(function exposeSync(root, factory) {
  const api = factory();
  if (typeof module === "object" && module.exports) module.exports = api;
  if (root) root.ValleySync = api;
})(typeof window === "undefined" ? globalThis : window, () => ({
  mergeSnapshot(localChecks, savingIds, currentRevision, snapshot) {
    if (!snapshot || !Number.isInteger(snapshot.revision) || snapshot.revision <= currentRevision) {
      return { applied: false, revision: currentRevision, checks: localChecks };
    }

    const checks = { ...(snapshot.checks || {}) };
    for (const itemId of savingIds) {
      if (Object.prototype.hasOwnProperty.call(localChecks, itemId)) {
        checks[itemId] = Boolean(localChecks[itemId]);
      }
    }
    return { applied: true, revision: snapshot.revision, checks };
  },

  confirmWrite(localChecks, currentRevision, result) {
    return {
      checks: { ...localChecks, [result.itemId]: Boolean(result.checked) },
      revision: Math.max(currentRevision, result.revision)
    };
  }
}));