# Bedrock-API API Reference

## Protocol Buffer Definition

**File**: `proto/bedrock_service.proto`  
**Lines**: 622  
**Package**: `bedrock`  
**Go Package**: `github.com/feralbureau/bedrock-api/proto`

## Service Definition

```protobuf
service BedrockService {
    // Search operations
    rpc SearchTracks(SearchRequest) returns (SearchTracksResponse);
    rpc SearchAlbums(SearchRequest) returns (SearchAlbumsResponse);
    rpc SearchArtists(SearchRequest) returns (SearchArtistsResponse);
    rpc SearchPlaylists(SearchRequest) returns (SearchPlaylistsResponse);
    
    // Retrieval operations
    rpc GetTrack(GetRequest) returns (Track);
    rpc GetAlbum(GetRequest) returns (Album);
    rpc GetArtist(GetRequest) returns (Artist);
    rpc GetPlaylist(GetRequest) returns (Playlist);
    
    // Streaming
    rpc GetStreamURL(GetRequest) returns (StreamURLResponse);
    
    // Recommendations
    rpc GetSimilarTracks(SimilarTracksRequest) returns (SearchTracksResponse);
    
    // Lyrics
    rpc GetLyrics(LyricsRequest) returns (LyricsResponse);
    rpc GetSyncedLyrics(LyricsRequest) returns (SyncedLyricsResponse);
    
    // Statistics
    rpc GetTopTracks(TopRequest) returns (SearchTracksResponse);
    rpc GetTopAlbums(TopRequest) returns (SearchAlbumsResponse);
    rpc GetTopArtists(TopRequest) returns (SearchArtistsResponse);
    
    // Import
    rpc ImportPlaylist(ImportPlaylistRequest) returns (Playlist);
    
    // Service status
    rpc GetServiceStatus(Empty) returns (ServiceStatusResponse);
    
    // Authentication
    rpc Register(AuthRequest) returns (AuthResponse);
    rpc Login(AuthRequest) returns (AuthResponse);
    rpc RefreshToken(RefreshTokenRequest) returns (AuthResponse);
}
```

**Total Methods**: 23

## Method Categories

| Category | Methods | Authentication Required |
|----------|---------|------------------------|
| Search | 4 | Yes |
| Retrieval | 4 | Yes |
| Streaming | 1 | Yes |
| Recommendations | 1 | Yes |
| Lyrics | 2 | Yes |
| Statistics | 3 | Yes |
| Import | 1 | Yes |
| Service Status | 1 | No |
| Authentication | 3 | No (except RefreshToken) |

## Search Operations

### SearchTracks

**Request**:
```protobuf
message SearchRequest {
    string query = 1;
    int32 limit = 2;  // Default: 20, Max: 50
    Platform platform = 3;  // Optional: filter by platform
}
```

**Response**:
```protobuf
message SearchTracksResponse {
    repeated Track tracks = 1;
    ResponseStatus status = 2;
    repeated ProviderError errors = 3;
}
```

**Behavior**:
- Queries all enabled providers in parallel
- Aggregates results from all platforms
- Returns partial results if some providers fail
- Results are not deduplicated (same track from multiple platforms appears multiple times)

**Example**:
```go
resp, err := client.SearchTracks(ctx, &pb.SearchRequest{
    Query: "Bohemian Rhapsody",
    Limit: 10,
})

// resp.Tracks contains results from Spotify, SoundCloud, Deezer, YouTube Music
// Each track has platform-namespaced ID (e.g., "spotify:track:abc123")
```

### SearchAlbums

**Request**: Same as SearchTracks

**Response**:
```protobuf
message SearchAlbumsResponse {
    repeated Album albums = 1;
    ResponseStatus status = 2;
    repeated ProviderError errors = 3;
}
```

**Behavior**: Same parallel fan-out pattern as SearchTracks

### SearchArtists

**Request**: Same as SearchTracks

**Response**:
```protobuf
message SearchArtistsResponse {
    repeated Artist artists = 1;
    ResponseStatus status = 2;
    repeated ProviderError errors = 3;
}
```

**Behavior**: Same parallel fan-out pattern as SearchTracks

### SearchPlaylists

**Request**: Same as SearchTracks

**Response**:
```protobuf
message SearchPlaylistsResponse {
    repeated Playlist playlists = 1;
    ResponseStatus status = 2;
    repeated ProviderError errors = 3;
}
```

**Behavior**: Same parallel fan-out pattern as SearchTracks

## Retrieval Operations

### GetTrack

**Request**:
```protobuf
message GetRequest {
    string id = 1;  // Namespaced ID (e.g., "spotify:track:abc123")
}
```

**Response**:
```protobuf
message Track {
    string id = 1;
    string title = 2;
    string artist = 3;
    string artist_id = 4;
    string album = 5;
    string album_id = 6;
    int32 duration = 7;  // Seconds
    string cover_url = 8;
    int32 year = 9;
    string genre = 10;
    int64 play_count = 11;
    bool explicit = 12;
    string isrc = 13;
    Platform platform = 14;
}
```

**Behavior**:
- Parses namespaced ID to determine platform
- Routes request to specific provider
- Returns single track or error

**Example**:
```go
track, err := client.GetTrack(ctx, &pb.GetRequest{
    Id: "spotify:track:3n3Ppam7vgaVa1iaRUc9Lp",
})
```

### GetAlbum

**Request**: Same as GetTrack

**Response**:
```protobuf
message Album {
    string id = 1;
    string title = 2;
    string artist = 3;
    string artist_id = 4;
    int32 year = 5;
    string cover_url = 6;
    int32 track_count = 7;
    repeated Track tracks = 8;
    string genre = 9;
    string label = 10;
    Platform platform = 11;
}
```

**Behavior**:
- Returns album metadata
- Includes full track list in `tracks` field
- Track IDs are namespaced to same platform as album

### GetArtist

**Request**: Same as GetTrack

**Response**:
```protobuf
message Artist {
    string id = 1;
    string name = 2;
    string image_url = 3;
    repeated string genres = 4;
    int64 followers = 5;
    repeated Album albums = 6;  // Artist discography
    Platform platform = 7;
}
```

**Behavior**:
- Returns artist metadata
- Includes full discography in `albums` field (can be large)
- Deezer provider fetches albums concurrently

### GetPlaylist

**Request**: Same as GetTrack

**Response**:
```protobuf
message Playlist {
    string id = 1;
    string name = 2;
    string description = 3;
    string owner = 4;
    string cover_url = 5;
    int32 track_count = 6;
    repeated Track tracks = 7;
    bool public = 8;
    Platform platform = 9;
}
```

**Behavior**:
- Returns playlist metadata
- Includes full track list in `tracks` field
- SoundCloud uses batch hydration for track details (30 IDs per request)

## Streaming Operations

### GetStreamURL

**Request**:
```protobuf
message GetRequest {
    string id = 1;  // Track ID (namespaced)
}
```

**Response**:
```protobuf
message StreamURLResponse {
    string url = 1;
    int32 bitrate = 2;  // kbps
    string format = 3;  // mp3, opus, aac, etc.
    int32 expires_at = 4;  // Unix timestamp
}
```

**Behavior**:
- For SoundCloud/YouTube Music: Returns direct stream URL
- For Spotify/Deezer: Searches SoundCloud/YouTube Music for matching track, returns bridged stream URL
- Stream URLs are temporary (expire after 1-6 hours depending on provider)

**Stream Resolution Algorithm**:
```
1. Parse platform from namespaced ID
2. If platform is SoundCloud or YouTube Music:
   - Call platform's GetStreamURL directly
3. If platform is Spotify or Deezer:
   - Get track metadata (artist, title)
   - Search SoundCloud for "{artist} - {title}"
   - If found, return SoundCloud stream URL
   - If not found, search YouTube Music
   - If found, return YouTube Music stream URL
   - If not found, return error
```

**Example**:
```go
// Direct streaming platform
resp, err := client.GetStreamURL(ctx, &pb.GetRequest{
    Id: "soundcloud:track:1234567890",
})
// resp.Url = "https://cf-media.sndcdn.com/..."

// Non-streaming platform (bridged)
resp, err := client.GetStreamURL(ctx, &pb.GetRequest{
    Id: "spotify:track:3n3Ppam7vgaVa1iaRUc9Lp",
})
// resp.Url = "https://cf-media.sndcdn.com/..." (SoundCloud match)
```

**YouTube Music Stream Selection**:
- Tries 7 different client types sequentially
- Prefers itag 251 (opus) > 140 (aac)
- Skips ciphered streams (encrypted, requires decryption)
- Falls back to SoundCloud if all YouTube clients fail

## Recommendation Operations

### GetSimilarTracks

**Request**:
```protobuf
message SimilarTracksRequest {
    string track_id = 1;  // Namespaced track ID
    int32 limit = 2;  // Default: 20
}
```

**Response**: Same as SearchTracksResponse

**Behavior**:
- Queries provider's recommendation API
- Spotify: Uses "Get Recommendations" endpoint with seed track
- YouTube Music: Uses "Get Watch Playlist" (radio)
- SoundCloud: Uses "Related Tracks" endpoint
- Deezer: No similar tracks API (returns empty)

**Example**:
```go
resp, err := client.GetSimilarTracks(ctx, &pb.SimilarTracksRequest{
    TrackId: "spotify:track:3n3Ppam7vgaVa1iaRUc9Lp",
    Limit:   10,
})
// Returns 10 similar tracks from Spotify's recommendation engine
```

## Lyrics Operations

### GetLyrics

**Request**:
```protobuf
message LyricsRequest {
    string artist = 1;
    string title = 2;
    string album = 3;  // Optional
    int32 duration = 4;  // Optional, seconds
}
```

**Response**:
```protobuf
message LyricsResponse {
    string lyrics = 1;  // Plain text
    string source = 2;  // "genius"
    repeated Annotation annotations = 3;  // Genius annotations
}

message Annotation {
    string fragment = 1;  // Lyric fragment
    string annotation = 2;  // Explanation/context
}
```

**Behavior**:
- Queries Genius API
- Returns plain text lyrics
- Includes annotations (explanations of lyric meanings)
- Requires `GENIUS_ACCESS_TOKEN` environment variable

**Example**:
```go
resp, err := client.GetLyrics(ctx, &pb.LyricsRequest{
    Artist: "Queen",
    Title:  "Bohemian Rhapsody",
})
// resp.Lyrics = "Is this the real life?\nIs this just fantasy?..."
// resp.Annotations contains explanations of lyric meanings
```

### GetSyncedLyrics

**Request**: Same as GetLyrics

**Response**:
```protobuf
message SyncedLyricsResponse {
    repeated LyricLine lines = 1;
    string source = 2;  // "lrclib"
}

message LyricLine {
    int32 timestamp = 1;  // Milliseconds
    string text = 2;
}
```

**Behavior**:
- Queries LrcLib API
- Returns timestamped lyrics (LRC format)
- Matches by artist, title, album, duration
- 5 second timeout
- No authentication required

**Example**:
```go
resp, err := client.GetSyncedLyrics(ctx, &pb.LyricsRequest{
    Artist:   "Queen",
    Title:    "Bohemian Rhapsody",
    Album:    "A Night at the Opera",
    Duration: 354,
})
// resp.Lines = [
//   {Timestamp: 0, Text: "Is this the real life?"},
//   {Timestamp: 3500, Text: "Is this just fantasy?"},
//   ...
// ]
```

## Statistics Operations

### GetTopTracks

**Request**:
```protobuf
message TopRequest {
    Platform platform = 1;  // Required
    string region = 2;  // ISO country code (e.g., "US", "GB")
    int32 limit = 3;  // Default: 20
}
```

**Response**: Same as SearchTracksResponse

**Behavior**:
- Queries platform's charts/top tracks API
- Spotify: Uses "Get Playlist" on regional top 50 playlists
- YouTube Music: Uses trending charts
- SoundCloud: Uses "Trending" endpoint
- Deezer: Uses "Chart" endpoint

**Example**:
```go
resp, err := client.GetTopTracks(ctx, &pb.TopRequest{
    Platform: pb.Platform_SPOTIFY,
    Region:   "US",
    Limit:    10,
})
// Returns top 10 tracks in US Spotify charts
```

### GetTopAlbums

**Request**: Same as GetTopTracks

**Response**: Same as SearchAlbumsResponse

**Behavior**: Similar to GetTopTracks, queries platform-specific album charts

### GetTopArtists

**Request**: Same as GetTopTracks

**Response**: Same as SearchArtistsResponse

**Behavior**: Similar to GetTopTracks, queries platform-specific artist charts

## Import Operations

### ImportPlaylist

**Request**:
```protobuf
message ImportPlaylistRequest {
    string url = 1;  // Playlist URL from any supported platform
    Platform target_platform = 2;  // Platform to import to
}
```

**Response**: Same as Playlist message

**Behavior**:
- Parses playlist URL to determine source platform
- Fetches playlist tracks from source
- Creates new playlist on target platform
- Matches tracks across platforms (by ISRC or artist+title search)
- Returns created playlist

**Example**:
```go
resp, err := client.ImportPlaylist(ctx, &pb.ImportPlaylistRequest{
    Url:            "https://open.spotify.com/playlist/37i9dQZF1DXcBWIGoYBM5M",
    TargetPlatform: pb.Platform_SOUNDCLOUD,
})
// Creates SoundCloud playlist with matched tracks from Spotify playlist
```

**Limitations**:
- Requires authentication on target platform (not implemented)
- Track matching is best-effort (some tracks may not match)
- No progress reporting for large playlists

## Service Status Operations

### GetServiceStatus

**Request**:
```protobuf
message Empty {}
```

**Response**:
```protobuf
message ServiceStatusResponse {
    ServiceStatus status = 1;
    repeated DependencyStatus dependencies = 2;
}

enum ServiceStatus {
    HEALTHY = 0;
    DEGRADED = 1;
    UNHEALTHY = 2;
}

message DependencyStatus {
    string name = 1;  // Provider name
    HealthStatus health = 2;
    int32 latency = 3;  // Milliseconds
}

enum HealthStatus {
    HEALTHY = 0;
    UNHEALTHY = 1;
    UNKNOWN = 2;
}
```

**Behavior**:
- **Current**: Stub implementation, always returns HEALTHY
- **Planned**: Ping each provider, measure latency, return actual health status

**Example**:
```go
resp, err := client.GetServiceStatus(ctx, &pb.Empty{})
// resp.Status = HEALTHY
// resp.Dependencies = [
//   {Name: "spotify", Health: HEALTHY, Latency: 0},
//   {Name: "soundcloud", Health: HEALTHY, Latency: 0},
//   ...
// ]
```

## Authentication Operations

### Register

**Request**:
```protobuf
message AuthRequest {
    string email = 1;
    string password = 2;
}
```

**Response**:
```protobuf
message AuthResponse {
    string access_token = 1;  // JWT, 15 minute expiry
    string refresh_token = 2;  // JWT, 7 day expiry
    User user = 3;
}

message User {
    string id = 1;  // UUID
    string email = 2;
    string role = 3;  // "user" or "admin"
    bool is_verified = 4;
}
```

**Behavior**:
- Validates email format
- Hashes password with bcrypt (cost 10)
- Stores user in PostgreSQL
- Generates JWT access and refresh tokens
- Returns tokens and user info

**Validation**:
- Email must be valid format
- Email must be unique (returns error if exists)
- No password requirements (any length, no complexity rules)

**Example**:
```go
resp, err := client.Register(ctx, &pb.AuthRequest{
    Email:    "user@example.com",
    Password: "password123",
})
// resp.AccessToken = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
// resp.RefreshToken = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9..."
```

### Login

**Request**: Same as Register

**Response**: Same as Register

**Behavior**:
- Fetches user by email from PostgreSQL
- Verifies password with bcrypt
- Generates new JWT access and refresh tokens
- Returns tokens and user info

**Security**:
- No rate limiting (brute force possible)
- No account lockout after failed attempts
- No login attempt logging

**Example**:
```go
resp, err := client.Login(ctx, &pb.AuthRequest{
    Email:    "user@example.com",
    Password: "password123",
})
```

### RefreshToken

**Request**:
```protobuf
message RefreshTokenRequest {
    string refresh_token = 1;
}
```

**Response**: Same as AuthResponse

**Behavior**:
- Validates refresh token signature and expiration
- Extracts user ID and email from token claims
- Generates new access and refresh tokens
- Returns new tokens

**Token Rotation**: Both access and refresh tokens are regenerated (refresh token rotation).

**Example**:
```go
resp, err := client.RefreshToken(ctx, &pb.RefreshTokenRequest{
    RefreshToken: "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
})
// resp.AccessToken = new 15-minute token
// resp.RefreshToken = new 7-day token
```

## HTTP Proxy Endpoints

### Stream Proxy

**Endpoint**: `GET /stream/{service}/{id}`

**Parameters**:
- `service`: Platform name (spotify, soundcloud, deezer, youtube)
- `id`: Native track ID (not namespaced)

**Headers**:
- `Range`: Optional, for seeking (e.g., "bytes=0-1023")

**Response**:
- `200 OK`: Full stream
- `206 Partial Content`: Range response
- `400 Bad Request`: Invalid service or ID
- `404 Not Found`: Stream not found
- `500 Internal Server Error`: Upstream failure

**Behavior**:
- Constructs namespaced ID from service and ID
- Calls GetStreamURL gRPC method
- Proxies stream from provider
- Forwards range requests to upstream
- Streams response to client

**Example**:
```bash
curl http://localhost:8080/stream/soundcloud/1234567890 \
  -H "Range: bytes=0-1023" \
  -o audio.mp3
```

### Cover Proxy

**Endpoint**: `GET /cover/{service}/{id}`

**Parameters**:
- `service`: Platform name
- `id`: Album or track ID

**Response**: Same status codes as stream proxy

**Behavior**:
- Fetches album/track metadata
- Extracts cover URL
- Proxies image from provider
- Supports range requests

**Example**:
```bash
curl http://localhost:8080/cover/spotify/3n3Ppam7vgaVa1iaRUc9Lp \
  -o cover.jpg
```

## Platform Enum

```protobuf
enum Platform {
    SPOTIFY = 0;
    YANDEX = 1;
    VK = 2;
    DEEZER = 3;
    SOUNDCLOUD = 4;
    YOUTUBE = 5;
}
```

**Active Platforms**: SPOTIFY, DEEZER, SOUNDCLOUD, YOUTUBE  
**Stub Platforms**: YANDEX, VK

## Response Status Enum

```protobuf
enum ResponseStatus {
    OK = 0;       // All providers succeeded
    PARTIAL = 1;  // Some providers failed, some succeeded
    ERROR = 2;    // All providers failed
}
```

**Usage**: All search and multi-provider operations return this status

**Client Handling**:
```go
switch resp.Status {
case pb.ResponseStatus_OK:
    // Use resp.Tracks/Albums/Artists
case pb.ResponseStatus_PARTIAL:
    // Use resp.Tracks/Albums/Artists (partial results)
    // Log resp.Errors for debugging
case pb.ResponseStatus_ERROR:
    // No results available
    // Check resp.Errors for failure reasons
}
```

## Error Handling

### gRPC Status Codes

| Code | Scenario |
|------|----------|
| `OK` | Successful operation |
| `Unauthenticated` | Missing or invalid JWT token |
| `InvalidArgument` | Invalid request parameters |
| `NotFound` | Entity not found |
| `Internal` | Server error |

### Provider Errors

```protobuf
message ProviderError {
    string provider = 1;  // "spotify", "soundcloud", etc.
    string message = 2;   // Error description
}
```

**Included In**: All search and multi-provider responses

**Example**:
```go
resp, err := client.SearchTracks(ctx, &pb.SearchRequest{Query: "test"})
if err != nil {
    // gRPC-level error
    return err
}

if resp.Status == pb.ResponseStatus_PARTIAL {
    for _, providerErr := range resp.Errors {
        log.Printf("Provider %s failed: %s", providerErr.Provider, providerErr.Message)
    }
}
```

## Authentication Flow

### Initial Registration

```
Client                          Server
  |                               |
  |-- Register(email, password)-->|
  |                               |
  |                               |-- Hash password (bcrypt)
  |                               |-- Store in PostgreSQL
  |                               |-- Generate access token (15min)
  |                               |-- Generate refresh token (7 days)
  |                               |
  |<-- access_token, refresh_token|
  |                               |
```

### Authenticated Request

```
Client                          Server
  |                               |
  |-- SearchTracks(query) ------->|
  |   + metadata:                 |
  |     authorization: Bearer <token>
  |                               |
  |                               |-- authInterceptor validates JWT
  |                               |-- Extract user claims
  |                               |-- Execute search
  |                               |
  |<-- SearchTracksResponse ------|
  |                               |
```

### Token Refresh

```
Client                          Server
  |                               |
  |-- RefreshToken(refresh_token)|
  |                               |
  |                               |-- Validate refresh token
  |                               |-- Extract user claims
  |                               |-- Generate new access token
  |                               |-- Generate new refresh token
  |                               |
  |<-- new access_token, refresh_token
  |                               |
```

## Client Implementation Examples

### Go Client

```go
package main

import (
    "context"
    "log"
    
    "google.golang.org/grpc"
    "google.golang.org/grpc/metadata"
    pb "github.com/feralbureau/bedrock-api/proto"
)

func main() {
    conn, err := grpc.Dial("localhost:50052", grpc.WithInsecure())
    if err != nil {
        log.Fatal(err)
    }
    defer conn.Close()
    
    client := pb.NewBedrockServiceClient(conn)
    
    // Register
    authResp, err := client.Register(context.Background(), &pb.AuthRequest{
        Email:    "user@example.com",
        Password: "password123",
    })
    if err != nil {
        log.Fatal(err)
    }
    
    accessToken := authResp.AccessToken
    
    // Authenticated request
    ctx := metadata.AppendToOutgoingContext(context.Background(), "authorization", "Bearer "+accessToken)
    
    searchResp, err := client.SearchTracks(ctx, &pb.SearchRequest{
        Query: "Bohemian Rhapsody",
        Limit: 10,
    })
    if err != nil {
        log.Fatal(err)
    }
    
    for _, track := range searchResp.Tracks {
        log.Printf("%s - %s (%s)", track.Artist, track.Title, track.Platform)
    }
}
```

### Python Client

```python
import grpc
import bedrock_pb2
import bedrock_pb2_grpc

channel = grpc.insecure_channel('localhost:50052')
client = bedrock_pb2_grpc.BedrockServiceStub(channel)

# Register
auth_resp = client.Register(bedrock_pb2.AuthRequest(
    email='user@example.com',
    password='password123'
))

access_token = auth_resp.access_token

# Authenticated request
metadata = [('authorization', f'Bearer {access_token}')]

search_resp = client.SearchTracks(
    bedrock_pb2.SearchRequest(query='Bohemian Rhapsody', limit=10),
    metadata=metadata
)

for track in search_resp.tracks:
    print(f"{track.artist} - {track.title} ({track.platform})")
```

### JavaScript Client (Node.js)

```javascript
const grpc = require('@grpc/grpc-js');
const protoLoader = require('@grpc/proto-loader');

const packageDefinition = protoLoader.loadSync('bedrock_service.proto');
const bedrock = grpc.loadPackageDefinition(packageDefinition).bedrock;

const client = new bedrock.BedrockService('localhost:50052', grpc.credentials.createInsecure());

// Register
client.Register({ email: 'user@example.com', password: 'password123' }, (err, authResp) => {
    if (err) throw err;
    
    const accessToken = authResp.access_token;
    
    // Authenticated request
    const metadata = new grpc.Metadata();
    metadata.add('authorization', `Bearer ${accessToken}`);
    
    client.SearchTracks(
        { query: 'Bohemian Rhapsody', limit: 10 },
        metadata,
        (err, searchResp) => {
            if (err) throw err;
            
            searchResp.tracks.forEach(track => {
                console.log(`${track.artist} - ${track.title} (${track.platform})`);
            });
        }
    );
});
```

## Rate Limiting

**Current**: No rate limiting implemented

**Risks**:
- Provider API rate limits can be exceeded
- No protection against abuse
- No per-user quotas

**Recommendations**:
- Implement per-user rate limiting (e.g., 100 requests/minute)
- Implement per-IP rate limiting for unauthenticated endpoints
- Cache responses to reduce provider API calls
- Implement circuit breakers for failing providers

## Pagination

**Current**: No pagination support

**Limitations**:
- Search results limited by `limit` parameter (max 50)
- No cursor or offset-based pagination
- Large result sets cannot be retrieved incrementally

**Workarounds**:
- Increase `limit` parameter (up to 50)
- Make multiple searches with different queries

**Recommendations**:
- Add cursor-based pagination for search results
- Add offset/limit pagination for playlists and albums
- Return total result count in responses

## Versioning

**Current**: No API versioning

**Implications**:
- Breaking changes affect all clients
- No backward compatibility guarantees
- No deprecation path for old endpoints

**Recommendations**:
- Add version to package name (e.g., `bedrock.v1`)
- Support multiple versions simultaneously
- Document breaking changes and migration paths

## Performance Characteristics

### Response Times (Typical)

| Operation | Latency | Notes |
|-----------|---------|-------|
| SearchTracks | 200-500ms | Parallel provider queries |
| GetTrack | 100-300ms | Single provider query |
| GetStreamURL | 200-800ms | Includes bridge resolution |
| GetLyrics | 1-3s | Genius API can be slow |
| GetSyncedLyrics | 100-500ms | LrcLib is fast |
| Register/Login | 100-200ms | bcrypt hashing overhead |

### Payload Sizes (Typical)

| Operation | Response Size | Notes |
|-----------|---------------|-------|
| SearchTracks (10 results) | 5-10 KB | Depends on metadata richness |
| GetAlbum (with tracks) | 20-100 KB | Depends on track count |
| GetArtist (with discography) | 50-500 KB | Can be very large |
| GetPlaylist (100 tracks) | 50-100 KB | Includes full track metadata |
| GetLyrics | 2-10 KB | Plain text |
| GetSyncedLyrics | 5-20 KB | Timestamped lines |

## Security Considerations

### Authentication

- JWT tokens transmitted in gRPC metadata
- No TLS by default (tokens sent in plaintext)
- No token revocation mechanism
- No refresh token rotation (fixed 7-day expiry)

### Authorization

- No role-based access control (RBAC)
- All authenticated users have same permissions
- No resource ownership checks
- No admin-only endpoints

### Input Validation

- No query sanitization (SQL injection risk if queries touch DB)
- No limit enforcement on request parameters
- No URL validation for ImportPlaylist

### Recommendations

- Deploy behind TLS-terminating reverse proxy
- Implement token revocation list (Redis)
- Add RBAC for admin operations
- Validate and sanitize all inputs
- Add request size limits