feat(backend): delete flag endpoint

Foxnouns.Backend/Controllers/FlagsController.cs

@@ -1,6 +1,7 @@
 using Coravel.Queuing.Interfaces;
 using Foxnouns.Backend.Database;
 using Foxnouns.Backend.Database.Models;
+using Foxnouns.Backend.Extensions;
 using Foxnouns.Backend.Jobs;
 using Foxnouns.Backend.Middleware;
 using Foxnouns.Backend.Services;
@@ -11,11 +12,15 @@ namespace Foxnouns.Backend.Controllers;
 
 [Route("/api/v2/users/@me/flags")]
 public class FlagsController(
+    ILogger logger,
     DatabaseContext db,
     UserRendererService userRenderer,
+    ObjectStorageService objectStorageService,
     ISnowflakeGenerator snowflakeGenerator,
     IQueue queue) : ApiControllerBase
 {
+    private readonly ILogger _logger = logger.ForContext<FlagsController>();
+    
     [HttpGet]
     [Authorize("identify")]
     [ProducesResponseType<IEnumerable<PrideFlagResponse>>(statusCode: StatusCodes.Status200OK)]
@@ -40,8 +45,40 @@ public class FlagsController(
     }
 
     public record CreateFlagRequest(string Name, string Image, string? Description);
+    private record CreateFlagResponse(Snowflake Id, string Name, string? Description);
 
-    public record CreateFlagResponse(Snowflake Id, string Name, string? Description);
+    [HttpDelete("{id}")]
+    [Authorize("user.update")]
+    public async Task<IActionResult> DeleteFlagAsync(Snowflake id)
+    {
+        await using var tx = await db.Database.BeginTransactionAsync();
+        
+        var flag = await db.PrideFlags.FirstOrDefaultAsync(f => f.Id == id && f.UserId == CurrentUser!.Id);
+        if (flag == null) throw new ApiError.NotFound("Unknown flag ID, or it's not your flag.");
+
+        var hash = flag.Hash;
+
+        db.PrideFlags.Remove(flag);
+        await db.SaveChangesAsync();
+
+        var flagCount = await db.PrideFlags.CountAsync(f => f.Hash == flag.Hash);
+        if (flagCount == 0)
+        {
+            try
+            {
+                _logger.Information("Deleting flag file {Hash} as it is no longer used by any flags", hash);
+                await objectStorageService.DeleteFlagAsync(hash);
+            }
+            catch (Exception e)
+            {
+                _logger.Error(e, "Error deleting flag file {Hash}", hash);
+            }
+        } else _logger.Debug("Flag file {Hash} is used by other flags, not deleting", hash);
+        
+        await tx.CommitAsync();
+
+        return NoContent();
+    }
 
     private PrideFlagResponse ToResponse(PrideFlag flag) =>
         new(flag.Id, userRenderer.ImageUrlFor(flag), flag.Name, flag.Description);

Foxnouns.Backend/Extensions/AvatarObjectExtensions.cs

@@ -24,6 +24,10 @@ public static class AvatarObjectExtensions
             CancellationToken ct = default) =>
         await objectStorageService.RemoveObjectAsync(UserAvatarUpdateInvocable.Path(id, hash), ct);
 
+    public static async Task DeleteFlagAsync(this ObjectStorageService objectStorageService, string hash,
+        CancellationToken ct = default) =>
+        await objectStorageService.RemoveObjectAsync(CreateFlagInvocable.Path(hash), ct);
+
     public static async Task<(string Hash, Stream Image)> ConvertBase64UriToImage(this string uri, int size, bool crop)
     {
         if (!uri.StartsWith("data:image/"))

Foxnouns.Backend/Jobs/CreateFlagInvocable.cs

@@ -1,4 +1,3 @@
-using System.Security.Cryptography;
 using Coravel.Invocable;
 using Foxnouns.Backend.Database;
 using Foxnouns.Backend.Database.Models;
@@ -45,5 +44,5 @@ public class CreateFlagInvocable(DatabaseContext db, ObjectStorageService object
         throw new NotImplementedException();
     }
 
-    private static string Path(string hash) => $"flags/{hash}.webp";
+    public static string Path(string hash) => $"flags/{hash}.webp";
 }