"""
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")
    flask_app = Flask(__name__)
    flask_app.config.from_object(config_by_name[config_name])

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

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

    from app.api import register_blueprints
    register_blueprints(flask_app)

    from app.admin_login_routes import register_admin_login_routes
    register_admin_login_routes(flask_app)  # /admin-login、/admin-logout

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

    with flask_app.app_context():
        try:
            from app.utils.ensure_admin import ensure_admin_user
            ensure_admin_user()  # 默认管理员 admin / 123456
        except Exception as e:
            import warnings
            warnings.warn(f"ensure_admin_user skipped: {e}", UserWarning)

    # Flask-Admin 在 create_app 内初始化会因包名 app 冲突失败，改在 run.py 中初始化
    # try:
    #     from app.admin import init_admin
    #     init_admin(flask_app)
    # except Exception as e:
    #     import warnings
    #     warnings.warn(f"Flask-Admin init skipped: {e}", UserWarning)

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

    return flask_app