"""
QuantDinger Python API - Flask application factory.
"""
from flask import Flask
from flask_cors import CORS
import logging
import traceback

from app.utils.logger import setup_logger, get_logger

logger = get_logger(__name__)

# Global singletons (avoid duplicate strategy threads).
_trading_executor = None
_pending_order_worker = None


def get_trading_executor():
    """Get the trading executor singleton."""
    global _trading_executor
    if _trading_executor is None:
        from app.services.trading_executor import TradingExecutor
        _trading_executor = TradingExecutor()
    return _trading_executor


def get_pending_order_worker():
    """Get the pending order worker singleton."""
    global _pending_order_worker
    if _pending_order_worker is None:
        from app.services.pending_order_worker import PendingOrderWorker
        _pending_order_worker = PendingOrderWorker()
    return _pending_order_worker


def start_pending_order_worker():
    """Start the pending order worker (disabled by default in paper mode).

    To enable it, set ENABLE_PENDING_ORDER_WORKER=true.
    """
    import os
    # Local deployment: default to enabled so queued orders can be dispatched automatically.
    # To disable it, set ENABLE_PENDING_ORDER_WORKER=false explicitly.
    if os.getenv('ENABLE_PENDING_ORDER_WORKER', 'true').lower() != 'true':
        logger.info("Pending order worker is disabled (paper mode). Set ENABLE_PENDING_ORDER_WORKER=true to enable.")
        return
    try:
        get_pending_order_worker().start()
    except Exception as e:
        logger.error(f"Failed to start pending order worker: {e}")


def restore_running_strategies():
    """
    Restore running strategies on startup.
    Local deployment: only restores IndicatorStrategy.
    """
    import os
    # You can disable auto-restore to avoid starting many threads on low-resource hosts.
    if os.getenv('DISABLE_RESTORE_RUNNING_STRATEGIES', 'false').lower() == 'true':
        logger.info("Startup strategy restore is disabled via DISABLE_RESTORE_RUNNING_STRATEGIES")
        return
    try:
        from app.services.strategy import StrategyService
        
        strategy_service = StrategyService()
        trading_executor = get_trading_executor()
        
        running_strategies = strategy_service.get_running_strategies_with_type()
        
        if not running_strategies:
            logger.info("No running strategies to restore.")
            return
        
        logger.info(f"Restoring {len(running_strategies)} running strategies...")
        
        restored_count = 0
        for strategy_info in running_strategies:
            strategy_id = strategy_info['id']
            strategy_type = strategy_info.get('strategy_type', '')
            
            try:
                if strategy_type and strategy_type != 'IndicatorStrategy':
                    logger.info(f"Skip restore unsupported strategy type: id={strategy_id}, type={strategy_type}")
                    continue

                success = trading_executor.start_strategy(strategy_id)
                strategy_type_name = 'IndicatorStrategy'
                
                if success:
                    restored_count += 1
                    logger.info(f"[OK] {strategy_type_name} {strategy_id} restored")
                else:
                    logger.warning(f"[FAIL] {strategy_type_name} {strategy_id} restore failed (state may be stale)")
            except Exception as e:
                logger.error(f"Error restoring strategy {strategy_id}: {str(e)}")
                logger.error(traceback.format_exc())
        
        logger.info(f"Strategy restore completed: {restored_count}/{len(running_strategies)} restored")
        
    except Exception as e:
        logger.error(f"Failed to restore running strategies: {str(e)}")
        logger.error(traceback.format_exc())
        # Do not raise; avoid breaking app startup.


def create_app(config_name='default'):
    """
    Flask application factory.
    
    Args:
        config_name: config name
        
    Returns:
        Flask app
    """
    app = Flask(__name__)
    
    app.config['JSON_AS_ASCII'] = False
    
    CORS(app)
    
    setup_logger()
    
    from app.routes import register_routes
    register_routes(app)
    
    # Startup hooks.
    with app.app_context():
        start_pending_order_worker()
        restore_running_strategies()
    
    return app