from __future__ import annotations

import os
from pathlib import Path

from flask import Flask, jsonify, request, send_from_directory

from compiler import CompileError, compile_graph


def create_app() -> Flask:
    app = Flask(
        __name__,
        static_folder="static",
        static_url_path="/",
    )

    @app.get("/")
    def spa_index():
        static_dir = Path(app.static_folder or "static")
        return send_from_directory(static_dir, "index.html")

    @app.get("/<path:path>")
    def spa_assets(path: str):
        static_dir = Path(app.static_folder or "static")
        file_path = static_dir / path
        if file_path.exists() and file_path.is_file():
            return send_from_directory(static_dir, path)
        return send_from_directory(static_dir, "index.html")

    @app.post("/api/compile")
    def api_compile():
        payload = request.get_json(silent=True)
        if not isinstance(payload, dict):
            return jsonify({"ok": False, "error": "request body must be a JSON object"}), 400

        graph = payload.get("graph")
        if not isinstance(graph, dict):
            return jsonify({"ok": False, "error": "missing 'graph' object"}), 400

        try:
            yml = compile_graph(graph)
        except CompileError as e:
            return jsonify({"ok": False, "error": str(e)}), 400
        except Exception:
            return jsonify({"ok": False, "error": "internal error"}), 500

        return jsonify({"ok": True, "yaml": yml})

    return app


if __name__ == "__main__":
    port = int(os.environ.get("PORT", "7860"))
    app = create_app()
    app.run(host="0.0.0.0", port=port, debug=True)