Function fileHistoryRewind

src/utils/fileHistory.ts:347–397

(
  updateFileHistoryState: (
    updater: (prev: FileHistoryState) => FileHistoryState,
  ) => void,
  messageId: UUID,
)

 * Rewinds the file system to a previous snapshot.
 */
export async function fileHistoryRewind(
  updateFileHistoryState: (
    updater: (prev: FileHistoryState) => FileHistoryState,
  ) => void,
  messageId: UUID,
): Promise<void> {
  if (!fileHistoryEnabled()) {
    return
  }

  // Rewind is a pure filesystem side-effect and does not mutate
  // FileHistoryState. Capture state with a no-op updater, then do IO async.
  let captured: FileHistoryState | undefined
  updateFileHistoryState(state => {
    captured = state
    return state
  })
  if (!captured) return

  const targetSnapshot = captured.snapshots.findLast(
    snapshot => snapshot.messageId === messageId,
  )
  if (!targetSnapshot) {
    logError(new Error(`FileHistory: Snapshot for ${messageId} not found`))
    logEvent('tengu_file_history_rewind_failed', {
      trackedFilesCount: captured.trackedFiles.size,
      snapshotFound: false,
    })
    throw new Error('The selected snapshot was not found')
  }

  try {
    logForDebugging(
      `FileHistory: [Rewind] Rewinding to snapshot for ${messageId}`,
    )
    const filesChanged = await applySnapshot(captured, targetSnapshot)

    logForDebugging(`FileHistory: [Rewind] Finished rewinding to ${messageId}`)
    logEvent('tengu_file_history_rewind_success', {
      trackedFilesCount: captured.trackedFiles.size,
      filesChangedCount: filesChanged.length,
    })
  } catch (error) {
    logError(error)
    logEvent('tengu_file_history_rewind_failed', {
      trackedFilesCount: captured.trackedFiles.size,
      snapshotFound: true,
    })
    throw error
  }
}

export function fileHistoryCanRestore(
  state: FileHistoryState,