"""
Flask Application Factory

Creates and configures the Flask application with SocketIO support for real-time
updates of the Markov economics simulation.
"""

import os
from flask import Flask
from flask_socketio import SocketIO
from config import config
from app.models import SimulationManager

# Initialize SocketIO with enhanced proxy support
# For Gunicorn compatibility, we need to set the async_mode to 'gevent'
socketio = SocketIO(
    cors_allowed_origins="*",
    async_mode='gevent' if os.getenv('FLASK_ENV') == 'production' else 'threading',
    logger=False,  # Disable to avoid log spam in production
    engineio_logger=False,
    # Transport order: try websocket first, then polling
    transports=['websocket', 'polling'],
    # Ping settings for better connection detection
    ping_timeout=60,
    ping_interval=25,
    # Proxy compatibility settings
    allow_upgrades=True,
    upgrade_timeout=30
)

# Global simulation manager instance
simulation_manager = SimulationManager()


def create_app(config_name=None):
    """
    Create and configure the Flask application.
    
    Args:
        config_name: Configuration profile to use
        
    Returns:
        Configured Flask application instance
    """
    if config_name is None:
        config_name = os.getenv('FLASK_CONFIG', os.getenv('FLASK_ENV', 'development'))
        
    app = Flask(__name__)
    app.config.from_object(config[config_name])
    
    # Configure for reverse proxy
    from werkzeug.middleware.proxy_fix import ProxyFix
    app.wsgi_app = ProxyFix(app.wsgi_app, x_for=1, x_proto=1, x_host=1, x_prefix=1)
    
    # Initialize extensions with proxy-friendly settings
    socketio.init_app(
        app, 
        async_mode='gevent' if config_name == 'production' else 'threading',
        cors_allowed_origins="*",
        allow_upgrades=True,
        transports=['websocket', 'polling'],
        ping_timeout=60,
        ping_interval=25,
        upgrade_timeout=30,
        manage_session=False  # Important for proxy compatibility
    )
    
    # Register blueprints
    from .routes.main import main_bp
    from .routes.api import api_bp
    
    app.register_blueprint(main_bp)
    app.register_blueprint(api_bp, url_prefix='/api')
    
    return app