// 单独拉起后端（不开桌面端）：npm run backend
// 端口取环境变量 API_PORT，其次 .env 里的 API_PORT，默认 8788。
const { spawn } = require("child_process");
const path = require("path");
const fs = require("fs");

const root = path.join(__dirname, "..");

function readEnvFile(file) {
  const values = {};
  if (!fs.existsSync(file)) return values;
  for (const line of fs.readFileSync(file, "utf8").split(/\r?\n/)) {
    const trimmed = line.trim();
    if (!trimmed || trimmed.startsWith("#")) continue;
    const eq = trimmed.indexOf("=");
    if (eq <= 0) continue;
    values[trimmed.slice(0, eq).trim()] = trimmed.slice(eq + 1).trim();
  }
  return values;
}

const envFile = readEnvFile(path.join(root, ".env"));
const port = process.env.API_PORT || envFile.API_PORT || "8788";

const venvPy =
  process.platform === "win32"
    ? path.join(root, ".venv", "Scripts", "python.exe")
    : path.join(root, ".venv", "bin", "python");
const py = fs.existsSync(venvPy) ? venvPy : process.platform === "win32" ? "python" : "python3";

const child = spawn(py, ["backend/main.py"], {
  cwd: root,
  stdio: "inherit",
  env: { ...process.env, PYTHONUTF8: "1", API_PORT: port },
});
child.on("exit", (code) => process.exit(code ?? 0));