import os
from flask import Flask, send_from_directory
from flask_cors import CORS
from flask_sqlalchemy import SQLAlchemy
from dotenv import load_dotenv

load_dotenv()
db = SQLAlchemy()

def create_app():
    app = Flask(__name__, instance_relative_config=True)
    
    # CORS Configuration
    CORS(app, resources={
        r"/*": {
            "origins": ["http://localhost:4200", "http://localhost:4300"],
            "methods": ["GET", "POST", "PUT", "DELETE", "OPTIONS"],
            "allow_headers": ["Content-Type", "Authorization"],
            "supports_credentials": True
        }
    })

    # Ensure directories exist
    instance_path = os.path.abspath(os.path.join(os.path.dirname(__file__), 'instance'))
    uploads_path = os.path.abspath(os.path.join(os.path.dirname(__file__), 'Uploads'))
    
    for path in [instance_path, uploads_path]:
        if not os.path.exists(path):
            os.makedirs(path)
    
    app.config['UPLOAD_FOLDER'] = uploads_path

    # Database configuration
    flask_env = os.getenv('FLASK_ENV', 'development').lower()
    
    if flask_env == 'production':
        mysql_host = os.getenv('MYSQL_HOST')
        mysql_user = os.getenv('MYSQL_USER')
        mysql_password = os.getenv('MYSQL_PASSWORD')
        mysql_db = os.getenv('MYSQL_DATABASE')
        
        if not all([mysql_host, mysql_user, mysql_password, mysql_db]):
            raise ValueError("Missing required MySQL environment variables")
        
        app.config['SQLALCHEMY_DATABASE_URI'] = (
            f'mysql+pymysql://{mysql_user}:{mysql_password}@{mysql_host}:3306/{mysql_db}'
        )
    else:
        sqlite_db_path = os.getenv('SQLITE_DB_PATH', 'machines.db')
        db_path = os.path.join(instance_path, sqlite_db_path)
        app.config['SQLALCHEMY_DATABASE_URI'] = f'sqlite:///{db_path}'

    app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
    app.config['SQLALCHEMY_ECHO'] = os.getenv('SQLALCHEMY_ECHO', 'False').lower() == 'true'

    # Initialize extensions
    db.init_app(app)

    # Import models
    from app.models.models import Machine, User, Product, VendingSlot, Transaction

    # Create tables
    with app.app_context():
        db.create_all()
        print(f"✓ Database initialized ({flask_env})")
        
        # FIXED: Serial service connection BEFORE return
        from app.services.services import serial_service
        try:
            connected = serial_service.connect_to_machine('/dev/ttyUSB0', 9600)
            if connected:
                print("✓ Vending machine connected successfully")
            else:
                print("✗ Failed to connect to vending machine")
        except Exception as e:
            print(f"⚠ Serial connection error: {e}")

    # Register blueprints
    from app.routes.routes import bp
    app.register_blueprint(bp, url_prefix='/')

    @app.route('/uploads/<filename>')
    def uploaded_file(filename):
        return send_from_directory(app.config['UPLOAD_FOLDER'], filename)

    return app