app/__init__.py

from flask import Flask, render_template, request, jsonify
from flask_cors import CORS
import os
from dotenv import load_dotenv

load_dotenv()

def create_app(test_config=None):
    # create and configure the app
    app = Flask(__name__, instance_relative_config=True)
    app.config.from_mapping(
        SECRET_KEY=os.environ.get('SECRET_KEY', 'change-me-in-production'),
        UPLOAD_FOLDER=os.path.join(app.root_path, 'static', 'uploads'),
        ALLOWED_EXTENSIONS={'png', 'jpg', 'jpeg'},
        MAX_CONTENT_LENGTH=16 * 1024 * 1024, # 16MB max
    )

    if test_config is None:
        # load the instance config, if it exists, when not testing
        app.config.from_pyfile('config.py', silent=True)
    else:
        # load the test config if passed in
        app.config.from_mapping(test_config)

    # ensure the upload folder exists
    os.makedirs(app.config['UPLOAD_FOLDER'], exist_ok=True)

    CORS(app)

    # Register Blueprints
    from .routes import main_routes, analysis_routes, recognition_routes
    app.register_blueprint(main_routes.bp)
    app.register_blueprint(analysis_routes.bp)
    app.register_blueprint(recognition_routes.bp)

    @app.errorhandler(404)
    def page_not_found(e):
        return render_template('404.html'), 404

    @app.errorhandler(500)
    def internal_server_error(e):
        return render_template('500.html'), 500

    return app