allstarr/README.md

# Octo-Fiesta

A Subsonic API proxy server that transparently integrates Deezer as a music source. When a song is not available in your local Navidrome library, it is automatically fetched from Deezer, downloaded, and served to your Subsonic-compatible client.

## Features

- **Transparent Proxy**: Acts as a middleware between Subsonic clients (like Aonsoku, Sublime Music, etc.) and your Navidrome server
- **Deezer Integration**: Seamlessly searches and streams music from Deezer when not available locally
- **Automatic Downloads**: Songs are downloaded on-the-fly and cached for future use
- **Full Metadata Embedding**: Downloaded files include complete ID3 tags (title, artist, album, track number, year, genre, BPM, ISRC, etc.) and embedded cover art
- **Organized Library**: Downloads are saved in a clean `Artist/Album/Track.mp3` folder structure
- **Artist Deduplication**: Merges local and Deezer artists to avoid duplicates in search results
- **Album Enrichment**: Local albums are enriched with missing tracks from Deezer
- **Cover Art Proxy**: Serves cover art for external content transparently

## Architecture

```
┌─────────────────┐     ┌──────────────────┐     ┌─────────────────┐
│  Subsonic       │────▶│   Octo-Fiesta    │────▶│   Navidrome     │
│  Client         │◀────│   (Proxy)        │◀────│   Server        │
│  (Aonsoku)      │     │                  │     │                 │
└─────────────────┘     └────────┬─────────┘     └─────────────────┘
                                 │
                                 ▼
                        ┌─────────────────┐
                        │   Deezer API    │
                        │   (Metadata +   │
                        │    Downloads)   │
                        └─────────────────┘
```

## Requirements

- [.NET 9.0 SDK](https://dotnet.microsoft.com/download/dotnet/9.0)
- A running [Navidrome](https://www.navidrome.org/) server
- A Deezer ARL token (for downloading)

## Installation

1. **Clone the repository**
   ```bash
   git clone https://github.com/your-username/octo-fiesta.git
   cd octo-fiesta
   ```

2. **Restore dependencies**
   ```bash
   dotnet restore
   ```

3. **Configure the application**
   
   Edit `octo-fiesta/appsettings.json`:
   ```json
   {
     "Subsonic": {
       "Url": "http://your-navidrome-server:4533"
     },
     "Library": {
       "DownloadPath": "./downloads"
     },
     "Deezer": {
       "Arl": "your-deezer-arl-token",
       "ArlFallback": ""
     }
   }
   ```

4. **Run the server**
   ```bash
   cd octo-fiesta
   dotnet run
   ```
   
   The proxy will start on `http://localhost:5274` by default.

5. **Configure your Subsonic client**
   
   Point your Subsonic client to `http://localhost:5274` instead of your Navidrome server directly.

## Configuration

### Subsonic Settings

| Setting | Description |
|---------|-------------|
| `Subsonic:Url` | URL of your Navidrome/Subsonic server |

### Library Settings

| Setting | Description |
|---------|-------------|
| `Library:DownloadPath` | Directory where downloaded songs are stored |

### Deezer Settings

| Setting | Description |
|---------|-------------|
| `Deezer:Arl` | Your Deezer ARL token (required for downloads) |
| `Deezer:ArlFallback` | Backup ARL token if primary fails |

### Getting a Deezer ARL Token

1. Log in to [Deezer](https://www.deezer.com) in your browser
2. Open Developer Tools (F12)
3. Go to Application > Cookies > `https://www.deezer.com`
4. Find the `arl` cookie and copy its value

> **Note**: ARL tokens expire periodically and need to be refreshed.

## API Endpoints

The proxy implements the Subsonic API and adds transparent Deezer integration to:

| Endpoint | Description |
|----------|-------------|
| `GET /rest/search3` | Merged search results from Navidrome + Deezer |
| `GET /rest/stream` | Streams audio, downloading from Deezer if needed |
| `GET /rest/getSong` | Returns song details (local or Deezer) |
| `GET /rest/getAlbum` | Returns album with tracks from both sources |
| `GET /rest/getArtist` | Returns artist with albums from both sources |
| `GET /rest/getCoverArt` | Proxies cover art for external content |

All other Subsonic API endpoints are passed through to Navidrome unchanged.

## External ID Format

External (Deezer) content uses typed IDs:

| Type | Format | Example |
|------|--------|---------|
| Song | `ext-deezer-song-{id}` | `ext-deezer-song-123456` |
| Album | `ext-deezer-album-{id}` | `ext-deezer-album-789012` |
| Artist | `ext-deezer-artist-{id}` | `ext-deezer-artist-259` |

Legacy format `ext-deezer-{id}` is also supported (assumes song type).

## Download Folder Structure

Downloaded music is organized as:
```
downloads/
├── Artist Name/
│   ├── Album Title/
│   │   ├── 01 - Track One.mp3
│   │   ├── 02 - Track Two.mp3
│   │   └── ...
│   └── Another Album/
│       └── ...
└── Another Artist/
    └── ...
```

## Metadata Embedding

Downloaded files include:
- **Basic**: Title, Artist, Album, Album Artist
- **Track Info**: Track Number, Total Tracks, Disc Number
- **Dates**: Year, Release Date
- **Audio**: BPM, Duration
- **Identifiers**: ISRC (in comments)
- **Credits**: Contributors/Composers
- **Visual**: Embedded cover art (high resolution)
- **Rights**: Copyright, Label

## Development

### Build
```bash
dotnet build
```

### Run Tests
```bash
dotnet test
```

### Project Structure

```
octo-fiesta/
├── Controllers/
│   └── SubsonicController.cs    # Main API controller
├── Models/
│   ├── MusicModels.cs           # Song, Album, Artist, etc.
│   └── SubsonicSettings.cs      # Configuration model
├── Services/
│   ├── DeezerDownloadService.cs # Deezer download & decryption
│   ├── DeezerMetadataService.cs # Deezer API integration
│   ├── IDownloadService.cs      # Download interface
│   ├── IMusicMetadataService.cs # Metadata interface
│   └── LocalLibraryService.cs   # Local file management
├── Program.cs                   # Application entry point
└── appsettings.json             # Configuration

octo-fiesta.Tests/
├── DeezerDownloadServiceTests.cs
├── DeezerMetadataServiceTests.cs
└── LocalLibraryServiceTests.cs
```

### Dependencies

- **BouncyCastle.Cryptography** - Blowfish decryption for Deezer streams
- **TagLibSharp** - ID3 tag and cover art embedding
- **Swashbuckle.AspNetCore** - Swagger/OpenAPI documentation

## Limitations

- **Playlist Search**: Subsonic clients like Aonsoku filter playlists client-side from a cached `getPlaylists` call. Deezer playlists appear in global search (`search3`) but not in the Playlists tab filter.
- **Region Restrictions**: Some Deezer tracks may be unavailable depending on your region.
- **ARL Expiration**: Deezer ARL tokens expire and need periodic refresh.

## License

MIT

## Acknowledgments

- [Navidrome](https://www.navidrome.org/) - The excellent self-hosted music server
- [Deezer](https://www.deezer.com/) - Music streaming service
- [Subsonic API](http://www.subsonic.org/pages/api.jsp) - The API specification