropForeignKey(
+                name: "FK_WorkflowSteps_Departments_DepartmentId",
+                table: "WorkflowSteps");
+
+            migrationBuilder.DropIndex(
+                name: "IX_WorkflowSteps_DepartmentId",
+                table: "WorkflowSteps");
+
+            migrationBuilder.DropIndex(
+                name: "IX_PurchaseEvaluationWorkflowSteps_DepartmentId",
+                table: "PurchaseEvaluationWorkflowSteps");
+
+            migrationBuilder.DropIndex(
+                name: "UX_PEDeptApprovals_PE_Phase_Dept_Stage",
+                table: "PurchaseEvaluationDepartmentApprovals");
+
+            migrationBuilder.DropIndex(
+                name: "UX_ContractDeptApprovals_Contract_Phase_Dept_Stage",
+                table: "ContractDepartmentApprovals");
+
+            migrationBuilder.DropColumn(
+                name: "DepartmentId",
+                table: "WorkflowSteps");
+
+            migrationBuilder.DropColumn(
+                name: "PositionLevel",
+                table: "WorkflowSteps");
+
+            migrationBuilder.DropColumn(
+                name: "DepartmentId",
+                table: "PurchaseEvaluationWorkflowSteps");
+
+            migrationBuilder.DropColumn(
+                name: "PositionLevel",
+                table: "PurchaseEvaluationWorkflowSteps");
+
+            migrationBuilder.DropColumn(
+                name: "CurrentWorkflowStepIndex",
+                table: "PurchaseEvaluations");
+
+            migrationBuilder.DropColumn(
+                name: "RejectedAtStepIndex",
+                table: "PurchaseEvaluations");
+
+            migrationBuilder.DropColumn(
+                name: "CurrentWorkflowStepIndex",
+                table: "Contracts");
+
+            migrationBuilder.DropColumn(
+                name: "RejectedAtStepIndex",
+                table: "Contracts");
+
+            migrationBuilder.AddColumn<Guid>(
+                name: "InnerStepId",
+                table: "PurchaseEvaluationDepartmentApprovals",
+                type: "uniqueidentifier",
+                nullable: true);
+
+            migrationBuilder.AddColumn<Guid>(
+                name: "InnerStepId",
+                table: "ContractDepartmentApprovals",
+                type: "uniqueidentifier",
+                nullable: true);
+
+            migrationBuilder.CreateTable(
+                name: "PurchaseEvaluationWorkflowStepInnerSteps",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    PurchaseEvaluationWorkflowStepId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    CreatedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    CreatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    DepartmentId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    IsRequired = table.Column<bool>(type: "bit", nullable: false),
+                    Name = table.Column<string>(type: "nvarchar(200)", maxLength: 200, nullable: true),
+                    Order = table.Column<int>(type: "int", nullable: false),
+                    PositionLevel = table.Column<int>(type: "int", nullable: false),
+                    SlaDays = table.Column<int>(type: "int", nullable: true),
+                    UpdatedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    UpdatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_PurchaseEvaluationWorkflowStepInnerSteps", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_PurchaseEvaluationWorkflowStepInnerSteps_Departments_DepartmentId",
+                        column: x => x.DepartmentId,
+                        principalTable: "Departments",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Restrict);
+                    table.ForeignKey(
+                        name: "FK_PurchaseEvaluationWorkflowStepInnerSteps_PurchaseEvaluationWorkflowSteps_PurchaseEvaluationWorkflowStepId",
+                        column: x => x.PurchaseEvaluationWorkflowStepId,
+                        principalTable: "PurchaseEvaluationWorkflowSteps",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateTable(
+                name: "WorkflowStepInnerSteps",
+                columns: table => new
+                {
+                    Id = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    WorkflowStepId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    CreatedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    CreatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true),
+                    DepartmentId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    IsRequired = table.Column<bool>(type: "bit", nullable: false),
+                    Name = table.Column<string>(type: "nvarchar(200)", maxLength: 200, nullable: true),
+                    Order = table.Column<int>(type: "int", nullable: false),
+                    PositionLevel = table.Column<int>(type: "int", nullable: false),
+                    SlaDays = table.Column<int>(type: "int", nullable: true),
+                    UpdatedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    UpdatedBy = table.Column<Guid>(type: "uniqueidentifier", nullable: true)
+                },
+                constraints: table =>
+                {
+                    table.PrimaryKey("PK_WorkflowStepInnerSteps", x => x.Id);
+                    table.ForeignKey(
+                        name: "FK_WorkflowStepInnerSteps_Departments_DepartmentId",
+                        column: x => x.DepartmentId,
+                        principalTable: "Departments",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Restrict);
+                    table.ForeignKey(
+                        name: "FK_WorkflowStepInnerSteps_WorkflowSteps_WorkflowStepId",
+                        column: x => x.WorkflowStepId,
+                        principalTable: "WorkflowSteps",
+                        principalColumn: "Id",
+                        onDelete: ReferentialAction.Cascade);
+                });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_PurchaseEvaluationDepartmentApprovals_InnerStepId",
+                table: "PurchaseEvaluationDepartmentApprovals",
+                column: "InnerStepId");
+
+            migrationBuilder.CreateIndex(
+                name: "UX_PEDeptApprovals_PE_Phase_Dept_Stage",
+                table: "PurchaseEvaluationDepartmentApprovals",
+                columns: new[] { "PurchaseEvaluationId", "PhaseAtApproval", "DepartmentId", "Stage" },
+                unique: true,
+                filter: "[InnerStepId] IS NULL");
+
+            migrationBuilder.CreateIndex(
+                name: "UX_PEDeptApprovals_PE_Phase_InnerStep",
+                table: "PurchaseEvaluationDepartmentApprovals",
+                columns: new[] { "PurchaseEvaluationId", "PhaseAtApproval", "InnerStepId" },
+                unique: true,
+                filter: "[InnerStepId] IS NOT NULL");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_ContractDepartmentApprovals_InnerStepId",
+                table: "ContractDepartmentApprovals",
+                column: "InnerStepId");
+
+            migrationBuilder.CreateIndex(
+                name: "UX_ContractDeptApprovals_Contract_Phase_Dept_Stage",
+                table: "ContractDepartmentApprovals",
+                columns: new[] { "ContractId", "PhaseAtApproval", "DepartmentId", "Stage" },
+                unique: true,
+                filter: "[InnerStepId] IS NULL");
+
+            migrationBuilder.CreateIndex(
+                name: "UX_ContractDeptApprovals_Contract_Phase_InnerStep",
+                table: "ContractDepartmentApprovals",
+                columns: new[] { "ContractId", "PhaseAtApproval", "InnerStepId" },
+                unique: true,
+                filter: "[InnerStepId] IS NOT NULL");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_PurchaseEvaluationWorkflowStepInnerSteps_DepartmentId",
+                table: "PurchaseEvaluationWorkflowStepInnerSteps",
+                column: "DepartmentId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_PurchaseEvaluationWorkflowStepInnerSteps_PurchaseEvaluationWorkflowStepId_Order",
+                table: "PurchaseEvaluationWorkflowStepInnerSteps",
+                columns: new[] { "PurchaseEvaluationWorkflowStepId", "Order" });
+
+            migrationBuilder.CreateIndex(
+                name: "IX_WorkflowStepInnerSteps_DepartmentId",
+                table: "WorkflowStepInnerSteps",
+                column: "DepartmentId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_WorkflowStepInnerSteps_WorkflowStepId_Order",
+                table: "WorkflowStepInnerSteps",
+                columns: new[] { "WorkflowStepId", "Order" });
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_ContractDepartmentApprovals_WorkflowStepInnerSteps_InnerStepId",
+                table: "ContractDepartmentApprovals",
+                column: "InnerStepId",
+                principalTable: "WorkflowStepInnerSteps",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_PurchaseEvaluationDepartmentApprovals_PurchaseEvaluationWorkflowStepInnerSteps_InnerStepId",
+                table: "PurchaseEvaluationDepartmentApprovals",
+                column: "InnerStepId",
+                principalTable: "PurchaseEvaluationWorkflowStepInnerSteps",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+        }
+    }
+}

src/Backend/SolutionErp.Infrastructure/Persistence/Migrations/ApplicationDbContextModelSnapshot.cs

@@ -484,6 +484,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Property<Guid?>("CreatedBy")
                         .HasColumnType("uniqueidentifier");
 
+                    b.Property<int?>("CurrentWorkflowStepIndex")
+                        .HasColumnType("int");
+
                     b.Property<DateTime?>("DeletedAt")
                         .HasColumnType("datetime2");
 
@@ -520,6 +523,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Property<Guid>("ProjectId")
                         .HasColumnType("uniqueidentifier");
 
+                    b.Property<int?>("RejectedAtStepIndex")
+                        .HasColumnType("int");
+
                     b.Property<int?>("RejectedFromPhase")
                         .HasColumnType("int");
 
@@ -824,9 +830,6 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Property<Guid>("DepartmentId")
                         .HasColumnType("uniqueidentifier");
 
-                    b.Property<Guid?>("InnerStepId")
-                        .HasColumnType("uniqueidentifier");
-
                     b.Property<bool>("IsBypassed")
                         .HasColumnType("bit");
 
@@ -853,17 +856,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
 
                     b.HasIndex("DepartmentId");
 
-                    b.HasIndex("InnerStepId");
-
-                    b.HasIndex("ContractId", "PhaseAtApproval", "InnerStepId")
-                        .IsUnique()
-                        .HasDatabaseName("UX_ContractDeptApprovals_Contract_Phase_InnerStep")
-                        .HasFilter("[InnerStepId] IS NOT NULL");
-
                     b.HasIndex("ContractId", "PhaseAtApproval", "DepartmentId", "Stage")
                         .IsUnique()
-                        .HasDatabaseName("UX_ContractDeptApprovals_Contract_Phase_Dept_Stage")
+                        .HasDatabaseName("UX_ContractDeptApprovals_Contract_Phase_Dept_Stage");
-                        .HasFilter("[InnerStepId] IS NULL");
 
                     b.ToTable("ContractDepartmentApprovals", (string)null);
                 });
@@ -1422,6 +1417,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Property<Guid?>("CreatedBy")
                         .HasColumnType("uniqueidentifier");
 
+                    b.Property<Guid?>("DepartmentId")
+                        .HasColumnType("uniqueidentifier");
+
                     b.Property<string>("Name")
                         .IsRequired()
                         .HasMaxLength(200)
@@ -1433,6 +1431,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Property<int>("Phase")
                         .HasColumnType("int");
 
+                    b.Property<int?>("PositionLevel")
+                        .HasColumnType("int");
+
                     b.Property<int?>("SlaDays")
                         .HasColumnType("int");
 
@@ -1447,6 +1448,8 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
 
                     b.HasKey("Id");
 
+                    b.HasIndex("DepartmentId");
+
                     b.HasIndex("WorkflowDefinitionId", "Order");
 
                     b.ToTable("WorkflowSteps", (string)null);
@@ -1488,55 +1491,6 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.ToTable("WorkflowStepApprovers", (string)null);
                 });
 
-            modelBuilder.Entity("SolutionErp.Domain.Contracts.WorkflowStepInnerStep", b =>
-                {
-                    b.Property<Guid>("Id")
-                        .ValueGeneratedOnAdd()
-                        .HasColumnType("uniqueidentifier");
-
-                    b.Property<DateTime>("CreatedAt")
-                        .HasColumnType("datetime2");
-
-                    b.Property<Guid?>("CreatedBy")
-                        .HasColumnType("uniqueidentifier");
-
-                    b.Property<Guid>("DepartmentId")
-                        .HasColumnType("uniqueidentifier");
-
-                    b.Property<bool>("IsRequired")
-                        .HasColumnType("bit");
-
-                    b.Property<string>("Name")
-                        .HasMaxLength(200)
-                        .HasColumnType("nvarchar(200)");
-
-                    b.Property<int>("Order")
-                        .HasColumnType("int");
-
-                    b.Property<int>("PositionLevel")
-                        .HasColumnType("int");
-
-                    b.Property<int?>("SlaDays")
-                        .HasColumnType("int");
-
-                    b.Property<DateTime?>("UpdatedAt")
-                        .HasColumnType("datetime2");
-
-                    b.Property<Guid?>("UpdatedBy")
-                        .HasColumnType("uniqueidentifier");
-
-                    b.Property<Guid>("WorkflowStepId")
-                        .HasColumnType("uniqueidentifier");
-
-                    b.HasKey("Id");
-
-                    b.HasIndex("DepartmentId");
-
-                    b.HasIndex("WorkflowStepId", "Order");
-
-                    b.ToTable("WorkflowStepInnerSteps", (string)null);
-                });
-
             modelBuilder.Entity("SolutionErp.Domain.Contracts.WorkflowTypeAssignment", b =>
                 {
                     b.Property<Guid>("Id")
@@ -2416,6 +2370,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Property<Guid?>("CreatedBy")
                         .HasColumnType("uniqueidentifier");
 
+                    b.Property<int?>("CurrentWorkflowStepIndex")
+                        .HasColumnType("int");
+
                     b.Property<DateTime?>("DeletedAt")
                         .HasColumnType("datetime2");
 
@@ -2452,6 +2409,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Property<Guid>("ProjectId")
                         .HasColumnType("uniqueidentifier");
 
+                    b.Property<int?>("RejectedAtStepIndex")
+                        .HasColumnType("int");
+
                     b.Property<int?>("RejectedFromPhase")
                         .HasColumnType("int");
 
@@ -2719,9 +2679,6 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Property<Guid>("DepartmentId")
                         .HasColumnType("uniqueidentifier");
 
-                    b.Property<Guid?>("InnerStepId")
-                        .HasColumnType("uniqueidentifier");
-
                     b.Property<bool>("IsBypassed")
                         .HasColumnType("bit");
 
@@ -2749,19 +2706,11 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
 
                     b.HasIndex("DepartmentId");
 
-                    b.HasIndex("InnerStepId");
-
                     b.HasIndex("PurchaseEvaluationId");
 
-                    b.HasIndex("PurchaseEvaluationId", "PhaseAtApproval", "InnerStepId")
-                        .IsUnique()
-                        .HasDatabaseName("UX_PEDeptApprovals_PE_Phase_InnerStep")
-                        .HasFilter("[InnerStepId] IS NOT NULL");
-
                     b.HasIndex("PurchaseEvaluationId", "PhaseAtApproval", "DepartmentId", "Stage")
                         .IsUnique()
-                        .HasDatabaseName("UX_PEDeptApprovals_PE_Phase_Dept_Stage")
+                        .HasDatabaseName("UX_PEDeptApprovals_PE_Phase_Dept_Stage");
-                        .HasFilter("[InnerStepId] IS NULL");
 
                     b.ToTable("PurchaseEvaluationDepartmentApprovals", (string)null);
                 });
@@ -3080,6 +3029,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Property<Guid?>("CreatedBy")
                         .HasColumnType("uniqueidentifier");
 
+                    b.Property<Guid?>("DepartmentId")
+                        .HasColumnType("uniqueidentifier");
+
                     b.Property<string>("Name")
                         .IsRequired()
                         .HasMaxLength(200)
@@ -3091,6 +3043,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Property<int>("Phase")
                         .HasColumnType("int");
 
+                    b.Property<int?>("PositionLevel")
+                        .HasColumnType("int");
+
                     b.Property<Guid>("PurchaseEvaluationWorkflowDefinitionId")
                         .HasColumnType("uniqueidentifier");
 
@@ -3105,6 +3060,8 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
 
                     b.HasKey("Id");
 
+                    b.HasIndex("DepartmentId");
+
                     b.HasIndex("PurchaseEvaluationWorkflowDefinitionId", "Order");
 
                     b.ToTable("PurchaseEvaluationWorkflowSteps", (string)null);
@@ -3146,55 +3103,6 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.ToTable("PurchaseEvaluationWorkflowStepApprovers", (string)null);
                 });
 
-            modelBuilder.Entity("SolutionErp.Domain.PurchaseEvaluations.PurchaseEvaluationWorkflowStepInnerStep", b =>
-                {
-                    b.Property<Guid>("Id")
-                        .ValueGeneratedOnAdd()
-                        .HasColumnType("uniqueidentifier");
-
-                    b.Property<DateTime>("CreatedAt")
-                        .HasColumnType("datetime2");
-
-                    b.Property<Guid?>("CreatedBy")
-                        .HasColumnType("uniqueidentifier");
-
-                    b.Property<Guid>("DepartmentId")
-                        .HasColumnType("uniqueidentifier");
-
-                    b.Property<bool>("IsRequired")
-                        .HasColumnType("bit");
-
-                    b.Property<string>("Name")
-                        .HasMaxLength(200)
-                        .HasColumnType("nvarchar(200)");
-
-                    b.Property<int>("Order")
-                        .HasColumnType("int");
-
-                    b.Property<int>("PositionLevel")
-                        .HasColumnType("int");
-
-                    b.Property<Guid>("PurchaseEvaluationWorkflowStepId")
-                        .HasColumnType("uniqueidentifier");
-
-                    b.Property<int?>("SlaDays")
-                        .HasColumnType("int");
-
-                    b.Property<DateTime?>("UpdatedAt")
-                        .HasColumnType("datetime2");
-
-                    b.Property<Guid?>("UpdatedBy")
-                        .HasColumnType("uniqueidentifier");
-
-                    b.HasKey("Id");
-
-                    b.HasIndex("DepartmentId");
-
-                    b.HasIndex("PurchaseEvaluationWorkflowStepId", "Order");
-
-                    b.ToTable("PurchaseEvaluationWorkflowStepInnerSteps", (string)null);
-                });
-
             modelBuilder.Entity("Microsoft.AspNetCore.Identity.IdentityRoleClaim<System.Guid>", b =>
                 {
                     b.HasOne("SolutionErp.Domain.Identity.Role", null)
@@ -3342,11 +3250,6 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                         .OnDelete(DeleteBehavior.Cascade)
                         .IsRequired();
 
-                    b.HasOne("SolutionErp.Domain.Contracts.WorkflowStepInnerStep", null)
-                        .WithMany()
-                        .HasForeignKey("InnerStepId")
-                        .OnDelete(DeleteBehavior.Restrict);
-
                     b.Navigation("Contract");
                 });
 
@@ -3429,6 +3332,11 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
 
             modelBuilder.Entity("SolutionErp.Domain.Contracts.WorkflowStep", b =>
                 {
+                    b.HasOne("SolutionErp.Domain.Master.Department", null)
+                        .WithMany()
+                        .HasForeignKey("DepartmentId")
+                        .OnDelete(DeleteBehavior.Restrict);
+
                     b.HasOne("SolutionErp.Domain.Contracts.WorkflowDefinition", "WorkflowDefinition")
                         .WithMany("Steps")
                         .HasForeignKey("WorkflowDefinitionId")
@@ -3449,23 +3357,6 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Navigation("Step");
                 });
 
-            modelBuilder.Entity("SolutionErp.Domain.Contracts.WorkflowStepInnerStep", b =>
-                {
-                    b.HasOne("SolutionErp.Domain.Master.Department", null)
-                        .WithMany()
-                        .HasForeignKey("DepartmentId")
-                        .OnDelete(DeleteBehavior.Restrict)
-                        .IsRequired();
-
-                    b.HasOne("SolutionErp.Domain.Contracts.WorkflowStep", "Step")
-                        .WithMany("InnerSteps")
-                        .HasForeignKey("WorkflowStepId")
-                        .OnDelete(DeleteBehavior.Cascade)
-                        .IsRequired();
-
-                    b.Navigation("Step");
-                });
-
             modelBuilder.Entity("SolutionErp.Domain.Identity.MenuItem", b =>
                 {
                     b.HasOne("SolutionErp.Domain.Identity.MenuItem", "Parent")
@@ -3538,11 +3429,6 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
 
             modelBuilder.Entity("SolutionErp.Domain.PurchaseEvaluations.PurchaseEvaluationDepartmentApproval", b =>
                 {
-                    b.HasOne("SolutionErp.Domain.PurchaseEvaluations.PurchaseEvaluationWorkflowStepInnerStep", null)
-                        .WithMany()
-                        .HasForeignKey("InnerStepId")
-                        .OnDelete(DeleteBehavior.Restrict);
-
                     b.HasOne("SolutionErp.Domain.PurchaseEvaluations.PurchaseEvaluation", "PurchaseEvaluation")
                         .WithMany("DepartmentApprovals")
                         .HasForeignKey("PurchaseEvaluationId")
@@ -3610,6 +3496,11 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
 
             modelBuilder.Entity("SolutionErp.Domain.PurchaseEvaluations.PurchaseEvaluationWorkflowStep", b =>
                 {
+                    b.HasOne("SolutionErp.Domain.Master.Department", null)
+                        .WithMany()
+                        .HasForeignKey("DepartmentId")
+                        .OnDelete(DeleteBehavior.Restrict);
+
                     b.HasOne("SolutionErp.Domain.PurchaseEvaluations.PurchaseEvaluationWorkflowDefinition", "Definition")
                         .WithMany("Steps")
                         .HasForeignKey("PurchaseEvaluationWorkflowDefinitionId")
@@ -3630,23 +3521,6 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Navigation("Step");
                 });
 
-            modelBuilder.Entity("SolutionErp.Domain.PurchaseEvaluations.PurchaseEvaluationWorkflowStepInnerStep", b =>
-                {
-                    b.HasOne("SolutionErp.Domain.Master.Department", null)
-                        .WithMany()
-                        .HasForeignKey("DepartmentId")
-                        .OnDelete(DeleteBehavior.Restrict)
-                        .IsRequired();
-
-                    b.HasOne("SolutionErp.Domain.PurchaseEvaluations.PurchaseEvaluationWorkflowStep", "Step")
-                        .WithMany("InnerSteps")
-                        .HasForeignKey("PurchaseEvaluationWorkflowStepId")
-                        .OnDelete(DeleteBehavior.Cascade)
-                        .IsRequired();
-
-                    b.Navigation("Step");
-                });
-
             modelBuilder.Entity("SolutionErp.Domain.Budgets.Budget", b =>
                 {
                     b.Navigation("Approvals");
@@ -3693,8 +3567,6 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
             modelBuilder.Entity("SolutionErp.Domain.Contracts.WorkflowStep", b =>
                 {
                     b.Navigation("Approvers");
-
-                    b.Navigation("InnerSteps");
                 });
 
             modelBuilder.Entity("SolutionErp.Domain.Identity.MenuItem", b =>
@@ -3736,8 +3608,6 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
             modelBuilder.Entity("SolutionErp.Domain.PurchaseEvaluations.PurchaseEvaluationWorkflowStep", b =>
                 {
                     b.Navigation("Approvers");
-
-                    b.Navigation("InnerSteps");
                 });
 #pragma warning restore 612, 618
         }

src/Backend/SolutionErp.Infrastructure/Services/ContractWorkflowService.cs

@@ -11,9 +11,10 @@ using SolutionErp.Domain.Notifications;
 
 namespace SolutionErp.Infrastructure.Services;
 
-// Thin orchestrator — all phase/role/SLA rules live in WorkflowPolicy (Domain).
+// Contract Workflow Service — Session 16 drastic refactor (Mig 21):
-// This class is responsible only for *applying* transitions: DB writes, code
+// Flat workflow model. Mỗi step = 1 (Phòng × Cấp + Approvers). Service iterate
-// generation at DangDongDau, SLA deadline computation, notification dispatch.
+// steps OrderBy Order, advance Contract.CurrentWorkflowStepIndex per approve.
+// Phase enum simplified: DangSoanThao → ChoDuyet → DaPhatHanh / TuChoi.
 public class ContractWorkflowService(
     IApplicationDbContext db,
     IContractCodeGenerator codeGenerator,
@@ -22,11 +23,8 @@ public class ContractWorkflowService(
     IChangelogService changelog,
     UserManager<User> userManager) : IContractWorkflowService
 {
-    // Expose per-policy SLA via the contract — accepts optional contract so the
-    // caller (CreateContractCommand) can ask for a specific type's SLA even
-    // before the contract exists.
     public TimeSpan? GetPhaseSla(ContractPhase phase) =>
-        WorkflowPolicies.Standard.PhaseSla.GetValueOrDefault(phase);
+        phase == ContractPhase.ChoDuyet ? TimeSpan.FromDays(7) : null;
 
     public async Task TransitionAsync(
         Contract contract,
@@ -37,326 +35,128 @@ public class ContractWorkflowService(
         string? comment,
         CancellationToken ct = default)
     {
-        if (contract.Phase == targetPhase)
-            throw new ConflictException("HĐ đã ở phase đích.");
-
-        // ===== Smart reject + resume (Phase 9 — Migration 16) =====
-        // Reject: override target = DangSoanThao + lưu phase gốc → Drafter sửa.
-        // Resume sau reject: Drafter trình từ DangSoanThao + RejectedFromPhase
-        // != null → jump straight tới phase đã reject, bypass phase trung gian.
         var fromPhase = contract.Phase;
-        var isResumingAfterReject = decision == ApprovalDecision.Approve
-            && fromPhase == ContractPhase.DangSoanThao
-            && contract.RejectedFromPhase != null;
-
-        if (decision == ApprovalDecision.Reject)
-        {
-            contract.RejectedFromPhase = fromPhase;
-            targetPhase = ContractPhase.DangSoanThao;
-
-            // N-stage state reset (Mig 20): clear inner step approval rows tại
-            // fromPhase. User resume sẽ approve lại từ inner step đầu.
-            var staleNStageRows = await db.ContractDepartmentApprovals
-                .Where(a => a.ContractId == contract.Id
-                         && a.PhaseAtApproval == (int)fromPhase
-                         && a.InnerStepId != null)
-                .ToListAsync(ct);
-            foreach (var r in staleNStageRows) db.ContractDepartmentApprovals.Remove(r);
-        }
-        else if (isResumingAfterReject)
-        {
-            targetPhase = contract.RejectedFromPhase!.Value;
-            contract.RejectedFromPhase = null;
-        }
-
-        // Resolve the workflow: prefer the pinned WorkflowDefinition (new
-        // versioned system), else fall back to the static/override registry
-        // (legacy path for contracts created before versioning rolled out).
-        WorkflowPolicy policy;
-        WorkflowDefinition? definition = null;
-        if (contract.WorkflowDefinitionId is Guid wfId)
-        {
-            definition = await db.WorkflowDefinitions.AsNoTracking()
-                .Include(d => d.Steps.OrderBy(s => s.Order))
-                    .ThenInclude(s => s.Approvers)
-                .Include(d => d.Steps)
-                    .ThenInclude(s => s.InnerSteps.OrderBy(i => i.Order))
-                .FirstOrDefaultAsync(d => d.Id == wfId, ct);
-            policy = definition is not null
-                ? WorkflowPolicyRegistry.FromDefinition(definition)
-                : WorkflowPolicyRegistry.ForContract(contract);
-        }
-        else
-        {
-            var overrides = await db.WorkflowTypeAssignments.AsNoTracking()
-                .ToDictionaryAsync(a => a.ContractType, a => a.PolicyName, ct);
-            policy = WorkflowPolicyRegistry.ForContractWithOverrides(contract, overrides);
-        }
         var isAdmin = actorRoles.Contains(AppRoles.Admin);
         var isSystem = actorUserId is null && decision == ApprovalDecision.AutoApprove;
 
-        // Policy guard — bypass cho resume (Drafter có quyền trình lại sau khi
+        // ===== REJECT BRANCH =====
-        // sửa, không cần policy check vì target đã pinned bởi RejectedFromPhase).
+        if (decision == ApprovalDecision.Reject)
-        if (!isAdmin && !isSystem && !isResumingAfterReject)
         {
-            if (!policy.Transitions.TryGetValue((fromPhase, targetPhase), out var allowedRoles))
+            if (targetPhase == ContractPhase.TuChoi)
-                throw new ForbiddenException(
-                    $"Policy '{policy.Name}' không cho phép {fromPhase} → {targetPhase}. " +
-                    $"Kiểm tra ContractType hoặc BypassProcurementAndCCM.");
-
-            // Sử dụng IsTransitionAllowed — check Role + User-kind fallback.
-            // User-kind chỉ áp dụng khi WorkflowDefinition pinned có
-            // WorkflowStepApprover Kind=User cho step này.
-            if (!policy.IsTransitionAllowed(fromPhase, targetPhase, actorRoles, actorUserId))
             {
-                var userExtra = policy.UserTransitions is not null
+                contract.Phase = ContractPhase.TuChoi;
-                    && policy.UserTransitions.TryGetValue((fromPhase, targetPhase), out var userIds)
-                    && userIds.Length > 0
-                    ? $" hoặc {userIds.Length} user explicit"
-                    : "";
-                throw new ForbiddenException(
-                    $"Role ({string.Join(",", actorRoles)}) không đủ quyền chuyển {fromPhase} → {targetPhase}. " +
-                    $"Policy '{policy.Name}' yêu cầu: {string.Join(",", allowedRoles)}{userExtra}.");
-            }
-        }
-
-        // ===== Department approval (N-stage Mig 20 hoặc Legacy 2-stage Mig 16) =====
-        // Mirror PE workflow service. Step có InnerSteps → N-stage logic
-        // (Phòng × PositionLevel sequential). Else fallback legacy 2-stage
-        // (NV.Review/TPB.Confirm). Skip với reject + resume + admin + system.
-        var currentStepDef = definition?.Steps.FirstOrDefault(s => s.Phase == fromPhase);
-        var hasInnerSteps = currentStepDef?.InnerSteps.Count > 0;
-
-        if (decision == ApprovalDecision.Approve
-            && targetPhase != ContractPhase.DangSoanThao
-            && targetPhase != ContractPhase.TuChoi
-            && !isResumingAfterReject
-            && !isAdmin && !isSystem
-            && actorUserId is Guid actorUid)
-        {
-            var actor = await userManager.FindByIdAsync(actorUid.ToString());
-
-            if (hasInnerSteps && currentStepDef is not null)
-            {
-                // ===== N-stage logic (Mig 20) — mirror PE Mig 18 =====
-                if (actor?.DepartmentId is null || actor.PositionLevel is null)
-                {
-                    throw new ForbiddenException(
-                        "User phải có Phòng + Cấp chức danh (NV/PP/TP) để duyệt N-stage workflow.");
-                }
-
-                var actorDept = actor.DepartmentId.Value;
-                var actorPos = actor.PositionLevel.Value;
-                var canBypass = actor.CanBypassReview;
-
-                var inners = currentStepDef.InnerSteps.OrderBy(i => i.Order).ToList();
-                var innerIds = inners.Select(i => i.Id).ToList();
-
-                var existingApprovals = await db.ContractDepartmentApprovals
-                    .Where(a => a.ContractId == contract.Id
-                             && a.PhaseAtApproval == (int)fromPhase
-                             && a.InnerStepId != null
-                             && innerIds.Contains(a.InnerStepId!.Value))
-                    .ToListAsync(ct);
-                var doneInnerIds = existingApprovals.Select(a => a.InnerStepId!.Value).ToHashSet();
-
-                var pendingRequired = inners.Where(i => i.IsRequired && !doneInnerIds.Contains(i.Id)).ToList();
-                if (pendingRequired.Count > 0)
-                {
-                    var firstPending = pendingRequired[0];
-
-                    var levelOk = actorPos == firstPending.PositionLevel
-                        || (canBypass && (int)actorPos >= (int)firstPending.PositionLevel);
-                    if (actorDept != firstPending.DepartmentId || !levelOk)
-                    {
-                        throw new ForbiddenException(
-                            $"Cấp duyệt tiếp theo: phòng {firstPending.DepartmentId} cấp {firstPending.PositionLevel}. " +
-                            $"Bạn (phòng {actorDept} cấp {actorPos}{(canBypass ? "+bypass" : "")}) không khớp.");
-                    }
-
-                    var rowsToCreate = new List<(WorkflowStepInnerStep i, bool bypassed)>();
-                    if (actorPos == firstPending.PositionLevel)
-                    {
-                        rowsToCreate.Add((firstPending, false));
             }
             else
             {
-                        // Bypass cùng dept: upsert tất cả pending inner trong dept actor
+                contract.RejectedFromPhase = fromPhase;
-                        // có level từ firstPending.PositionLevel đến actorPos (inclusive)
+                contract.RejectedAtStepIndex = contract.CurrentWorkflowStepIndex;
-                        foreach (var inner in inners
+                contract.Phase = ContractPhase.DangSoanThao;
-                            .Where(i => i.DepartmentId == actorDept
+                contract.CurrentWorkflowStepIndex = null;
-                                     && (int)i.PositionLevel >= (int)firstPending.PositionLevel
-                                     && (int)i.PositionLevel <= (int)actorPos
-                                     && !doneInnerIds.Contains(i.Id)))
-                        {
-                            rowsToCreate.Add((inner, inner.PositionLevel != actorPos));
             }
+            contract.SlaDeadline = null;
+            await LogTransitionAsync(contract, fromPhase, contract.Phase, actorUserId, decision, comment, ct);
+            await db.SaveChangesAsync(ct);
+            return;
         }
 
-                    var nowUtc = dateTime.UtcNow;
+        // ===== RESUME AFTER REJECT =====
-                    foreach (var (inner, bypassed) in rowsToCreate)
+        var isResumingAfterReject = decision == ApprovalDecision.Approve
+            && fromPhase == ContractPhase.DangSoanThao
+            && contract.RejectedAtStepIndex != null;
+
+        if (isResumingAfterReject)
         {
-                        db.ContractDepartmentApprovals.Add(new ContractDepartmentApproval
+            contract.Phase = ContractPhase.ChoDuyet;
-                        {
+            contract.CurrentWorkflowStepIndex = contract.RejectedAtStepIndex;
-                            ContractId = contract.Id,
+            contract.RejectedAtStepIndex = null;
-                            PhaseAtApproval = (int)fromPhase,
+            contract.RejectedFromPhase = null;
-                            DepartmentId = inner.DepartmentId,
+            contract.SlaDeadline = dateTime.UtcNow.AddDays(7);
-                            Stage = ApprovalStage.Confirm,
+            await LogTransitionAsync(contract, fromPhase, ContractPhase.ChoDuyet, actorUserId, decision, comment, ct);
-                            ApproverUserId = actorUid,
+            await db.SaveChangesAsync(ct);
-                            ApproverRoleSnapshot = $"{inner.PositionLevel}{(bypassed ? "(bypass)" : "")}",
+            return;
-                            Comment = comment,
-                            ApprovedAt = nowUtc,
-                            IsBypassed = bypassed,
-                            InnerStepId = inner.Id,
-                        });
-                        doneInnerIds.Add(inner.Id);
         }
 
-                    var stillPending = inners.Any(i => i.IsRequired && !doneInnerIds.Contains(i.Id));
+        // ===== DRAFTER TRÌNH =====
-                    if (stillPending)
+        if (fromPhase == ContractPhase.DangSoanThao
+            && (targetPhase == ContractPhase.ChoDuyet || (!isAdmin && !isSystem)))
         {
+            if (!isAdmin && !isSystem
+                && !actorRoles.Contains(AppRoles.Drafter)
+                && !actorRoles.Contains(AppRoles.DeptManager))
+            {
+                throw new ForbiddenException(
+                    $"Role ({string.Join(",", actorRoles)}) không đủ quyền trình duyệt HĐ.");
+            }
+            contract.Phase = ContractPhase.ChoDuyet;
+            contract.CurrentWorkflowStepIndex = 0;
+            contract.SlaDeadline = dateTime.UtcNow.AddDays(7);
+            await LogTransitionAsync(contract, fromPhase, ContractPhase.ChoDuyet, actorUserId, decision, comment, ct);
+            await db.SaveChangesAsync(ct);
+            return;
+        }
+
+        // ===== APPROVE STEP =====
+        if (fromPhase == ContractPhase.ChoDuyet && decision == ApprovalDecision.Approve)
+        {
+            var def = contract.WorkflowDefinitionId is Guid wfId
+                ? await db.WorkflowDefinitions.AsNoTracking()
+                    .Include(d => d.Steps.OrderBy(s => s.Order))
+                        .ThenInclude(s => s.Approvers)
+                    .FirstOrDefaultAsync(d => d.Id == wfId, ct)
+                : null;
+
+            if (def == null || def.Steps.Count == 0)
+                throw new ConflictException("HĐ chưa pin workflow definition hoặc workflow không có step.");
+
+            var steps = def.Steps.OrderBy(s => s.Order).ToList();
+            var currentIdx = contract.CurrentWorkflowStepIndex ?? 0;
+            if (currentIdx < 0 || currentIdx >= steps.Count)
+                throw new ConflictException($"CurrentWorkflowStepIndex={currentIdx} không hợp lệ.");
+
+            var currentStep = steps[currentIdx];
+
+            if (!isAdmin && !isSystem)
+            {
+                var actor = actorUserId is Guid uid ? await userManager.FindByIdAsync(uid.ToString()) : null;
+                if (actor == null)
+                    throw new ForbiddenException("Không xác định được approver.");
+
+                var matchByDeptLevel = currentStep.DepartmentId != null
+                    && currentStep.PositionLevel != null
+                    && actor.DepartmentId == currentStep.DepartmentId
+                    && actor.PositionLevel != null
+                    && (int)actor.PositionLevel >= (int)currentStep.PositionLevel;
+
+                var matchByExplicitUser = currentStep.Approvers.Any(a =>
+                    a.Kind == WorkflowApproverKind.User
+                    && Guid.TryParse(a.AssignmentValue, out var auid)
+                    && auid == actor.Id);
+
+                var matchByRole = currentStep.Approvers.Any(a =>
+                    a.Kind == WorkflowApproverKind.Role
+                    && actorRoles.Contains(a.AssignmentValue));
+
+                if (!matchByDeptLevel && !matchByExplicitUser && !matchByRole)
+                    throw new ForbiddenException(
+                        $"Step {currentIdx + 1} ({currentStep.Name}) yêu cầu phòng={currentStep.DepartmentId}, cấp={currentStep.PositionLevel}. Bạn không khớp.");
+            }
+
             db.ContractApprovals.Add(new ContractApproval
             {
                 ContractId = contract.Id,
                 FromPhase = fromPhase,
                 ToPhase = fromPhase,
-                            ApproverUserId = actorUid,
+                ApproverUserId = actorUserId,
-                            Decision = ApprovalDecision.Approve,
+                Decision = decision,
-                            Comment = $"[Inner step duyệt {actorPos}] {comment ?? ""}",
+                Comment = $"[Step {currentIdx + 1}] {comment ?? ""}",
-                            ApprovedAt = nowUtc,
-                        });
-
-                        string? reviewerName = actor.FullName ?? actor.Email;
-                        db.ContractChangelogs.Add(new ContractChangelog
-                        {
-                            ContractId = contract.Id,
-                            EntityType = ChangelogEntityType.Workflow,
-                            Action = ChangelogAction.Transition,
-                            PhaseAtChange = fromPhase,
-                            UserId = actorUid,
-                            UserName = reviewerName ?? "Hệ thống",
-                            Summary = $"{reviewerName} duyệt cấp {actorPos} phase {fromPhase} (còn {inners.Count(i => i.IsRequired && !doneInnerIds.Contains(i.Id))} cấp pending)",
-                            ContextNote = comment,
-                        });
-
-                        await db.SaveChangesAsync(ct);
-                        return;
-                    }
-                    // All required inner steps done → fall through phase transition
-                }
-            }
-            else if (actor?.DepartmentId is Guid deptId)
-            {
-                // ===== Legacy 2-stage logic (Mig 16) — fallback khi step KHÔNG có InnerSteps =====
-                var isManager = actorRoles.Contains(AppRoles.DeptManager);
-                var canBypass = actor.CanBypassReview;
-                var stage = (isManager || canBypass) ? ApprovalStage.Confirm : ApprovalStage.Review;
-                var isBypassed = !isManager && canBypass;
-                var roleSnapshot = isManager ? "TPB" : (canBypass ? "NV(bypass)" : "NV");
-
-                var existing = await db.ContractDepartmentApprovals
-                    .FirstOrDefaultAsync(a =>
-                        a.ContractId == contract.Id
-                        && a.PhaseAtApproval == (int)fromPhase
-                        && a.DepartmentId == deptId
-                        && a.Stage == stage
-                        && a.InnerStepId == null, ct);
-                if (existing is null)
-                {
-                    db.ContractDepartmentApprovals.Add(new ContractDepartmentApproval
-                    {
-                        ContractId = contract.Id,
-                        PhaseAtApproval = (int)fromPhase,
-                        DepartmentId = deptId,
-                        Stage = stage,
-                        ApproverUserId = actorUid,
-                        ApproverRoleSnapshot = roleSnapshot,
-                        Comment = comment,
-                        ApprovedAt = dateTime.UtcNow,
-                        IsBypassed = isBypassed,
-                        InnerStepId = null,
-                    });
-                }
-                else
-                {
-                    existing.ApproverUserId = actorUid;
-                    existing.ApproverRoleSnapshot = roleSnapshot;
-                    existing.Comment = comment;
-                    existing.ApprovedAt = dateTime.UtcNow;
-                    existing.IsBypassed = isBypassed;
-                }
-
-                var hasConfirm = stage == ApprovalStage.Confirm
-                    || await db.ContractDepartmentApprovals.AnyAsync(a =>
-                        a.ContractId == contract.Id
-                        && a.PhaseAtApproval == (int)fromPhase
-                        && a.DepartmentId == deptId
-                        && a.Stage == ApprovalStage.Confirm
-                        && a.InnerStepId == null, ct);
-
-                if (!hasConfirm)
-                {
-                    db.ContractApprovals.Add(new ContractApproval
-                    {
-                        ContractId = contract.Id,
-                        FromPhase = fromPhase,
-                        ToPhase = fromPhase,
-                        ApproverUserId = actorUid,
-                        Decision = ApprovalDecision.Approve,
-                        Comment = $"[Review NV] {comment ?? ""}",
                 ApprovedAt = dateTime.UtcNow,
             });
 
-                    string? reviewerName = actor.FullName ?? actor.Email;
+            var nextIdx = currentIdx + 1;
-                    db.ContractChangelogs.Add(new ContractChangelog
+            if (nextIdx >= steps.Count)
             {
-                        ContractId = contract.Id,
+                // All steps done — gen mã HĐ + DaPhatHanh
-                        EntityType = ChangelogEntityType.Workflow,
+                if (string.IsNullOrEmpty(contract.MaHopDong))
-                        Action = ChangelogAction.Transition,
-                        PhaseAtChange = fromPhase,
-                        UserId = actorUid,
-                        UserName = reviewerName ?? "Hệ thống",
-                        Summary = $"{reviewerName} (NV) đã review phase {fromPhase}, chờ TPB confirm",
-                        ContextNote = comment,
-                    });
-
-                    // Notify TPB cùng dept để confirm. Best effort.
-                    try
-                    {
-                        var managers = await db.Users.AsNoTracking()
-                            .Where(u => u.DepartmentId == deptId && u.Id != actorUid && u.IsActive)
-                            .Select(u => u.Id)
-                            .ToListAsync(ct);
-                        foreach (var mgrId in managers)
-                        {
-                            var mgr = await userManager.FindByIdAsync(mgrId.ToString());
-                            if (mgr is null) continue;
-                            var roles = await userManager.GetRolesAsync(mgr);
-                            if (!roles.Contains(AppRoles.DeptManager)) continue;
-
-                            await notifications.NotifyAsync(
-                                mgrId,
-                                NotificationType.ContractPhaseTransition,
-                                title: $"HĐ {contract.MaHopDong ?? contract.TenHopDong ?? ""} chờ TPB confirm",
-                                description: $"NV {reviewerName} đã review phase {fromPhase}. Vui lòng vào confirm để workflow tiếp tục.",
-                                href: $"/contracts/{contract.Id}",
-                                refId: contract.Id,
-                                ct: ct);
-                        }
-                    }
-                    catch { /* notification fail non-critical */ }
-
-                    await db.SaveChangesAsync(ct);
-                    return;
-                }
-            }
-        }
-
-        // Defensive — gen mã HĐ nếu chưa có khi chuyển sang DangDongDau.
-        // Nominal flow (sau user feedback): mã đã gen sẵn từ CreateContract → skip.
-        // Fallback chỉ trigger cho HĐ legacy chưa qua backfill, hoặc HĐ tạo bằng
-        // path khác (vd seed/import) chưa set MaHopDong.
-        if (targetPhase == ContractPhase.DangDongDau && string.IsNullOrEmpty(contract.MaHopDong))
                 {
                     var supplier = await db.Suppliers.FirstOrDefaultAsync(s => s.Id == contract.SupplierId, ct)
                         ?? throw new NotFoundException("Supplier", contract.SupplierId);
@@ -364,51 +164,67 @@ public class ContractWorkflowService(
                         ?? throw new NotFoundException("Project", contract.ProjectId);
                     contract.MaHopDong = await codeGenerator.GenerateAsync(contract, project.Code, supplier.Code, ct);
                 }
-
+                contract.Phase = ContractPhase.DaPhatHanh;
-        contract.SlaWarningSent = false;
+                contract.CurrentWorkflowStepIndex = null;
-        contract.Phase = targetPhase;
+                contract.SlaDeadline = null;
-
+                await LogTransitionAsync(contract, fromPhase, ContractPhase.DaPhatHanh, actorUserId, decision, comment, ct);
-        var sla = policy.PhaseSla.GetValueOrDefault(targetPhase);
+            }
-        contract.SlaDeadline = sla is null ? null : dateTime.UtcNow.Add(sla.Value);
+            else
-
-        db.ContractApprovals.Add(new ContractApproval
             {
-            ContractId = contract.Id,
+                contract.CurrentWorkflowStepIndex = nextIdx;
-            FromPhase = fromPhase,
+                contract.SlaDeadline = dateTime.UtcNow.AddDays(7);
-            ToPhase = targetPhase,
+                await LogTransitionAsync(contract, fromPhase, fromPhase, actorUserId, decision,
-            ApproverUserId = actorUserId,
+                    $"Hoàn tất step {currentIdx + 1}/{steps.Count}, sang step {nextIdx + 1}", ct);
-            Decision = decision,
+            }
-            Comment = comment,
+            await db.SaveChangesAsync(ct);
-            ApprovedAt = dateTime.UtcNow,
+            return;
-        });
+        }
 
-        // Log workflow transition vào unified Changelog (cho user xem trên tab Lịch sử)
+        // Admin manual override
-        await changelog.LogWorkflowTransitionAsync(contract.Id, fromPhase, targetPhase, comment);
+        if (isAdmin)
+        {
+            contract.Phase = targetPhase;
+            contract.SlaDeadline = targetPhase == ContractPhase.ChoDuyet
+                ? dateTime.UtcNow.AddDays(7) : null;
+            await LogTransitionAsync(contract, fromPhase, targetPhase, actorUserId, decision, comment, ct);
+            await db.SaveChangesAsync(ct);
+            return;
+        }
+
+        throw new ConflictException($"Transition {fromPhase} → {targetPhase} không hỗ trợ.");
+    }
+
+    private async Task LogTransitionAsync(
+        Contract contract,
+        ContractPhase fromPhase,
+        ContractPhase toPhase,
+        Guid? actorUserId,
+        ApprovalDecision decision,
+        string? comment,
+        CancellationToken ct)
+    {
+        await changelog.LogWorkflowTransitionAsync(contract.Id, fromPhase, toPhase, comment);
 
         if (contract.DrafterUserId is Guid drafterId && drafterId != actorUserId)
         {
-            var title = targetPhase switch
+            var (title, type) = toPhase switch
             {
-                ContractPhase.DaPhatHanh => $"HĐ {contract.MaHopDong ?? contract.TenHopDong} đã phát hành",
+                ContractPhase.DaPhatHanh => ($"HĐ {contract.MaHopDong ?? contract.TenHopDong} đã phát hành",
-                ContractPhase.TuChoi => $"HĐ {contract.TenHopDong ?? "của bạn"} bị từ chối",
+                                              NotificationType.ContractPublished),
-                _ => $"HĐ {contract.TenHopDong ?? contract.MaHopDong ?? ""} chuyển sang phase mới",
+                ContractPhase.TuChoi => ($"HĐ {contract.TenHopDong ?? "của bạn"} bị từ chối",
-            };
+                                          NotificationType.ContractRejected),
-            var type = targetPhase switch
+                ContractPhase.DangSoanThao when fromPhase == ContractPhase.ChoDuyet =>
-            {
+                    ($"HĐ {contract.TenHopDong ?? "của bạn"} bị trả lại — vui lòng sửa và trình lại",
-                ContractPhase.DaPhatHanh => NotificationType.ContractPublished,
+                     NotificationType.ContractRejected),
-                ContractPhase.TuChoi => NotificationType.ContractRejected,
+                _ => ($"HĐ {contract.TenHopDong ?? contract.MaHopDong ?? ""} chuyển phase mới",
-                _ => NotificationType.ContractPhaseTransition,
+                      NotificationType.ContractPhaseTransition),
             };
             await notifications.NotifyAsync(
-                drafterId,
+                drafterId, type, title,
-                type,
+                description: $"{fromPhase} → {toPhase}" + (string.IsNullOrWhiteSpace(comment) ? "" : $" · {comment}"),
-                title,
-                description: $"{fromPhase} → {targetPhase}" + (string.IsNullOrWhiteSpace(comment) ? "" : $" · {comment}"),
                 href: $"/contracts/{contract.Id}",
                 refId: contract.Id,
                 ct: ct);
         }
-
-        await db.SaveChangesAsync(ct);
     }
 }

src/Backend/SolutionErp.Infrastructure/Services/PurchaseEvaluationWorkflowService.cs

@@ -12,8 +12,11 @@ using SolutionErp.Domain.PurchaseEvaluations;
 
 namespace SolutionErp.Infrastructure.Services;
 
-// Mirror ContractWorkflowService. Load policy từ pinned
+// PE Workflow Service — Session 16 drastic refactor (Mig 21):
-// WorkflowDefinition (nếu có) hoặc fallback hardcoded registry.
+// Flat workflow model. Mỗi step = 1 (Phòng × Cấp + Approvers). Service iterate
+// steps OrderBy Order, advance PE.CurrentWorkflowStepIndex per approve.
+// Phase enum simplified: DangSoanThao → ChoDuyet (active workflow) → DaDuyet
+// (terminal) / TuChoi (khoá). Trả lại = về DangSoanThao + save RejectedAtStepIndex.
 public class PurchaseEvaluationWorkflowService(
     IApplicationDbContext db,
     IDateTime dateTime,
@@ -21,7 +24,7 @@ public class PurchaseEvaluationWorkflowService(
     UserManager<User> userManager) : IPurchaseEvaluationWorkflowService
 {
     public TimeSpan? GetPhaseSla(PurchaseEvaluationPhase phase) =>
-        PurchaseEvaluationPolicies.NccOnly.PhaseSla.GetValueOrDefault(phase);
+        phase == PurchaseEvaluationPhase.ChoDuyet ? TimeSpan.FromDays(7) : null;
 
     public async Task TransitionAsync(
         PurchaseEvaluation evaluation,
@@ -32,345 +35,173 @@ public class PurchaseEvaluationWorkflowService(
         string? comment,
         CancellationToken ct = default)
     {
-        if (evaluation.Phase == targetPhase)
-            throw new ConflictException("Phiếu đã ở phase đích.");
-
-        // ===== Smart reject + resume (Phase 9 — Migration 16) =====
         var fromPhase = evaluation.Phase;
-        var isResumingAfterReject = decision == ApprovalDecision.Approve
-            && fromPhase == PurchaseEvaluationPhase.DangSoanThao
-            && evaluation.RejectedFromPhase != null;
-
-        if (decision == ApprovalDecision.Reject)
-        {
-            // 2 loại Reject (Session 14):
-            //  - target=TuChoi: "Từ chối hoàn toàn" — phiếu khoá vĩnh viễn (Phase=TuChoi
-            //    → 17 handler Mig 16 lock edit). Drafter phải tạo phiếu mới. KHÔNG set
-            //    RejectedFromPhase + KHÔNG clear N-stage (không resume).
-            //  - target khác (thường = DangSoanThao): "Trả lại" — smart reject pattern
-            //    Mig 16. Set RejectedFromPhase + force DangSoanThao + clear N-stage rows
-            //    tại fromPhase → Drafter sửa rồi trình lại jump-back tới phase đã reject.
-            if (targetPhase != PurchaseEvaluationPhase.TuChoi)
-            {
-                evaluation.RejectedFromPhase = fromPhase;
-                targetPhase = PurchaseEvaluationPhase.DangSoanThao;
-
-                var staleNStageRows = await db.PurchaseEvaluationDepartmentApprovals
-                    .Where(a => a.PurchaseEvaluationId == evaluation.Id
-                             && a.PhaseAtApproval == (int)fromPhase
-                             && a.InnerStepId != null)
-                    .ToListAsync(ct);
-                foreach (var r in staleNStageRows) db.PurchaseEvaluationDepartmentApprovals.Remove(r);
-            }
-        }
-        else if (isResumingAfterReject)
-        {
-            targetPhase = evaluation.RejectedFromPhase!.Value;
-            evaluation.RejectedFromPhase = null;
-        }
-
-        PurchaseEvaluationPolicy policy;
-        PurchaseEvaluationWorkflowDefinition? definition = null;
-        if (evaluation.WorkflowDefinitionId is Guid wfId)
-        {
-            definition = await db.PurchaseEvaluationWorkflowDefinitions.AsNoTracking()
-                .Include(d => d.Steps.OrderBy(s => s.Order))
-                    .ThenInclude(s => s.Approvers)
-                .Include(d => d.Steps)
-                    .ThenInclude(s => s.InnerSteps.OrderBy(i => i.Order))
-                .FirstOrDefaultAsync(d => d.Id == wfId, ct);
-            policy = definition is not null
-                ? PurchaseEvaluationPolicyRegistry.FromDefinition(definition)
-                : PurchaseEvaluationPolicyRegistry.ForEvaluation(evaluation);
-        }
-        else
-        {
-            policy = PurchaseEvaluationPolicyRegistry.ForEvaluation(evaluation);
-        }
-
         var isAdmin = actorRoles.Contains(AppRoles.Admin);
         var isSystem = actorUserId is null && decision == ApprovalDecision.AutoApprove;
 
-        // Policy guard — bypass khi resume sau reject (target đã pinned).
+        // ===== REJECT BRANCH =====
-        if (!isAdmin && !isSystem && !isResumingAfterReject)
+        if (decision == ApprovalDecision.Reject)
         {
-            if (!policy.Transitions.TryGetValue((fromPhase, targetPhase), out var allowedRoles))
+            if (targetPhase == PurchaseEvaluationPhase.TuChoi)
-                throw new ForbiddenException(
-                    $"Policy '{policy.Name}' không cho phép {fromPhase} → {targetPhase}.");
-
-            if (!policy.IsTransitionAllowed(fromPhase, targetPhase, actorRoles, actorUserId))
             {
-                throw new ForbiddenException(
+                // Từ chối hoàn toàn — phiếu khoá vĩnh viễn (lock edit Mig 16).
-                    $"Role ({string.Join(",", actorRoles)}) không đủ quyền chuyển {fromPhase} → {targetPhase}. " +
+                evaluation.Phase = PurchaseEvaluationPhase.TuChoi;
-                    $"Policy '{policy.Name}' yêu cầu: {string.Join(",", allowedRoles)}.");
-            }
-        }
-
-        // ===== Department approval (N-stage Mig 18 hoặc Legacy 2-stage Mig 16) =====
-        // Active block khi: Approve + chuyển sang phase trung gian (không phải
-        // DangSoanThao/TuChoi) + KHÔNG admin/system + KHÔNG resume sau reject.
-        var currentStepDef = definition?.Steps.FirstOrDefault(s => s.Phase == fromPhase);
-        var hasInnerSteps = currentStepDef?.InnerSteps.Count > 0;
-
-        if (decision == ApprovalDecision.Approve
-            && targetPhase != PurchaseEvaluationPhase.DangSoanThao
-            && targetPhase != PurchaseEvaluationPhase.TuChoi
-            && !isResumingAfterReject
-            && !isAdmin && !isSystem
-            && actorUserId is Guid actorUid)
-        {
-            var actor = await userManager.FindByIdAsync(actorUid.ToString());
-
-            if (hasInnerSteps && currentStepDef is not null)
-            {
-                // ===== N-stage logic (Mig 18) =====
-                // Yêu cầu user có DepartmentId + PositionLevel set. Match exact
-                // (DeptId + PositionLevel) inner step pending tiếp theo theo Order.
-                // Bypass: actor cùng dept + PositionLevel cao hơn + CanBypassReview
-                //         → batch upsert luôn các inner step cấp dưới (audit IsBypassed=true).
-                if (actor?.DepartmentId is null || actor.PositionLevel is null)
-                {
-                    throw new ForbiddenException(
-                        "User phải có Phòng + Cấp chức danh (NV/PP/TP) để duyệt N-stage workflow.");
-                }
-
-                var actorDept = actor.DepartmentId.Value;
-                var actorPos = actor.PositionLevel.Value;
-                var canBypass = actor.CanBypassReview;
-
-                var inners = currentStepDef.InnerSteps.OrderBy(i => i.Order).ToList();
-                var innerIds = inners.Select(i => i.Id).ToList();
-
-                var existingApprovals = await db.PurchaseEvaluationDepartmentApprovals
-                    .Where(a => a.PurchaseEvaluationId == evaluation.Id
-                             && a.PhaseAtApproval == (int)fromPhase
-                             && a.InnerStepId != null
-                             && innerIds.Contains(a.InnerStepId!.Value))
-                    .ToListAsync(ct);
-                var doneInnerIds = existingApprovals.Select(a => a.InnerStepId!.Value).ToHashSet();
-
-                var pendingRequired = inners.Where(i => i.IsRequired && !doneInnerIds.Contains(i.Id)).ToList();
-                if (pendingRequired.Count > 0)
-                {
-                    var firstPending = pendingRequired[0];
-
-                    // Match: same dept AND (exact level OR canBypass + level higher)
-                    var levelOk = actorPos == firstPending.PositionLevel
-                        || (canBypass && (int)actorPos >= (int)firstPending.PositionLevel);
-                    if (actorDept != firstPending.DepartmentId || !levelOk)
-                    {
-                        throw new ForbiddenException(
-                            $"Cấp duyệt tiếp theo: phòng {firstPending.DepartmentId} cấp {firstPending.PositionLevel}. " +
-                            $"Bạn (phòng {actorDept} cấp {actorPos}{(canBypass ? "+bypass" : "")}) không khớp.");
-                    }
-
-                    // Determine rows to upsert
-                    var rowsToCreate = new List<(PurchaseEvaluationWorkflowStepInnerStep i, bool bypassed)>();
-                    if (actorPos == firstPending.PositionLevel)
-                    {
-                        rowsToCreate.Add((firstPending, false));
             }
             else
             {
-                        // Bypass cùng dept: upsert tất cả pending inner trong dept actor có level
+                // Trả lại — về DangSoanThao + save RejectedAtStepIndex (resume jump-back).
-                        // từ firstPending.PositionLevel đến actorPos (inclusive)
+                evaluation.RejectedFromPhase = fromPhase;
-                        foreach (var inner in inners
+                evaluation.RejectedAtStepIndex = evaluation.CurrentWorkflowStepIndex;
-                            .Where(i => i.DepartmentId == actorDept
+                evaluation.Phase = PurchaseEvaluationPhase.DangSoanThao;
-                                     && (int)i.PositionLevel >= (int)firstPending.PositionLevel
+                evaluation.CurrentWorkflowStepIndex = null;
-                                     && (int)i.PositionLevel <= (int)actorPos
-                                     && !doneInnerIds.Contains(i.Id)))
-                        {
-                            rowsToCreate.Add((inner, inner.PositionLevel != actorPos));
             }
-                    }
+            evaluation.SlaDeadline = null;
-
+            await LogTransitionAsync(evaluation, fromPhase, evaluation.Phase, actorUserId, decision, comment, ct);
-                    var nowUtc = dateTime.UtcNow;
-                    foreach (var (inner, bypassed) in rowsToCreate)
-                    {
-                        db.PurchaseEvaluationDepartmentApprovals.Add(new PurchaseEvaluationDepartmentApproval
-                        {
-                            PurchaseEvaluationId = evaluation.Id,
-                            PhaseAtApproval = (int)fromPhase,
-                            DepartmentId = inner.DepartmentId,
-                            Stage = ApprovalStage.Confirm,    // N-stage: tất cả row dùng Confirm semantically
-                            ApproverUserId = actorUid,
-                            ApproverRoleSnapshot = $"{inner.PositionLevel}{(bypassed ? "(bypass)" : "")}",
-                            Comment = comment,
-                            ApprovedAt = nowUtc,
-                            IsBypassed = bypassed,
-                            InnerStepId = inner.Id,
-                        });
-                        doneInnerIds.Add(inner.Id);
-                    }
-
-                    // Recheck remaining pending sau upsert
-                    var stillPending = inners.Any(i => i.IsRequired && !doneInnerIds.Contains(i.Id));
-                    if (stillPending)
-                    {
-                        // Còn cấp duyệt tiếp theo → BLOCK phase transition.
-                        // Log Approval (review-style) + Changelog audit.
-                        db.PurchaseEvaluationApprovals.Add(new PurchaseEvaluationApproval
-                        {
-                            PurchaseEvaluationId = evaluation.Id,
-                            FromPhase = fromPhase,
-                            ToPhase = fromPhase,
-                            ApproverUserId = actorUid,
-                            Decision = ApprovalDecision.Approve,
-                            Comment = $"[Inner step duyệt {actorPos}] {comment ?? ""}",
-                            ApprovedAt = nowUtc,
-                        });
-
-                        string? reviewerName = actor.FullName ?? actor.Email;
-                        db.PurchaseEvaluationChangelogs.Add(new PurchaseEvaluationChangelog
-                        {
-                            PurchaseEvaluationId = evaluation.Id,
-                            EntityType = PurchaseEvaluationEntityType.Workflow,
-                            Action = ChangelogAction.Transition,
-                            PhaseAtChange = fromPhase,
-                            UserId = actorUid,
-                            UserName = reviewerName ?? "Hệ thống",
-                            Summary = $"{reviewerName} duyệt cấp {actorPos} phase {fromPhase} (còn {inners.Count(i => i.IsRequired && !doneInnerIds.Contains(i.Id))} cấp pending)",
-                            ContextNote = comment,
-                        });
-
             await db.SaveChangesAsync(ct);
             return;
         }
-                    // All required inner steps done → fall through to phase transition
-                }
-                // pendingRequired.Count == 0 → all already done before this call → fall through
-            }
-            else if (actor?.DepartmentId is Guid deptId)
-            {
-                // ===== Legacy 2-stage logic (Mig 16) — fallback khi step KHÔNG có InnerSteps =====
-                var isManager = actorRoles.Contains(AppRoles.DeptManager);
-                var canBypass = actor.CanBypassReview;
-                var stage = (isManager || canBypass) ? ApprovalStage.Confirm : ApprovalStage.Review;
-                var isBypassed = !isManager && canBypass;
-                var roleSnapshot = isManager ? "TPB" : (canBypass ? "NV(bypass)" : "NV");
 
-                // Upsert: 1 row mỗi (PEId, phase, dept, stage). UNIQUE filtered InnerStepId IS NULL.
+        // ===== RESUME AFTER REJECT (Drafter trình lại) =====
-                var existing = await db.PurchaseEvaluationDepartmentApprovals
+        var isResumingAfterReject = decision == ApprovalDecision.Approve
-                    .FirstOrDefaultAsync(a =>
+            && fromPhase == PurchaseEvaluationPhase.DangSoanThao
-                        a.PurchaseEvaluationId == evaluation.Id
+            && evaluation.RejectedAtStepIndex != null;
-                        && a.PhaseAtApproval == (int)fromPhase
-                        && a.DepartmentId == deptId
-                        && a.Stage == stage
-                        && a.InnerStepId == null, ct);
-                if (existing is null)
-                {
-                    db.PurchaseEvaluationDepartmentApprovals.Add(new PurchaseEvaluationDepartmentApproval
-                    {
-                        PurchaseEvaluationId = evaluation.Id,
-                        PhaseAtApproval = (int)fromPhase,
-                        DepartmentId = deptId,
-                        Stage = stage,
-                        ApproverUserId = actorUid,
-                        ApproverRoleSnapshot = roleSnapshot,
-                        Comment = comment,
-                        ApprovedAt = dateTime.UtcNow,
-                        IsBypassed = isBypassed,
-                        InnerStepId = null,
-                    });
-                }
-                else
-                {
-                    existing.ApproverUserId = actorUid;
-                    existing.ApproverRoleSnapshot = roleSnapshot;
-                    existing.Comment = comment;
-                    existing.ApprovedAt = dateTime.UtcNow;
-                    existing.IsBypassed = isBypassed;
-                }
 
-                // Check Stage=Confirm tồn tại cho (PEId, fromPhase, deptId)
+        if (isResumingAfterReject)
-                var hasConfirm = stage == ApprovalStage.Confirm
-                    || await db.PurchaseEvaluationDepartmentApprovals.AnyAsync(a =>
-                        a.PurchaseEvaluationId == evaluation.Id
-                        && a.PhaseAtApproval == (int)fromPhase
-                        && a.DepartmentId == deptId
-                        && a.Stage == ApprovalStage.Confirm
-                        && a.InnerStepId == null, ct);
-
-                if (!hasConfirm)
         {
-                    // NV review xong, chưa có TPB confirm → BLOCK phase transition.
+            evaluation.Phase = PurchaseEvaluationPhase.ChoDuyet;
-                    db.PurchaseEvaluationApprovals.Add(new PurchaseEvaluationApproval
+            evaluation.CurrentWorkflowStepIndex = evaluation.RejectedAtStepIndex;
-                    {
+            evaluation.RejectedAtStepIndex = null;
-                        PurchaseEvaluationId = evaluation.Id,
+            evaluation.RejectedFromPhase = null;
-                        FromPhase = fromPhase,
+            evaluation.SlaDeadline = dateTime.UtcNow.AddDays(7);
-                        ToPhase = fromPhase,
+            await LogTransitionAsync(evaluation, fromPhase, PurchaseEvaluationPhase.ChoDuyet, actorUserId, decision, comment, ct);
-                        ApproverUserId = actorUid,
-                        Decision = ApprovalDecision.Approve,
-                        Comment = $"[Review NV] {comment ?? ""}",
-                        ApprovedAt = dateTime.UtcNow,
-                    });
-
-                    string? reviewerName = actor.FullName ?? actor.Email;
-                    db.PurchaseEvaluationChangelogs.Add(new PurchaseEvaluationChangelog
-                    {
-                        PurchaseEvaluationId = evaluation.Id,
-                        EntityType = PurchaseEvaluationEntityType.Workflow,
-                        Action = ChangelogAction.Transition,
-                        PhaseAtChange = fromPhase,
-                        UserId = actorUid,
-                        UserName = reviewerName ?? "Hệ thống",
-                        Summary = $"{reviewerName} (NV) đã review phase {fromPhase}, chờ TPB confirm",
-                        ContextNote = comment,
-                    });
-
-                    // Notify TPB cùng dept để confirm. Best effort — fail OK.
-                    try
-                    {
-                        var managers = await db.Users.AsNoTracking()
-                            .Where(u => u.DepartmentId == deptId && u.Id != actorUid && u.IsActive)
-                            .Select(u => u.Id)
-                            .ToListAsync(ct);
-                        if (managers.Count > 0)
-                        {
-                            foreach (var mgrId in managers)
-                            {
-                                var mgr = await userManager.FindByIdAsync(mgrId.ToString());
-                                if (mgr is null) continue;
-                                var roles = await userManager.GetRolesAsync(mgr);
-                                if (!roles.Contains(AppRoles.DeptManager)) continue;
-
-                                await notifications.NotifyAsync(
-                                    mgrId,
-                                    NotificationType.ContractPhaseTransition,
-                                    title: $"Phiếu {evaluation.MaPhieu ?? evaluation.TenGoiThau} chờ TPB confirm",
-                                    description: $"NV {reviewerName} đã review phase {fromPhase}. Vui lòng vào confirm để workflow tiếp tục.",
-                                    href: $"/purchase-evaluations/{evaluation.Id}",
-                                    refId: evaluation.Id,
-                                    ct: ct);
-                            }
-                        }
-                    }
-                    catch { /* notification fail non-critical */ }
-
             await db.SaveChangesAsync(ct);
             return;
         }
+
+        // ===== DRAFTER TRÌNH (DangSoanThao → ChoDuyet) =====
+        if (fromPhase == PurchaseEvaluationPhase.DangSoanThao
+            && (targetPhase == PurchaseEvaluationPhase.ChoDuyet || !isAdmin && !isSystem))
+        {
+            // Drafter/DeptManager only (or Admin bypass).
+            if (!isAdmin && !isSystem
+                && !actorRoles.Contains(AppRoles.Drafter)
+                && !actorRoles.Contains(AppRoles.DeptManager))
+            {
+                throw new ForbiddenException(
+                    $"Role ({string.Join(",", actorRoles)}) không đủ quyền trình duyệt phiếu.");
             }
+            evaluation.Phase = PurchaseEvaluationPhase.ChoDuyet;
+            evaluation.CurrentWorkflowStepIndex = 0;
+            evaluation.SlaDeadline = dateTime.UtcNow.AddDays(7);
+            await LogTransitionAsync(evaluation, fromPhase, PurchaseEvaluationPhase.ChoDuyet, actorUserId, decision, comment, ct);
+            await db.SaveChangesAsync(ct);
+            return;
         }
 
-        evaluation.SlaWarningSent = false;
+        // ===== APPROVE STEP (advance pointer trong ChoDuyet) =====
-        evaluation.Phase = targetPhase;
+        if (fromPhase == PurchaseEvaluationPhase.ChoDuyet && decision == ApprovalDecision.Approve)
+        {
+            var def = evaluation.WorkflowDefinitionId is Guid wfId
+                ? await db.PurchaseEvaluationWorkflowDefinitions.AsNoTracking()
+                    .Include(d => d.Steps.OrderBy(s => s.Order))
+                        .ThenInclude(s => s.Approvers)
+                    .FirstOrDefaultAsync(d => d.Id == wfId, ct)
+                : null;
 
-        var sla = policy.PhaseSla.GetValueOrDefault(targetPhase);
+            if (def == null || def.Steps.Count == 0)
-        evaluation.SlaDeadline = sla is null ? null : dateTime.UtcNow.Add(sla.Value);
+                throw new ConflictException("Phiếu chưa pin workflow definition hoặc workflow không có step.");
 
+            var steps = def.Steps.OrderBy(s => s.Order).ToList();
+            var currentIdx = evaluation.CurrentWorkflowStepIndex ?? 0;
+            if (currentIdx < 0 || currentIdx >= steps.Count)
+                throw new ConflictException($"CurrentWorkflowStepIndex={currentIdx} không hợp lệ (max={steps.Count - 1}).");
+
+            var currentStep = steps[currentIdx];
+
+            // Match approver — admin bypass policy
+            if (!isAdmin && !isSystem)
+            {
+                var actor = actorUserId is Guid uid ? await userManager.FindByIdAsync(uid.ToString()) : null;
+                if (actor == null)
+                    throw new ForbiddenException("Không xác định được approver.");
+
+                var matchByDeptLevel = currentStep.DepartmentId != null
+                    && currentStep.PositionLevel != null
+                    && actor.DepartmentId == currentStep.DepartmentId
+                    && actor.PositionLevel != null
+                    && (int)actor.PositionLevel >= (int)currentStep.PositionLevel;
+
+                var matchByExplicitUser = currentStep.Approvers.Any(a =>
+                    a.Kind == WorkflowApproverKind.User
+                    && Guid.TryParse(a.AssignmentValue, out var auid)
+                    && auid == actor.Id);
+
+                var matchByRole = currentStep.Approvers.Any(a =>
+                    a.Kind == WorkflowApproverKind.Role
+                    && actorRoles.Contains(a.AssignmentValue));
+
+                if (!matchByDeptLevel && !matchByExplicitUser && !matchByRole)
+                    throw new ForbiddenException(
+                        $"Step {currentIdx + 1} ({currentStep.Name}) yêu cầu phòng={currentStep.DepartmentId}, cấp={currentStep.PositionLevel}. Bạn không khớp.");
+            }
+
+            // Log approval row
             db.PurchaseEvaluationApprovals.Add(new PurchaseEvaluationApproval
             {
                 PurchaseEvaluationId = evaluation.Id,
                 FromPhase = fromPhase,
-            ToPhase = targetPhase,
+                ToPhase = fromPhase,    // step advance — phase same
                 ApproverUserId = actorUserId,
                 Decision = decision,
-            Comment = comment,
+                Comment = $"[Step {currentIdx + 1}] {comment ?? ""}",
                 ApprovedAt = dateTime.UtcNow,
             });
 
-        // Resolve actor name for changelog
+            // Advance pointer
+            var nextIdx = currentIdx + 1;
+            if (nextIdx >= steps.Count)
+            {
+                // All steps done — terminal DaDuyet
+                evaluation.Phase = PurchaseEvaluationPhase.DaDuyet;
+                evaluation.CurrentWorkflowStepIndex = null;
+                evaluation.SlaDeadline = null;
+                await LogTransitionAsync(evaluation, fromPhase, PurchaseEvaluationPhase.DaDuyet, actorUserId, decision, comment, ct);
+            }
+            else
+            {
+                evaluation.CurrentWorkflowStepIndex = nextIdx;
+                evaluation.SlaDeadline = dateTime.UtcNow.AddDays(7);
+                await LogTransitionAsync(evaluation, fromPhase, fromPhase, actorUserId, decision,
+                    $"Hoàn tất step {currentIdx + 1}/{steps.Count}, sang step {nextIdx + 1}", ct);
+            }
+            await db.SaveChangesAsync(ct);
+            return;
+        }
+
+        // Admin manual override (vd test cứng phase)
+        if (isAdmin)
+        {
+            evaluation.Phase = targetPhase;
+            evaluation.SlaDeadline = targetPhase == PurchaseEvaluationPhase.ChoDuyet
+                ? dateTime.UtcNow.AddDays(7) : null;
+            await LogTransitionAsync(evaluation, fromPhase, targetPhase, actorUserId, decision, comment, ct);
+            await db.SaveChangesAsync(ct);
+            return;
+        }
+
+        throw new ConflictException($"Transition {fromPhase} → {targetPhase} không hỗ trợ.");
+    }
+
+    private async Task LogTransitionAsync(
+        PurchaseEvaluation evaluation,
+        PurchaseEvaluationPhase fromPhase,
+        PurchaseEvaluationPhase toPhase,
+        Guid? actorUserId,
+        ApprovalDecision decision,
+        string? comment,
+        CancellationToken ct)
+    {
+        // Save Approval history (đã làm trong main flow — chỉ log Changelog ở đây)
         string? actorName = null;
         if (actorUserId is Guid uid)
         {
@@ -383,36 +214,34 @@ public class PurchaseEvaluationWorkflowService(
             PurchaseEvaluationId = evaluation.Id,
             EntityType = PurchaseEvaluationEntityType.Workflow,
             Action = ChangelogAction.Transition,
-            PhaseAtChange = targetPhase,
+            PhaseAtChange = toPhase,
             UserId = actorUserId,
             UserName = actorName ?? "Hệ thống",
-            Summary = $"Chuyển phase {fromPhase} → {targetPhase}",
+            Summary = $"Chuyển phase {fromPhase} → {toPhase}",
             ContextNote = comment,
         });
 
-        // Notify drafter
+        // Notify drafter on terminal states
         if (evaluation.DrafterUserId is Guid drafterId && drafterId != actorUserId)
         {
-            var title = targetPhase switch
+            var (title, type) = toPhase switch
             {
-                PurchaseEvaluationPhase.DaDuyet => $"Phiếu {evaluation.MaPhieu ?? evaluation.TenGoiThau} đã duyệt",
+                PurchaseEvaluationPhase.DaDuyet => ($"Phiếu {evaluation.MaPhieu ?? evaluation.TenGoiThau} đã duyệt",
-                PurchaseEvaluationPhase.TuChoi => $"Phiếu {evaluation.TenGoiThau} bị từ chối",
+                                                    NotificationType.ContractPublished),
-                _ => $"Phiếu {evaluation.TenGoiThau} chuyển phase mới",
+                PurchaseEvaluationPhase.TuChoi => ($"Phiếu {evaluation.TenGoiThau} bị từ chối",
-            };
+                                                    NotificationType.ContractRejected),
-            var type = targetPhase switch
+                PurchaseEvaluationPhase.DangSoanThao when fromPhase == PurchaseEvaluationPhase.ChoDuyet =>
-            {
+                    ($"Phiếu {evaluation.TenGoiThau} bị trả lại — vui lòng sửa và trình lại",
-                PurchaseEvaluationPhase.DaDuyet => NotificationType.ContractPublished,
+                     NotificationType.ContractRejected),
-                PurchaseEvaluationPhase.TuChoi => NotificationType.ContractRejected,
+                _ => ($"Phiếu {evaluation.TenGoiThau} chuyển phase mới",
-                _ => NotificationType.ContractPhaseTransition,
+                      NotificationType.ContractPhaseTransition),
             };
             await notifications.NotifyAsync(
                 drafterId, type, title,
-                description: $"{fromPhase} → {targetPhase}" + (string.IsNullOrWhiteSpace(comment) ? "" : $" · {comment}"),
+                description: $"{fromPhase} → {toPhase}" + (string.IsNullOrWhiteSpace(comment) ? "" : $" · {comment}"),
                 href: $"/purchase-evaluations/{evaluation.Id}",
                 refId: evaluation.Id,
                 ct: ct);
         }
-
-        await db.SaveChangesAsync(ct);
     }
 }

tests/SolutionErp.Infrastructure.Tests/Application/PeWorkflowAdminTests.cs

@@ -23,12 +23,14 @@ public class CreatePeWorkflowDefinitionCommandHandlerTests
             Description: null,
             Steps: new List<CreatePeWorkflowStepInput>
             {
-                new(Order: 1, Phase: (int)PurchaseEvaluationPhase.DangSoanThao, Name: "Soạn", SlaDays: 3,
+                new(Order: 1, Phase: (int)PurchaseEvaluationPhase.ChoDuyet, Name: "Soạn",
+                    SlaDays: 3, DepartmentId: null, PositionLevel: null,
                     Approvers: new List<CreatePeWorkflowStepApproverInput>
                     {
                         new(Kind: (int)WorkflowApproverKind.Role, AssignmentValue: AppRoles.Drafter),
                     }),
-                new(Order: 2, Phase: (int)PurchaseEvaluationPhase.ChoCCM, Name: "CCM duyệt", SlaDays: 2,
+                new(Order: 2, Phase: (int)PurchaseEvaluationPhase.ChoDuyet, Name: "CCM duyệt",
+                    SlaDays: 2, DepartmentId: null, PositionLevel: null,
                     Approvers: new List<CreatePeWorkflowStepApproverInput>
                     {
                         new(Kind: (int)WorkflowApproverKind.Role, AssignmentValue: AppRoles.CostControl),
@@ -110,10 +112,10 @@ public class CreatePeWorkflowDefinitionCommandHandlerTests
 
         steps.Should().HaveCount(2);
         steps[0].Order.Should().Be(1);
-        steps[0].Phase.Should().Be(PurchaseEvaluationPhase.DangSoanThao);
+        steps[0].Phase.Should().Be(PurchaseEvaluationPhase.ChoDuyet);
         steps[0].Name.Should().Be("Soạn");
         steps[1].Order.Should().Be(2);
-        steps[1].Phase.Should().Be(PurchaseEvaluationPhase.ChoCCM);
+        steps[1].Phase.Should().Be(PurchaseEvaluationPhase.ChoDuyet);
     }
 
     [Fact]

tests/SolutionErp.Infrastructure.Tests/Services/ContractNStageApprovalTests.cs

@@ -1,350 +0,0 @@
-using Microsoft.AspNetCore.Identity;
-using Microsoft.EntityFrameworkCore;
-using Microsoft.Extensions.DependencyInjection;
-using SolutionErp.Application.Common.Exceptions;
-using SolutionErp.Application.Common.Interfaces;
-using SolutionErp.Application.Contracts.Services;
-using SolutionErp.Application.Notifications;
-using SolutionErp.Domain.Common;
-using SolutionErp.Domain.Contracts;
-using SolutionErp.Domain.Identity;
-using SolutionErp.Domain.Notifications;
-using SolutionErp.Infrastructure.Services;
-using SolutionErp.Infrastructure.Tests.Common;
-
-namespace SolutionErp.Infrastructure.Tests.Services;
-
-// Tests cho N-stage department approval logic ở ContractWorkflowService (Mig 20).
-// Mirror PeNStageApprovalTests pattern. Cover Phòng × PositionLevel sequential
-// trong cùng phase + bypass cùng dept + reject reset + legacy fallback.
-public class ContractNStageApprovalTests : IClassFixture<IdentityFixture>
-{
-    private readonly IdentityFixture _fx;
-    private readonly TestApplicationDbContext _db;
-    private readonly UserManager<User> _userManager;
-    private readonly ContractWorkflowService _service;
-    private readonly Guid _deptPro;
-    private readonly Guid _deptCcm;
-
-    public ContractNStageApprovalTests(IdentityFixture fx)
-    {
-        _fx = fx;
-        _db = fx.Services.GetRequiredService<TestApplicationDbContext>();
-        _userManager = fx.Services.GetRequiredService<UserManager<User>>();
-
-        _deptPro = SeedDept("PRO-CTR-NS", "Phòng Cung ứng (CTR-NS)");
-        _deptCcm = SeedDept("CCM-CTR-NS", "Phòng Kiểm soát (CTR-NS)");
-
-        var clock = new FixedDateTime(new DateTime(2026, 5, 7, 11, 0, 0, DateTimeKind.Utc));
-        var fakeNotifications = new FakeNotificationService();
-        var fakeChangelog = new FakeChangelogService();
-        var fakeCodeGen = new FakeContractCodeGenerator();
-
-        _service = new ContractWorkflowService(
-            _db, fakeCodeGen, clock, fakeNotifications, fakeChangelog, _userManager);
-    }
-
-    private Guid SeedDept(string code, string name)
-    {
-        var existing = _db.Departments.FirstOrDefault(d => d.Code == code);
-        if (existing is not null) return existing.Id;
-        var d = new SolutionErp.Domain.Master.Department { Id = Guid.NewGuid(), Code = code, Name = name };
-        _db.Departments.Add(d);
-        _db.SaveChanges();
-        return d.Id;
-    }
-
-    private async Task<Guid> SeedWorkflowDefinitionAsync(
-        params (Guid deptId, PositionLevel level)[] innerSteps)
-    {
-        // 2 step adjacent: DangGopY (current, có inner steps) → DangDamPhan (next).
-        // FromDefinition build transition (DangGopY → DangDamPhan) từ step[1].Approvers role.
-        var def = new WorkflowDefinition
-        {
-            Id = Guid.NewGuid(),
-            Code = $"NS-CTR-{Guid.NewGuid():N}".Substring(0, 18),
-            Version = 1,
-            ContractType = ContractType.HopDongThauPhu,
-            Name = "N-stage Contract test workflow",
-            IsActive = true,
-            ActivatedAt = DateTime.UtcNow,
-        };
-        var step1 = new WorkflowStep
-        {
-            Id = Guid.NewGuid(),
-            Order = 1,
-            Phase = ContractPhase.DangGopY,
-            Name = "Góp ý",
-            Approvers =
-            {
-                new WorkflowStepApprover
-                {
-                    Kind = WorkflowApproverKind.Role,
-                    AssignmentValue = "Procurement",
-                },
-            },
-        };
-        for (int i = 0; i < innerSteps.Length; i++)
-        {
-            step1.InnerSteps.Add(new WorkflowStepInnerStep
-            {
-                Id = Guid.NewGuid(),
-                Order = i + 1,
-                DepartmentId = innerSteps[i].deptId,
-                PositionLevel = innerSteps[i].level,
-                IsRequired = true,
-            });
-        }
-        def.Steps.Add(step1);
-        // Step 2 — chỉ để FromDefinition build transition (DangGopY → DangDamPhan).
-        def.Steps.Add(new WorkflowStep
-        {
-            Id = Guid.NewGuid(),
-            Order = 2,
-            Phase = ContractPhase.DangDamPhan,
-            Name = "Đàm phán",
-            Approvers =
-            {
-                new WorkflowStepApprover
-                {
-                    Kind = WorkflowApproverKind.Role,
-                    AssignmentValue = "Procurement",
-                },
-            },
-        });
-        _db.WorkflowDefinitions.Add(def);
-        await _db.SaveChangesAsync();
-        return def.Id;
-    }
-
-    private async Task<Contract> SeedContractAsync(
-        ContractPhase phase,
-        Guid? workflowDefinitionId = null)
-    {
-        var pid = Guid.NewGuid();
-        if (!_db.Projects.Any(p => p.Id == pid))
-        {
-            _db.Projects.Add(new SolutionErp.Domain.Master.Project
-            {
-                Id = pid,
-                Code = $"PRJ-CTR-{Random.Shared.Next(10000):D4}",
-                Name = "Test project CTR-NS",
-            });
-        }
-        var sid = Guid.NewGuid();
-        if (!_db.Suppliers.Any(s => s.Id == sid))
-        {
-            _db.Suppliers.Add(new SolutionErp.Domain.Master.Supplier
-            {
-                Id = sid,
-                Code = $"NCC-{Random.Shared.Next(10000):D4}",
-                Name = "Test supplier",
-                Type = SolutionErp.Domain.Master.SupplierType.NhaCungCap,
-            });
-        }
-
-        var contract = new Contract
-        {
-            Id = Guid.NewGuid(),
-            Type = ContractType.HopDongThauPhu,
-            Phase = phase,
-            TenHopDong = "Test HĐ N-stage",
-            ProjectId = pid,
-            SupplierId = sid,
-            WorkflowDefinitionId = workflowDefinitionId,
-        };
-        _db.Contracts.Add(contract);
-        await _db.SaveChangesAsync();
-        return contract;
-    }
-
-    [Fact]
-    public async Task NStage_FirstInner_NV_Approve_Blocks_Phase_Transition()
-    {
-        var defId = await SeedWorkflowDefinitionAsync(
-            (_deptPro, PositionLevel.NhanVien),
-            (_deptPro, PositionLevel.PhoPhong),
-            (_deptPro, PositionLevel.TruongPhong));
-        var contract = await SeedContractAsync(ContractPhase.DangGopY, defId);
-
-        var nv = await _fx.CreateUserAsync(
-            $"nv-pro-ctr-{Guid.NewGuid():N}@test", "NV PRO Contract",
-            _deptPro, ["Procurement"], positionLevel: PositionLevel.NhanVien);
-
-        await _service.TransitionAsync(
-            contract, ContractPhase.DangDamPhan, nv.Id, ["Procurement"],
-            ApprovalDecision.Approve, "duyệt NV");
-
-        var fresh = await _db.Contracts.AsNoTracking().FirstAsync(x => x.Id == contract.Id);
-        fresh.Phase.Should().Be(ContractPhase.DangGopY);
-
-        var rows = await _db.ContractDepartmentApprovals.AsNoTracking()
-            .Where(a => a.ContractId == contract.Id).ToListAsync();
-        rows.Should().HaveCount(1);
-        rows[0].InnerStepId.Should().NotBeNull();
-        rows[0].IsBypassed.Should().BeFalse();
-        rows[0].ApproverRoleSnapshot.Should().Contain("NhanVien");
-    }
-
-    [Fact]
-    public async Task NStage_All_3_Levels_Sequential_Pass_Allow_Phase_Transition()
-    {
-        var defId = await SeedWorkflowDefinitionAsync(
-            (_deptPro, PositionLevel.NhanVien),
-            (_deptPro, PositionLevel.PhoPhong),
-            (_deptPro, PositionLevel.TruongPhong));
-        var contract = await SeedContractAsync(ContractPhase.DangGopY, defId);
-
-        var nv = await _fx.CreateUserAsync($"nv-{Guid.NewGuid():N}@test", "NV", _deptPro, ["Procurement"], positionLevel: PositionLevel.NhanVien);
-        var pp = await _fx.CreateUserAsync($"pp-{Guid.NewGuid():N}@test", "PP", _deptPro, ["Procurement"], positionLevel: PositionLevel.PhoPhong);
-        var tp = await _fx.CreateUserAsync($"tp-{Guid.NewGuid():N}@test", "TP", _deptPro, ["Procurement"], positionLevel: PositionLevel.TruongPhong);
-
-        await _service.TransitionAsync(contract, ContractPhase.DangDamPhan, nv.Id, ["Procurement"], ApprovalDecision.Approve, "NV");
-        contract = await _db.Contracts.FirstAsync(x => x.Id == contract.Id);
-        await _service.TransitionAsync(contract, ContractPhase.DangDamPhan, pp.Id, ["Procurement"], ApprovalDecision.Approve, "PP");
-        contract = await _db.Contracts.FirstAsync(x => x.Id == contract.Id);
-        await _service.TransitionAsync(contract, ContractPhase.DangDamPhan, tp.Id, ["Procurement"], ApprovalDecision.Approve, "TP");
-
-        var fresh = await _db.Contracts.AsNoTracking().FirstAsync(x => x.Id == contract.Id);
-        fresh.Phase.Should().Be(ContractPhase.DangDamPhan);
-
-        var rows = await _db.ContractDepartmentApprovals.AsNoTracking()
-            .Where(a => a.ContractId == contract.Id && a.InnerStepId != null).ToListAsync();
-        rows.Should().HaveCount(3);
-        rows.All(r => !r.IsBypassed).Should().BeTrue();
-    }
-
-    [Fact]
-    public async Task NStage_TP_Bypass_Skips_Lower_Levels_Same_Dept()
-    {
-        var defId = await SeedWorkflowDefinitionAsync(
-            (_deptPro, PositionLevel.NhanVien),
-            (_deptPro, PositionLevel.PhoPhong),
-            (_deptPro, PositionLevel.TruongPhong));
-        var contract = await SeedContractAsync(ContractPhase.DangGopY, defId);
-
-        var tp = await _fx.CreateUserAsync(
-            $"tp-bypass-{Guid.NewGuid():N}@test", "TP bypass",
-            _deptPro, ["Procurement"],
-            canBypassReview: true, positionLevel: PositionLevel.TruongPhong);
-
-        await _service.TransitionAsync(
-            contract, ContractPhase.DangDamPhan, tp.Id, ["Procurement"],
-            ApprovalDecision.Approve, "TP bypass");
-
-        var fresh = await _db.Contracts.AsNoTracking().FirstAsync(x => x.Id == contract.Id);
-        fresh.Phase.Should().Be(ContractPhase.DangDamPhan);
-
-        var rows = await _db.ContractDepartmentApprovals.AsNoTracking()
-            .Where(a => a.ContractId == contract.Id && a.InnerStepId != null)
-            .ToListAsync();
-        rows.Should().HaveCount(3);
-        rows.Count(r => r.IsBypassed).Should().Be(2);
-        rows.Count(r => !r.IsBypassed).Should().Be(1);
-    }
-
-    [Fact]
-    public async Task NStage_Wrong_Department_Throws_Forbidden()
-    {
-        var defId = await SeedWorkflowDefinitionAsync(
-            (_deptPro, PositionLevel.NhanVien));
-        var contract = await SeedContractAsync(ContractPhase.DangGopY, defId);
-
-        var ccmActor = await _fx.CreateUserAsync(
-            $"ccm-wrong-{Guid.NewGuid():N}@test", "CCM wrong",
-            _deptCcm, ["Procurement"], positionLevel: PositionLevel.NhanVien);
-
-        var act = async () => await _service.TransitionAsync(
-            contract, ContractPhase.DangDamPhan, ccmActor.Id, ["Procurement"],
-            ApprovalDecision.Approve, "wrong dept");
-        await act.Should().ThrowAsync<ForbiddenException>();
-    }
-
-    [Fact]
-    public async Task NStage_Reject_Clears_InnerStep_Rows_At_Phase()
-    {
-        var defId = await SeedWorkflowDefinitionAsync(
-            (_deptPro, PositionLevel.NhanVien),
-            (_deptPro, PositionLevel.PhoPhong));
-        var contract = await SeedContractAsync(ContractPhase.DangGopY, defId);
-
-        var nv = await _fx.CreateUserAsync($"nv-rej-{Guid.NewGuid():N}@test", "NV", _deptPro, ["Procurement"], positionLevel: PositionLevel.NhanVien);
-        await _service.TransitionAsync(contract, ContractPhase.DangDamPhan, nv.Id, ["Procurement"], ApprovalDecision.Approve, "NV");
-
-        var rowsBefore = await _db.ContractDepartmentApprovals.AsNoTracking()
-            .Where(a => a.ContractId == contract.Id && a.InnerStepId != null).CountAsync();
-        rowsBefore.Should().Be(1);
-
-        contract = await _db.Contracts.FirstAsync(x => x.Id == contract.Id);
-
-        // Admin reject (skip dept block guard).
-        var admin = await _fx.CreateUserAsync($"adm-rej-{Guid.NewGuid():N}@test", "Admin", null, ["Admin"]);
-        await _service.TransitionAsync(
-            contract, ContractPhase.TuChoi, admin.Id, ["Admin"],
-            ApprovalDecision.Reject, "reject test");
-
-        var fresh = await _db.Contracts.AsNoTracking().FirstAsync(x => x.Id == contract.Id);
-        fresh.Phase.Should().Be(ContractPhase.DangSoanThao);
-        fresh.RejectedFromPhase.Should().Be(ContractPhase.DangGopY);
-
-        var rowsAfter = await _db.ContractDepartmentApprovals.AsNoTracking()
-            .Where(a => a.ContractId == contract.Id && a.InnerStepId != null).CountAsync();
-        rowsAfter.Should().Be(0);
-    }
-
-    [Fact]
-    public async Task LegacyFallback_NoInnerSteps_Uses_2Stage_Logic()
-    {
-        // Không pin WorkflowDefinitionId → service fallback hardcoded Standard
-        // policy → no inner steps → legacy 2-stage logic kick in.
-        // Phase pair DangKiemTraCCM → DangTrinhKy yêu cầu role CostControl
-        // (Standard.Transitions). NV.CCM (role CostControl, KHÔNG DeptManager)
-        // → Stage=Review block.
-        var contract = await SeedContractAsync(ContractPhase.DangKiemTraCCM, workflowDefinitionId: null);
-
-        var nv = await _fx.CreateUserAsync(
-            $"nv-legacy-ctr-{Guid.NewGuid():N}@test", "NV legacy CTR",
-            _deptCcm, ["CostControl"]);
-
-        await _service.TransitionAsync(
-            contract, ContractPhase.DangTrinhKy, nv.Id, ["CostControl"],
-            ApprovalDecision.Approve, "legacy review");
-
-        var fresh = await _db.Contracts.AsNoTracking().FirstAsync(x => x.Id == contract.Id);
-        fresh.Phase.Should().Be(ContractPhase.DangKiemTraCCM);
-
-        var rows = await _db.ContractDepartmentApprovals.AsNoTracking()
-            .Where(a => a.ContractId == contract.Id).ToListAsync();
-        rows.Should().HaveCount(1);
-        rows[0].InnerStepId.Should().BeNull();
-        rows[0].Stage.Should().Be(ApprovalStage.Review);
-    }
-}
-
-// Stub services — Contract workflow tests không cần verify changelog/codegen
-// (best effort try/catch ở service đã cover fail case).
-internal class FakeChangelogService : IChangelogService
-{
-    public Task LogContractChangeAsync(Guid contractId, ChangelogAction action,
-        string? summary = null, string? fieldChangesJson = null, string? contextNote = null,
-        ContractPhase? phaseAtChange = null, CancellationToken ct = default) => Task.CompletedTask;
-
-    public Task LogDetailChangeAsync(Guid contractId, Guid detailId, ChangelogAction action,
-        string? summary = null, string? fieldChangesJson = null,
-        ContractPhase? phaseAtChange = null, CancellationToken ct = default) => Task.CompletedTask;
-
-    public Task LogWorkflowTransitionAsync(Guid contractId, ContractPhase fromPhase,
-        ContractPhase toPhase, string? comment, CancellationToken ct = default) => Task.CompletedTask;
-
-    public Task LogCommentAddedAsync(Guid contractId, string content, ContractPhase phase,
-        CancellationToken ct = default) => Task.CompletedTask;
-
-    public Task LogAttachmentAsync(Guid contractId, Guid attachmentId, ChangelogAction action,
-        string fileName, ContractPhase phase, CancellationToken ct = default) => Task.CompletedTask;
-}
-
-internal class FakeContractCodeGenerator : IContractCodeGenerator
-{
-    public Task<string> GenerateAsync(Contract contract, string projectCode, string supplierCode,
-        CancellationToken ct = default) => Task.FromResult($"FAKE-{projectCode}-{supplierCode}-001");
-}

tests/SolutionErp.Infrastructure.Tests/Services/PeNStageApprovalTests.cs

@@ -1,324 +0,0 @@
-using Microsoft.AspNetCore.Identity;
-using Microsoft.EntityFrameworkCore;
-using Microsoft.Extensions.DependencyInjection;
-using SolutionErp.Application.Common.Exceptions;
-using SolutionErp.Domain.Common;
-using SolutionErp.Domain.Contracts;
-using SolutionErp.Domain.Identity;
-using SolutionErp.Domain.PurchaseEvaluations;
-using SolutionErp.Infrastructure.Services;
-using SolutionErp.Infrastructure.Tests.Common;
-
-namespace SolutionErp.Infrastructure.Tests.Services;
-
-// Tests cho N-stage department approval logic (Mig 18) ở
-// PurchaseEvaluationWorkflowService. Cover chuỗi inner step Order asc theo
-// Department × PositionLevel. Bypass cùng dept (TP có CanBypassReview).
-//
-// Pattern: dùng IdentityFixture + seed WorkflowDefinition pinned to PE.
-// Reuse FakeNotificationService + FixedDateTime từ PeTwoStageApprovalTests.cs.
-public class PeNStageApprovalTests : IClassFixture<IdentityFixture>
-{
-    private readonly IdentityFixture _fx;
-    private readonly TestApplicationDbContext _db;
-    private readonly UserManager<User> _userManager;
-    private readonly PurchaseEvaluationWorkflowService _service;
-    private readonly Guid _deptPro;
-    private readonly Guid _deptCcm;
-
-    public PeNStageApprovalTests(IdentityFixture fx)
-    {
-        _fx = fx;
-        _db = fx.Services.GetRequiredService<TestApplicationDbContext>();
-        _userManager = fx.Services.GetRequiredService<UserManager<User>>();
-
-        _deptPro = SeedDept("PRO-NS", "Phòng Cung ứng (NS)");
-        _deptCcm = SeedDept("CCM-NS", "Phòng Kiểm soát (NS)");
-
-        var clock = new FixedDateTime(new DateTime(2026, 5, 7, 10, 0, 0, DateTimeKind.Utc));
-        var fakeNotifications = new FakeNotificationService();
-
-        _service = new PurchaseEvaluationWorkflowService(
-            _db, clock, fakeNotifications, _userManager);
-    }
-
-    private Guid SeedDept(string code, string name)
-    {
-        var existing = _db.Departments.FirstOrDefault(d => d.Code == code);
-        if (existing is not null) return existing.Id;
-        var d = new SolutionErp.Domain.Master.Department { Id = Guid.NewGuid(), Code = code, Name = name };
-        _db.Departments.Add(d);
-        _db.SaveChanges();
-        return d.Id;
-    }
-
-    private async Task<Guid> SeedWorkflowDefinitionAsync(
-        params (Guid deptId, PositionLevel level)[] innerSteps)
-    {
-        // 2 step adjacent: ChoPurchasing (current, có inner steps) → ChoCCM (next).
-        // FromDefinition build transition (ChoPurchasing → ChoCCM) từ step[1].Approvers role.
-        var def = new PurchaseEvaluationWorkflowDefinition
-        {
-            Id = Guid.NewGuid(),
-            Code = $"NS-TEST-{Guid.NewGuid():N}".Substring(0, 20),
-            Version = 1,
-            EvaluationType = PurchaseEvaluationType.DuyetNcc,
-            Name = "N-stage test workflow",
-            IsActive = true,
-            ActivatedAt = DateTime.UtcNow,
-        };
-        var step1 = new PurchaseEvaluationWorkflowStep
-        {
-            Id = Guid.NewGuid(),
-            Order = 1,
-            Phase = PurchaseEvaluationPhase.ChoPurchasing,
-            Name = "Duyệt Purchasing",
-            Approvers =
-            {
-                new PurchaseEvaluationWorkflowStepApprover
-                {
-                    Kind = WorkflowApproverKind.Role,
-                    AssignmentValue = "Procurement",
-                },
-            },
-        };
-        for (int i = 0; i < innerSteps.Length; i++)
-        {
-            step1.InnerSteps.Add(new PurchaseEvaluationWorkflowStepInnerStep
-            {
-                Id = Guid.NewGuid(),
-                Order = i + 1,
-                DepartmentId = innerSteps[i].deptId,
-                PositionLevel = innerSteps[i].level,
-                IsRequired = true,
-            });
-        }
-        def.Steps.Add(step1);
-        // Step 2 — chỉ để FromDefinition build transition (ChoPurchasing → ChoCCM).
-        // KHÔNG có inner steps → nếu PE chuyển tiếp tới phase này, sẽ fallback legacy
-        // hoặc admin bypass (test scope chỉ chuyển tới đây 1 lần).
-        def.Steps.Add(new PurchaseEvaluationWorkflowStep
-        {
-            Id = Guid.NewGuid(),
-            Order = 2,
-            Phase = PurchaseEvaluationPhase.ChoCCM,
-            Name = "Duyệt CCM",
-            Approvers =
-            {
-                new PurchaseEvaluationWorkflowStepApprover
-                {
-                    Kind = WorkflowApproverKind.Role,
-                    AssignmentValue = "Procurement",   // mirror step 1 để policy guard accept actor cùng role
-                },
-            },
-        });
-        _db.PurchaseEvaluationWorkflowDefinitions.Add(def);
-        await _db.SaveChangesAsync();
-        return def.Id;
-    }
-
-    private async Task<PurchaseEvaluation> SeedPeAsync(
-        PurchaseEvaluationPhase phase,
-        Guid? workflowDefinitionId = null,
-        Guid? projectId = null)
-    {
-        var pid = projectId ?? Guid.NewGuid();
-        if (!_db.Projects.Any(p => p.Id == pid))
-        {
-            _db.Projects.Add(new SolutionErp.Domain.Master.Project
-            {
-                Id = pid,
-                Code = $"PRJ-NS-{Random.Shared.Next(10000):D4}",
-                Name = "Test project NS",
-            });
-        }
-
-        var pe = new PurchaseEvaluation
-        {
-            Id = Guid.NewGuid(),
-            Type = PurchaseEvaluationType.DuyetNcc,
-            Phase = phase,
-            TenGoiThau = "Test gói thầu NS",
-            ProjectId = pid,
-            WorkflowDefinitionId = workflowDefinitionId,
-        };
-        _db.PurchaseEvaluations.Add(pe);
-        await _db.SaveChangesAsync();
-        return pe;
-    }
-
-    [Fact]
-    public async Task NStage_FirstInner_NV_Approve_Blocks_Phase_Transition()
-    {
-        // Arrange: 1 dept (PRO) × 3 cấp.
-        var defId = await SeedWorkflowDefinitionAsync(
-            (_deptPro, PositionLevel.NhanVien),
-            (_deptPro, PositionLevel.PhoPhong),
-            (_deptPro, PositionLevel.TruongPhong));
-        var pe = await SeedPeAsync(PurchaseEvaluationPhase.ChoPurchasing, defId);
-
-        var nv = await _fx.CreateUserAsync(
-            $"nv-pro-ns-{Guid.NewGuid():N}@test", "NV PRO NS",
-            _deptPro, ["Procurement"], positionLevel: PositionLevel.NhanVien);
-
-        // Act: NV.PRO duyệt cấp 1 (NV).
-        await _service.TransitionAsync(
-            pe, PurchaseEvaluationPhase.ChoCCM, nv.Id, ["Procurement"],
-            ApprovalDecision.Approve, "duyệt NV");
-
-        // Assert: phase chưa đổi (còn 2 cấp PP+TP), 1 row InnerStepId set.
-        var fresh = await _db.PurchaseEvaluations.AsNoTracking().FirstAsync(x => x.Id == pe.Id);
-        fresh.Phase.Should().Be(PurchaseEvaluationPhase.ChoPurchasing);
-
-        var rows = await _db.PurchaseEvaluationDepartmentApprovals.AsNoTracking()
-            .Where(a => a.PurchaseEvaluationId == pe.Id).ToListAsync();
-        rows.Should().HaveCount(1);
-        rows[0].InnerStepId.Should().NotBeNull();
-        rows[0].IsBypassed.Should().BeFalse();
-        rows[0].ApproverRoleSnapshot.Should().Contain("NhanVien");
-    }
-
-    [Fact]
-    public async Task NStage_All_3_Levels_Sequential_Pass_Allow_Phase_Transition()
-    {
-        // Arrange: 1 dept × 3 cấp.
-        var defId = await SeedWorkflowDefinitionAsync(
-            (_deptPro, PositionLevel.NhanVien),
-            (_deptPro, PositionLevel.PhoPhong),
-            (_deptPro, PositionLevel.TruongPhong));
-        var pe = await SeedPeAsync(PurchaseEvaluationPhase.ChoPurchasing, defId);
-
-        var nv = await _fx.CreateUserAsync($"nv-{Guid.NewGuid():N}@test", "NV", _deptPro, ["Procurement"], positionLevel: PositionLevel.NhanVien);
-        var pp = await _fx.CreateUserAsync($"pp-{Guid.NewGuid():N}@test", "PP", _deptPro, ["Procurement"], positionLevel: PositionLevel.PhoPhong);
-        var tp = await _fx.CreateUserAsync($"tp-{Guid.NewGuid():N}@test", "TP", _deptPro, ["Procurement"], positionLevel: PositionLevel.TruongPhong);
-
-        // Act: lần lượt NV → PP → TP.
-        await _service.TransitionAsync(pe, PurchaseEvaluationPhase.ChoCCM, nv.Id, ["Procurement"], ApprovalDecision.Approve, "NV");
-        pe = await _db.PurchaseEvaluations.FirstAsync(x => x.Id == pe.Id);
-        await _service.TransitionAsync(pe, PurchaseEvaluationPhase.ChoCCM, pp.Id, ["Procurement"], ApprovalDecision.Approve, "PP");
-        pe = await _db.PurchaseEvaluations.FirstAsync(x => x.Id == pe.Id);
-        await _service.TransitionAsync(pe, PurchaseEvaluationPhase.ChoCCM, tp.Id, ["Procurement"], ApprovalDecision.Approve, "TP");
-
-        // Assert: phase chuyển + 3 rows + KHÔNG bypass.
-        var fresh = await _db.PurchaseEvaluations.AsNoTracking().FirstAsync(x => x.Id == pe.Id);
-        fresh.Phase.Should().Be(PurchaseEvaluationPhase.ChoCCM);
-
-        var rows = await _db.PurchaseEvaluationDepartmentApprovals.AsNoTracking()
-            .Where(a => a.PurchaseEvaluationId == pe.Id && a.InnerStepId != null).ToListAsync();
-        rows.Should().HaveCount(3);
-        rows.All(r => !r.IsBypassed).Should().BeTrue();
-    }
-
-    [Fact]
-    public async Task NStage_TP_Bypass_Skips_Lower_Levels_Same_Dept()
-    {
-        // Arrange: 1 dept × 3 cấp. TP có CanBypassReview=true.
-        var defId = await SeedWorkflowDefinitionAsync(
-            (_deptPro, PositionLevel.NhanVien),
-            (_deptPro, PositionLevel.PhoPhong),
-            (_deptPro, PositionLevel.TruongPhong));
-        var pe = await SeedPeAsync(PurchaseEvaluationPhase.ChoPurchasing, defId);
-
-        var tp = await _fx.CreateUserAsync(
-            $"tp-bypass-{Guid.NewGuid():N}@test", "TP bypass",
-            _deptPro, ["Procurement"],
-            canBypassReview: true, positionLevel: PositionLevel.TruongPhong);
-
-        // Act: TP bypass approve trực tiếp (skip NV+PP cùng dept).
-        await _service.TransitionAsync(
-            pe, PurchaseEvaluationPhase.ChoCCM, tp.Id, ["Procurement"],
-            ApprovalDecision.Approve, "TP bypass");
-
-        // Assert: phase chuyển, 3 rows (NV+PP=bypass true, TP=bypass false).
-        var fresh = await _db.PurchaseEvaluations.AsNoTracking().FirstAsync(x => x.Id == pe.Id);
-        fresh.Phase.Should().Be(PurchaseEvaluationPhase.ChoCCM);
-
-        var rows = await _db.PurchaseEvaluationDepartmentApprovals.AsNoTracking()
-            .Where(a => a.PurchaseEvaluationId == pe.Id && a.InnerStepId != null)
-            .ToListAsync();
-        rows.Should().HaveCount(3);
-        rows.Count(r => r.IsBypassed).Should().Be(2);     // NV + PP bypassed
-        rows.Count(r => !r.IsBypassed).Should().Be(1);    // TP exact match
-    }
-
-    [Fact]
-    public async Task NStage_Wrong_Department_Throws_Forbidden()
-    {
-        // Arrange: inner step yêu cầu dept PRO. Actor thuộc CCM.
-        var defId = await SeedWorkflowDefinitionAsync(
-            (_deptPro, PositionLevel.NhanVien));
-        var pe = await SeedPeAsync(PurchaseEvaluationPhase.ChoPurchasing, defId);
-
-        var ccmActor = await _fx.CreateUserAsync(
-            $"ccm-wrong-{Guid.NewGuid():N}@test", "CCM wrong",
-            _deptCcm, ["Procurement"], positionLevel: PositionLevel.NhanVien);
-
-        // Act + Assert.
-        var act = async () => await _service.TransitionAsync(
-            pe, PurchaseEvaluationPhase.ChoCCM, ccmActor.Id, ["Procurement"],
-            ApprovalDecision.Approve, "wrong dept");
-        await act.Should().ThrowAsync<ForbiddenException>();
-    }
-
-    [Fact]
-    public async Task NStage_Reject_Clears_InnerStep_Rows_At_Phase()
-    {
-        // Arrange: NV approve trước → 1 row N-stage. Sau đó reject.
-        var defId = await SeedWorkflowDefinitionAsync(
-            (_deptPro, PositionLevel.NhanVien),
-            (_deptPro, PositionLevel.PhoPhong));
-        var pe = await SeedPeAsync(PurchaseEvaluationPhase.ChoPurchasing, defId);
-
-        var nv = await _fx.CreateUserAsync($"nv-rej-{Guid.NewGuid():N}@test", "NV", _deptPro, ["Procurement"], positionLevel: PositionLevel.NhanVien);
-        await _service.TransitionAsync(pe, PurchaseEvaluationPhase.ChoCCM, nv.Id, ["Procurement"], ApprovalDecision.Approve, "NV");
-
-        var rowsBeforeReject = await _db.PurchaseEvaluationDepartmentApprovals.AsNoTracking()
-            .Where(a => a.PurchaseEvaluationId == pe.Id && a.InnerStepId != null).CountAsync();
-        rowsBeforeReject.Should().Be(1);
-
-        pe = await _db.PurchaseEvaluations.FirstAsync(x => x.Id == pe.Id);
-
-        // Act: admin "Trả lại" (target=DangSoanThao + decision=Reject Session 14).
-        var admin = await _fx.CreateUserAsync($"adm-rej-{Guid.NewGuid():N}@test", "Admin", null, ["Admin"]);
-        await _service.TransitionAsync(
-            pe, PurchaseEvaluationPhase.DangSoanThao, admin.Id, ["Admin"],
-            ApprovalDecision.Reject, "trả lại test");
-
-        // Assert: phase = DangSoanThao, RejectedFromPhase = ChoPurchasing,
-        // N-stage rows tại ChoPurchasing đã clear.
-        var fresh = await _db.PurchaseEvaluations.AsNoTracking().FirstAsync(x => x.Id == pe.Id);
-        fresh.Phase.Should().Be(PurchaseEvaluationPhase.DangSoanThao);
-        fresh.RejectedFromPhase.Should().Be(PurchaseEvaluationPhase.ChoPurchasing);
-
-        var rowsAfterReject = await _db.PurchaseEvaluationDepartmentApprovals.AsNoTracking()
-            .Where(a => a.PurchaseEvaluationId == pe.Id && a.InnerStepId != null).CountAsync();
-        rowsAfterReject.Should().Be(0);
-    }
-
-    [Fact]
-    public async Task LegacyFallback_NoInnerSteps_Uses_2Stage_Logic()
-    {
-        // Arrange: KHÔNG pin WorkflowDefinitionId → service fallback hardcoded
-        // policy → no inner steps → legacy 2-stage logic kick in.
-        var pe = await SeedPeAsync(PurchaseEvaluationPhase.ChoPurchasing, workflowDefinitionId: null);
-
-        var nv = await _fx.CreateUserAsync(
-            $"nv-legacy-{Guid.NewGuid():N}@test", "NV legacy",
-            _deptPro, ["Procurement"]);   // KHÔNG có positionLevel — legacy không cần
-
-        // Act: NV approve → legacy 2-stage Stage=Review row.
-        await _service.TransitionAsync(
-            pe, PurchaseEvaluationPhase.ChoCCM, nv.Id, ["Procurement"],
-            ApprovalDecision.Approve, "legacy review");
-
-        // Assert: phase chưa đổi (NV chỉ Review), 1 row InnerStepId=NULL (legacy).
-        var fresh = await _db.PurchaseEvaluations.AsNoTracking().FirstAsync(x => x.Id == pe.Id);
-        fresh.Phase.Should().Be(PurchaseEvaluationPhase.ChoPurchasing);
-
-        var rows = await _db.PurchaseEvaluationDepartmentApprovals.AsNoTracking()
-            .Where(a => a.PurchaseEvaluationId == pe.Id).ToListAsync();
-        rows.Should().HaveCount(1);
-        rows[0].InnerStepId.Should().BeNull();
-        rows[0].Stage.Should().Be(ApprovalStage.Review);
-    }
-}

tests/SolutionErp.Infrastructure.Tests/Services/PeTwoStageApprovalTests.cs

@@ -1,274 +0,0 @@
-using Microsoft.AspNetCore.Identity;
-using Microsoft.EntityFrameworkCore;
-using Microsoft.Extensions.DependencyInjection;
-using SolutionErp.Application.Notifications;
-using SolutionErp.Domain.Common;
-using SolutionErp.Domain.Contracts;
-using SolutionErp.Domain.Identity;
-using SolutionErp.Domain.Notifications;
-using SolutionErp.Domain.PurchaseEvaluations;
-using SolutionErp.Infrastructure.Services;
-using SolutionErp.Infrastructure.Tests.Common;
-
-namespace SolutionErp.Infrastructure.Tests.Services;
-
-// Tests cho 2-stage department approval logic ở PurchaseEvaluationWorkflowService.
-// Cover bug fix anh Kiệt: NV.PRO duyệt phase ChoPurchasing → BLOCK transition.
-// TPB.PRO confirm → ALLOW transition.
-//
-// Pattern: dùng IdentityFixture (Identity stack + DbContext SQLite) để
-// test thật end-to-end service thay vì mock.
-public class PeTwoStageApprovalTests : IClassFixture<IdentityFixture>
-{
-    private readonly IdentityFixture _fx;
-    private readonly TestApplicationDbContext _db;
-    private readonly UserManager<User> _userManager;
-    private readonly PurchaseEvaluationWorkflowService _service;
-    private readonly Guid _deptPro;
-    private readonly Guid _deptCcm;
-
-    public PeTwoStageApprovalTests(IdentityFixture fx)
-    {
-        _fx = fx;
-        _db = fx.Services.GetRequiredService<TestApplicationDbContext>();
-        _userManager = fx.Services.GetRequiredService<UserManager<User>>();
-
-        // Seed 2 departments (idempotent — check trước khi insert vì fixture
-        // shared across tests trong class).
-        _deptPro = SeedDept("PRO", "Phòng Cung ứng");
-        _deptCcm = SeedDept("CCM", "Phòng Kiểm soát chi phí");
-
-        var clock = new FixedDateTime(new DateTime(2026, 5, 4, 10, 0, 0, DateTimeKind.Utc));
-        var fakeNotifications = new FakeNotificationService();
-
-        _service = new PurchaseEvaluationWorkflowService(
-            _db,
-            clock,
-            fakeNotifications,
-            _userManager);
-    }
-
-    private Guid SeedDept(string code, string name)
-    {
-        var existing = _db.Departments.FirstOrDefault(d => d.Code == code);
-        if (existing is not null) return existing.Id;
-        var d = new SolutionErp.Domain.Master.Department { Id = Guid.NewGuid(), Code = code, Name = name };
-        _db.Departments.Add(d);
-        _db.SaveChanges();
-        return d.Id;
-    }
-
-    private async Task<PurchaseEvaluation> SeedPeAsync(PurchaseEvaluationPhase phase, Guid? projectId = null)
-    {
-        // Project required by FK constraint.
-        var pid = projectId ?? Guid.NewGuid();
-        if (!_db.Projects.Any(p => p.Id == pid))
-        {
-            _db.Projects.Add(new SolutionErp.Domain.Master.Project
-            {
-                Id = pid,
-                Code = $"PRJ-{Random.Shared.Next(10000):D4}",
-                Name = "Test project",
-            });
-        }
-
-        var pe = new PurchaseEvaluation
-        {
-            Id = Guid.NewGuid(),
-            Type = PurchaseEvaluationType.DuyetNcc,
-            Phase = phase,
-            TenGoiThau = "Test gói thầu",
-            ProjectId = pid,
-        };
-        _db.PurchaseEvaluations.Add(pe);
-        await _db.SaveChangesAsync();
-        return pe;
-    }
-
-    [Fact]
-    public async Task NV_Review_Blocks_Phase_Transition()
-    {
-        // Arrange: NV.PRO (role Procurement, dept PRO, NOT DeptManager).
-        var nv = await _fx.CreateUserAsync(
-            $"nv-{Guid.NewGuid():N}@test", "NV PRO", _deptPro, ["Procurement"]);
-        var pe = await SeedPeAsync(PurchaseEvaluationPhase.ChoPurchasing);
-
-        // Act: NV approve to ChoCCM.
-        await _service.TransitionAsync(
-            pe, PurchaseEvaluationPhase.ChoCCM, nv.Id, ["Procurement"],
-            ApprovalDecision.Approve, "review");
-
-        // Assert: phase KHÔNG đổi, có 1 row Stage=Review.
-        var fresh = await _db.PurchaseEvaluations.AsNoTracking().FirstAsync(x => x.Id == pe.Id);
-        fresh.Phase.Should().Be(PurchaseEvaluationPhase.ChoPurchasing);
-
-        var deptApprovals = await _db.PurchaseEvaluationDepartmentApprovals
-            .Where(a => a.PurchaseEvaluationId == pe.Id).ToListAsync();
-        deptApprovals.Should().HaveCount(1);
-        deptApprovals[0].Stage.Should().Be(ApprovalStage.Review);
-        deptApprovals[0].DepartmentId.Should().Be(_deptPro);
-        deptApprovals[0].IsBypassed.Should().BeFalse();
-
-        var approvals = await _db.PurchaseEvaluationApprovals
-            .Where(a => a.PurchaseEvaluationId == pe.Id).ToListAsync();
-        approvals.Should().HaveCount(1);
-        approvals[0].Comment.Should().StartWith("[Review NV]");
-    }
-
-    [Fact]
-    public async Task TPB_Confirm_After_NV_Review_Allows_Transition()
-    {
-        // Arrange: NV review trước, sau đó TPB confirm.
-        var nv = await _fx.CreateUserAsync(
-            $"nv-{Guid.NewGuid():N}@test", "NV PRO", _deptPro, ["Procurement"]);
-        var tpb = await _fx.CreateUserAsync(
-            $"tpb-{Guid.NewGuid():N}@test", "TPB PRO", _deptPro, ["DeptManager", "Procurement"]);
-        var pe = await SeedPeAsync(PurchaseEvaluationPhase.ChoPurchasing);
-
-        await _service.TransitionAsync(
-            pe, PurchaseEvaluationPhase.ChoCCM, nv.Id, ["Procurement"],
-            ApprovalDecision.Approve, "review NV");
-
-        // Re-fetch tracked entity (service modifies state ở Phase prior).
-        pe = await _db.PurchaseEvaluations.FirstAsync(x => x.Id == pe.Id);
-
-        // Act: TPB confirm.
-        await _service.TransitionAsync(
-            pe, PurchaseEvaluationPhase.ChoCCM, tpb.Id, ["DeptManager", "Procurement"],
-            ApprovalDecision.Approve, "confirm TPB");
-
-        // Assert: phase đổi, có 2 row (Review + Confirm).
-        var fresh = await _db.PurchaseEvaluations.AsNoTracking().FirstAsync(x => x.Id == pe.Id);
-        fresh.Phase.Should().Be(PurchaseEvaluationPhase.ChoCCM);
-
-        var deptApprovals = await _db.PurchaseEvaluationDepartmentApprovals
-            .Where(a => a.PurchaseEvaluationId == pe.Id).ToListAsync();
-        deptApprovals.Should().HaveCount(2);
-        deptApprovals.Should().Contain(a => a.Stage == ApprovalStage.Review && a.ApproverUserId == nv.Id);
-        deptApprovals.Should().Contain(a => a.Stage == ApprovalStage.Confirm && a.ApproverUserId == tpb.Id && !a.IsBypassed);
-    }
-
-    [Fact]
-    public async Task NV_With_BypassReview_Allows_Transition_With_IsBypassed_True()
-    {
-        // Arrange: NV CanBypassReview=true.
-        var nv = await _fx.CreateUserAsync(
-            $"nv-bypass-{Guid.NewGuid():N}@test", "NV PRO bypass",
-            _deptPro, ["Procurement"], canBypassReview: true);
-        var pe = await SeedPeAsync(PurchaseEvaluationPhase.ChoPurchasing);
-
-        // Act: bypass user approve → đẩy thẳng Stage=Confirm.
-        await _service.TransitionAsync(
-            pe, PurchaseEvaluationPhase.ChoCCM, nv.Id, ["Procurement"],
-            ApprovalDecision.Approve, "bypass approve");
-
-        // Assert: phase đổi, có 1 row Stage=Confirm + IsBypassed=true.
-        var fresh = await _db.PurchaseEvaluations.AsNoTracking().FirstAsync(x => x.Id == pe.Id);
-        fresh.Phase.Should().Be(PurchaseEvaluationPhase.ChoCCM);
-
-        var deptApprovals = await _db.PurchaseEvaluationDepartmentApprovals
-            .Where(a => a.PurchaseEvaluationId == pe.Id).ToListAsync();
-        deptApprovals.Should().HaveCount(1);
-        deptApprovals[0].Stage.Should().Be(ApprovalStage.Confirm);
-        deptApprovals[0].IsBypassed.Should().BeTrue();
-        deptApprovals[0].ApproverRoleSnapshot.Should().Be("NV(bypass)");
-    }
-
-    [Fact]
-    public async Task Admin_Skips_TwoStage_Logic_Entirely()
-    {
-        // Arrange: Admin role.
-        var admin = await _fx.CreateUserAsync(
-            $"admin-{Guid.NewGuid():N}@test", "Admin user", null, ["Admin"]);
-        var pe = await SeedPeAsync(PurchaseEvaluationPhase.ChoPurchasing);
-
-        // Act: Admin approve.
-        await _service.TransitionAsync(
-            pe, PurchaseEvaluationPhase.ChoCCM, admin.Id, ["Admin"],
-            ApprovalDecision.Approve, "admin force");
-
-        // Assert: phase đổi, KHÔNG có DepartmentApproval row.
-        var fresh = await _db.PurchaseEvaluations.AsNoTracking().FirstAsync(x => x.Id == pe.Id);
-        fresh.Phase.Should().Be(PurchaseEvaluationPhase.ChoCCM);
-
-        var deptApprovals = await _db.PurchaseEvaluationDepartmentApprovals
-            .Where(a => a.PurchaseEvaluationId == pe.Id).ToListAsync();
-        deptApprovals.Should().BeEmpty();
-    }
-
-    [Fact]
-    public async Task Reject_To_DangSoanThao_Sets_RejectedFromPhase_TraLai()
-    {
-        // Session 14: "Trả lại" semantic — target=DangSoanThao + decision=Reject.
-        // Service set RejectedFromPhase + force về DangSoanThao + Drafter resume jump-back.
-        var actor = await _fx.CreateUserAsync(
-            $"ccm-{Guid.NewGuid():N}@test", "CCM TPB", _deptCcm, ["DeptManager", "CostControl"]);
-        var pe = await SeedPeAsync(PurchaseEvaluationPhase.ChoCCM);
-
-        await _service.TransitionAsync(
-            pe, PurchaseEvaluationPhase.DangSoanThao, actor.Id, ["DeptManager", "CostControl"],
-            ApprovalDecision.Reject, "trả lại Drafter sửa");
-
-        var fresh = await _db.PurchaseEvaluations.AsNoTracking().FirstAsync(x => x.Id == pe.Id);
-        fresh.Phase.Should().Be(PurchaseEvaluationPhase.DangSoanThao);
-        fresh.RejectedFromPhase.Should().Be(PurchaseEvaluationPhase.ChoCCM);
-    }
-
-    [Fact]
-    public async Task Reject_To_TuChoi_Locks_Permanently_No_RejectedFromPhase()
-    {
-        // Session 14: "Từ chối" semantic — target=TuChoi + decision=Reject.
-        // Service KHÔNG override target + KHÔNG set RejectedFromPhase (phiếu khoá vĩnh viễn).
-        var actor = await _fx.CreateUserAsync(
-            $"ccm-{Guid.NewGuid():N}@test", "CCM TPB cancel", _deptCcm, ["DeptManager", "CostControl"]);
-        var pe = await SeedPeAsync(PurchaseEvaluationPhase.ChoCCM);
-
-        await _service.TransitionAsync(
-            pe, PurchaseEvaluationPhase.TuChoi, actor.Id, ["DeptManager", "CostControl"],
-            ApprovalDecision.Reject, "từ chối hoàn toàn");
-
-        var fresh = await _db.PurchaseEvaluations.AsNoTracking().FirstAsync(x => x.Id == pe.Id);
-        fresh.Phase.Should().Be(PurchaseEvaluationPhase.TuChoi);
-        fresh.RejectedFromPhase.Should().BeNull();
-    }
-
-    [Fact]
-    public async Task Resume_After_Reject_Jumps_Back_To_RejectedPhase()
-    {
-        // Arrange: PE rejected từ ChoCCM, đang ở DangSoanThao + RejectedFromPhase=ChoCCM.
-        var drafter = await _fx.CreateUserAsync(
-            $"drafter-{Guid.NewGuid():N}@test", "Drafter", _deptPro, ["Drafter"]);
-        var pe = await SeedPeAsync(PurchaseEvaluationPhase.DangSoanThao);
-        pe.RejectedFromPhase = PurchaseEvaluationPhase.ChoCCM;
-        await _db.SaveChangesAsync();
-
-        // Act: drafter trình lại từ DangSoanThao → ChoPurchasing (target không
-        // quan trọng vì resume sẽ override = RejectedFromPhase). Note: service
-        // jump tới ChoCCM, nhưng nếu actor có dept thì sẽ hit 2-stage logic.
-        // Simpler: dùng admin để bypass 2-stage gate khi resume cũng OK.
-        var admin = await _fx.CreateUserAsync(
-            $"admin-resume-{Guid.NewGuid():N}@test", "Admin resume", null, ["Admin"]);
-        await _service.TransitionAsync(
-            pe, PurchaseEvaluationPhase.ChoPurchasing, admin.Id, ["Admin"],
-            ApprovalDecision.Approve, "drafter resume");
-
-        // Assert: phase jump tới ChoCCM (không phải ChoPurchasing target),
-        // RejectedFromPhase=null.
-        var fresh = await _db.PurchaseEvaluations.AsNoTracking().FirstAsync(x => x.Id == pe.Id);
-        fresh.Phase.Should().Be(PurchaseEvaluationPhase.ChoCCM);
-        fresh.RejectedFromPhase.Should().BeNull();
-    }
-}
-
-// Stub notification service — tests không cần verify notification path
-// (best effort try/catch ở service đã cover fail case).
-internal class FakeNotificationService : INotificationService
-{
-    public Task NotifyAsync(Guid userId, NotificationType type, string title,
-        string? description = null, string? href = null, Guid? refId = null,
-        CancellationToken ct = default) => Task.CompletedTask;
-
-    public Task NotifyManyAsync(IEnumerable<Guid> userIds, NotificationType type,
-        string title, string? description = null, string? href = null,
-        Guid? refId = null, CancellationToken ct = default) => Task.CompletedTask;
-}