/**
 * FNXC:ReleaseChangelog 2026-07-12-00:00:
 * The root CHANGELOG.md is regenerated by scripts/release.mjs on every release, so pruning old release notes by hand would be reverted.
 * Keep the archive cutoff in generator-owned pure logic so current release notes stay in CHANGELOG.md and older notes are durably split into CHANGELOG-archive.md.
 *
 * FNXC:ReleaseChangelog 2026-07-13-22:55:
 * Raise the archive cutoff from 0.50.0 to 0.60.0 so CHANGELOG.md keeps only 0.60.x+ and everything below 0.60 moves into CHANGELOG-archive.md.
 */
export const CHANGELOG_ARCHIVE_CUTOFF = "0.60.0";
export const CHANGELOG_ARCHIVE_FILE = "CHANGELOG-archive.md";

/**
 * Partition version keys while preserving the source changelog order inside each bucket.
 * Versions greater than or equal to the cutoff remain in the current changelog; versions below it, including non-parseable keys treated as 0.0.0, move to the archive.
 *
 * @param {string[]} versionOrder
 * @param {string} cutoff
 * @returns {{ current: string[], archived: string[] }}
 */
export function partitionVersionsByCutoff(versionOrder, cutoff = CHANGELOG_ARCHIVE_CUTOFF) {
  const current = [];
  const archived = [];

  for (const version of versionOrder) {
    if (compareSemver(version, cutoff) >= 0) {
      current.push(version);
    } else {
      archived.push(version);
    }
  }

  return { current, archived };
}

/**
 * Return the stable archive pointer appended to the current root changelog.
 *
 * @param {string} archiveFile
 * @returns {string}
 */
export function archivePointerLine(archiveFile = CHANGELOG_ARCHIVE_FILE) {
  return `> Older releases (before ${CHANGELOG_ARCHIVE_CUTOFF}) are archived in [\`${archiveFile}\`](./${archiveFile}).`;
}

/** Compare two semver-ish version strings ("0.2.5", "0.4.0 (pre-release)"). */
function compareSemver(a, b) {
  const pa = parseVersionKey(a);
  const pb = parseVersionKey(b);
  for (let i = 0; i < 3; i++) {
    if (pa[i] !== pb[i]) return pa[i] - pb[i];
  }
  return 0;
}

function parseVersionKey(key) {
  const m = key.match(/^(\d+)\.(\d+)\.(\d+)/);
  if (!m) return [0, 0, 0];
  return [Number(m[1]), Number(m[2]), Number(m[3])];
}