feat: playlist implementation

octo-fiesta/Services/Common/BaseDownloadService.cs

@@ -4,6 +4,7 @@ using octo_fiesta.Models.Download;
 using octo_fiesta.Models.Search;
 using octo_fiesta.Models.Subsonic;
 using octo_fiesta.Services.Local;
+using octo_fiesta.Services.Subsonic;
 using TagLib;
 using IOFile = System.IO.File;
 
@@ -21,6 +22,7 @@ public abstract class BaseDownloadService : IDownloadService
     protected readonly IMusicMetadataService MetadataService;
     protected readonly SubsonicSettings SubsonicSettings;
     protected readonly ILogger Logger;
+    protected readonly IServiceProvider ServiceProvider;
     
     protected readonly string DownloadPath;
     protected readonly string CachePath;
@@ -38,12 +40,14 @@ public abstract class BaseDownloadService : IDownloadService
         ILocalLibraryService localLibraryService,
         IMusicMetadataService metadataService,
         SubsonicSettings subsonicSettings,
+        IServiceProvider serviceProvider,
         ILogger logger)
     {
         Configuration = configuration;
         LocalLibraryService = localLibraryService;
         MetadataService = metadataService;
         SubsonicSettings = subsonicSettings;
+        ServiceProvider = serviceProvider;
         Logger = logger;
         
         DownloadPath = configuration["Library:DownloadPath"] ?? "./downloads";
@@ -79,6 +83,30 @@ public abstract class BaseDownloadService : IDownloadService
         return info;
     }
     
+    public async Task<string?> GetLocalPathIfExistsAsync(string externalProvider, string externalId)
+    {
+        if (externalProvider != ProviderName)
+        {
+            return null;
+        }
+        
+        // Check local library
+        var localPath = await LocalLibraryService.GetLocalPathForExternalSongAsync(externalProvider, externalId);
+        if (localPath != null && IOFile.Exists(localPath))
+        {
+            return localPath;
+        }
+        
+        // Check cache directory
+        var cachedPath = GetCachedFilePath(externalProvider, externalId);
+        if (cachedPath != null && IOFile.Exists(cachedPath))
+        {
+            return cachedPath;
+        }
+        
+        return null;
+    }
+    
     public abstract Task<bool> IsAvailableAsync();
     
     public void DownloadRemainingAlbumTracksInBackground(string externalProvider, string albumExternalId, string excludeTrackExternalId)
@@ -240,6 +268,25 @@ public abstract class BaseDownloadService : IDownloadService
             
             song.LocalPath = localPath;
             
+            // Check if this track belongs to a playlist and update M3U
+            try
+            {
+                var playlistSyncService = ServiceProvider.GetService(typeof(PlaylistSyncService)) as PlaylistSyncService;
+                if (playlistSyncService != null)
+                {
+                    var playlistId = playlistSyncService.GetPlaylistIdForTrack(songId);
+                    if (playlistId != null)
+                    {
+                        Logger.LogInformation("Track {SongId} belongs to playlist {PlaylistId}, adding to M3U", songId, playlistId);
+                        await playlistSyncService.AddTrackToM3UAsync(playlistId, song, localPath);
+                    }
+                }
+            }
+            catch (Exception ex)
+            {
+                Logger.LogWarning(ex, "Failed to update playlist M3U for track {SongId}", songId);
+            }
+            
             // Only register and scan if NOT in cache mode
             if (!isCache)
             {

octo-fiesta/Services/Common/PlaylistIdHelper.cs

@@ -0,0 +1,76 @@
+namespace octo_fiesta.Services.Common;
+
+/// <summary>
+/// Helper class for handling external playlist IDs.
+/// Playlist IDs use the format: "pl-{provider}-{externalId}"
+/// Example: "pl-deezer-123456", "pl-qobuz-789"
+/// </summary>
+public static class PlaylistIdHelper
+{
+    private const string PlaylistPrefix = "pl-";
+    
+    /// <summary>
+    /// Checks if an ID represents an external playlist.
+    /// </summary>
+    /// <param name="id">The ID to check</param>
+    /// <returns>True if the ID starts with "pl-", false otherwise</returns>
+    public static bool IsExternalPlaylist(string? id)
+    {
+        return !string.IsNullOrEmpty(id) && id.StartsWith(PlaylistPrefix, StringComparison.OrdinalIgnoreCase);
+    }
+    
+    /// <summary>
+    /// Parses a playlist ID to extract provider and external ID.
+    /// </summary>
+    /// <param name="id">The playlist ID in format "pl-{provider}-{externalId}"</param>
+    /// <returns>A tuple containing (provider, externalId)</returns>
+    /// <exception cref="ArgumentException">Thrown if the ID format is invalid</exception>
+    public static (string provider, string externalId) ParsePlaylistId(string id)
+    {
+        if (!IsExternalPlaylist(id))
+        {
+            throw new ArgumentException($"Invalid playlist ID format. Expected 'pl-{{provider}}-{{externalId}}', got '{id}'", nameof(id));
+        }
+        
+        // Remove "pl-" prefix
+        var withoutPrefix = id.Substring(PlaylistPrefix.Length);
+        
+        // Split by first dash to get provider and externalId
+        var dashIndex = withoutPrefix.IndexOf('-');
+        if (dashIndex == -1)
+        {
+            throw new ArgumentException($"Invalid playlist ID format. Expected 'pl-{{provider}}-{{externalId}}', got '{id}'", nameof(id));
+        }
+        
+        var provider = withoutPrefix.Substring(0, dashIndex);
+        var externalId = withoutPrefix.Substring(dashIndex + 1);
+        
+        if (string.IsNullOrEmpty(provider) || string.IsNullOrEmpty(externalId))
+        {
+            throw new ArgumentException($"Invalid playlist ID format. Provider or external ID is empty in '{id}'", nameof(id));
+        }
+        
+        return (provider, externalId);
+    }
+    
+    /// <summary>
+    /// Creates a playlist ID from provider and external ID.
+    /// </summary>
+    /// <param name="provider">The provider name (e.g., "deezer", "qobuz")</param>
+    /// <param name="externalId">The external ID from the provider</param>
+    /// <returns>A playlist ID in format "pl-{provider}-{externalId}"</returns>
+    public static string CreatePlaylistId(string provider, string externalId)
+    {
+        if (string.IsNullOrEmpty(provider))
+        {
+            throw new ArgumentException("Provider cannot be null or empty", nameof(provider));
+        }
+        
+        if (string.IsNullOrEmpty(externalId))
+        {
+            throw new ArgumentException("External ID cannot be null or empty", nameof(externalId));
+        }
+        
+        return $"{PlaylistPrefix}{provider.ToLowerInvariant()}-{externalId}";
+    }
+}