/**
 * @file me.js
 * @description `/api/me` — the signed-in account's own UI preferences
 * (`user_prefs`) and its first-run setup (docs/plans/onboarding), so they
 * follow it to any browser, differ between the accounts of one dashboard, and
 * the setup wizard shows once per account. Local mode is one account,
 * `local`; server mode keys a row `u<id>` by the login cookie — the request
 * never names an account. Only the keys in `PREF_KEYS` are kept, each a
 * string of at most 8 KB, and a PUT merges into the row (`null` removes a
 * key). Writes are same-origin and touch only the caller's own row.
 * `agenthub.chatUi` ("1") opens Claude/Codex sessions as a chat (`PaneChat`);
 * the appearance keys are `useTheme`'s own (`theme`, `agenthub.theme.dark|light`).
 *
 * S3 (one Linux user per account): an account's dark/light choice also becomes
 * the theme in their own Claude Code settings, written as them.
 * @author Nguyễn Ngọc Trí Vĩ <vinnt@smartgift.vn>
 */

const { Router } = require("express");
const { db } = require("../db");
const auth = require("../lib/auth");
const { sameOriginGuard } = require("../lib/same-origin");

const router = Router();

/** The localStorage keys an account's preferences are made of. */
const PREF_KEYS = [
  "theme",
  "agenthub.theme.dark",
  "agenthub.theme.light",
  "i18nextLng",
  "agenthub.terminal.font",
  "agenthub.pet",
  "agenthub.pet.size",
  "agent-dashboard-sagi-enabled",
  "agent-dashboard-sagi-muted",
  "agent-monitor-notifications",
  "agenthub.defaultTool",
  "agenthub.permissionMode",
  "agenthub.tour",
  "agenthub.chatUi",
];
const MAX_VALUE = 8 * 1024;

/** `u<id>` for a server-mode account, `local` in local mode, null when nobody is signed in. */
function userKey(req) {
  if (!auth.isServerMode()) return "local";
  const user = req.user || auth.userFromRequest(req);
  return user ? `u${user.id}` : null;
}

const getRow = db.prepare("SELECT prefs, onboarded_at FROM user_prefs WHERE user_key = ?");
const upsert = db.prepare(
  `INSERT INTO user_prefs (user_key, prefs) VALUES (?, ?)
   ON CONFLICT(user_key) DO UPDATE SET prefs = excluded.prefs,
     updated_at = strftime('%Y-%m-%dT%H:%M:%fZ', 'now')`
);
const markOnboarded = db.prepare(
  `INSERT INTO user_prefs (user_key, onboarded_at) VALUES (?, strftime('%Y-%m-%dT%H:%M:%fZ', 'now'))
   ON CONFLICT(user_key) DO UPDATE SET onboarded_at = COALESCE(onboarded_at, excluded.onboarded_at)`
);

function read(key) {
  const row = getRow.get(key);
  let prefs = {};
  try {
    prefs = row ? JSON.parse(row.prefs) : {};
  } catch {
    /* a damaged row reads as empty */
  }
  return { prefs, onboardedAt: row?.onboarded_at || null };
}

const unauth = (res) =>
  res.status(401).json({ error: { code: "EAUTH", message: "sign in first" } });

router.get("/prefs", (req, res) => {
  const key = userKey(req);
  if (!key) return unauth(res);
  res.json(read(key));
});

router.put("/prefs", sameOriginGuard, (req, res) => {
  const key = userKey(req);
  if (!key) return unauth(res);
  const patch = req.body?.prefs;
  if (!patch || typeof patch !== "object" || Array.isArray(patch)) {
    return res.status(400).json({ error: { code: "EBADPREFS", message: "prefs: an object" } });
  }
  const { prefs } = read(key);
  for (const [k, v] of Object.entries(patch)) {
    if (!PREF_KEYS.includes(k)) {
      return res.status(400).json({ error: { code: "EBADPREFS", message: `unknown key ${k}` } });
    }
    if (v === null) delete prefs[k];
    else if (typeof v === "string" && v.length <= MAX_VALUE) prefs[k] = v;
    else
      return res
        .status(400)
        .json({ error: { code: "EBADPREFS", message: `${k}: a short string` } });
  }
  upsert.run(key, JSON.stringify(prefs));
  if ("theme" in patch) followClaudeTheme(req, patch.theme);
  res.json(read(key));
});

router.post("/onboarded", sameOriginGuard, (req, res) => {
  const key = userKey(req);
  if (!key) return unauth(res);
  markOnboarded.run(key);
  res.json(read(key));
});

/** S3: an account's dark/light mode becomes their Claude Code theme (best effort). */
function followClaudeTheme(req, mode) {
  if (mode !== "dark" && mode !== "light") return;
  try {
    const runAs = require("../lib/run-as");
    const acct = runAs.accountForUser(req.user?.username);
    if (acct) require("../lib/member-claude").setTheme(acct, mode);
  } catch (err) {
    console.warn("[me] Claude theme not written:", err.message);
  }
}

module.exports = router;
module.exports.PREF_KEYS = PREF_KEYS;