/**
 * @file HTTP surface for cross-lane named locks (`server/lib/named-lock.js`).
 * Every route is single-shot — this layer never blocks waiting for a lock to
 * free up. The CLI (`agenthub lock acquire`) owns the polling loop; AgentHub's
 * server-side primitives stay non-orchestrating, same as every other lane
 * route in this project. Lock names are one directory name each (named-lock.js
 * refuses a path), and in server mode a member's live in their own namespace.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

const { Router } = require("express");
const namedLock = require("../lib/named-lock");
const { sameOriginGuard } = require("./run");
const { memberId } = require("../lib/scope");

const router = Router();

// Server mode: a member's locks live in their own namespace (`u<id>.<name>`),
// so one user's agents can neither see nor take another user's locks.
const memberPrefix = (req) => {
  const uid = memberId(req);
  return uid == null ? "" : `u${uid}.`;
};
const lockName = (req) => memberPrefix(req) + req.params.name;

const badInput = (res, err) =>
  res.status(400).json({ error: { code: err.code, message: err.message } });

router.get("/", (req, res) => {
  const prefix = memberPrefix(req);
  const locks = namedLock.listLocks();
  res.json({
    locks: prefix
      ? locks
          .filter((l) => l.name.startsWith(prefix))
          .map((l) => ({ ...l, name: l.name.slice(prefix.length) }))
      : locks,
  });
});

router.post("/:name/acquire", sameOriginGuard, (req, res) => {
  const holder = typeof req.body?.holder === "string" ? req.body.holder.trim() : "";
  if (!holder) {
    return res.status(400).json({ error: { code: "EBADHOLDER", message: "holder is required" } });
  }
  let result;
  try {
    result = namedLock.tryAcquire(lockName(req), holder);
  } catch (err) {
    if (err.code === "EBADNAME" || err.code === "EBADHOLDER") return badInput(res, err);
    throw err;
  }
  if (result.acquired) return res.json(result);
  res.status(409).json(result);
});

router.post("/:name/release", sameOriginGuard, (req, res) => {
  const holder = typeof req.body?.holder === "string" ? req.body.holder.trim() : "";
  if (!holder) {
    return res.status(400).json({ error: { code: "EBADHOLDER", message: "holder is required" } });
  }
  try {
    namedLock.release(lockName(req), holder);
    res.json({ ok: true });
  } catch (err) {
    if (err.code === "EBADNAME" || err.code === "EBADHOLDER") return badInput(res, err);
    if (err.code === "ENOLOCK") {
      return res.status(404).json({ error: { code: err.code, message: err.message } });
    }
    if (err.code === "ENOTHOLDER") {
      return res.status(409).json({
        error: { code: err.code, message: err.message, currentHolder: err.currentHolder },
      });
    }
    res.status(500).json({ error: { code: err.code, message: err.message } });
  }
});

module.exports = router;