"""Twitch EventSub client for handling stream events."""

import logging
from typing import Callable, Optional

logger = logging.getLogger(__name__)


class TwitchEventSubClient:
    """
    Client for Twitch EventSub WebSocket connections.
    
    Handles real-time stream events like chat messages, follows, raids, etc.
    
    TODO: Implement real OAuth 2.0 token exchange flow
    TODO: Implement WebSocket connection to Twitch EventSub
    TODO: Handle subscription management (follow, subscribe, cheer, raid events)
    TODO: Implement heartbeat and reconnection logic
    """

    def __init__(self, client_id: str, access_token: str):
        """
        Initialize EventSub client.
        
        Args:
            client_id: Twitch application client ID
            access_token: OAuth token for API calls
        """
        self.client_id = client_id
        self.access_token = access_token
        self.connected = False
        self.event_handlers: dict[str, Callable] = {}

    async def connect(self, channel_id: str) -> bool:
        """
        Establish WebSocket connection to Twitch EventSub.
        
        Args:
            channel_id: Twitch channel ID to monitor
            
        Returns:
            True if connection successful
            
        TODO: Implement WebSocket handshake
        TODO: Subscribe to stream.online, stream.offline
        """
        logger.info(f"Attempting to connect to EventSub for channel {channel_id}")
        self.connected = True
        return True

    async def disconnect(self) -> None:
        """
        Close EventSub connection gracefully.
        
        TODO: Send close frame to WebSocket
        TODO: Clean up subscriptions
        """
        logger.info("Disconnecting from EventSub")
        self.connected = False

    async def listen(self) -> None:
        """
        Listen for incoming EventSub events (blocking call).
        
        Should run in a background task and emit events to registered handlers.
        
        TODO: Implement WebSocket message loop
        TODO: Parse and dispatch events to registered handlers
        TODO: Handle reconnection on failure
        """
        logger.info("EventSub listener started (stub)")
        pass

    def on(self, event_type: str) -> Callable:
        """
        Register an event handler for a specific event type.
        
        Args:
            event_type: Type of event (e.g., 'stream.online', 'channel.follow')
            
        Returns:
            Decorator function
        """
        def decorator(func: Callable) -> Callable:
            self.event_handlers[event_type] = func
            logger.debug(f"Registered handler for {event_type}")
            return func
        return decorator

    async def emit_event(self, event_type: str, data: dict) -> None:
        """
        Emit an event to registered handlers (internal use).
        
        Args:
            event_type: Type of event
            data: Event data payload
        """
        if event_type in self.event_handlers:
            handler = self.event_handlers[event_type]
            try:
                await handler(data)
            except Exception as e:
                logger.error(f"Error in event handler for {event_type}: {e}")