// JianF Nav Sync — Firefox WebExtension (MV2 background page)
// 与 Chrome MV3 共用逻辑；MV2 常驻后台，navigator 可用，device 检测更准。
'use strict';

const ALARM_NAME = 'navi-sync';
const SYNC_MINUTES = 0.5;
const FETCH_WINDOW = 2 * 60 * 60 * 1000;
const MAX_BATCH = 200;
const DEDUP_SECONDS = 600;

const SEARCH_HOSTS = new Set([
  'google.com', 'www.google.com', 'googleusercontent.com',
  'bing.com', 'www.bing.com', 'cn.bing.com',
  'baidu.com', 'www.baidu.com', 'm.baidu.com',
  'duckduckgo.com', 'www.duckduckgo.com', 'lite.duckduckgo.com',
  'sogou.com', 'www.sogou.com',
  'so.com', 'www.so.com',
  'yahoo.com', 'www.yahoo.com', 'search.yahoo.com',
  'ecosia.org', 'www.ecosia.org',
  'qwant.com', 'www.qwant.com',
  'startpage.com', 'www.startpage.com',
  'brave.com', 'search.brave.com',
  'yandex.com', 'yandex.ru',
  '360.cn', 'www.360.cn',
  'sm.cn', 'quark.sm.cn',
  'searx.be', 'searxng.site', 'paulgo.io',
]);

let lastSyncTime = 0;
let pendingItems = [];

// ── 检测标记：只向用户配置的导航站注册 content script ──
// 已安装的浏览器上，导航站会拿到 data-navi-ext 属性，从而隐藏安装入口。
let detectRegistration = null;

function hostMatchPattern(serverUrl) {
  try {
    const host = new URL(serverUrl).hostname;
    return host ? '*://' + host + '/*' : null;
  } catch (e) {
    return null;
  }
}

async function syncDetectScript(serverUrl) {
  if (detectRegistration) {
    try { await detectRegistration.unregister(); } catch (e) { /* 已失效 */ }
    detectRegistration = null;
  }
  const pattern = hostMatchPattern(serverUrl);
  if (!pattern) return;
  if (!browser.contentScripts || !browser.contentScripts.register) return;
  try {
    detectRegistration = await browser.contentScripts.register({
      matches: [pattern],
      js: [{ file: 'detect.js' }],
      runAt: 'document_start',
      allFrames: false,
    });
  } catch (e) {
    // 静默降级：未装扩展时只是多显示一个安装入口，不影响同步
  }
}

function ensureAlarm() {
  browser.alarms.get(ALARM_NAME, (alarm) => {
    if (!alarm) browser.alarms.create(ALARM_NAME, { periodInMinutes: SYNC_MINUTES });
  });
}

browser.runtime.onInstalled.addListener(() => {
  ensureAlarm();
  browser.storage.local.get(['pending', 'lastSyncTime', 'serverUrl'], (data) => {
    pendingItems = data.pending || [];
    lastSyncTime = data.lastSyncTime || 0;
    syncDetectScript(data.serverUrl);
  });
});

browser.runtime.onStartup.addListener(() => {
  browser.storage.local.get(['serverUrl'], (d) => syncDetectScript(d.serverUrl));
});

function isJunk(url) {
  try {
    const u = new URL(url);
    if (u.protocol !== 'http:' && u.protocol !== 'https:') return true;
    const host = u.hostname.toLowerCase().replace(/^www\./, '');
    if (SEARCH_HOSTS.has(host)) return true;
    const q = u.searchParams.get('q');
    const path = u.pathname.toLowerCase();
    if (q && (path === '/search' || path === '/s' || path === '/results' || path === '/web')) return true;
    if (url.startsWith('about:') || url.startsWith('moz-extension://')) return true;
    return false;
  } catch (e) { return true; }
}

function hostFrom(url) {
  try { return new URL(url).hostname.replace(/^www\./, ''); } catch { return ''; }
}

async function collectRecent(previousSyncTime = 0) {
  const initialCutoff = Date.now() - DEDUP_SECONDS * 1000;
  const cutoff = previousSyncTime > 0 ? previousSyncTime : initialCutoff;
  const since = Math.max(0, Date.now() - FETCH_WINDOW, cutoff);
  const items = await new Promise((resolve) => {
    browser.history.search({ text: '', startTime: since, maxResults: 10000 }, resolve);
  });
  const seen = new Set();
  const collected = [];
  for (const item of items) {
    if (isJunk(item.url)) continue;
    const key = hostFrom(item.url) + '|' + (item.url.split('?')[0] || '');
    if (seen.has(key)) continue;
    seen.add(key);
    const ts = item.lastVisitTime || Date.now();
    if (ts <= cutoff) continue;
    collected.push({
      url: item.url,
      title: item.title || '',
      timestamp: Math.floor(ts / 1000),
      visit_count: item.visitCount || 1,
    });
    if (collected.length >= MAX_BATCH) break;
  }
  return collected;
}

browser.alarms.onAlarm.addListener((alarm) => {
  if (alarm.name === ALARM_NAME) syncNow();
});

browser.runtime.onMessage.addListener((msg, _sender, sendResponse) => {
  if (msg && msg.action === 'sync') {
    syncNow().then((r) => sendResponse(r)).catch((e) => sendResponse({ ok: false, error: e.message }));
    return true;
  }
  if (msg && msg.action === 'getConfig') {
    browser.storage.local.get(['serverUrl', 'syncToken', 'deviceName'], (d) => sendResponse(d));
    return true;
  }
  if (msg && msg.action === 'setConfig') {
    const data = msg.data || {};
    browser.storage.local.set(data, () => {
      syncDetectScript(data.serverUrl);
      sendResponse({ ok: true });
    });
    return true;
  }
  if (msg && msg.action === 'clearPending') {
    pendingItems = [];
    browser.storage.local.set({ pending: [] }, () => sendResponse({ ok: true }));
    return true;
  }
});

async function syncNow() {
  ensureAlarm();
  const syncStartedAt = Date.now();
  const stored = await new Promise((resolve) => {
    browser.storage.local.get(
      ['serverUrl', 'syncToken', 'deviceName', 'pending', 'lastSyncTime'],
      resolve,
    );
  });
  const { serverUrl, syncToken, deviceName } = stored;
  if (!serverUrl) return { ok: false, reason: 'not configured' };

  pendingItems = Array.isArray(stored.pending) ? stored.pending : [];
  lastSyncTime = Number(stored.lastSyncTime) || 0;
  let recent;
  try { recent = await collectRecent(lastSyncTime); } catch (e) { recent = []; }
  const merged = dedup(recent.concat(pendingItems));
  if (merged.length === 0) {
    lastSyncTime = syncStartedAt;
    await new Promise((res) => browser.storage.local.set({ lastSyncTime }, res));
    return { ok: true, skipped: true, reason: 'nothing new' };
  }

  const body = JSON.stringify({
    items: merged.map((it) => ({
      url: it.url,
      title: it.title || '',
      device: deviceName || defaultDevice(),
      timestamp: it.timestamp,
      visit_count: it.visit_count || 1,
    })),
  });

  const headers = { 'Content-Type': 'application/json' };
  if (syncToken) headers['Authorization'] = 'Bearer ' + syncToken;

  try {
    const resp = await fetch(serverUrl.replace(/\/$/, '') + '/api/history/sync', {
      method: 'POST', headers, body,
    });
    if (!resp.ok) {
      const text = await resp.text().catch(() => '');
      pendingItems = merged;
      await new Promise((res) => browser.storage.local.set({ pending: merged }, res));
      return { ok: false, status: resp.status, error: text.slice(0, 200) };
    }
    const data = await resp.json().catch(() => ({}));
    pendingItems = [];
    lastSyncTime = syncStartedAt;
    await new Promise((res) => browser.storage.local.set({ pending: [], lastSyncTime }, res));
    return { ok: true, count: merged.length, total: data.total || 0 };
  } catch (e) {
    await new Promise((res) => browser.storage.local.set({ pending: merged }, res));
    return { ok: false, error: e.message };
  }
}

function dedup(list) {
  const seen = new Set();
  const out = [];
  for (const it of list) {
    if (seen.has(it.url)) continue;
    seen.add(it.url);
    out.push(it);
  }
  return out;
}

function defaultDevice() {
  try {
    const ua = navigator.userAgent.toLowerCase();
    const mobile = /mobile|android|iphone|ipad/.test(ua);
    const ff = /firefox/.test(ua);
    const edg = /edg\//.test(ua);
    const base = mobile ? 'mobile' : 'desktop';
    const browser = ff ? 'firefox' : (edg ? 'edge' : 'chrome');
    return base + '-' + browser;
  } catch (e) { return 'desktop-browser'; }
}