1/** Canonical raw log basename shared by every generation-addressed Session artifact. */

2

3import { sessionFormatVersion } from './json.ts'

4

5const CANONICAL_LOG_FILENAME = /^session(?:\.v([1-9][0-9]*))?\.jsonl$/u

6

7/**

8 * Name the raw JSONL log of one immutable Session format generation. Version

9 * zero keeps the original `session.jsonl`; every later generation carries a

10 * lowercase numeric `.vN` component before the `.jsonl` suffix.

11 * @param version - non-negative safe integer Session format version.

12 * @returns the canonical basename, without any compression suffix.

13 */

14export function sessionFormatLogFilename(version: number): string {

15 const generation = sessionFormatVersion(version, 'Session log generation version')

16 return generation === 0 ? 'session.jsonl' : `session.v${generation}.jsonl`

17}

18

19/**

20 * Read the generation named by one raw JSONL log basename. Temporary,

21 * uppercase, leading-zero, `.v0`, and compression-suffixed names are not

22 * canonical.

23 * @param filename - one basename from a Session directory or archive.

24 * @returns its Session format version, or `undefined` when the name is not canonical.

25 */

26export function parseSessionFormatLogFilename(filename: string): number | undefined {

27 const match = CANONICAL_LOG_FILENAME.exec(filename)

28 if (match === null) return undefined

29 if (match[1] === undefined) return 0

30 const version = Number(match[1])

31 return Number.isSafeInteger(version) ? version : undefined

32}