# conversation_manager.py

import os
import uuid
import hashlib
import logging
from typing import Dict, List, Any, Optional
from datetime import datetime
from supabase import create_client, Client
from dotenv import load_dotenv

# Configure logging
logging.basicConfig(level=logging.INFO)
logger = logging.getLogger(__name__)

load_dotenv()


class ConversationManager:
    """Enhanced ConversationManager with user authentication and session isolation"""
    
    def __init__(self):
        """Initialize the conversation manager with Supabase client"""
        try:
            # Initialize Supabase client
            supabase_url = os.getenv("SUPABASE_URL")
            supabase_key = os.getenv("SUPABASE_KEY")
            
            if not supabase_url or not supabase_key:
                raise ValueError("Missing Supabase credentials in environment variables")
            
            self.supabase: Client = create_client(supabase_url, supabase_key)
            logger.info("ConversationManager initialized successfully with Supabase")
            
        except Exception as e:
            logger.error(f"Failed to initialize ConversationManager: {e}")
            raise
    
    def generate_chat_id(self, user_id: str) -> str:
        """Generate a unique chat ID for a specific user"""
        timestamp = str(int(datetime.utcnow().timestamp()))
        random_part = uuid.uuid4().hex[:8]
        return f"chat_{user_id[:8]}_{timestamp}_{random_part}"
    
    def generate_user_id(self, device_info: Optional[str] = None, ip_address: Optional[str] = None) -> str:
        """
        Generate a unique user ID based on device info and/or IP
        This creates a consistent ID for the same device/IP combination
        """
        # Create a hash based on available info
        identifier_string = ""
        
        if device_info:
            identifier_string += device_info
        if ip_address:
            identifier_string += ip_address
        
        # Fallback to timestamp + random if no device info
        if not identifier_string:
            identifier_string = f"anonymous_{int(datetime.utcnow().timestamp())}_{uuid.uuid4().hex[:8]}"
        
        # Create consistent hash
        user_hash = hashlib.sha256(identifier_string.encode()).hexdigest()[:16]
        return f"user_{user_hash}"
    
    def generate_message_id(self, chat_id: str, user_id: str) -> int:
        """Generate the next message ID for a specific chat"""
        try:
            # Get current conversation to find the highest message ID
            history = self.get_history(chat_id, user_id)
            
            if not history:
                return 1
            
            # Find the highest message_id
            max_id = 0
            for message in history:
                msg_id = message.get('message_id', 0)
                if isinstance(msg_id, int) and msg_id > max_id:
                    max_id = msg_id
            
            return max_id + 1
            
        except Exception as e:
            logger.error(f"Error generating message ID for chat {chat_id}, user {user_id}: {e}")
            return 1
    
    def get_history(self, chat_id: str, user_id: str) -> List[Dict[str, Any]]:
        """
        Retrieve conversation history for a specific chat ID and user
        
        Args:
            chat_id: The chat ID to retrieve history for
            user_id: The user ID (for security/isolation)
            
        Returns:
            List of message dictionaries, empty list if chat doesn't exist or unauthorized
        """
        if not chat_id or not user_id:
            logger.warning("Cannot get history: chat_id or user_id is empty")
            return []
        
        try:
            response = self.supabase.table('conversations').select('history').eq('session_id', chat_id).eq('user_id', user_id).execute()
            
            if response.data and len(response.data) > 0:
                history = response.data[0].get('history', [])
                if isinstance(history, list):
                    logger.info(f"Retrieved {len(history)} messages for chat {chat_id}, user {user_id}")
                    return history
                else:
                    logger.warning(f"Invalid history format for chat {chat_id}")
                    return []
            else:
                logger.info(f"No history found for chat {chat_id}, user {user_id}")
                return []
                
        except Exception as e:
            logger.error(f"Error retrieving history for chat {chat_id}, user {user_id}: {e}")
            return []
    
    def save_history(self, chat_id: str, user_id: str, history: List[Dict[str, Any]]) -> bool:
        """
        Save conversation history for a specific chat ID and user
        
        Args:
            chat_id: The chat ID to save history for
            user_id: The user ID (for security/isolation)
            history: List of message dictionaries
            
        Returns:
            True if successful, False otherwise
        """
        if not chat_id or not user_id:
            logger.error("Cannot save history: chat_id or user_id is empty")
            return False
        
        if not isinstance(history, list):
            logger.error("Cannot save history: history must be a list")
            return False
        
        try:
            # Check if conversation exists for this user
            existing = self.supabase.table('conversations').select('session_id').eq('session_id', chat_id).eq('user_id', user_id).execute()
            
            current_time = datetime.utcnow().isoformat()
            
            if existing.data and len(existing.data) > 0:
                # Update existing conversation
                response = self.supabase.table('conversations').update({
                    'history': history,
                    'updated_at': current_time
                }).eq('session_id', chat_id).eq('user_id', user_id).execute()
                
                logger.info(f"Updated history for chat {chat_id}, user {user_id}")
            else:
                # Create new conversation
                response = self.supabase.table('conversations').insert({
                    'session_id': chat_id,
                    'user_id': user_id,
                    'history': history,
                    'created_at': current_time,
                    'updated_at': current_time
                }).execute()
                
                logger.info(f"Created new conversation for chat {chat_id}, user {user_id}")
            
            return True
            
        except Exception as e:
            logger.error(f"Error saving history for chat {chat_id}, user {user_id}: {e}")
            return False
    
    def add_message(self, chat_id: str, user_id: str, role: str, content: str, image_url: Optional[str] = None) -> Dict[str, Any]:
        """
        Add a single message to a chat and return the message with its ID
        
        Args:
            chat_id: The chat ID to add the message to
            user_id: The user ID (for security/isolation)
            role: Message role ('user' or 'assistant')
            content: Message content
            image_url: Optional image URL
            
        Returns:
            Dictionary containing the message with its assigned ID
        """
        if not chat_id or not user_id:
            logger.error("Cannot add message: chat_id or user_id is empty")
            return {}
        
        try:
            # Generate message ID
            message_id = self.generate_message_id(chat_id, user_id)
            
            # Create message object
            message = {
                "message_id": message_id,
                "role": role,
                "content": content,
                "timestamp": datetime.utcnow().isoformat()
            }
            
            # Add image URL if provided
            if image_url:
                message["imageUrl"] = image_url
            
            # Get current history and add the new message
            current_history = self.get_history(chat_id, user_id)
            current_history.append(message)
            
            # Save updated history
            if self.save_history(chat_id, user_id, current_history):
                logger.info(f"Added message {message_id} to chat {chat_id}, user {user_id}")
                return message
            else:
                logger.error(f"Failed to save message to chat {chat_id}, user {user_id}")
                return {}
                
        except Exception as e:
            logger.error(f"Error adding message to chat {chat_id}, user {user_id}: {e}")
            return {}
    
    def delete_history(self, chat_id: str, user_id: str) -> bool:
        """
        Delete conversation history for a specific chat ID and user
        
        Args:
            chat_id: The chat ID to delete
            user_id: The user ID (for security/isolation)
            
        Returns:
            True if successful, False otherwise
        """
        if not chat_id or not user_id:
            logger.error("Cannot delete history: chat_id or user_id is empty")
            return False
        
        try:
            response = self.supabase.table('conversations').delete().eq('session_id', chat_id).eq('user_id', user_id).execute()
            
            # Check if any rows were affected
            if hasattr(response, 'data') and response.data is not None:
                logger.info(f"Deleted conversation history for chat {chat_id}, user {user_id}")
                return True
            else:
                logger.warning(f"No conversation found to delete for chat {chat_id}, user {user_id}")
                return True  # Consider it successful if nothing to delete
                
        except Exception as e:
            logger.error(f"Error deleting history for chat {chat_id}, user {user_id}: {e}")
            return False
    
    def get_all_chat_sessions(self, user_id: str) -> List[Dict[str, Any]]:
        """
        Get all chat sessions for a specific user
        
        Args:
            user_id: The user ID to get sessions for
            
        Returns:
            List of dictionaries with chat session information
        """
        if not user_id:
            logger.error("Cannot get chat sessions: user_id is empty")
            return []
        
        try:
            response = self.supabase.table('conversations').select('session_id, history, created_at, updated_at').eq('user_id', user_id).execute()
            
            sessions = []
            for conv in response.data:
                session_id = conv.get('session_id')
                history = conv.get('history', [])
                created_at = conv.get('created_at')
                updated_at = conv.get('updated_at')
                
                # Generate title from first user message in the history
                title = "New Chat"
                if history and len(history) > 0:
                    first_user_msg = None
                    for msg in history:
                        if msg.get('role') == 'user':
                            first_user_msg = msg
                            break
                    
                    if first_user_msg:
                        content = first_user_msg.get('content', '')
                        if content:
                            title = content[:35] + '...' if len(content) > 35 else content
                        elif first_user_msg.get('imageUrl'):
                            title = "Image Query"

                sessions.append({
                    "session_id": session_id,
                    "title": title,
                    "message_count": len(history),
                    "created_at": created_at,
                    "updated_at": updated_at
                })
            
            # Sort by updated_at (most recent first)
            sessions.sort(key=lambda x: x.get('updated_at', ''), reverse=True)
            
            logger.info(f"Retrieved {len(sessions)} sessions for user {user_id}")
            return sessions
            
        except Exception as e:
            logger.error(f"Error fetching chat sessions for user {user_id}: {e}")
            return []
    
    def get_chat_info(self, chat_id: str, user_id: str) -> Dict[str, Any]:
        """
        Get information about a specific chat for a specific user
        
        Args:
            chat_id: The chat ID to get information for
            user_id: The user ID (for security/isolation)
            
        Returns:
            Dictionary with chat information
        """
        if not chat_id or not user_id:
            return {}
        
        try:
            response = self.supabase.table('conversations').select('*').eq('session_id', chat_id).eq('user_id', user_id).execute()
            
            if response.data and len(response.data) > 0:
                conv = response.data[0]
                history = conv.get('history', [])
                
                return {
                    "session_id": conv.get('session_id'),
                    "user_id": conv.get('user_id'),
                    "message_count": len(history),
                    "created_at": conv.get('created_at'),
                    "updated_at": conv.get('updated_at'),
                    "exists": True
                }
            else:
                return {
                    "session_id": chat_id,
                    "user_id": user_id,
                    "message_count": 0,
                    "exists": False
                }
                
        except Exception as e:
            logger.error(f"Error getting chat info for {chat_id}, user {user_id}: {e}")
            return {
                "session_id": chat_id,
                "user_id": user_id,
                "error": str(e),
                "exists": False
            }
    
    def chat_exists(self, chat_id: str, user_id: str) -> bool:
        """
        Check if a chat ID exists for a specific user
        
        Args:
            chat_id: The chat ID to check
            user_id: The user ID (for security/isolation)
            
        Returns:
            True if chat exists and belongs to user, False otherwise
        """
        if not chat_id or not user_id:
            return False
        
        try:
            response = self.supabase.table('conversations').select('session_id').eq('session_id', chat_id).eq('user_id', user_id).execute()
            exists = bool(response.data and len(response.data) > 0)
            
            if exists:
                logger.info(f"Chat {chat_id} exists for user {user_id}")
            
            return exists
            
        except Exception as e:
            logger.error(f"Error checking if chat {chat_id} exists for user {user_id}: {e}")
            return False
    
    def get_user_stats(self, user_id: str) -> Dict[str, Any]:
        """
        Get statistics for a specific user
        
        Args:
            user_id: The user ID to get stats for
            
        Returns:
            Dictionary with user statistics
        """
        if not user_id:
            return {}
        
        try:
            sessions = self.get_all_chat_sessions(user_id)
            total_sessions = len(sessions)
            total_messages = sum(session.get('message_count', 0) for session in sessions)
            
            # Calculate recent activity (last 24 hours)
            from datetime import datetime, timedelta
            now = datetime.utcnow()
            yesterday = now - timedelta(days=1)
            
            recent_sessions = 0
            for session in sessions:
                updated_at = session.get('updated_at')
                if updated_at:
                    try:
                        session_time = datetime.fromisoformat(updated_at.replace('Z', '+00:00'))
                        if session_time > yesterday:
                            recent_sessions += 1
                    except:
                        pass
            
            return {
                "user_id": user_id,
                "total_sessions": total_sessions,
                "total_messages": total_messages,
                "recent_sessions_24h": recent_sessions,
                "average_messages_per_session": round(total_messages / total_sessions, 2) if total_sessions > 0 else 0,
                "first_session": min(session.get('created_at', '') for session in sessions) if sessions else None,
                "last_activity": max(session.get('updated_at', '') for session in sessions) if sessions else None
            }
            
        except Exception as e:
            logger.error(f"Error getting user stats for {user_id}: {e}")
            return {"user_id": user_id, "error": str(e)}
    
    def delete_all_user_data(self, user_id: str) -> bool:
        """
        Delete all conversation data for a specific user
        
        Args:
            user_id: The user ID to delete all data for
            
        Returns:
            True if successful, False otherwise
        """
        if not user_id:
            logger.error("Cannot delete user data: user_id is empty")
            return False
        
        try:
            response = self.supabase.table('conversations').delete().eq('user_id', user_id).execute()
            
            logger.info(f"Deleted all conversation data for user {user_id}")
            return True
            
        except Exception as e:
            logger.error(f"Error deleting all user data for {user_id}: {e}")
            return False
    
    def migrate_anonymous_sessions(self, old_session_ids: List[str], new_user_id: str) -> bool:
        """
        Migrate anonymous sessions to a specific user ID
        Useful when user decides to create an account
        
        Args:
            old_session_ids: List of session IDs to migrate
            new_user_id: The new user ID to assign these sessions to
            
        Returns:
            True if successful, False otherwise
        """
        if not old_session_ids or not new_user_id:
            logger.error("Cannot migrate sessions: missing session_ids or user_id")
            return False
        
        try:
            migrated_count = 0
            
            for session_id in old_session_ids:
                try:
                    # Update the user_id for this session
                    response = self.supabase.table('conversations').update({
                        'user_id': new_user_id,
                        'updated_at': datetime.utcnow().isoformat()
                    }).eq('session_id', session_id).execute()
                    
                    migrated_count += 1
                    
                except Exception as e:
                    logger.error(f"Failed to migrate session {session_id}: {e}")
                    continue
            
            logger.info(f"Migrated {migrated_count} sessions to user {new_user_id}")
            return migrated_count > 0
            
        except Exception as e:
            logger.error(f"Error migrating sessions to user {new_user_id}: {e}")
            return False


# Example usage and testing
if __name__ == "__main__":
    print("=== ConversationManager with User Authentication Test ===")
    
    try:
        # Initialize manager
        manager = ConversationManager()
        
        # Test user ID generation
        test_user_id = manager.generate_user_id("test_device_info", "192.168.1.100")
        print(f"\n1. Generated user ID: {test_user_id}")
        
        # Create a new chat for this user
        test_chat_id = manager.generate_chat_id(test_user_id)
        print(f"2. Generated chat ID: {test_chat_id}")
        
        # Add some messages
        msg1 = manager.add_message(test_chat_id, test_user_id, "user", "Hello, I need help with farming")
        print(f"3. Added user message: {msg1}")
        
        msg2 = manager.add_message(test_chat_id, test_user_id, "assistant", "Hello! I'd be happy to help you with farming. What specific questions do you have?")
        print(f"4. Added assistant message: {msg2}")
        
        # Test retrieving history
        print(f"\n5. Retrieved history for {test_chat_id}:")
        history = manager.get_history(test_chat_id, test_user_id)
        for msg in history:
            print(f"  Message {msg.get('message_id')}: {msg.get('role')} - {msg.get('content')[:50]}...")
        
        # Test getting all sessions for this user
        print(f"\n6. All sessions for user {test_user_id}:")
        sessions = manager.get_all_chat_sessions(test_user_id)
        for session in sessions:
            print(f"  {session.get('session_id')}: {session.get('title')} ({session.get('message_count')} messages)")
        
        # Test user stats
        print(f"\n7. User statistics:")
        stats = manager.get_user_stats(test_user_id)
        for key, value in stats.items():
            print(f"  {key}: {value}")
        
        # Test security - try to access with wrong user ID
        print(f"\n8. Security test - trying to access with wrong user ID:")
        wrong_user_history = manager.get_history(test_chat_id, "wrong_user_id")
        print(f"  History with wrong user ID: {len(wrong_user_history)} messages (should be 0)")
        
        print("\n✅ All tests completed successfully!")
        
    except Exception as e:
        print(f"❌ Test failed: {e}")