"""Flask application factory"""
import os
from flask import Flask
from flask_login import LoginManager
from flask_limiter import Limiter
from flask_limiter.util import get_remote_address
from flask_wtf.csrf import CSRFProtect


def create_app(config_name='development'):
    """Create and configure the Flask application

    Args:
        config_name: Configuration environment (development, production, testing)

    Returns:
        Flask application instance
    """
    app = Flask(__name__)

    # Load configuration
    if config_name == 'production':
        from config.production import ProductionConfig
        app.config.from_object(ProductionConfig)
    elif config_name == 'testing':
        from config.testing import TestingConfig
        app.config.from_object(TestingConfig)
    else:
        from config.development import DevelopmentConfig
        app.config.from_object(DevelopmentConfig)

    # Ensure data directory exists
    os.makedirs(app.config['DATA_DIR'], exist_ok=True)

    # Initialize Flask-WTF CSRF Protection
    csrf = CSRFProtect()
    csrf.init_app(app)

    # Initialize Flask-Login
    login_manager = LoginManager()
    login_manager.init_app(app)
    login_manager.login_view = 'auth.login'
    login_manager.login_message = 'Please log in to access this page.'

    @login_manager.user_loader
    def load_user(user_id):
        """Load user by ID for Flask-Login"""
        from app.models.user import User
        return User.get_by_id(user_id)

    # Initialize Flask-Limiter
    limiter = Limiter(
        app=app,
        key_func=get_remote_address,
        storage_uri=app.config['RATELIMIT_STORAGE_URL'],
        default_limits=[f"{app.config['RATELIMIT_PER_HOUR']}/hour"] if app.config.get('RATELIMIT_ENABLED') else []
    )

    # Register blueprints
    from app.routes import submission, dashboard, admin, auth
    app.register_blueprint(submission.bp)
    app.register_blueprint(dashboard.bp)
    app.register_blueprint(admin.bp)
    app.register_blueprint(auth.bp)

    # Set index route
    @app.route('/')
    def index():
        """Welcome page"""
        from flask import render_template
        return render_template('index.html')

    return app