/** Trim values — .env files edited on Windows often include stray \\r */
function clean(value: string | undefined): string | undefined {
  return value?.trim().replace(/\r$/, "").replace(/\n$/, "");
}

export function getSupabaseEnv() {
  const url = clean(process.env.NEXT_PUBLIC_SUPABASE_URL);
  const anonKey = clean(
    process.env.NEXT_PUBLIC_SUPABASE_ANON_KEY ??
      process.env.NEXT_PUBLIC_SUPABASE_PUBLISHABLE_KEY
  );

  if (!url) {
    throw new Error(
      "Missing NEXT_PUBLIC_SUPABASE_URL in .env.local — restart dev server after editing."
    );
  }
  if (url.includes("your-project") || url.includes("YOUR_REF")) {
    throw new Error(
      "NEXT_PUBLIC_SUPABASE_URL is still the placeholder. Set your real URL in .env.local (e.g. https://vcxpcyafnlyiyqmapyyy.supabase.co) and restart npm run dev."
    );
  }
  if (!url.startsWith("https://") || !url.includes(".supabase.co")) {
    throw new Error(
      "NEXT_PUBLIC_SUPABASE_URL should look like https://YOUR_REF.supabase.co"
    );
  }
  if (!anonKey) {
    throw new Error(
      "Missing NEXT_PUBLIC_SUPABASE_ANON_KEY in .env.local — use the anon or publishable key from Dashboard → API."
    );
  }

  return { url, anonKey };
}

export function formatAuthNetworkError(cause: unknown): string {
  if (cause instanceof Error && cause.message.includes("NEXT_PUBLIC")) {
    return cause.message;
  }
  const msg = cause instanceof Error ? cause.message : String(cause);
  if (msg === "Failed to fetch" || msg.includes("NetworkError")) {
    return [
      "Cannot reach Supabase (network error).",
      "• Confirm project is active in the Supabase dashboard",
      "• Use the full API key from Dashboard → API (try the legacy anon key starting with eyJ… if publishable key fails)",
      "• Restart: npm run dev after changing .env.local",
      "• Add http://localhost:3000 to Auth → URL configuration → Redirect URLs",
    ].join("\n");
  }
  if (msg.includes("429") || /rate limit/i.test(msg)) {
    return [
      "Too many requests to Supabase Auth (rate limited).",
      "Wait about 60 minutes before trying password reset again.",
      "See docs/PASSWORD_RESET.md for dashboard and dev workarounds.",
    ].join("\n");
  }
  return msg || "Something went wrong. Please try again.";
}