from __future__ import annotations

from pathlib import Path
from flask import Flask, request, url_for
from flask_socketio import SocketIO
from .config import SECRET_KEY
from .db import init_db
from .utils import file_md5

socketio = SocketIO(cors_allowed_origins="*", ping_timeout=30, async_mode="threading")
_static_md5_cache: dict[tuple, str] = {}


def create_app() -> Flask:
    app = Flask(__name__)
    app.secret_key = SECRET_KEY

    @app.context_processor
    def static_helpers():
        def static_url(filename: str) -> str:
            path = Path(app.static_folder or "") / filename
            try:
                stat = path.stat()
                key = (filename, stat.st_mtime_ns, stat.st_size)
                version = _static_md5_cache.get(key)
                if not version:
                    _static_md5_cache.clear()
                    version = file_md5(path)
                    _static_md5_cache[key] = version
                return url_for("static", filename=filename, v=version)
            except OSError:
                return url_for("static", filename=filename)
        return {"static_url": static_url}

    @app.after_request
    def cache_headers(response):
        response.headers.pop('Content-Disposition', None)
        
        if request.endpoint == "static":
            response.headers["Cache-Control"] = "public, max-age=31536000, immutable"
        else:
            response.headers["Cache-Control"] = "no-cache, no-store, must-revalidate"
            response.headers["Pragma"] = "no-cache"
            response.headers["Expires"] = "0"
        return response

    from .routes.main import bp as main_bp
    from .routes.api import bp as api_bp
    app.register_blueprint(main_bp)
    app.register_blueprint(api_bp)
    init_db()

    socketio.init_app(app)
    from .services.workers import set_socketio
    set_socketio(socketio)
    from .services.websocket import register_socketio_handlers
    register_socketio_handlers(socketio)
    from .services.startup_config import schedule_startup_config_apply
    schedule_startup_config_apply(socketio)
    return app