from flask import Flask, g, redirect, url_for, render_template
import datetime
import os

def create_app(config_name='development'):
    app = Flask(__name__, 
                template_folder='templates',
                static_folder='static')
    
    # Import config
    try:
        from config.settings import config
        app.config.from_object(config.get(config_name, 'default'))
    except ImportError:
        # Fallback configuration
        app.config['SECRET_KEY'] = 'dev-key-placeholder'
        app.config['SQLALCHEMY_DATABASE_URI'] = 'sqlite:///app.db'
        app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False
    
    # Create the app instance folder if it doesn't exist
    # This is where SQLite database will be stored
    os.makedirs(os.path.join(app.instance_path), exist_ok=True)
    
    # Initialize extensions
    from app.core.extensions import db, migrate, login_manager, bcrypt, limiter, csrf
    db.init_app(app)
    migrate.init_app(app, db)
    login_manager.init_app(app)
    bcrypt.init_app(app)
    csrf.init_app(app)
    limiter.init_app(app)
    
    # Initialize login manager
    from app.core.auth import User
    
    @login_manager.user_loader
    def load_user(user_id):
        # Make sure we're in app context
        with app.app_context():
            return User.query.get(int(user_id))
    
    # Initialize CSRF protection
    from flask_wtf.csrf import CSRFProtect
    csrf = CSRFProtect()
    csrf.init_app(app)
    
    # Request hooks
    @app.before_request
    def before_request():
        g.user = None
        from flask_login import current_user
        if current_user.is_authenticated:
            g.user = current_user
        
        # Add datetime to all templates
        g.now = datetime.datetime.utcnow()
    
    @app.context_processor
    def inject_now():
        return {'now': datetime.datetime.utcnow()}
    
    @app.after_request
    def add_security_headers(response):
        # Security headers
        response.headers['X-Content-Type-Options'] = 'nosniff'
        response.headers['X-Frame-Options'] = 'SAMEORIGIN'
        response.headers['X-XSS-Protection'] = '1; mode=block'
        
        # Update last_seen for the user
        if hasattr(g, 'user') and g.user and g.user.is_authenticated:
            g.user.last_seen = datetime.datetime.utcnow()
            db.session.commit()
        return response
    
    # Add a basic index route that redirects to login or dashboard
    @app.route('/')
    def index():
        from flask_login import current_user
        if current_user.is_authenticated:
            return redirect(url_for('dashboard.dashboard_home'))
        return redirect(url_for('auth.login'))
    
    # Register blueprints - order matters!
    # First auth blueprint
    from app.routes.auth import bp as auth_bp
    app.register_blueprint(auth_bp)
    print("Registered Auth blueprint")
    
    # Then other blueprints
    try:
        from app.routes.dashboard import bp as dashboard_bp
        app.register_blueprint(dashboard_bp)
        print("Registered Dashboard blueprint")
    except ImportError as e:
        print(f"Could not import dashboard blueprint: {e}")
    
    try:
        from app.routes.ipam import bp as ipam_bp
        app.register_blueprint(ipam_bp)
        print("Registered IPAM blueprint")
    except ImportError as e:
        print(f"Could not import ipam blueprint: {e}")
    
    try:
        from app.routes.api import bp as api_bp
        app.register_blueprint(api_bp)
        print("Registered API blueprint")
    except ImportError as e:
        print(f"Could not import API blueprint: {e}")
    
    # Create database tables
    with app.app_context():
        try:
            db.create_all()
            print("Database tables created successfully")
            
            # Check if we need to seed the database
            from app.core.auth import User
            if User.query.count() == 0:
                # Run the seed database function if we have no users
                try:
                    from app.scripts.db_seed import seed_database
                    seed_database()
                    print("Database seeded with initial data")
                    
                    # Create an admin user
                    admin = User(email="admin@example.com", is_admin=True)
                    admin.set_password("admin")
                    db.session.add(admin)
                    db.session.commit()
                    print("Admin user created: admin@example.com / admin")
                except Exception as e:
                    print(f"Error seeding database: {e}")
        except Exception as e:
            print(f"Error with database setup: {e}")
    
    # After all blueprint registrations, add error handlers

    @app.errorhandler(404)
    def page_not_found(e):
        return render_template('errors/404.html', title='Page Not Found'), 404

    @app.errorhandler(500)
    def internal_server_error(e):
        return render_template('errors/500.html', title='Server Error'), 500

    @app.errorhandler(403)
    def forbidden(e):
        return render_template('errors/403.html', title='Forbidden'), 403

    @app.errorhandler(401)
    def unauthorized(e):
        return render_template('errors/401.html', title='Unauthorized'), 401
    
    return app