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
        }));
    }
}