# server.py

from flask import Flask, request, jsonify, render_template
from app import EasyFarmsAssistant
from conversation_manager import ConversationManager
import logging
from datetime import datetime
import os
from flask_cors import CORS

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

# Initialize the Flask application
app = Flask(__name__)
CORS(app)

# --- Initialize Core Services ---
try:
    conv_manager = ConversationManager()
    assistant = EasyFarmsAssistant(manager=conv_manager)
    logger.info("EasyFarmsAssistant and ConversationManager initialized successfully.")
except Exception as e:
    logger.error(f"FATAL: Could not initialize services. Error: {e}")
    assistant = None
    conv_manager = None

# --- Frontend Serving Route ---
@app.route('/')
def index():
    """Serves the main chat application page (index.html)."""
    return render_template('index.html')

# --- API Endpoints ---

@app.route('/config', methods=['GET'])
def get_config():
    """Provides public configuration keys to the frontend."""
    return jsonify({
        'imgbb_api_key': os.getenv('IMGBB_API_KEY')
    })

@app.route('/chat', methods=['POST'])
def chat():
    """
    Handles incoming user messages and returns the assistant's response.
    
    Request format:
    {
        "query": "user message text",
        "image_url": "optional image URL",
        "session_id": "optional chat ID for conversation memory",
        "user_id": "user identifier for authentication"
    }
    
    Response format:
    {
        "response": "assistant response",
        "chat_id": "unique chat identifier",
        "is_new_chat": true/false,
        "user_message_id": 1,
        "assistant_message_id": 2,
        "total_messages": 2
    }
    """
    if not assistant:
        return jsonify({"error": "Assistant is not available due to an initialization error."}), 503

    try:
        # Handle both JSON and form data
        if request.is_json:
            data = request.get_json()
            user_message = data.get('query')
            chat_id = data.get('session_id')
            image_url = data.get('image_url')
            user_id = data.get('user_id')
        else:
            # Fallback for form data (backward compatibility)
            data = request.form
            user_message = data.get('message') or data.get('query')
            chat_id = data.get('session_id')
            image_url = data.get('image_url')
            user_id = data.get('user_id')

        # Validate input
        if not user_message and not image_url:
            return jsonify({"error": "Cannot process an empty message. Provide either 'query' text or 'image_url'."}), 400
        
        if not user_id:
            return jsonify({"error": "User ID is required for authentication."}), 400
        
        # Clean up empty/null chat_id
        if chat_id in [None, '', 'null', 'undefined']:
            chat_id = None
        
        # Process the query with the assistant
        result = assistant.process_query(
            user_message=user_message or "",
            user_id=user_id,
            chat_id=chat_id,
            image_url=image_url
        )
        
        # Handle errors from assistant
        if "error" in result:
            return jsonify({
                "error": result["error"],
                "chat_id": result.get("chat_id"),
                "is_new_chat": result.get("is_new_chat", True)
            }), 500
        
        # Return successful response
        return jsonify({
            "response": result["response"],
            "chat_id": result["chat_id"],
            "is_new_chat": result["is_new_chat"],
            "user_message_id": result["user_message_id"],
            "assistant_message_id": result["assistant_message_id"],
            "total_messages": result["total_messages"]
        })
        
    except Exception as e:
        logger.error(f"Error in chat endpoint: {e}")
        return jsonify({"error": f"Server error: {str(e)}"}), 500

@app.route('/chats', methods=['GET'])
def get_all_chats():
    """
    Get all chat sessions with basic information for a specific user.
    
    Query parameters:
    - user_id: Required user identifier
    
    Response format:
    [
        {
            "session_id": "chat_abc123",
            "title": "Crop recommendations for...",
            "message_count": 4,
            "created_at": "2024-01-01T10:00:00",
            "updated_at": "2024-01-01T10:05:00"
        }
    ]
    """
    if not conv_manager:
        return jsonify({"error": "Conversation manager not available"}), 503
        
    try:
        user_id = request.args.get('user_id')
        if not user_id:
            return jsonify({"error": "User ID is required"}), 400
            
        chats = assistant.get_all_chats(user_id)
        return jsonify(chats)
        
    except Exception as e:
        logger.error(f"Error fetching all chats: {e}")
        return jsonify({"error": "Could not fetch chat list"}), 500

@app.route('/chat/<chat_id>/info', methods=['GET'])
def get_chat_info(chat_id):
    """
    Get information about a specific chat for a specific user.
    
    Query parameters:
    - user_id: Required user identifier
    
    Response format:
    {
        "session_id": "chat_abc123",
        "message_count": 4,
        "created_at": "2024-01-01T10:00:00",
        "updated_at": "2024-01-01T10:05:00",
        "exists": true
    }
    """
    if not assistant:
        return jsonify({"error": "Assistant not available"}), 503
        
    try:
        if not chat_id:
            return jsonify({"error": "Chat ID is required"}), 400
            
        user_id = request.args.get('user_id')
        if not user_id:
            return jsonify({"error": "User ID is required"}), 400
            
        info = assistant.get_chat_info(chat_id, user_id)
        return jsonify(info)
        
    except Exception as e:
        logger.error(f"Error getting chat info for {chat_id}: {e}")
        return jsonify({"error": "Could not fetch chat information"}), 500

@app.route('/chat/<chat_id>/messages', methods=['GET'])
def get_chat_messages(chat_id):
    """
    Get all messages for a specific chat and user.
    
    Query parameters:
    - user_id: Required user identifier
    
    Response format:
    [
        {
            "message_id": 1,
            "role": "user",
            "content": "Hello, I need help with farming",
            "timestamp": "2024-01-01T10:00:00",
            "imageUrl": "optional"
        },
        {
            "message_id": 2,
            "role": "assistant",
            "content": "Hello! I'd be happy to help...",
            "timestamp": "2024-01-01T10:00:05"
        }
    ]
    """
    if not assistant:
        return jsonify({"error": "Assistant not available"}), 503
        
    try:
        if not chat_id:
            return jsonify({"error": "Chat ID is required"}), 400
            
        user_id = request.args.get('user_id')
        if not user_id:
            return jsonify({"error": "User ID is required"}), 400
            
        messages = assistant.get_messages(chat_id, user_id)
        return jsonify(messages)
        
    except Exception as e:
        logger.error(f"Error fetching messages for chat {chat_id}: {e}")
        return jsonify({"error": "Could not fetch chat messages"}), 500

@app.route('/chat/<chat_id>', methods=['DELETE'])
def delete_chat(chat_id):
    """
    Delete a specific chat and all its messages for a specific user.
    
    Query parameters:
    - user_id: Required user identifier
    
    Response format:
    {
        "status": "success",
        "message": "Chat deleted successfully",
        "chat_id": "chat_abc123"
    }
    """
    if not assistant:
        return jsonify({"error": "Assistant not available"}), 503
        
    try:
        if not chat_id:
            return jsonify({"error": "Chat ID is required"}), 400
            
        user_id = request.args.get('user_id')
        if not user_id:
            return jsonify({"error": "User ID is required"}), 400
            
        success = assistant.clear_history(chat_id, user_id)
        
        if success:
            return jsonify({
                "status": "success",
                "message": f"Chat {chat_id} deleted successfully",
                "chat_id": chat_id
            })
        else:
            return jsonify({
                "status": "error",
                "message": f"Failed to delete chat {chat_id}",
                "chat_id": chat_id
            }), 500
            
    except Exception as e:
        logger.error(f"Error deleting chat {chat_id}: {e}")
        return jsonify({"error": "Could not delete chat"}), 500

# --- New User Management Endpoints ---

@app.route('/users/<user_id>/stats', methods=['GET'])
def get_user_stats(user_id):
    """
    Get statistics for a specific user.
    
    Response format:
    {
        "user_id": "user_abc123",
        "total_sessions": 5,
        "total_messages": 42,
        "recent_sessions_24h": 2,
        "average_messages_per_session": 8.4,
        "first_session": "2024-01-01T10:00:00",
        "last_activity": "2024-01-01T15:30:00"
    }
    """
    if not conv_manager:
        return jsonify({"error": "Conversation manager not available"}), 503
        
    try:
        if not user_id:
            return jsonify({"error": "User ID is required"}), 400
            
        stats = conv_manager.get_user_stats(user_id)
        return jsonify(stats)
        
    except Exception as e:
        logger.error(f"Error getting user stats for {user_id}: {e}")
        return jsonify({"error": "Could not fetch user statistics"}), 500

@app.route('/users/<user_id>/chats', methods=['DELETE'])
def delete_all_user_chats(user_id):
    """
    Delete all chats for a specific user.
    
    Response format:
    {
        "status": "success",
        "message": "All chats deleted successfully",
        "user_id": "user_abc123"
    }
    """
    if not conv_manager:
        return jsonify({"error": "Conversation manager not available"}), 503
        
    try:
        if not user_id:
            return jsonify({"error": "User ID is required"}), 400
            
        success = conv_manager.delete_all_user_data(user_id)
        
        if success:
            return jsonify({
                "status": "success",
                "message": f"All chats deleted for user {user_id}",
                "user_id": user_id
            })
        else:
            return jsonify({
                "status": "error",
                "message": f"Failed to delete chats for user {user_id}",
                "user_id": user_id
            }), 500
            
    except Exception as e:
        logger.error(f"Error deleting all chats for user {user_id}: {e}")
        return jsonify({"error": "Could not delete user chats"}), 500

@app.route('/users/<user_id>/export', methods=['GET'])
def export_user_data(user_id):
    """
    Export all data for a specific user.
    
    Response format:
    {
        "user_id": "user_abc123",
        "export_date": "2024-01-01T10:00:00",
        "stats": {...},
        "sessions": [...]
    }
    """
    if not conv_manager:
        return jsonify({"error": "Conversation manager not available"}), 503
        
    try:
        if not user_id:
            return jsonify({"error": "User ID is required"}), 400
            
        # Get user stats and sessions
        stats = conv_manager.get_user_stats(user_id)
        sessions = conv_manager.get_all_chat_sessions(user_id)
        
        # Get all messages for each session
        detailed_sessions = []
        for session in sessions:
            session_data = session.copy()
            messages = conv_manager.get_history(session['session_id'], user_id)
            session_data['messages'] = messages
            detailed_sessions.append(session_data)
        
        export_data = {
            "user_id": user_id,
            "export_date": datetime.utcnow().isoformat(),
            "stats": stats,
            "sessions": detailed_sessions,
            "total_exported_sessions": len(detailed_sessions),
            "total_exported_messages": sum(len(s.get('messages', [])) for s in detailed_sessions)
        }
        
        return jsonify(export_data)
        
    except Exception as e:
        logger.error(f"Error exporting data for user {user_id}: {e}")
        return jsonify({"error": "Could not export user data"}), 500

@app.route('/users/<user_id>', methods=['DELETE'])
def delete_user_account(user_id):
    """
    Delete a user account and all associated data.
    
    Response format:
    {
        "status": "success",
        "message": "User account deleted successfully",
        "user_id": "user_abc123"
    }
    """
    if not conv_manager:
        return jsonify({"error": "Conversation manager not available"}), 503
        
    try:
        if not user_id:
            return jsonify({"error": "User ID is required"}), 400
            
        # Delete all user data
        success = conv_manager.delete_all_user_data(user_id)
        
        if success:
            return jsonify({
                "status": "success",
                "message": f"User account {user_id} deleted successfully",
                "user_id": user_id
            })
        else:
            return jsonify({
                "status": "error",
                "message": f"Failed to delete user account {user_id}",
                "user_id": user_id
            }), 500
            
    except Exception as e:
        logger.error(f"Error deleting user account {user_id}: {e}")
        return jsonify({"error": "Could not delete user account"}), 500

# --- Legacy Endpoints for Backward Compatibility ---

@app.route('/history/sessions', methods=['GET'])
def get_sessions():
    """Legacy endpoint - redirects to /chats"""
    return get_all_chats()

@app.route('/history/messages/<session_id>', methods=['GET'])
def get_messages(session_id):
    """Legacy endpoint - redirects to /chat/<session_id>/messages"""
    return get_chat_messages(session_id)

@app.route('/clear', methods=['POST'])
def clear_history():
    """Legacy endpoint for clearing chat history"""
    if not assistant:
        return jsonify({"error": "Assistant is not available."}), 503
    
    try:
        data = request.get_json()
        if not data:
            return jsonify({"error": "Request body is required"}), 400
            
        session_id = data.get('session_id')
        if not session_id:
            return jsonify({"error": "Missing 'session_id' in request body"}), 400

        success = assistant.clear_history(session_id)
        
        if success:
            return jsonify({
                "status": "success",
                "message": f"History for session {session_id} was cleared."
            })
        else:
            return jsonify({"error": "Failed to clear history."}), 500
            
    except Exception as e:
        logger.error(f"Error in legacy clear endpoint: {e}")
        return jsonify({"error": f"Server error: {str(e)}"}), 500

# --- Health Check and Status Endpoints ---

@app.route('/health', methods=['GET'])
def health_check():
    """Health check endpoint for monitoring"""
    try:
        # Check if core services are available
        services_status = {
            "assistant": assistant is not None,
            "conversation_manager": conv_manager is not None,
            "database": False
        }
        
        # Test database connectivity
        if conv_manager:
            try:
                # Try to get chat sessions (will test DB connection)
                conv_manager.get_all_chat_sessions()
                services_status["database"] = True
            except:
                services_status["database"] = False
        
        all_healthy = all(services_status.values())
        
        return jsonify({
            "status": "healthy" if all_healthy else "degraded",
            "services": services_status,
            "timestamp": conv_manager.manager._get_timestamp() if conv_manager else None
        }), 200 if all_healthy else 503
        
    except Exception as e:
        logger.error(f"Health check failed: {e}")
        return jsonify({
            "status": "unhealthy",
            "error": str(e)
        }), 503

@app.route('/stats', methods=['GET'])
def get_stats():
    """Get system statistics"""
    if not conv_manager:
        return jsonify({"error": "Conversation manager not available"}), 503
        
    try:
        chats = assistant.get_all_chats()
        
        total_chats = len(chats)
        total_messages = sum(chat.get('message_count', 0) for chat in chats)
        
        # Recent activity (chats updated in last 24 hours)
        from datetime import datetime, timedelta
        now = datetime.utcnow()
        yesterday = now - timedelta(days=1)
        
        recent_chats = 0
        for chat in chats:
            updated_at = chat.get('updated_at')
            if updated_at:
                try:
                    chat_time = datetime.fromisoformat(updated_at.replace('Z', '+00:00'))
                    if chat_time > yesterday:
                        recent_chats += 1
                except:
                    pass
        
        return jsonify({
            "total_chats": total_chats,
            "total_messages": total_messages,
            "recent_chats_24h": recent_chats,
            "average_messages_per_chat": round(total_messages / total_chats, 2) if total_chats > 0 else 0
        })
        
    except Exception as e:
        logger.error(f"Error getting stats: {e}")
        return jsonify({"error": "Could not fetch statistics"}), 500

# --- Error Handlers ---

@app.errorhandler(404)
def not_found(error):
    """Handle 404 errors"""
    return jsonify({"error": "Endpoint not found"}), 404

@app.errorhandler(500)
def internal_error(error):
    """Handle 500 errors"""
    logger.error(f"Internal server error: {error}")
    return jsonify({"error": "Internal server error"}), 500

# --- Main Execution ---
if __name__ == '__main__':
    # Set debug=False for production
    port = int(os.environ.get('PORT', 7860))
    app.run(debug=False, port=port, host='0.0.0.0')