/**
 * @file Merge the user's login-shell PATH into `process.env.PATH`. A systemd
 * unit or LaunchAgent snapshots PATH when it is installed, so a CLI installed
 * later into a new directory (nvm, ~/.local/bin, a vendor installer) is
 * invisible to AI Tools detection and to every lane pane. `$SHELL -ilc` runs
 * the rc files where those installers add to PATH; delimiters discard
 * whatever the rc files print, stdin is closed so a prompt gets EOF, and a
 * timeout bounds a hang. Off with `AGENTHUB_SHELL_PATH=0`. The shell's own
 * PATH is also kept in ITS order (`shellPath()`): the merge appends, so an
 * install job that must use the shell's npm puts this first. Adapted from Orca's
 * `hydrate-shell-path.ts` (MIT).
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

const { execFile } = require("node:child_process");
const path = require("node:path");

const MARK = "__AGENTHUB_PATH__";

let lastShellPath = null;

/** The PATH the login shell last printed, in its order; null before/without one. */
const shellPath = () => lastShellPath;

/**
 * @returns {Promise<boolean>} whether a shell PATH was read and merged.
 */
function hydrateShellPath({
  spawn = execFile,
  shell = process.env.SHELL || "/bin/bash",
  timeoutMs = 5000,
} = {}) {
  if (/^(0|false|off)$/i.test(process.env.AGENTHUB_SHELL_PATH || "")) return Promise.resolve(false);
  return new Promise((resolve) => {
    let child;
    try {
      child = spawn(
        shell,
        ["-ilc", `printf '${MARK}%s${MARK}' "$PATH"`],
        { timeout: timeoutMs, encoding: "utf8" },
        (err, stdout) => {
          const m = String(stdout || "").match(new RegExp(`${MARK}(.*?)${MARK}`, "s"));
          if (!m) return resolve(false); // timeout, spawn error, no output
          lastShellPath = m[1];
          const have = (process.env.PATH || "").split(path.delimiter).filter(Boolean);
          const add = m[1].split(path.delimiter).filter((d) => d && !have.includes(d));
          process.env.PATH = [...have, ...new Set(add)].join(path.delimiter);
          resolve(true);
        }
      );
    } catch {
      return resolve(false);
    }
    // An rc file that reads stdin gets EOF instead of hanging until the timeout.
    child?.stdin?.end();
  });
}

module.exports = { hydrateShellPath, shellPath };