feat: add asset access signing endpoints

Tiku.Api/Middleware/ExceptionHandlingMiddleware.cs

@@ -1,6 +1,8 @@
 using Microsoft.AspNetCore.Mvc;
 using Tiku.Api.Controllers;
+using Tiku.Application.Assets;
 using Tiku.Application.Auth;
+using Tiku.Application.Storage;
 using Tiku.Infrastructure.Content;
 using Tiku.Infrastructure.QuestionBanks;
 
@@ -75,6 +77,28 @@ public sealed class ExceptionHandlingMiddleware(
                 return;
             }
 
+            if (exception is AssetAccessException assetAccessException)
+            {
+                await WriteProblemAsync(
+                    context,
+                    assetAccessException.Message,
+                    AssetAccessStatusCode(assetAccessException.Code),
+                    assetAccessException.Code.ToLowerInvariant());
+                return;
+            }
+
+            if (exception is ObjectStorageException storageException)
+            {
+                await WriteProblemAsync(
+                    context,
+                    storageException.Message,
+                    storageException is ObjectStorageNotConfiguredException
+                        ? StatusCodes.Status503ServiceUnavailable
+                        : StatusCodes.Status400BadRequest,
+                    storageException.Code.ToLowerInvariant());
+                return;
+            }
+
             logger.LogError(exception, "Unhandled API exception");
 
             var problem = new ProblemDetails
@@ -132,4 +156,17 @@ public sealed class ExceptionHandlingMiddleware(
         context.Response.StatusCode = status;
         await context.Response.WriteAsJsonAsync(problem);
     }
+
+    private static int AssetAccessStatusCode(string code)
+    {
+        return code switch
+        {
+            "ASSET_NOT_FOUND" => StatusCodes.Status404NotFound,
+            "AUTH_REQUIRED" => StatusCodes.Status401Unauthorized,
+            "ASSET_HIDDEN" or "ASSET_MEMBERSHIP_REQUIRED" or "ASSET_SVIP_REQUIRED" => StatusCodes.Status403Forbidden,
+            "ASSET_UPLOAD_NOT_VERIFIED" or "ASSET_SECURITY_SCAN_NOT_PASSED" => StatusCodes.Status409Conflict,
+            "ASSET_PREVIEW_NOT_SUPPORTED" => StatusCodes.Status400BadRequest,
+            _ => StatusCodes.Status400BadRequest
+        };
+    }
 }