function createDraftInbox({ storage, now = () => Date.now() }) {
  const indexKey = 'stackchain.draft-index.v1';

  function readIndex() {
    try {
      const value = JSON.parse(storage?.getItem(indexKey) || '{}');
      return value && typeof value === 'object' && !Array.isArray(value) ? value : {};
    } catch (_error) { return {}; }
  }

  function writeIndex(index) {
    try { storage?.setItem(indexKey, JSON.stringify(index)); }
    catch (_error) { /* Draft discovery remains available without metadata. */ }
  }

  function keys() {
    try {
      return Array.from({ length: Number(storage?.length || 0) }, (_, index) => storage.key(index))
        .filter(Boolean);
    } catch (_error) { return []; }
  }

  function textPreview(value) {
    return String(value || '').replace(/\s+/g, ' ').trim().slice(0, 180);
  }

  function parseTarget(value) {
    const match = String(value || '').match(/^(.+)#(\d+)$/);
    return match ? { repository: match[1], number: Number(match[2]) } : null;
  }

  function parse(key, raw) {
    let match;
    if (key === 'stackchain.issue-capture.v1') {
      try {
        const value = JSON.parse(raw);
        const preview = textPreview([value?.title, value?.body].filter(Boolean).join(' — '));
        if (!preview && !value?.repository) return null;
        return {
          kind: 'new-issue', label: 'New issue', repository: String(value?.repository || ''),
          title: textPreview(value?.title) || 'Untitled new issue', preview,
        };
      } catch (_error) { return null; }
    }
    match = key.match(/^stackchain\.(issue|pull)-comment\.v1:(.+#\d+)$/);
    if (match) {
      const target = parseTarget(match[2]);
      const preview = textPreview(raw);
      if (!target || !preview) return null;
      const routeKind = match[1] === 'issue' ? 'issue' : 'pull';
      return {
        kind: routeKind + '-comment', label: routeKind === 'issue' ? 'Issue comment' : 'PR comment',
        ...target, title: target.repository + '#' + target.number, preview,
        route: { kind: routeKind, ...target },
      };
    }
    match = key.match(/^stackchain\.issue-content\.v1:(.+#\d+)$/);
    if (match) {
      const target = parseTarget(match[1]);
      try {
        const value = JSON.parse(raw);
        const preview = textPreview([value?.title, value?.body].filter(Boolean).join(' — '));
        if (!target || !preview || typeof value?.expectedUpdatedAt !== 'string') return null;
        return {
          kind: 'issue-edit', label: 'Issue edit', ...target,
          title: target.repository + '#' + target.number, preview,
          route: { kind: 'issue', ...target },
        };
      } catch (_error) { return null; }
    }
    match = key.match(/^stackchain\.update-reply\.v1\.(\d+)$/);
    if (match) {
      const preview = textPreview(raw);
      if (!preview) return null;
      const notificationId = Number(match[1]);
      return {
        kind: 'update-reply', label: 'Update reply', notification_id: notificationId,
        title: 'Update #' + notificationId, preview,
        route: { kind: 'update', notification_id: notificationId },
      };
    }
    match = key.match(/^stackchain\.review-draft\.v1:(.+#\d+)@([^:]+)$/);
    if (match) {
      const target = parseTarget(match[1]);
      try {
        const value = JSON.parse(raw);
        const notes = Object.values(value?.notes || {});
        const comments = Array.isArray(value?.comments) ? value.comments.map(item => item?.body) : [];
        const preview = textPreview([value?.summary, ...notes, ...comments].filter(Boolean).join(' — '));
        if (!target || !preview) return null;
        return {
          kind: 'review', label: 'PR review', ...target, head_sha: match[2],
          title: target.repository + '#' + target.number, preview,
          route: { kind: 'review', ...target },
        };
      } catch (_error) { return null; }
    }
    return null;
  }

  function list() {
    const index = readIndex();
    const seen = new Set();
    const drafts = [];
    keys().forEach(key => {
      if (key === indexKey || key.endsWith(':operation')) return;
      let raw;
      try { raw = storage.getItem(key); }
      catch (_error) { return; }
      const parsed = parse(key, raw);
      if (!parsed) return;
      seen.add(key);
      const fingerprint = String(raw);
      const previous = index[key];
      if (!previous || previous.fingerprint !== fingerprint) {
        index[key] = { fingerprint, updated_at: Number(now()) };
      }
      drafts.push({ id: key, ...parsed, updated_at: index[key].updated_at });
    });
    Object.keys(index).forEach(key => { if (!seen.has(key)) delete index[key]; });
    writeIndex(index);
    return drafts.sort((left, right) =>
      Number(right.updated_at || 0) - Number(left.updated_at || 0) || left.id.localeCompare(right.id)
    );
  }

  function discard(id) {
    if (typeof id !== 'string' || !parse(id, (() => {
      try { return storage?.getItem(id); } catch (_error) { return null; }
    })())) return false;
    try {
      storage?.removeItem(id);
      storage?.removeItem(id + ':operation');
      const index = readIndex();
      delete index[id];
      writeIndex(index);
      return true;
    } catch (_error) { return false; }
  }

  return { list, discard };
}

if (typeof module !== 'undefined' && module.exports) module.exports = createDraftInbox;