[CLAUDE] Office: P11-D ItTicket auto-assign round-robin + SLA timer (Wave 2, Mig 46)

Mig 46 AddSlaFieldsToItTicket (SlaDueAt/SlaWarnedSent/SlaBreached). CreateItTicketHandler: round-robin least-loaded assign cho IT staff (dept Code=IT, tie-break Id) + SlaDueAt theo Priority (Urgent 4h/High 8h/Medium 24h/Low 72h). ItTicketSlaJob background (breach+warning notify, KHONG auto-transition). PUT /{id}/assign admin override. DbInitializer seed dept IT + 2 sample staff (nv.cao/nv.truong). FE ItTicketsPage +MaTicket+assignee+SLA badge (2 app SHA256 mirror). +9 test (191->200). Self-review PASS (seed<->query dept-code verified; em main solo review do session-limit kill reviewer-spawn).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/Backend/SolutionErp.Infrastructure/HostedServices/ItTicketSlaJob.cs

@@ -0,0 +1,143 @@
+using Microsoft.EntityFrameworkCore;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using SolutionErp.Application.Common.Interfaces;
+using SolutionErp.Application.Notifications;
+using SolutionErp.Application.Office;
+using SolutionErp.Domain.Notifications;
+using SolutionErp.Domain.Office;
+
+namespace SolutionErp.Infrastructure.HostedServices;
+
+// P11-D (Mig 46 — Phase 11 Wave 2) — SLA timer cho IT helpdesk ticket.
+// Mirror pattern SlaExpiryJob (HĐ) NHƯNG KHÔNG auto-transition status — ticket
+// chỉ CẢNH BÁO (warning ≤20% window + breach quá hạn) gửi notification cho assignee.
+// Status flow (Open → InProgress → Resolved → Closed) do IT staff điều khiển tay.
+// Chạy mỗi 15 phút, warmup 30s tránh race DbInitializer migrate.
+// SLA window theo Priority = source-of-truth CreateItTicketHandler.SlaWindow (shared).
+public class ItTicketSlaJob : BackgroundService
+{
+    private readonly IServiceProvider _sp;
+    private readonly ILogger<ItTicketSlaJob> _logger;
+    private static readonly TimeSpan Interval = TimeSpan.FromMinutes(15);
+
+    public ItTicketSlaJob(IServiceProvider sp, ILogger<ItTicketSlaJob> logger)
+    {
+        _sp = sp;
+        _logger = logger;
+    }
+
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        await Task.Delay(TimeSpan.FromSeconds(30), stoppingToken);
+
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            try
+            {
+                await ProcessAsync(stoppingToken);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "ItTicketSlaJob iteration failed");
+            }
+            await Task.Delay(Interval, stoppingToken);
+        }
+    }
+
+    private async Task ProcessAsync(CancellationToken ct)
+    {
+        await using var scope = _sp.CreateAsyncScope();
+        var db = scope.ServiceProvider.GetRequiredService<IApplicationDbContext>();
+        var dateTime = scope.ServiceProvider.GetRequiredService<IDateTime>();
+        var notifications = scope.ServiceProvider.GetRequiredService<INotificationService>();
+
+        var now = dateTime.UtcNow;
+
+        await ProcessBreachesAsync(db, notifications, now, ct);
+        await ProcessWarningsAsync(db, notifications, now, ct);
+    }
+
+    // Breach: ticket quá hạn SLA mà chưa đánh dấu breach + còn open (chưa Resolved/Closed).
+    // Set SlaBreached=true + notify assignee (nếu có). Idempotent qua !SlaBreached guard.
+    private async Task ProcessBreachesAsync(
+        IApplicationDbContext db, INotificationService notifications,
+        DateTime now, CancellationToken ct)
+    {
+        var breached = await db.ItTickets
+            .Where(t => t.SlaDueAt != null && t.SlaDueAt < now
+                && !t.SlaBreached
+                && t.Status != ItTicketStatus.Resolved && t.Status != ItTicketStatus.Closed
+                && !t.IsDeleted)
+            .ToListAsync(ct);
+
+        if (breached.Count == 0) return;
+
+        foreach (var t in breached)
+        {
+            if (t.AssignedToUserId is Guid assignee)
+            {
+                await notifications.NotifyAsync(
+                    assignee,
+                    NotificationType.SlaWarning,
+                    title: $"⚠ Ticket {t.MaTicket ?? t.Title} quá hạn SLA",
+                    description: $"Ticket \"{t.Title}\" đã quá hạn xử lý SLA. Vui lòng ưu tiên xử lý.",
+                    href: $"/it-tickets/{t.Id}",
+                    refId: t.Id,
+                    ct: ct);
+            }
+            t.SlaBreached = true;
+        }
+
+        await db.SaveChangesAsync(ct);
+        _logger.LogInformation("ItTicketSlaJob: {Count} tickets breached SLA.", breached.Count);
+    }
+
+    // Warning: ticket chưa warning + còn open + còn ≤20% window (theo Priority) trước hạn.
+    // Notify assignee + set SlaWarnedSent=true. Idempotent qua !SlaWarnedSent guard.
+    private async Task ProcessWarningsAsync(
+        IApplicationDbContext db, INotificationService notifications,
+        DateTime now, CancellationToken ct)
+    {
+        var candidates = await db.ItTickets
+            .Where(t => !t.SlaWarnedSent
+                && t.SlaDueAt != null && t.SlaDueAt > now
+                && t.Status != ItTicketStatus.Resolved && t.Status != ItTicketStatus.Closed
+                && !t.IsDeleted)
+            .ToListAsync(ct);
+
+        if (candidates.Count == 0) return;
+
+        int warned = 0;
+        foreach (var t in candidates)
+        {
+            var window = CreateItTicketHandler.SlaWindow.TryGetValue(t.Priority, out var w)
+                ? w : TimeSpan.FromHours(24);
+            var threshold = TimeSpan.FromTicks((long)(window.Ticks * 0.2));
+            var remaining = t.SlaDueAt!.Value - now;
+            if (remaining > threshold) continue;       // còn nhiều SLA → skip
+
+            if (t.AssignedToUserId is Guid assignee)
+            {
+                var hoursLeft = Math.Max(1, (int)remaining.TotalHours);
+                await notifications.NotifyAsync(
+                    assignee,
+                    NotificationType.SlaWarning,
+                    title: $"⚠ Ticket {t.MaTicket ?? t.Title} sắp quá hạn ({hoursLeft}h)",
+                    description: $"Ticket \"{t.Title}\" còn ~{hoursLeft}h trước hạn xử lý SLA.",
+                    href: $"/it-tickets/{t.Id}",
+                    refId: t.Id,
+                    ct: ct);
+            }
+            t.SlaWarnedSent = true;
+            warned++;
+        }
+
+        if (warned > 0)
+        {
+            await db.SaveChangesAsync(ct);
+            _logger.LogInformation("ItTicketSlaJob: {Count} warnings dispatched (≤20% SLA).", warned);
+        }
+    }
+}