import fs from "node:fs";
import os from "node:os";
import path from "node:path";
import crypto from "node:crypto";
import { proxyAwareFetch } from "../utils/proxyFetch.js";

/**
 * Xiaomi MiMo account-session helpers (used for weekly quota).
 *
 * The weekly quota endpoint lives on the account service domain and is authorized
 * by an account session cookie, NOT the sk- API key. Acquiring that cookie is a
 * 1:1 port of MiMo Desktop's ServiceTokenManager (app.asar) — the GOLD STANDARD:
 *
 *   getServiceToken(sid) / refreshServiceToken(sid):
 *     PHASE 1: GET https://account.xiaomi.com/pass/serviceLogin
 *                ?_locale=zh_CN&_snsNone=true&sid=<clusterSid>&_json=true
 *                Cookie: {userId, passToken, cUserId}
 *              -> {code, location, ssecurity, nonce, bSecondValidation, notificationUrl}
 *              -> code !== 0 is an error (never silent)
 *     PHASE 2: GET {location}&clientSign=sha1(nonce & ssecurity), follow the
 *              redirect chain absorbing Set-Cookie -> serviceToken
 *
 * sid is per-cluster (SID_BY_REGION): CN = mimopc, SGP = mimosgp.
 */

// Account-service cluster hosts. MiMo Desktop declares five regions
// (rn = {CN, SGP, RU, IN, EU}); the EU cluster is deployed in Amsterdam.
// Host + sid naming is unified: mimo-server-<code> / sid = mimo<code>
// (ams is the only non-country code). Verified live via /api/user/xiaomi/me.
const API_BASE_BY_REGION = {
  cn: "https://mimo-server-cn.xiaomimimo.com",
  sgp: "https://mimo-server-sgp.xiaomimimo.com",
  ams: "https://mimo-server-ams.xiaomimimo.com",
  ru: "https://mimo-server-ru.xiaomimimo.com",
  in: "https://mimo-server-in.xiaomimimo.com",
};
const DEFAULT_API_BASE = API_BASE_BY_REGION.sgp;

// Cluster service sid — 1:1 with the host code: mimo<code>.
// Unknown/absent region falls back to SGP (the international/open cluster).
const SID_BY_REGION = { cn: "mimopc", sgp: "mimosgp", ams: "mimoams", ru: "mimoru", in: "mimoin" };
function sidForRegion(region) {
  const r = String(region || "").toLowerCase();
  return SID_BY_REGION[r] || SID_BY_REGION.sgp;
}
const API_BASE = DEFAULT_API_BASE;
const ACCOUNT_HOST = "account.xiaomi.com";
const API_UA =
  "miNative PC/Normal Windows_NT/10.0.19045 SDKV/1.0.0 DEVT/PC DEVS/Windows APP/miaccount_desktop APPV/0.1.0";
const SSO_UA = "MiClaw/1.0";
const COOKIE_TTL_MS = 30 * 60 * 1000;

// Per-account session caches (keyed by passToken hash) so multiple Xiaomi
// accounts / connections can rotate without clobbering each other.
const _cache = new Map(); // key -> { cookie, at }
const _inflight = new Map(); // key -> Promise<cookie|null>

function desktopCookiePath() {
  const home = os.homedir();
  if (process.platform === "win32") {
    return path.join(home, "AppData", "Roaming", "Xiaomi MiMo", "Partitions", "xiaomi-account", "Network", "Cookies");
  }
  if (process.platform === "darwin") {
    return path.join(home, "Library", "Application Support", "Xiaomi MiMo", "Partitions", "xiaomi-account", "Network", "Cookies");
  }
  return path.join(home, ".config", "Xiaomi MiMo", "Partitions", "xiaomi-account", "Network", "Cookies");
}

/**
 * Read the persisted Xiaomi account cookies from MiMo Desktop's Electron profile.
 * The Chromium cookie DB is held with an exclusive lock while Desktop runs, so we
 * copy it first and bail (return null) if that fails.
 * @returns {Promise<Record<string,string>|null>}
 */
async function readDesktopAccountCookies() {
  const src = desktopCookiePath();
  if (!fs.existsSync(src)) return null;
  const tmp = path.join(os.tmpdir(), `9r-mimo-cookies-${process.pid}-${crypto.randomBytes(4).toString("hex")}.db`);
  try {
    fs.copyFileSync(src, tmp);
  } catch {
    return null; // locked by a running Desktop
  }
  try {
    const { DatabaseSync } = await import("node:sqlite");
    const db = new DatabaseSync(tmp, { readOnly: true });
    const rows = db.prepare("SELECT name, value FROM cookies WHERE host_key = ?").all("." + ACCOUNT_HOST);
    db.close();
    const jar = Object.fromEntries(rows.map((r) => [r.name, r.value]));
    return jar.passToken ? jar : null;
  } catch {
    return null;
  } finally {
    try {
      fs.unlinkSync(tmp);
    } catch {
      /* ignore */
    }
  }
}

/**
 * Read just the passToken + identity cookies from Desktop's profile.
 * Exported so the connect flow can persist a per-account passToken into the
 * connection's providerSpecificData — this is what enables multi-account rotation.
 * @returns {Promise<{passToken:string, userId:string|null, cUserId:string|null}|null>}
 */
export async function readDesktopPassToken() {
  try {
    const jar = await readDesktopAccountCookies();
    if (!jar?.passToken) return null;
    return { passToken: jar.passToken, userId: jar.userId || null, cUserId: jar.cUserId || null };
  } catch {
    return null;
  }
}

function signatureClientSign(nonce, ssecurity) {
  const input = `nonce=${nonce}` + (ssecurity && ssecurity.trim() ? `&${ssecurity}` : "");
  return encodeURIComponent(crypto.createHash("sha1").update(input).digest("base64"));
}

function absorbSetCookie(jar, res) {
  for (const c of res.headers.getSetCookie?.() || []) {
    const m = /^([^=]+)=([^;]*)/.exec(c.trim());
    if (m && m[2]) jar[m[1]] = m[2];
  }
}

function cookieHeader(jar) {
  return Object.entries(jar)
    .filter(([, v]) => v)
    .map(([k, v]) => `${k}=${v}`)
    .join("; ");
}

/**
 * Resolve the account-service base URL for a connection.
 * @param {object|null} providerSpecificData - may carry `region` ("cn"|"sgp"|"ams"|"ru"|"in")
 */
export function resolveMimoServerBase(providerSpecificData = null) {
  const region = String(providerSpecificData?.region || "").toLowerCase();
  return API_BASE_BY_REGION[region] || DEFAULT_API_BASE;
}

/**
 * Exchange a passToken for a mimo-server service session cookie.
 * Primary path mirrors the Desktop ServiceTokenManager (app.asar):
 *   PHASE 1: GET /pass/serviceLogin?_locale=zh_CN&_snsNone=true&sid=<clusterSid>&_json=true
 *            Cookie {userId,passToken,cUserId} -> {code,location,ssecurity,nonce}
 *   PHASE 2: GET {location}&clientSign=sha1(nonce&ssecurity), follow the chain
 *            (manual, absorbing Set-Cookie) -> serviceToken
 * sid is per-cluster (SID_BY_REGION): cn=mimopc, sgp=mimosgp, ams=mimoams, ru=mimoru, in=mimoin.
 * @returns {Promise<string|null>} Cookie header value, or null on failure.
 */
async function acquireServiceCookie(passJar, proxyOptions, apiBase = DEFAULT_API_BASE, region = "sgp") {
  const r = String(region || "").toLowerCase();
  // Hard constraint: CN is ALWAYS direct (ignores proxy even if set)
  const effectiveProxy = r === "cn" ? null : proxyOptions;
  const sid = sidForRegion(r);
  const viaDesktop = await acquireViaDesktopPhases(passJar, effectiveProxy, apiBase, sid);
  if (viaDesktop) console.log(`[mimoAccount] desktop 2-phase OK (sid=${sid})`);
  return viaDesktop;
}

async function acquireViaDesktopPhases(passJar, proxyOptions, apiBase, sid) {
  const failLog = (reason) => console.log(`[mimoAccount] desktopPhase fail: ${reason}`);
  const jar = { ...passJar };

  // PHASE 1 — single serviceLogin call with the TARGET sid (no passportapi
  // prelude; ssecurity/nonce come straight from this response).
  // Desktop only sends: userId, passToken, cUserId (no extra cookies)
  const p1Jar = {};
  if (jar.userId) p1Jar.userId = jar.userId;
  if (jar.passToken) p1Jar.passToken = jar.passToken;
  if (jar.cUserId) p1Jar.cUserId = jar.cUserId;

  const p1Url = `https://${ACCOUNT_HOST}/pass/serviceLogin?_locale=zh_CN&_snsNone=true&sid=${encodeURIComponent(sid)}&_json=true`;
  const p1 = await proxyAwareFetch(
    p1Url,
    { headers: { Cookie: cookieHeader(p1Jar), "User-Agent": SSO_UA, Accept: "application/json" } },
    proxyOptions,
  );
  const raw = await p1.text();
  const clean = raw.replace(/^&&&START&&&/, "");
  // Nonce > 2^53 loses precision in JSON.parse — extract raw literal for signing
  const rawNonce = clean.match(/"nonce"\s*:\s*(\d+)/)?.[1];
  let j = null;
  try { j = JSON.parse(clean); } catch { /* handled below */ }
  if (rawNonce && j) j.nonce = rawNonce;

  if (!j || typeof j.code !== "number" || j.code !== 0 || !j.location || !j.nonce || !j.ssecurity) {
    failLog(
      `phase1 sid=${sid} http=${p1.status} code=${j?.code ?? "?"} hasLoc=${!!j?.location}`
      + ` secondValidation=${j?.bSecondValidation ?? "?"} notificationUrl=${j?.notificationUrl ? "present" : "no"}`
      + ` body=${JSON.stringify(raw.slice(0, 200))}`,
    );
    return null;
  }
  absorbSetCookie(jar, p1);

  // PHASE 2 — clientSign the redirect, follow the redirect chain server-side.
  // ⚠️ CRITICAL DESKTOP SPEC (app.asar / SSO_curl.cpp line 728: cookies.clear()):
  // Phase 2 MUST NOT send ANY Cookie header! The server returns 200 OK with Set-Cookie: serviceToken!
  const sep = j.location.includes("?") ? "&" : "?";
  let current = `${j.location}${sep}clientSign=${signatureClientSign(rawNonce || j.nonce, j.ssecurity)}`;

  for (let hop = 0; hop < 8; hop++) {
    const res = await proxyAwareFetch(
      current,
      { redirect: "manual", headers: { "User-Agent": SSO_UA } },
      proxyOptions,
    );
    absorbSetCookie(jar, res);
    const loc = res.headers.get("location");
    if (res.status >= 300 && res.status < 400 && loc) {
      current = new URL(loc, current).toString();
      continue;
    }
    break;
  }

  const sidKey = `${sid}_serviceToken`;
  if (!jar.serviceToken && jar[sidKey]) {
    jar.serviceToken = jar[sidKey];
  }

  if (!jar.serviceToken) {
    failLog(`phase2 no serviceToken sid=${sid} jar=[${Object.keys(jar).join(",")}]`);
    return null;
  }
  const out = {};
  for (const [k, v] of Object.entries(jar)) {
    if (!v) continue;
    if (k === "serviceToken" || k === "userId" || /_(ph|slh)$/.test(k)) out[k] = v;
  }
  return cookieHeader(out);
}

/**
 * Get (and cache) the mimo-server account cookie.
 * @param {object|null} providerSpecificData - may carry `mimoPassToken` override
 */
async function getServiceCookie(providerSpecificData, proxyOptions) {
  const apiBase = resolveMimoServerBase(providerSpecificData);
  const passJar = providerSpecificData?.mimoPassToken
    ? { passToken: providerSpecificData.mimoPassToken, userId: providerSpecificData.mimoUserId, cUserId: providerSpecificData.mimoCUserId }
    : await readDesktopAccountCookies();
  if (!passJar) return { cookie: null, reason: "no-pass-token" };

  // One cached session per passToken+cluster — accounts/connections rotate
  // independently, and the same passToken maps to different sessions per region.
  const key = crypto.createHash("sha256").update(`${apiBase}|${passJar.passToken}`).digest("hex");

  const cached = _cache.get(key);
  if (cached && Date.now() - cached.at < COOKIE_TTL_MS) {
    return { cookie: cached.cookie };
  }

  // De-dupe concurrent handshakes for the same account: a burst of requests must
  // not each run the full 5-step SSO chain.
  const inflight = _inflight.get(key);
  if (inflight) {
    const cookie = await inflight;
    return cookie ? { cookie } : { cookie: null, reason: "sso-failed" };
  }

  const promise = (async () => {
    try {
      return await acquireServiceCookie(passJar, proxyOptions, apiBase, providerSpecificData?.region);
    } catch (e) {
      console.log(`[mimoAccount] acquire threw: ${e?.message || e} | ${String(e?.stack || "").split("\n").slice(1, 4).join(" <- ")}`);
      return null; // network/parse failure — callers degrade, never throw
    } finally {
      _inflight.delete(key);
    }
  })();
  _inflight.set(key, promise);

  const cookie = await promise;
  if (!cookie) return { cookie: null, reason: "sso-failed" };
  _cache.set(key, { cookie, at: Date.now() });
  return { cookie };
}

/** Drop cached sessions so the next call re-runs the handshake (e.g. after a 401). */
export function invalidateMimoAccountCookieCache() {
  _cache.clear();
}

/** mimo-server account API base + the User-Agent its backend expects. */
export const MIMO_API_BASE = API_BASE;
export const MIMO_API_UA = API_UA;

/**
 * Resolve the mimo-server account-session cookie, for upstream /api/route/* calls.
 * @returns {Promise<string|null>} Cookie header value, or null when unavailable.
 */
export async function getMimoAccountCookie(providerSpecificData = null, proxyOptions = null) {
  try {
    const { cookie } = await getServiceCookie(providerSpecificData, proxyOptions);
    return cookie;
  } catch (e) {
    console.log(`[mimoAccount] getMimoAccountCookie threw: ${e?.message || e} | ${String(e?.stack || "").split("\n").slice(1, 4).join(" <- ")}`);
    return null;
  }
}

/**
 * Fetch the weekly quota from the account service.
 * @returns {Promise<{percent?:number, resetDate?:string, resetAt?:number, error?:string}>}
 */
export async function getMimoAccountUsage(providerSpecificData = null, proxyOptions = null) {
  const { cookie, reason } = await getServiceCookie(providerSpecificData, proxyOptions);
  if (!cookie) {
    return { error: reason === "no-pass-token" ? "no-session" : "session-failed" };
  }
  try {
    const res = await proxyAwareFetch(
      `${resolveMimoServerBase(providerSpecificData)}/api/user/usage`,
      { headers: { "User-Agent": API_UA, Cookie: cookie, Accept: "application/json" }, signal: AbortSignal.timeout(10000) },
      proxyOptions,
    );
    if (!res.ok) return { error: `http-${res.status}` };
    const data = await res.json().catch(() => null);
    if (!data || data.code !== 0 || !data.data) return { error: "bad-response" };
    return { percent: data.data.percent, resetDate: data.data.resetDate, resetAt: data.data.resetAt };
  } catch (e) {
    return { error: e.message };
  }
}