Plugin System

class BeetsPlugin:
    def __init__(self, name: str):
        """
        Initialize a beets plugin.
        
        Parameters:
        - name: Plugin name for identification and configuration
        """
    
    def commands(self) -> List[Subcommand]:
        """
        Return list of CLI commands provided by this plugin.
        
        Returns:
        List of Subcommand objects that will be added to beets CLI
        """
    
    def template_funcs(self) -> Dict[str, Callable]:
        """
        Return template functions for path formatting.
        
        Returns:
        Dictionary mapping function names to callable functions
        """
    
    def item_types(self) -> Dict[str, Type]:
        """
        Return field types for Item model extensions.
        
        Returns:
        Dictionary mapping field names to database type objects
        """
    
    def album_types(self) -> Dict[str, Type]:
        """
        Return field types for Album model extensions.
        
        Returns:
        Dictionary mapping field names to database type objects
        """
    
    def queries(self) -> Dict[str, Type]:
        """
        Return custom query types for database searches.
        
        Returns:
        Dictionary mapping query prefixes to Query class types
        """
    
    def album_distance(self, items: List[Item], album_info: AlbumInfo) -> float:
        """
        Calculate custom distance for album matching.
        
        Parameters:
        - items: List of Item objects being matched
        - album_info: AlbumInfo candidate from metadata source
        
        Returns:
        Distance value (lower means better match)
        """
    
    def track_distance(self, item: Item, track_info: TrackInfo) -> float:
        """
        Calculate custom distance for track matching.
        
        Parameters:
        - item: Item object being matched
        - track_info: TrackInfo candidate from metadata source
        
        Returns:
        Distance value (lower means better match)
        """

class MetadataSourcePlugin(BeetsPlugin):
    """Base class for plugins that provide metadata sources."""
    
    def get_albums(self, query: str) -> Iterator[AlbumInfo]:
        """
        Search for album metadata.
        
        Parameters:
        - query: Search query string
        
        Returns:
        Iterator of AlbumInfo objects matching the query
        """
    
    def get_tracks(self, query: str) -> Iterator[TrackInfo]:
        """
        Search for track metadata.
        
        Parameters:
        - query: Search query string
        
        Returns:
        Iterator of TrackInfo objects matching the query
        """
    
    def candidates(self, items: List[Item], artist: str, album: str) -> Iterator[AlbumInfo]:
        """
        Get album candidates for a set of items.
        
        Parameters:
        - items: List of Item objects to find matches for
        - artist: Artist hint for search
        - album: Album hint for search
        
        Returns:
        Iterator of AlbumInfo candidates
        """
    
    def item_candidates(self, item: Item, artist: str, title: str) -> Iterator[TrackInfo]:
        """
        Get track candidates for a single item.
        
        Parameters:
        - item: Item object to find matches for
        - artist: Artist hint for search
        - title: Title hint for search
        
        Returns:
        Iterator of TrackInfo candidates
        """

def load_plugins(names: List[str]) -> None:
    """
    Load specified plugins by name.
    
    Parameters:
    - names: List of plugin names to load
    """

def find_plugins() -> List[str]:
    """
    Discover all available plugins.
    
    Returns:
    List of plugin names that can be loaded
    """

def commands() -> List[Subcommand]:
    """
    Get all CLI commands from loaded plugins.
    
    Returns:
    List of Subcommand objects from all plugins
    """

def types(model_cls: Type) -> Dict[str, Type]:
    """
    Get field types from all plugins for a model class.
    
    Parameters:
    - model_cls: Item or Album class
    
    Returns:
    Dictionary of field name to type mappings
    """

def named_queries(model_cls: Type) -> Dict[str, Query]:
    """
    Get named queries from all plugins for a model class.
    
    Parameters:
    - model_cls: Item or Album class
    
    Returns:
    Dictionary of query name to Query object mappings
    """

def send(event: str, **kwargs) -> None:
    """
    Send event to all registered plugin listeners.
    
    Parameters:
    - event: Event name string
    - **kwargs: Event-specific parameters
    """

def listen(event: str, func: Callable) -> None:
    """
    Register function to listen for specific event.
    
    Parameters:
    - event: Event name to listen for
    - func: Callback function for event
    """

# Library events
'library_opened'        # Library instance created
'database_change'       # Database schema changed

# Import events
'import_begin'          # Import process starting
'import_task_start'     # Individual import task starting  
'import_task_choice'    # User making import choice
'import_task_files'     # Files being processed
'album_imported'        # Album successfully imported
'item_imported'         # Item successfully imported
'import_task_end'       # Import task completed

# Item/Album events
'item_copied'           # Item file copied
'item_moved'            # Item file moved
'item_removed'          # Item removed from library
'item_written'          # Item metadata written to file
'album_removed'         # Album removed from library

# CLI events
'cli_exit'              # CLI command completed
'before_choose_candidate'  # Before metadata choice UI
'after_convert'         # After audio conversion

from beets.plugins import BeetsPlugin
from beets.ui import Subcommand, decargs

class HelloPlugin(BeetsPlugin):
    """Simple plugin adding a hello command."""
    
    def commands(self):
        hello_cmd = Subcommand('hello', help='Say hello')
        hello_cmd.func = self.hello_command
        return [hello_cmd]
    
    def hello_command(self, lib, opts, args):
        """Implementation of hello command."""
        name = args[0] if args else 'World'
        print(f"Hello, {name}!")

# Register plugin
hello_plugin = HelloPlugin('hello')

from beets.plugins import BeetsPlugin
from beets.dbcore.types import STRING, INTEGER

class CustomFieldsPlugin(BeetsPlugin):
    """Plugin adding custom fields to items."""
    
    def item_types(self):
        return {
            'myrating': INTEGER,      # Custom rating field
            'notes': STRING,          # Notes field
            'customtag': STRING,      # Custom tag field
        }
    
    def album_types(self):
        return {
            'albumrating': INTEGER,   # Album-level rating
        }

# Register plugin  
fields_plugin = CustomFieldsPlugin('customfields')

from beets.plugins import BeetsPlugin
from beets import plugins

class LoggingPlugin(BeetsPlugin):
    """Plugin that logs various beets events."""
    
    def __init__(self, name):
        super().__init__(name)
        
        # Register event listeners
        plugins.listen('item_imported', self.on_item_imported)
        plugins.listen('album_imported', self.on_album_imported)
        plugins.listen('item_moved', self.on_item_moved)
    
    def on_item_imported(self, lib, item):
        """Called when an item is imported."""
        print(f"Imported: {item.artist} - {item.title}")
    
    def on_album_imported(self, lib, album):
        """Called when an album is imported."""
        print(f"Album imported: {album.albumartist} - {album.album}")
    
    def on_item_moved(self, item, source, destination):
        """Called when an item file is moved."""
        print(f"Moved: {source} -> {destination}")

logging_plugin = LoggingPlugin('logging')

from beets.plugins import MetadataSourcePlugin
from beets.autotag.hooks import AlbumInfo, TrackInfo
import requests

class CustomAPIPlugin(MetadataSourcePlugin):
    """Plugin providing metadata from custom API."""
    
    def get_albums(self, query):
        """Search for albums via custom API."""
        response = requests.get(f'https://api.example.com/albums?q={query}')
        
        for result in response.json()['albums']:
            yield AlbumInfo(
                album=result['title'],
                artist=result['artist'],
                year=result.get('year'),
                tracks=[
                    TrackInfo(
                        title=track['title'],
                        artist=track.get('artist', result['artist']),
                        track=track['number'],
                        length=track.get('duration')
                    ) for track in result.get('tracks', [])
                ]
            )
    
    def get_tracks(self, query):
        """Search for individual tracks."""
        response = requests.get(f'https://api.example.com/tracks?q={query}')
        
        for result in response.json()['tracks']:
            yield TrackInfo(
                title=result['title'],
                artist=result['artist'],
                length=result.get('duration'),
                trackid=str(result['id'])
            )

api_plugin = CustomAPIPlugin('customapi')

from beets.plugins import BeetsPlugin
import re

class TemplatePlugin(BeetsPlugin):
    """Plugin adding custom template functions."""
    
    def template_funcs(self):
        return {
            'acronym': self.acronymize,
            'sanitize': self.sanitize_filename,
            'shorten': self.shorten_text,
        }
    
    def acronymize(self, text):
        """Convert text to acronym (first letters)."""
        words = text.split()
        return ''.join(word[0].upper() for word in words if word)
    
    def sanitize_filename(self, text):
        """Remove/replace invalid filename characters."""
        # Remove invalid filename characters
        return re.sub(r'[<>:"/\\|?*]', '', text)
    
    def shorten_text(self, text, length=20):
        """Shorten text to specified length."""
        if len(text) <= length:
            return text
        return text[:length-3] + '...'

template_plugin = TemplatePlugin('templates')

# Usage in path formats:
# paths:
#   default: $albumartist/$album/$track $title
#   short: %acronym{$albumartist}/%shorten{$album,15}/$track %sanitize{$title}

from beets.plugins import BeetsPlugin
from beets.dbcore.query import StringQuery

class MyRatingQuery(StringQuery):
    """Custom query for rating ranges."""
    
    def __init__(self, field, pattern):
        # Convert rating range (e.g., "8..10") to appropriate query
        if '..' in pattern:
            start, end = pattern.split('..')
            # Implement range logic
            pattern = f">={start} AND <={end}"
        super().__init__(field, pattern)

class RatingPlugin(BeetsPlugin):
    """Plugin adding rating query support."""
    
    def queries(self):
        return {
            'myrating': MyRatingQuery,
        }

rating_plugin = RatingPlugin('rating')

# Usage: beet list myrating:8..10

from beets import config

class ConfigurablePlugin(BeetsPlugin):
    """Plugin with configuration options."""
    
    def __init__(self, name):
        super().__init__(name)
        
        # Set default configuration values
        config[name].add({
            'enabled': True,
            'api_key': '',
            'timeout': 10,
            'format': 'json'
        })
    
    def get_config(self, key, default=None):
        """Get plugin configuration value."""
        return config[self.name][key].get(default)
    
    def commands(self):
        # Only provide commands if enabled
        if self.get_config('enabled', True):
            return [self.create_command()]
        return []

# Configuration in config.yaml
plugins: 
  - fetchart
  - lyrics
  - discogs
  - mycustomplugin

# Plugin-specific configuration
fetchart:
  auto: yes
  sources: coverart lastfm amazon

mycustomplugin:
  enabled: true
  api_key: "your-api-key"
  timeout: 30

class PluginConflictError(Exception):
    """Raised when plugins conflict with each other."""

class PluginLoadError(Exception):
    """Raised when plugin cannot be loaded."""