feat: add current user and tenant endpoints

Tiku.Api/Controllers/TenantsController.cs

@@ -0,0 +1,61 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.EntityFrameworkCore;
+using System.Text.Json;
+using Tiku.Application.Auth;
+using Tiku.Application.Security;
+using Tiku.Domain.Tenancy;
+using Tiku.Infrastructure.Persistence;
+
+namespace Tiku.Api.Controllers;
+
+[ApiController]
+[Authorize(Policy = TikuPolicies.CurrentTenantMember)]
+[Route("api/tenants")]
+public sealed class TenantsController(
+    ICurrentUser currentUser,
+    ICurrentTenant currentTenant,
+    TikuDbContext dbContext) : ControllerBase
+{
+    [HttpGet("current")]
+    public async Task<ActionResult<CurrentTenantResponse>> GetCurrent(CancellationToken cancellationToken)
+    {
+        if (currentUser.UserId is null || currentTenant.TenantId is null)
+        {
+            throw new TenantAccessDeniedException();
+        }
+
+        var result = await dbContext.TenantMemberships
+            .Where(membership =>
+                membership.UserId == currentUser.UserId.Value &&
+                membership.TenantId == currentTenant.TenantId.Value &&
+                membership.Status == MembershipStatus.Active)
+            .Join(
+                dbContext.Tenants,
+                membership => membership.TenantId,
+                tenant => tenant.Id,
+                (membership, tenant) => new CurrentTenantResponse(
+                    tenant.Id,
+                    tenant.Name,
+                    tenant.Slug,
+                    tenant.Status,
+                    membership.Role,
+                    membership.Permissions))
+            .SingleOrDefaultAsync(cancellationToken);
+
+        if (result is null)
+        {
+            throw new TenantAccessDeniedException();
+        }
+
+        return Ok(result);
+    }
+}
+
+public sealed record CurrentTenantResponse(
+    Guid TenantId,
+    string TenantName,
+    string TenantSlug,
+    TenantStatus Status,
+    TenantRole Role,
+    JsonElement Permissions);