"""
Flask application factory for chat platform backend.
"""
import os
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from flask_migrate import Migrate
from flask_jwt_extended import JWTManager
from flask_cors import CORS
from flask_socketio import SocketIO
from flask_limiter import Limiter
from flask_limiter.util import get_remote_address
from redis import Redis

from app.config import config_by_name

db = SQLAlchemy()
migrate = Migrate()
jwt = JWTManager()
socketio = SocketIO(cors_allowed_origins="*", async_mode="eventlet")
limiter = Limiter(key_func=get_remote_address, default_limits=["200 per day", "50 per hour"])


def create_app(config_name=None):
    config_name = config_name or os.getenv("FLASK_ENV", "development")
    app = Flask(__name__)
    app.config.from_object(config_by_name[config_name])

    CORS(app, resources={r"/api/*": {"origins": "*"}}, supports_credentials=True)
    db.init_app(app)
    migrate.init_app(app, db)
    jwt.init_app(app)
    limiter.init_app(app)
    socketio.init_app(app, message_queue=app.config.get("CELERY_BROKER_URL") or None)

    app.redis = Redis.from_url(app.config["REDIS_URL"]) if app.config.get("REDIS_URL") else None

    from app.api import register_blueprints
    register_blueprints(app)

    import app.socket_events  # noqa: F401 - register SocketIO handlers

    from app.admin import init_admin
    init_admin(app)

    @app.route("/health")
    def health():
        return {"status": "healthy"}, 200

    return app