feat: 增加角色/权限管理 API 与应用层命令

src/Application/TakeoutSaaS.Application/Identity/Handlers/SearchPermissionsQueryHandler.cs

@@ -0,0 +1,54 @@
+using System;
+using System.Linq;
+using MediatR;
+using TakeoutSaaS.Application.Identity.Contracts;
+using TakeoutSaaS.Application.Identity.Queries;
+using TakeoutSaaS.Domain.Identity.Repositories;
+using TakeoutSaaS.Shared.Abstractions.Results;
+using TakeoutSaaS.Shared.Abstractions.Tenancy;
+
+namespace TakeoutSaaS.Application.Identity.Handlers;
+
+/// <summary>
+/// 权限分页查询处理器。
+/// </summary>
+public sealed class SearchPermissionsQueryHandler(
+    IPermissionRepository permissionRepository,
+    ITenantProvider tenantProvider)
+    : IRequestHandler<SearchPermissionsQuery, PagedResult<PermissionDto>>
+{
+    public async Task<PagedResult<PermissionDto>> Handle(SearchPermissionsQuery request, CancellationToken cancellationToken)
+    {
+        var tenantId = tenantProvider.GetCurrentTenantId();
+        var permissions = await permissionRepository.SearchAsync(tenantId, request.Keyword, cancellationToken);
+
+        var sorted = request.SortBy?.ToLowerInvariant() switch
+        {
+            "name" => request.SortDescending
+                ? permissions.OrderByDescending(x => x.Name)
+                : permissions.OrderBy(x => x.Name),
+            "code" => request.SortDescending
+                ? permissions.OrderByDescending(x => x.Code)
+                : permissions.OrderBy(x => x.Code),
+            _ => request.SortDescending
+                ? permissions.OrderByDescending(x => x.CreatedAt)
+                : permissions.OrderBy(x => x.CreatedAt)
+        };
+
+        var paged = sorted
+            .Skip((request.Page - 1) * request.PageSize)
+            .Take(request.PageSize)
+            .ToList();
+
+        var items = paged.Select(permission => new PermissionDto
+        {
+            Id = permission.Id,
+            TenantId = permission.TenantId,
+            Name = permission.Name,
+            Code = permission.Code,
+            Description = permission.Description
+        }).ToList();
+
+        return new PagedResult<PermissionDto>(items, request.Page, request.PageSize, permissions.Count);
+    }
+}