import logging
import logging.handlers
import os
from flask import Flask, redirect, url_for
from app.config import Config
from app.services.db_service import db

def create_app():
    app = Flask(__name__)
    app.config.from_object(Config)

    # Initialize extensions
    db.init_app(app)
    
    # Configure logging
    setup_logging(app)

    # Register blueprints
    register_blueprints(app)
    # Register error handlers
    register_error_handlers(app)

    # ROOT → LOGIN
    @app.route("/")
    def index():
        return redirect(url_for("auth.login"))

    return app


def setup_logging(app):
    """Configure comprehensive logging for debugging"""
    
    # Ensure logs directory exists
    logs_dir = os.path.join(os.path.dirname(os.path.dirname(__file__)), 'logs')
    os.makedirs(logs_dir, exist_ok=True)
    
    # Create logger
    logger = logging.getLogger()
    logger.setLevel(logging.DEBUG)
    
    # Remove existing handlers
    logger.handlers.clear()
    
    # Create formatters
    detailed_formatter = logging.Formatter(
        '%(asctime)s - %(name)s - %(levelname)s - [%(filename)s:%(lineno)d] - %(message)s',
        datefmt='%Y-%m-%d %H:%M:%S'
    )
    
    # File handler for all logs
    file_handler = logging.handlers.RotatingFileHandler(
        os.path.join(logs_dir, 'app.log'),
        maxBytes=10485760,  # 10MB
        backupCount=5
    )
    file_handler.setLevel(logging.DEBUG)
    file_handler.setFormatter(detailed_formatter)
    logger.addHandler(file_handler)
    
    # File handler for RA bill fetching only
    ra_bill_handler = logging.handlers.RotatingFileHandler(
        os.path.join(logs_dir, 'ra_bill_fetch.log'),
        maxBytes=5242880,  # 5MB
        backupCount=5
    )
    ra_bill_handler.setLevel(logging.DEBUG)
    ra_bill_handler.setFormatter(detailed_formatter)
    
    # Only attach to relevant loggers
    ra_loggers = ['app.routes.dashboard', 'app.routes.file_report']
    for logger_name in ra_loggers:
        logging.getLogger(logger_name).addHandler(ra_bill_handler)
    
    # Console handler for important messages
    console_handler = logging.StreamHandler()
    console_handler.setLevel(logging.INFO)
    console_formatter = logging.Formatter(
        '%(levelname)s - %(name)s - %(message)s'
    )
    console_handler.setFormatter(console_formatter)
    logger.addHandler(console_handler)
    
    # Suppress verbose libraries
    logging.getLogger('werkzeug').setLevel(logging.WARNING)
    logging.getLogger('sqlalchemy.engine').setLevel(logging.WARNING)
    
    app.logger.info("Logging initialized successfully")
    app.logger.info(f"Log files location: {logs_dir}")



def register_blueprints(app):
    from app.routes.auth import auth_bp
    from app.routes.user import user_bp
    from app.routes.dashboard import dashboard_bp
    from app.routes.subcontractor_routes import subcontractor_bp
    from app.routes.file_import import file_import_bp
    from app.routes.file_report import file_report_bp
    from app.routes.generate_comparison_report import generate_report_bp
    from app.routes.file_format import file_format_bp 

    app.register_blueprint(auth_bp) 
    app.register_blueprint(user_bp)
    app.register_blueprint(dashboard_bp)
    app.register_blueprint(subcontractor_bp)
    app.register_blueprint(file_import_bp)
    app.register_blueprint(file_report_bp)
    app.register_blueprint(generate_report_bp)
    app.register_blueprint(file_format_bp )


def register_error_handlers(app):
    @app.errorhandler(404)
    def page_not_found(e):
        return "Page Not Found", 404

    @app.errorhandler(500)
    def internal_error(e):
        return "Internal Server Error", 500