/**
 * The oldest terminal app that may use the backoffice. Raise it with every app release that older versions must not
 * keep syncing past; MIN_APP_VERSION overrides it without a deploy.
 */
export const MIN_APP_VERSION = '1.4.0';

export const APP_VERSION_HEADER = 'x-app-version';

export function minAppVersion(): string {
  return process.env.MIN_APP_VERSION?.trim() || MIN_APP_VERSION;
}

/** `1.4.2+37` → [1, 4, 2]; the build number after `+` is ignored. Null for anything that isn't a version */
export function parseAppVersion(value: unknown): number[] | null {
  if (typeof value !== 'string') return null;
  const match = /^\s*v?(\d+(?:\.\d+)*)(?:[-+].*)?\s*$/.exec(value);
  return match ? match[1].split('.').map(Number) : null;
}

/** Whether [version] is at least [minimum]. Apps from before the version header send none and are outdated */
export function isAppVersionSupported(version: unknown, minimum = minAppVersion()): boolean {
  const current = parseAppVersion(version);
  const required = parseAppVersion(minimum);
  if (!required) return true;
  if (!current) return false;
  for (let i = 0; i < Math.max(current.length, required.length); i++) {
    const diff = (current[i] ?? 0) - (required[i] ?? 0);
    if (diff !== 0) return diff > 0;
  }
  return true;
}