refactor: change ConvertBase64UriToImage from extension method to static method

Foxnouns.Backend/Extensions/ImageObjectExtensions.cs

@@ -0,0 +1,82 @@
+using System.Security.Cryptography;
+using Foxnouns.Backend.Database;
+using Foxnouns.Backend.Jobs;
+using Foxnouns.Backend.Services;
+using Foxnouns.Backend.Utils;
+using SixLabors.ImageSharp;
+using SixLabors.ImageSharp.Formats.Webp;
+using SixLabors.ImageSharp.Processing;
+using SixLabors.ImageSharp.Processing.Processors.Transforms;
+
+namespace Foxnouns.Backend.Extensions;
+
+public static class ImageObjectExtensions
+{
+    private static readonly string[] ValidContentTypes = ["image/png", "image/webp", "image/jpeg"];
+
+    public static async Task DeleteMemberAvatarAsync(
+        this ObjectStorageService objectStorageService,
+        Snowflake id,
+        string hash,
+        CancellationToken ct = default
+    ) =>
+        await objectStorageService.RemoveObjectAsync(
+            MemberAvatarUpdateInvocable.Path(id, hash),
+            ct
+        );
+
+    public static async Task DeleteUserAvatarAsync(
+        this ObjectStorageService objectStorageService,
+        Snowflake id,
+        string hash,
+        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(
+        string uri,
+        int size,
+        bool crop
+    )
+    {
+        if (!uri.StartsWith("data:image/"))
+            throw new ArgumentException("Not a data URI", nameof(uri));
+
+        var split = uri.Remove(0, "data:".Length).Split(";base64,");
+        var contentType = split[0];
+        var encoded = split[1];
+        if (!ValidContentTypes.Contains(contentType))
+            throw new ArgumentException("Invalid content type for image", nameof(uri));
+
+        if (!AuthUtils.TryFromBase64String(encoded, out var rawImage))
+            throw new ArgumentException("Invalid base64 string", nameof(uri));
+
+        var image = Image.Load(rawImage);
+
+        var processor = new ResizeProcessor(
+            new ResizeOptions
+            {
+                Size = new Size(size),
+                Mode = crop ? ResizeMode.Crop : ResizeMode.Max,
+                Position = AnchorPositionMode.Center,
+            },
+            image.Size
+        );
+
+        image.Mutate(x => x.ApplyProcessor(processor));
+
+        var stream = new MemoryStream(64 * 1024);
+        await image.SaveAsync(stream, new WebpEncoder { Quality = 95, NearLossless = false });
+
+        stream.Seek(0, SeekOrigin.Begin);
+        var hash = Convert.ToHexString(await SHA256.HashDataAsync(stream)).ToLower();
+        stream.Seek(0, SeekOrigin.Begin);
+
+        return (hash, stream);
+    }
+}