/**
 * Shared github.com remote URL → owner/repo parse (#676 B/D7).
 * One authority for collector admission origin and upstream head owner.
 */

/** Parse owner from a github.com remote URL; undefined when not a GitHub owner/repo remote. */
export function ownerFromGitHubRemoteUrl(remoteUrl: string): string | undefined {
  const ownerRepo = ownerRepoFromGitHubRemoteUrl(remoteUrl);
  if (ownerRepo === undefined) return undefined;
  return ownerRepo.split("/")[0]!.toLowerCase();
}

/** Parse owner/repo identity from a github.com remote URL; undefined when not exact. */
export function ownerRepoFromGitHubRemoteUrl(remoteUrl: string): string | undefined {
  const trimmed = remoteUrl.trim();
  // git@github.com:owner/repo.git — exact owner/repo identity only.
  const scp = /^git@github\.com:([^/\s]+)\/([^/\s]+?)(?:\.git)?$/i.exec(trimmed);
  if (scp) {
    return `${scp[1]}/${stripGitSuffix(scp[2]!)}`;
  }
  // ssh://git@github.com/owner/repo(.git) — exact owner/repo identity only.
  const ssh = /^ssh:\/\/git@github\.com\/([^/\s]+)\/([^/\s]+?)(?:\.git)?\/?$/i.exec(
    trimmed,
  );
  if (ssh) {
    return `${ssh[1]}/${stripGitSuffix(ssh[2]!)}`;
  }
  // https://github.com/owner/repo(.git) and git://github.com/... — exact two-segment path.
  let parsed: URL;
  try {
    parsed = new URL(trimmed);
  } catch {
    return undefined;
  }
  if (!/^github\.com$/i.test(parsed.hostname)) return undefined;
  // Non-identity URL material (query/hash/extra path) is not a repository remote.
  if (parsed.search !== "" || parsed.hash !== "") return undefined;
  const parts = parsed.pathname.split("/").filter((p) => p.length > 0);
  if (parts.length !== 2) return undefined;
  return `${parts[0]}/${stripGitSuffix(parts[1]!)}`;
}

function stripGitSuffix(name: string): string {
  return name.toLowerCase().endsWith(".git") ? name.slice(0, -4) : name;
}