(function (root, factory) {
  const api = factory();
  if (typeof module !== 'undefined' && module.exports) module.exports = api;
  else root.createOfflineWorkStore = api;
})(typeof self !== 'undefined' ? self : this, function () {
  'use strict';

  const ENABLED_KEY = 'stackchain.offline-work.enabled.v1';
  const SNAPSHOT_KEY = 'stackchain.offline-work.snapshot.v1';
  const VERSION = 1;
  const DEFAULT_MAX_AGE_MS = 7 * 24 * 60 * 60 * 1000;
  const ITEM_FIELDS = [
    'id', 'number', 'title', 'state', 'repository', 'labels', 'assignees',
    'updated_at', 'due_date', 'milestone', 'url', 'work_reasons',
  ];
  const NOTIFICATION_FIELDS = [
    'id', 'number', 'title', 'unread', 'repository', 'subject_type', 'updated_at', 'url',
  ];

  function pick(source, fields) {
    const output = {};
    fields.forEach(field => {
      if (source && source[field] !== undefined) output[field] = source[field];
    });
    return output;
  }

  function createOfflineWorkStore({ storage, now = () => new Date(), maxAgeMs = DEFAULT_MAX_AGE_MS }) {
    function enabled() {
      try { return storage.getItem(ENABLED_KEY) === 'true'; }
      catch (_) { return false; }
    }

    function clear() {
      try { storage.removeItem(SNAPSHOT_KEY); }
      catch (_) { return false; }
      return true;
    }

    function setEnabled(value) {
      try {
        storage.setItem(ENABLED_KEY, value ? 'true' : 'false');
        if (!value) clear();
        return true;
      } catch (_) { return false; }
    }

    function save(snapshot) {
      if (!enabled() || !snapshot?.user?.login) return false;
      const record = {
        version: VERSION,
        user_login: String(snapshot.user.login),
        saved_at: now().toISOString(),
        data: {
          user: pick(snapshot.user, ['login', 'full_name']),
          issues: (snapshot.issues || []).map(item => pick(item, ITEM_FIELDS)),
          pull_requests: (snapshot.pull_requests || []).map(item => pick(item, ITEM_FIELDS)),
          notifications: (snapshot.notifications || []).map(item => pick(item, NOTIFICATION_FIELDS)),
          work_pagination: snapshot.work_pagination || {},
          notification_pagination: snapshot.notification_pagination || {},
        },
      };
      try { storage.setItem(SNAPSHOT_KEY, JSON.stringify(record)); }
      catch (_) { return false; }
      return true;
    }

    function load(expectedLogin) {
      let record;
      try { record = JSON.parse(storage.getItem(SNAPSHOT_KEY) || 'null'); }
      catch (_) { clear(); return null; }
      const savedAt = Date.parse(record?.saved_at || '');
      const invalid = record?.version !== VERSION || !record?.user_login || !record?.data ||
        !Number.isFinite(savedAt);
      const expired = Number.isFinite(savedAt) && now().getTime() - savedAt > maxAgeMs;
      if (invalid || expired) {
        clear();
        return null;
      }
      if (expectedLogin && record.user_login !== expectedLogin) return null;
      return { ...record.data, saved_at: record.saved_at };
    }

    return { enabled, setEnabled, save, load, clear };
  }

  return createOfflineWorkStore;
});