"""
Fuseki Signal Manager - No-op implementation for HTTP-based notifications.

This is a no-op implementation that satisfies the SignalManagerInterface
requirements but doesn't actually send notifications. This allows the
Fuseki backend to work without implementing complex HTTP webhook or
polling mechanisms initially.

Future enhancements could include:
- HTTP webhook notifications to external services
- Polling-based change detection
"""

import asyncio
import logging
from typing import Dict, Any, Optional, Callable, List

from ..backend_config import SignalManagerInterface

logger = logging.getLogger(__name__)


class FusekiSignalManager(SignalManagerInterface):
    """
    No-op signal manager for Fuseki backend.
    
    This implementation satisfies the SignalManagerInterface but doesn't
    actually send notifications. All methods are implemented as no-ops
    with appropriate logging.
    """
    
    def __init__(self, **config):
        """
        Initialize the Fuseki signal manager.
        
        Args:
            **config: Configuration parameters (currently unused)
        """
        self.config = config
        self.callbacks: List[Callable] = []
        self.space_callbacks: Dict[str, List[Callable]] = {}
        self.closed = False
        
        logger.info("🔔 FusekiSignalManager initialized (no-op implementation)")
        if config:
            logger.debug(f"🔔 Configuration: {config}")
    
    async def notify_space_created(self, space_id: str) -> None:
        """
        Notify that a space was created (no-op).
        
        Args:
            space_id: Space identifier
        """
        if self.closed:
            return
            
        logger.info(f"🔔 [NO-OP] Space created notification: {space_id}")
        
        # Execute callbacks for demonstration (though none expected in no-op mode)
        await self._execute_callbacks('space_created', {
            'space_id': space_id,
            'event_type': 'created'
        })
    
    async def notify_space_deleted(self, space_id: str) -> None:
        """
        Notify that a space was deleted (no-op).
        
        Args:
            space_id: Space identifier
        """
        if self.closed:
            return
            
        logger.info(f"🔔 [NO-OP] Space deleted notification: {space_id}")
        
        # Execute callbacks for demonstration
        await self._execute_callbacks('space_deleted', {
            'space_id': space_id,
            'event_type': 'deleted'
        })
    
    async def notify_space_updated(self, space_id: str, update_type: str, metadata: Dict[str, Any] = None) -> None:
        """
        Notify that a space was updated (no-op).
        
        Args:
            space_id: Space identifier
            update_type: Type of update (e.g., 'quad_added', 'namespace_added')
            metadata: Optional metadata about the update
        """
        if self.closed:
            return
            
        logger.info(f"🔔 [NO-OP] Space updated notification: {space_id}, type: {update_type}")
        if metadata:
            logger.debug(f"🔔 Update metadata: {metadata}")
        
        # Execute callbacks for demonstration
        await self._execute_callbacks('space_updated', {
            'space_id': space_id,
            'event_type': 'updated',
            'update_type': update_type,
            'metadata': metadata or {}
        })
    
    async def subscribe_to_space_events(self, callback: Callable, space_id: Optional[str] = None) -> None:
        """
        Subscribe to space events (no-op registration).
        
        Args:
            callback: Function to call when events occur
            space_id: Optional space ID to filter events, None for all spaces
        """
        if self.closed:
            logger.warning("🔔 Cannot subscribe to events - signal manager is closed")
            return
            
        if not callable(callback):
            logger.error(f"🔔 Invalid callback provided: {callback}")
            return
        
        if space_id:
            # Space-specific callback
            if space_id not in self.space_callbacks:
                self.space_callbacks[space_id] = []
            self.space_callbacks[space_id].append(callback)
            logger.info(f"🔔 [NO-OP] Subscribed to events for space: {space_id}")
        else:
            # Global callback
            self.callbacks.append(callback)
            logger.info(f"🔔 [NO-OP] Subscribed to all space events")
        
        logger.debug(f"🔔 Total callbacks: global={len(self.callbacks)}, space-specific={sum(len(cbs) for cbs in self.space_callbacks.values())}")
    
    async def unsubscribe_from_space_events(self, callback: Callable) -> None:
        """
        Unsubscribe from space events (no-op removal).
        
        Args:
            callback: Function to remove from event notifications
        """
        if self.closed:
            return
            
        removed_count = 0
        
        # Remove from global callbacks
        if callback in self.callbacks:
            self.callbacks.remove(callback)
            removed_count += 1
        
        # Remove from space-specific callbacks
        for space_id, space_callbacks in self.space_callbacks.items():
            if callback in space_callbacks:
                space_callbacks.remove(callback)
                removed_count += 1
        
        if removed_count > 0:
            logger.info(f"🔔 [NO-OP] Unsubscribed callback from {removed_count} event sources")
        else:
            logger.warning(f"🔔 [NO-OP] Callback not found for unsubscription: {callback}")
    
    def close(self) -> None:
        """
        Close signal manager and clean up resources (no-op cleanup).
        """
        if self.closed:
            return
            
        self.closed = True
        callback_count = len(self.callbacks) + sum(len(cbs) for cbs in self.space_callbacks.values())
        
        # Clear all callbacks
        self.callbacks.clear()
        self.space_callbacks.clear()
        
        logger.info(f"🔔 [NO-OP] FusekiSignalManager closed, cleared {callback_count} callbacks")
    
    async def _execute_callbacks(self, event_type: str, event_data: Dict[str, Any]) -> None:
        """
        Execute registered callbacks for an event (for demonstration purposes).
        
        Args:
            event_type: Type of event
            event_data: Event data to pass to callbacks
        """
        if self.closed:
            return
        
        space_id = event_data.get('space_id')
        executed_count = 0
        
        # Execute global callbacks
        for callback in self.callbacks:
            try:
                if asyncio.iscoroutinefunction(callback):
                    await callback(event_data)
                else:
                    callback(event_data)
                executed_count += 1
            except Exception as e:
                logger.error(f"🔔 Error executing global callback for {event_type}: {e}")
        
        # Execute space-specific callbacks
        if space_id and space_id in self.space_callbacks:
            for callback in self.space_callbacks[space_id]:
                try:
                    if asyncio.iscoroutinefunction(callback):
                        await callback(event_data)
                    else:
                        callback(event_data)
                    executed_count += 1
                except Exception as e:
                    logger.error(f"🔔 Error executing space callback for {event_type}: {e}")
        
        if executed_count > 0:
            logger.debug(f"🔔 Executed {executed_count} callbacks for {event_type}")
    
    # Additional utility methods for future enhancement
    
    def is_closed(self) -> bool:
        """Check if the signal manager is closed."""
        return self.closed
    
    def get_callback_count(self) -> Dict[str, int]:
        """Get count of registered callbacks."""
        return {
            'global': len(self.callbacks),
            'space_specific': sum(len(cbs) for cbs in self.space_callbacks.values()),
            'total': len(self.callbacks) + sum(len(cbs) for cbs in self.space_callbacks.values())
        }
    
    def get_subscribed_spaces(self) -> List[str]:
        """Get list of spaces with registered callbacks."""
        return list(self.space_callbacks.keys())


# Future enhancement placeholder for HTTP-based notifications
class FusekiHTTPSignalManager(FusekiSignalManager):
    """
    Future implementation for HTTP-based Fuseki notifications.
    
    This could include:
    - HTTP webhook endpoints for external notification services
    - Polling-based change detection using Fuseki's SPARQL endpoints
    - Integration with Fuseki's built-in notification mechanisms
    """
    
    def __init__(self, webhook_url: Optional[str] = None, poll_interval: int = 30, **config):
        """
        Initialize HTTP-based signal manager.
        
        Args:
            webhook_url: Optional webhook URL for notifications
            poll_interval: Polling interval in seconds for change detection
            **config: Additional configuration parameters
        """
        super().__init__(**config)
        self.webhook_url = webhook_url
        self.poll_interval = poll_interval
        
        logger.info(f"🔔 FusekiHTTPSignalManager initialized (future implementation)")
        logger.info(f"🔔 Webhook URL: {webhook_url}")
        logger.info(f"🔔 Poll interval: {poll_interval}s")
    
    # Future methods would override parent methods to implement actual HTTP notifications
    # async def notify_space_created(self, space_id: str) -> None:
    #     # Send HTTP POST to webhook_url with space creation event
    #     pass
    
    # async def _start_polling(self) -> None:
    #     # Start background polling task to detect changes
    #     pass
