from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
from flask_login import LoginManager
import pymysql
import os
from config import Config

db = SQLAlchemy()
migrate = Migrate()
login_manager = LoginManager()

def create_app():
    app = Flask(__name__)
    app.config.from_object(Config)
    
    # Initialize enhanced logging
    setup_enhanced_logging(app)
    
    # Initialize extensions
    db.init_app(app)
    migrate.init_app(app, db)
    login_manager.init_app(app)
    login_manager.login_view = 'auth.login'
    login_manager.login_message = 'Please log in to access this page.'
    
    # MySQL connection (read-only) - initialized when needed
    def get_mysql_connection():
        if not hasattr(app, 'mysql_connection') or app.mysql_connection is None:
            try:
                app.mysql_connection = pymysql.connect(
                    host=app.config['MYSQL_CONFIG']['host'],
                    database=app.config['MYSQL_CONFIG']['database'],
                    user=app.config['MYSQL_CONFIG']['user'],
                    password=app.config['MYSQL_CONFIG']['password'],
                    port=app.config['MYSQL_CONFIG']['port'],
                    autocommit=False  # Ensure read-only behavior
                )
            except Exception as e:
                print(f"MySQL connection failed: {e}")
                app.mysql_connection = None
        return app.mysql_connection
    
    # Make connection function available to app context
    app.get_mysql_connection = get_mysql_connection
    
    # Register blueprints
    from blueprints.auth import auth_bp
    from blueprints.main import main_bp
    from blueprints.search import search_bp
    from blueprints.analytics import analytics_bp
    
    app.register_blueprint(auth_bp, url_prefix='/auth')
    app.register_blueprint(main_bp)
    app.register_blueprint(search_bp)
    app.register_blueprint(analytics_bp)
    
    # User loader for Flask-Login
    from models import Users
    
    @login_manager.user_loader
    def load_user(user_id):
        return Users.query.get(int(user_id))
    
    # Add permission functions to template context
    from permissions import (
        can_manage_users, can_manage_payments, can_view_data, 
        can_process_single_payments, can_manage_batch_payments, 
        can_manage_payment_plans, can_view_logs, can_export_data,
        has_permission, get_user_permission_level
    )
    
    @app.context_processor
    def inject_permissions():
        return {
            'can_manage_users': can_manage_users,
            'can_manage_payments': can_manage_payments, 
            'can_view_data': can_view_data,
            'can_process_single_payments': can_process_single_payments,
            'can_manage_batch_payments': can_manage_batch_payments,
            'can_manage_payment_plans': can_manage_payment_plans,
            'can_view_logs': can_view_logs,
            'can_export_data': can_export_data,
            'has_permission': has_permission,
            'get_user_permission_level': get_user_permission_level
        }
    
    # Note: Database tables will be managed by Flask-Migrate
    # Use 'flask db init', 'flask db migrate', 'flask db upgrade' commands
    
    return app

def setup_enhanced_logging(app):
    """Setup enhanced logging system for the application."""
    try:
        # Create logs directory first
        os.makedirs('logs', exist_ok=True)
        
        from logging_config import setup_flask_logging
        from middleware import RequestLoggingMiddleware, DatabaseLoggingMiddleware, SecurityMiddleware
        
        # Setup Flask logging
        setup_flask_logging(app)
        
        # Initialize middleware with error handling
        try:
            RequestLoggingMiddleware(app)
            app.logger.info("Request logging middleware initialized")
        except Exception as e:
            app.logger.warning(f"Request logging middleware failed: {e}")
        
        try:
            DatabaseLoggingMiddleware(app)
            app.logger.info("Database logging middleware initialized")
        except Exception as e:
            app.logger.warning(f"Database logging middleware failed: {e}")
        
        try:
            SecurityMiddleware(app)
            app.logger.info("Security middleware initialized")
        except Exception as e:
            app.logger.warning(f"Security middleware failed: {e}")
        
    except ImportError as e:
        print(f"Enhanced logging not available: {e}")
    except Exception as e:
        print(f"Error setting up enhanced logging: {e}")
        # Don't let logging errors prevent the app from starting
        pass

if __name__ == '__main__':
    app = create_app()
    app.run(debug=True)