Added AudioFileScanner and AudioImageExtractor logic.

Harmonia.Core/Imaging/AudioImageExtractor.cs

@@ -0,0 +1,27 @@
+using Harmonia.Core.Tags;
+
+namespace Harmonia.Core.Imaging;
+
+public class AudioImageExtractor(ITagResolver tagResolver) : IAudioImageExtractor
+{
+    public SongPictureInfo ExtractImage(string fileName)
+    {
+        SongTagInfo songTagInfo = tagResolver.GetSongTagInfo(fileName);
+
+        return ExtractImage(fileName, songTagInfo);
+    }
+
+    public SongPictureInfo ExtractImage(string fileName, SongTagInfo songTagInfo)
+    {
+        if (songTagInfo.FrontCover != null)
+        {
+            using MemoryStream memoryStream = new(songTagInfo.FrontCover.Data);
+
+            return SongPictureInfo.FromStream(memoryStream);
+        }
+        else
+        {
+            return SongPictureInfo.FromFile(fileName);
+        }
+    }
+}

Harmonia.Core/Imaging/IAudioImageExtractor.cs

@@ -0,0 +1,9 @@
+using Harmonia.Core.Tags;
+
+namespace Harmonia.Core.Imaging;
+
+public interface IAudioImageExtractor
+{
+    SongPictureInfo ExtractImage(string fileName);
+    SongPictureInfo ExtractImage(string fileName, SongTagInfo songTagInfo);
+}

Harmonia.Core/Imaging/SongPictureInfo.cs

@@ -0,0 +1,59 @@
+using System.Security.Cryptography;
+
+namespace Harmonia.Core.Imaging;
+
+public class SongPictureInfo : IDisposable
+{
+    public required Stream Stream { get; init; }
+    public string? ImageHash { get; init; }
+    public required string ImageName { get; init; }
+    public ulong Size { get; init; }
+
+    private SongPictureInfo()
+    {
+
+    }
+
+    public static SongPictureInfo FromStream(Stream stream)
+    {
+        string imageHash = ComputeImageHash(stream);
+
+        return GetSongPictureInfo(stream, "Embedded", imageHash);
+    }
+
+    private static string ComputeImageHash(Stream stream)
+    {
+        using var md5 = MD5.Create();
+        byte[] hash = md5.ComputeHash(stream);
+
+        return Convert.ToHexStringLower(hash);
+    }
+
+    public static SongPictureInfo FromFile(string fileName)
+    {
+        using FileStream fileStream = File.OpenRead(fileName);
+
+        return GetSongPictureInfo(fileStream, fileName);
+    }
+
+    private static SongPictureInfo GetSongPictureInfo(Stream stream, string imageName, string? imageHash = null)
+    {
+        stream.Seek(0, SeekOrigin.Begin);
+
+        SongPictureInfo songPictureInfo = new()
+        {
+            Stream = stream,
+            ImageHash = imageHash,
+            ImageName = imageName,
+            Size = (ulong)stream.Length
+        };
+
+        return songPictureInfo;
+    }
+
+    public void Dispose()
+    {
+        Stream.Dispose();
+        GC.SuppressFinalize(this);
+    }
+}