# App package initialization 
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_login import LoginManager
from flask_migrate import Migrate
from flask_wtf.csrf import CSRFProtect
import os
from datetime import timedelta

# Initialize SQLAlchemy outside of create_app
db = SQLAlchemy()
login_manager = LoginManager()
csrf = CSRFProtect()
migrate = Migrate()

# App configuration
class Config:
    SECRET_KEY = os.environ.get('SECRET_KEY') or os.urandom(24)
    SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL') or 'sqlite:///docs.db'
    SQLALCHEMY_TRACK_MODIFICATIONS = False
    PERMANENT_SESSION_LIFETIME = timedelta(hours=12)
    SESSION_TYPE = 'filesystem'

def create_app(config_class=Config):
    app = Flask(__name__)
    app.config.from_object(config_class)
    
    # Initialize extensions
    db.init_app(app)
    login_manager.init_app(app)
    csrf.init_app(app)
    migrate.init_app(app, db)
    
    # Configure login manager
    login_manager.login_view = 'auth.login'
    login_manager.login_message = 'Please log in to access this page.'
    login_manager.login_message_category = 'info'
    
    # Configure session
    app.config['SESSION_PERMANENT'] = True
    
    # Register blueprints
    from app.routes import main as main_bp
    app.register_blueprint(main_bp)
    
    from app.auth import bp as auth_bp
    app.register_blueprint(auth_bp, url_prefix='/auth')
    
    return app

# Create app instance
app = create_app()

# Import models after db initialization to avoid circular imports
from app.models.document import Document, Category, Tag
from app.models.user import User