refactor(jobs): modularize background job handlers

Tiku.Infrastructure/TenantAdmin/Dashboard/StatisticsAggregationJobHandler.cs

@@ -0,0 +1,52 @@
+using System.Text.Json;
+using Microsoft.EntityFrameworkCore;
+using Tiku.Application.Jobs;
+using Tiku.Application.Security;
+using Tiku.Domain.Commerce;
+using Tiku.Infrastructure.Persistence;
+
+namespace Tiku.Infrastructure.TenantAdmin.Dashboard;
+
+internal sealed class StatisticsAggregationJobHandler(
+    TikuDbContext dbContext,
+    IFeatureUsageReconciliationService featureUsageReconciliationService) : IBackgroundJobHandler
+{
+    public string JobType => "statistics_aggregation";
+
+    public async Task<BackgroundJobHandlerResult> HandleAsync(
+        BackgroundJobExecutionContext context,
+        CancellationToken cancellationToken = default)
+    {
+        var since = DateTimeOffset.UtcNow.AddDays(-7);
+        var activeLearnerCount = await dbContext.PracticeSessions
+            .Where(item => item.TenantId == context.TenantId && item.StartedAt >= since)
+            .Select(item => item.UserId)
+            .Distinct()
+            .CountAsync(cancellationToken);
+        var paidOrderCount = await dbContext.Orders
+            .CountAsync(item => item.TenantId == context.TenantId && item.Status == OrderStatus.Paid,
+                cancellationToken);
+        var revenueCents = await dbContext.Orders
+            .Where(item => item.TenantId == context.TenantId &&
+                           (item.Status == OrderStatus.Paid ||
+                            item.Status == OrderStatus.PartiallyRefunded ||
+                            item.Status == OrderStatus.Refunded))
+            .SumAsync(item => item.AmountCents - item.RefundedAmountCents, cancellationToken);
+        var quotaUsage = await featureUsageReconciliationService.ReconcileTenantAsync(
+            new ReconcileFeatureUsageRequest(
+                context.TenantId,
+                SystemScopeCallerType.Worker,
+                nameof(StatisticsAggregationJobHandler),
+                "Reconcile tenant current feature usage during statistics aggregation",
+                $"feature-usage-{context.JobId:N}"),
+            cancellationToken);
+        return new BackgroundJobHandlerResult(JsonSerializer.SerializeToElement(new
+        {
+            since,
+            activeLearnerCount,
+            paidOrderCount,
+            revenueCents,
+            quotaUsage
+        }));
+    }
+}