[CLAUDE] Domain+Infra: Migration 18 PE workflow inner steps + User.PositionLevel (Chunk A)

N-stage workflow approval — mỗi WorkflowStep cha (= 1 phase) cấu hình
được chuỗi InnerSteps con theo Department × PositionLevel với Order
sequential. Phase 9+ feature, mở rộng từ 2-stage Mig 16.

Schema:
- enum PositionLevel { NhanVien=1, PhoPhong=2, TruongPhong=3 } (Domain/Identity)
- ALTER Users + PositionLevel int? NULL (admin/system user vẫn null)
- CREATE TABLE PurchaseEvaluationWorkflowStepInnerSteps:
  Id PK, PurchaseEvaluationWorkflowStepId FK Cascade,
  Order int, DepartmentId FK Restrict, PositionLevel int,
  Name nvarchar(200), SlaDays int?, IsRequired bit
- ALTER PurchaseEvaluationDepartmentApprovals + InnerStepId Guid? FK Restrict
  (null cho data legacy 2-stage Review/Confirm Mig 16)

Backward compat: step KHÔNG có InnerSteps → service fallback logic
2-stage Stage=Review|Confirm cũ (Chunk C). Data Mig 16 hiện có giữ
nguyên, InnerStepId=null.

Verify:
- dotnet build SolutionErp.slnx pass (0 error, 2 pre-existing warning DocxRenderer)
- dotnet ef database update LocalDB applied OK
- dotnet test SolutionErp.slnx 83 pass (54 Domain + 29 Infra) — no regression
- 3-file rule: Migration.cs + Designer.cs + Snapshot updated

Pending Chunk B: Application CQRS — extend CreatePeWorkflowDefinitionCommand
với InnerSteps DTO + UpdateUserPositionLevelCommand.

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

src/Backend/SolutionErp.Domain/Identity/PositionLevel.cs

@@ -0,0 +1,16 @@
+namespace SolutionErp.Domain.Identity;
+
+// Cấp chức danh trong phòng ban — phục vụ N-stage workflow inner step (Mig 18).
+// Mỗi WorkflowStep cha (= 1 phase) có thể cấu hình 1 chuỗi inner step
+// con (Order asc) khớp Department × PositionLevel. Ai đúng phòng + đúng cấp
+// (+ Order tiếp theo chưa duyệt) thì duyệt được.
+//
+// Default null cho admin/system/external user không thuộc cấp cụ thể.
+// CanBypassReview=true ở User cho phép cấp cao hơn (TP) skip cấp dưới
+// (NV+PP) cùng Department khi duyệt 1 inner step block.
+public enum PositionLevel
+{
+    NhanVien = 1,        // NV
+    PhoPhong = 2,        // PP
+    TruongPhong = 3,     // TP
+}

src/Backend/SolutionErp.Domain/Identity/User.cs

@@ -18,6 +18,13 @@ public class User : IdentityUser<Guid>
 
     // 2-stage department approval (Phase 9 — Migration 16): khi true, NV
     // được quyền duyệt thay TPB (skip Stage Review, đẩy thẳng Stage Confirm).
+    // Cũng dùng cho N-stage inner step (Mig 18) — TP có CanBypassReview
+    // skip NV+PP cùng Department.
     // Mặc định false (an toàn). Admin set ở UserManager UI.
     public bool CanBypassReview { get; set; }
+
+    // Cấp chức danh trong phòng — phục vụ N-stage workflow inner step (Mig 18).
+    // Mỗi inner step yêu cầu user khớp DepartmentId + PositionLevel mới duyệt
+    // được sub-step đó. Null cho admin/system/external user.
+    public PositionLevel? PositionLevel { get; set; }
 }

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

@@ -15,12 +15,18 @@ public class PurchaseEvaluationDepartmentApproval : AuditableEntity
     public Guid PurchaseEvaluationId { get; set; }
     public int PhaseAtApproval { get; set; }              // snapshot PurchaseEvaluationPhase int
     public Guid DepartmentId { get; set; }
-    public ApprovalStage Stage { get; set; }               // 1=Review (NV), 2=Confirm (TPB)
+    public ApprovalStage Stage { get; set; }               // 1=Review (NV), 2=Confirm (TPB) — legacy 2-stage Mig 16
     public Guid ApproverUserId { get; set; }
     public string? ApproverRoleSnapshot { get; set; }
     public string? Comment { get; set; }
     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/PurchaseEvaluationWorkflowDefinition.cs

@@ -1,5 +1,6 @@
 using SolutionErp.Domain.Common;
 using SolutionErp.Domain.Contracts;   // reuse WorkflowApproverKind
+using SolutionErp.Domain.Identity;     // reuse PositionLevel
 
 namespace SolutionErp.Domain.PurchaseEvaluations;
 
@@ -34,6 +35,12 @@ public class PurchaseEvaluationWorkflowStep : BaseEntity
 
     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
@@ -44,3 +51,24 @@ 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

@@ -59,6 +59,7 @@ 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

@@ -59,11 +59,19 @@ public class PurchaseEvaluationDepartmentApprovalConfiguration
         b.HasIndex(x => x.PurchaseEvaluationId);
         b.HasIndex(x => x.DepartmentId);
         b.HasIndex(x => x.ApproverUserId);
+        b.HasIndex(x => x.InnerStepId);     // Mig 18 — query rows by sub-step
 
         b.HasOne(x => x.PurchaseEvaluation)
             .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

@@ -209,6 +209,37 @@ 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/Migrations/20260507111034_AddPeWorkflowInnerStepsAndPositionLevel.cs

@@ -0,0 +1,107 @@
+using System;
+using Microsoft.EntityFrameworkCore.Migrations;
+
+#nullable disable
+
+namespace SolutionErp.Infrastructure.Persistence.Migrations
+{
+    /// <inheritdoc />
+    public partial class AddPeWorkflowInnerStepsAndPositionLevel : Migration
+    {
+        /// <inheritdoc />
+        protected override void Up(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.AddColumn<int>(
+                name: "PositionLevel",
+                table: "Users",
+                type: "int",
+                nullable: true);
+
+            migrationBuilder.AddColumn<Guid>(
+                name: "InnerStepId",
+                table: "PurchaseEvaluationDepartmentApprovals",
+                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),
+                    Order = table.Column<int>(type: "int", nullable: false),
+                    DepartmentId = table.Column<Guid>(type: "uniqueidentifier", nullable: false),
+                    PositionLevel = table.Column<int>(type: "int", nullable: false),
+                    Name = table.Column<string>(type: "nvarchar(200)", maxLength: 200, nullable: true),
+                    SlaDays = table.Column<int>(type: "int", nullable: true),
+                    IsRequired = table.Column<bool>(type: "bit", nullable: false),
+                    CreatedAt = table.Column<DateTime>(type: "datetime2", nullable: false),
+                    UpdatedAt = table.Column<DateTime>(type: "datetime2", nullable: true),
+                    CreatedBy = table.Column<Guid>(type: "uniqueidentifier", 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.CreateIndex(
+                name: "IX_PurchaseEvaluationDepartmentApprovals_InnerStepId",
+                table: "PurchaseEvaluationDepartmentApprovals",
+                column: "InnerStepId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_PurchaseEvaluationWorkflowStepInnerSteps_DepartmentId",
+                table: "PurchaseEvaluationWorkflowStepInnerSteps",
+                column: "DepartmentId");
+
+            migrationBuilder.CreateIndex(
+                name: "IX_PurchaseEvaluationWorkflowStepInnerSteps_PurchaseEvaluationWorkflowStepId_Order",
+                table: "PurchaseEvaluationWorkflowStepInnerSteps",
+                columns: new[] { "PurchaseEvaluationWorkflowStepId", "Order" });
+
+            migrationBuilder.AddForeignKey(
+                name: "FK_PurchaseEvaluationDepartmentApprovals_PurchaseEvaluationWorkflowStepInnerSteps_InnerStepId",
+                table: "PurchaseEvaluationDepartmentApprovals",
+                column: "InnerStepId",
+                principalTable: "PurchaseEvaluationWorkflowStepInnerSteps",
+                principalColumn: "Id",
+                onDelete: ReferentialAction.Restrict);
+        }
+
+        /// <inheritdoc />
+        protected override void Down(MigrationBuilder migrationBuilder)
+        {
+            migrationBuilder.DropForeignKey(
+                name: "FK_PurchaseEvaluationDepartmentApprovals_PurchaseEvaluationWorkflowStepInnerSteps_InnerStepId",
+                table: "PurchaseEvaluationDepartmentApprovals");
+
+            migrationBuilder.DropTable(
+                name: "PurchaseEvaluationWorkflowStepInnerSteps");
+
+            migrationBuilder.DropIndex(
+                name: "IX_PurchaseEvaluationDepartmentApprovals_InnerStepId",
+                table: "PurchaseEvaluationDepartmentApprovals");
+
+            migrationBuilder.DropColumn(
+                name: "PositionLevel",
+                table: "Users");
+
+            migrationBuilder.DropColumn(
+                name: "InnerStepId",
+                table: "PurchaseEvaluationDepartmentApprovals");
+        }
+    }
+}

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

@@ -1809,6 +1809,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                         .HasMaxLength(200)
                         .HasColumnType("nvarchar(200)");
 
+                    b.Property<int?>("PositionLevel")
+                        .HasColumnType("int");
+
                     b.Property<string>("RefreshToken")
                         .HasMaxLength(512)
                         .HasColumnType("nvarchar(512)");
@@ -2656,6 +2659,9 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
                     b.Property<Guid>("DepartmentId")
                         .HasColumnType("uniqueidentifier");
 
+                    b.Property<Guid?>("InnerStepId")
+                        .HasColumnType("uniqueidentifier");
+
                     b.Property<bool>("IsBypassed")
                         .HasColumnType("bit");
 
@@ -2683,6 +2689,8 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
 
                     b.HasIndex("DepartmentId");
 
+                    b.HasIndex("InnerStepId");
+
                     b.HasIndex("PurchaseEvaluationId");
 
                     b.HasIndex("PurchaseEvaluationId", "PhaseAtApproval", "DepartmentId", "Stage")
@@ -3072,6 +3080,55 @@ 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)
@@ -3393,6 +3450,11 @@ 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")
@@ -3480,6 +3542,23 @@ 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");
@@ -3567,6 +3646,8 @@ namespace SolutionErp.Infrastructure.Persistence.Migrations
             modelBuilder.Entity("SolutionErp.Domain.PurchaseEvaluations.PurchaseEvaluationWorkflowStep", b =>
                 {
                     b.Navigation("Approvers");
+
+                    b.Navigation("InnerSteps");
                 });
 #pragma warning restore 612, 618
         }