// Build/version metadata for the МЕРА product — sourced from build-time
// `NEXT_PUBLIC_*` env vars, baked in by `frontend/Dockerfile` via
// `--build-arg` (see `.forgejo/workflows/deploy-tradein.yml`, build-frontend
// job). Safe to import from BOTH server and client components: Next.js
// inlines `NEXT_PUBLIC_*` references at build time into every bundle that
// references them — there is no runtime env lookup in the browser.
//
// Fallback "dev" — a local `npm run dev` / `next build` without the
// build-args set (i.e. every local run, and CI unless explicitly passed)
// reads honestly as "not a tagged deploy" instead of leaking "undefined"
// into the UI or crashing.

export const APP_VERSION = process.env.NEXT_PUBLIC_APP_VERSION || "dev";
export const BUILD_SHA = process.env.NEXT_PUBLIC_BUILD_SHA || "dev";
export const BUILD_DATE = process.env.NEXT_PUBLIC_BUILD_DATE || "";

/**
 * ISO-8601 (`2026-08-10` or `2026-08-10T12:00:00Z`) → `10.08.2026`.
 *
 * Deliberately a plain regex, not `Date#toLocaleDateString("ru-RU")`: the
 * input is already a plain calendar date (no timezone conversion needed),
 * and a regex keeps formatting identical between server-render and
 * client-render without depending on locale data being present/consistent
 * in whichever runtime executes it.
 */
export function formatRuDate(iso: string | undefined | null): string {
  const match = iso ? /^(\d{4})-(\d{2})-(\d{2})/.exec(iso) : null;
  if (!match) return "dev";
  const [, year, month, day] = match;
  return `${day}.${month}.${year}`;
}

/** "Мера v1.0.0 · a1b2c3d · 10.08.2026" (or "Мера dev · dev · dev" locally). */
export function formatVersionLabel(): string {
  const versionPart = APP_VERSION === "dev" ? "dev" : `v${APP_VERSION}`;
  return `Мера ${versionPart} · ${BUILD_SHA} · ${formatRuDate(BUILD_DATE)}`;
}