import apprise
import logging
from typing import List, Optional, Dict, Any, Union

from app.config import settings

logger = logging.getLogger(__name__)

# Global Apprise instance
_apprise = None

def init_apprise() -> apprise.Apprise:
    """Initialize the Apprise instance with configured notification services"""
    global _apprise
    
    if _apprise is None:
        _apprise = apprise.Apprise()
        
        # Add all configured notification services
        if settings.notification_urls:
            for url in settings.notification_urls:
                try:
                    _apprise.add(url)
                    logger.info(f"Added notification service: {_mask_sensitive_url(url)}")
                except Exception as e:
                    logger.error(f"Failed to add notification service: {str(e)}")
        else:
            logger.warning("No notification services configured")
    
    return _apprise

def _mask_sensitive_url(url: str) -> str:
    """Mask sensitive parts of notification URLs for logging"""
    # Simple masking for common URL formats with credentials
    import re
    # Match patterns like user:pass@host or token in URL parameters
    masked = re.sub(r'://([^:]+):([^@]+)@', r'://\1:****@', url)
    masked = re.sub(r'(discord://)[^/]+/[^/]+', r'\1webhook_id/****', masked)
    masked = re.sub(r'(tgram://)[^/]+/[^/]+', r'\1bot_token/****', masked)
    masked = re.sub(r'([?&](token|key|api_key|password|secret)=)([^&]+)', r'\1****', masked)
    return masked

def send_notification(
    title: str, 
    message: str, 
    notification_type: str = "info",
    tags: Optional[List[str]] = None,
    attachments: Optional[List[str]] = None,
    data: Optional[Dict[str, Any]] = None
) -> bool:
    """
    Send a notification through all configured channels
    
    Args:
        title: The notification title
        message: The notification body message
        notification_type: Type of notification (info, success, warning, failure)
        tags: Optional list of tags for filtering notifications
        attachments: Optional list of file paths to attach
        data: Optional additional data for the notification
        
    Returns:
        bool: True if notification was sent successfully to at least one service
    """
    if not settings.notification_urls:
        logger.debug(f"Notification not sent (no services configured): {title}")
        return False
        
    try:
        apprise_obj = init_apprise()
        
        # Set notification type
        notify_type = apprise.NotifyType.INFO
        if notification_type == "success":
            notify_type = apprise.NotifyType.SUCCESS
        elif notification_type in ("warning", "warn"):
            notify_type = apprise.NotifyType.WARNING
        elif notification_type in ("failure", "error", "failed"):
            notify_type = apprise.NotifyType.FAILURE
        
        # Send the notification to each service individually for better error reporting
        if not apprise_obj.servers:  # Access servers as an attribute, not a method
            logger.warning("No notification servers available despite having URLs configured")
            return False
            
        total_services = len(apprise_obj.servers)
        successful_services = 0
        
        for server in apprise_obj.servers:  # Iterate through the list directly
            try:
                service_name = str(server).split("://")[0] if "://" in str(server) else str(server)
                service_result = server.notify(
                    title=title,
                    body=message,
                    notify_type=notify_type,
                    attach=attachments
                )
                
                if service_result:
                    successful_services += 1
                    logger.debug(f"Notification sent via {service_name}")
                else:
                    logger.warning(f"Failed to send notification via {service_name}")
            except Exception as e:
                logger.error(f"Error sending notification via {str(server)}: {str(e)}")
        
        overall_result = successful_services > 0
        
        if overall_result:
            logger.debug(f"Notification sent: '{title}' (successful: {successful_services}/{total_services})")
        else:
            logger.warning(f"Failed to send notification to ALL services: '{title}' (0/{total_services})")
        
        return overall_result
    
    except Exception as e:
        logger.exception(f"Error sending notification: {e}")
        return False

def notify_celery_failure(task_name: str, task_id: str, exc: Exception, args: list, kwargs: dict) -> bool:
    """Send a notification about a failed Celery task"""
    if not settings.notify_on_task_failure:
        return False
        
    title = f"Task Failed: {task_name}"
    message = f"""
Task {task_name} ({task_id}) failed with error:
{type(exc).__name__}: {str(exc)}

Arguments: {args}
Keyword arguments: {kwargs}
"""
    return send_notification(
        title=title,
        message=message,
        notification_type="failure",
        tags=["celery", "failure", task_name]
    )

def notify_credential_failure(service_name: str, error: str) -> bool:
    """Send a notification about a credential failure"""
    if not settings.notify_on_credential_failure:
        return False
        
    title = f"Credential Failure: {service_name}"
    message = f"""
The credentials for {service_name} have failed:
{error}

Please check and update the credentials in the system settings.
"""
    return send_notification(
        title=title,
        message=message,
        notification_type="warning",
        tags=["credentials", "warning", service_name]
    )

def notify_startup() -> bool:
    """Send a notification that the application has started"""
    if not settings.notify_on_startup:
        return False
        
    title = f"DocuElevate Started"
    message = f"DocuElevate has been started successfully on {settings.external_hostname}"
    return send_notification(
        title=title,
        message=message,
        notification_type="success",
        tags=["system", "startup"]
    )

def notify_shutdown() -> bool:
    """Send a notification that the application is shutting down"""
    if not settings.notify_on_shutdown:
        return False
        
    title = f"DocuElevate Shutting Down"
    message = f"DocuElevate on {settings.external_hostname} is shutting down"
    return send_notification(
        title=title,
        message=message,
        notification_type="info",
        tags=["system", "shutdown"]
    )

def notify_file_processed(filename: str, file_size: int, metadata: dict, destinations: list) -> bool:
    """Send a notification that a file has been successfully processed"""
    if not settings.notify_on_file_processed:
        return False
    
    # Format file size for display
    size_mb = file_size / (1024 * 1024)
    size_str = f"{size_mb:.2f} MB" if size_mb >= 1 else f"{file_size / 1024:.2f} KB"
    
    # Extract key metadata fields
    doc_type = metadata.get('document_type', 'Unknown')
    tags = metadata.get('tags', [])
    tags_str = ', '.join(tags) if tags else 'None'
    
    # Format destinations
    destinations_str = ', '.join(destinations) if destinations else 'None configured'
    
    title = f"File Processed: {filename}"
    message = f"""
File: {filename}
Size: {size_str}
Document Type: {doc_type}
Tags: {tags_str}
Destinations: {destinations_str}

The file has been successfully processed and is being uploaded to all configured destinations.
"""
    
    return send_notification(
        title=title,
        message=message.strip(),
        notification_type="success",
        tags=["document", "processed", "success"]
    )