const RELEASE_VERSION_PATTERN = /^\d+(?:\.\d+)*$/;

export function normalizeReleaseVersionTag(value) {
  if (typeof value !== "string") {
    return null;
  }

  const normalized = value.trim().replace(/^v/i, "");
  if (!RELEASE_VERSION_PATTERN.test(normalized)) {
    return null;
  }

  return normalized;
}

export function resolveReleaseVersion(
  env = process.env,
  fallbackVersion = "0.2.0421.2"
) {
  const candidates = [env.EXTENSION_VERSION, env.DRONE_TAG, fallbackVersion];

  for (const candidate of candidates) {
    const normalized = normalizeReleaseVersionTag(candidate);
    if (normalized) {
      return normalized;
    }
  }

  throw new Error("unable to resolve a valid release version");
}