feat: 实现租户管理及套餐流程

src/Application/TakeoutSaaS.Application/App/Tenants/Handlers/GetTenantByIdQueryHandler.cs

@@ -0,0 +1,34 @@
+using MediatR;
+using TakeoutSaaS.Application.App.Tenants.Dto;
+using TakeoutSaaS.Application.App.Tenants.Queries;
+using TakeoutSaaS.Domain.Tenants.Repositories;
+using TakeoutSaaS.Shared.Abstractions.Constants;
+using TakeoutSaaS.Shared.Abstractions.Exceptions;
+
+namespace TakeoutSaaS.Application.App.Tenants.Handlers;
+
+/// <summary>
+/// 租户详情查询处理器。
+/// </summary>
+public sealed class GetTenantByIdQueryHandler(ITenantRepository tenantRepository)
+    : IRequestHandler<GetTenantByIdQuery, TenantDetailDto>
+{
+    private readonly ITenantRepository _tenantRepository = tenantRepository;
+
+    /// <inheritdoc />
+    public async Task<TenantDetailDto> Handle(GetTenantByIdQuery request, CancellationToken cancellationToken)
+    {
+        var tenant = await _tenantRepository.FindByIdAsync(request.TenantId, cancellationToken)
+            ?? throw new BusinessException(ErrorCodes.NotFound, "租户不存在");
+
+        var subscription = await _tenantRepository.GetActiveSubscriptionAsync(request.TenantId, cancellationToken);
+        var verification = await _tenantRepository.GetVerificationProfileAsync(request.TenantId, cancellationToken);
+
+        return new TenantDetailDto
+        {
+            Tenant = TenantMapping.ToDto(tenant, subscription, verification),
+            Verification = verification.ToVerificationDto(),
+            Subscription = subscription.ToSubscriptionDto()
+        };
+    }
+}