import os
from flask import Flask, send_from_directory
from flask_cors import CORS
from flask_migrate import Migrate
from flask_socketio import SocketIO

from backend.models import db
from backend.config import config

# Initialize extensions
migrate = Migrate()
socketio = SocketIO(cors_allowed_origins="*", async_mode='eventlet')


def create_app(config_name=None):
    """Flask application factory"""
    if config_name is None:
        config_name = os.environ.get('FLASK_ENV', 'development')

    app = Flask(__name__,
                static_folder='static',
                static_url_path='/static')

    # Load configuration
    app.config.from_object(config[config_name])

    # Configure session for OAuth state management
    app.config['SESSION_COOKIE_SAMESITE'] = 'Lax'  # Allow cross-site on redirects
    app.config['SESSION_COOKIE_HTTPONLY'] = True

    # Ensure required directories exist
    os.makedirs(app.config['UPLOAD_FOLDER'], exist_ok=True)
    os.makedirs(app.config['AUDIO_FOLDER'], exist_ok=True)

    # Ensure database instance directory exists
    db_path = app.config['SQLALCHEMY_DATABASE_URI'].replace('sqlite:///', '')
    if db_path and db_path != ':memory:':
        os.makedirs(os.path.dirname(db_path), exist_ok=True)

    # Initialize extensions
    db.init_app(app)
    migrate.init_app(app, db)
    socketio.init_app(app)
    CORS(app,
         resources={r"/api/*": {"origins": app.config['CORS_ORIGINS']}},
         supports_credentials=True)

    # Initialize OAuth/OIDC
    from backend.auth import init_oauth
    init_oauth(app)

    # Register blueprints
    from backend.routes import questions, games, teams, admin, categories, download_jobs, auth
    app.register_blueprint(auth.bp)
    app.register_blueprint(questions.bp)
    app.register_blueprint(games.bp)
    app.register_blueprint(teams.bp)
    app.register_blueprint(admin.bp)
    app.register_blueprint(categories.bp)
    app.register_blueprint(download_jobs.bp)

    # Register socket events
    from backend.sockets import events

    # Serve React frontend in production
    @app.route('/', defaults={'path': ''})
    @app.route('/<path:path>')
    def serve_frontend(path):
        """Serve React frontend"""
        if path and os.path.exists(os.path.join(app.static_folder, path)):
            return send_from_directory(app.static_folder, path)
        elif path.startswith('api/'):
            # API routes should 404 if not found
            return {'error': 'Not found'}, 404
        else:
            # Serve index.html for all other routes (React Router)
            index_path = os.path.join(app.static_folder, 'index.html')
            if os.path.exists(index_path):
                return send_from_directory(app.static_folder, 'index.html')
            else:
                return {'message': 'Trivia Game API', 'status': 'running'}, 200

    # Health check endpoint
    @app.route('/api/health')
    def health_check():
        """Health check endpoint"""
        return {'status': 'ok', 'message': 'Trivia Game API is running'}, 200

    return app