export function safeHttpUrl(input: string) {
  try {
    const url = new URL(input);
    if (!["http:", "https:"].includes(url.protocol)) return null;
    return url;
  } catch {
    return null;
  }
}

export function extractXhsPublishUrl(input: string) {
  const candidates =
    input.match(/https?:\/\/[^\s<>"'，。！？；：、【】（）]+/gi) ?? [];
  for (const candidate of candidates) {
    const cleaned = candidate.replace(/[.,!?;:~)\]}]+$/g, "");
    const url = safeHttpUrl(cleaned);
    if (!url) continue;
    const hostname = url.hostname.toLowerCase();
    const isXhs =
      hostname === "xiaohongshu.com" ||
      hostname.endsWith(".xiaohongshu.com") ||
      hostname === "xhslink.cn" ||
      hostname.endsWith(".xhslink.cn");
    if (isXhs) return url.toString();
  }
  return "";
}

export type SupportedPlatform = "小红书" | "抖音";

function platformMatches(url: URL, platform: SupportedPlatform) {
  const hostname = url.hostname.toLowerCase();
  if (platform === "抖音") {
    return hostname === "douyin.com" || hostname.endsWith(".douyin.com");
  }
  return (
    hostname === "xiaohongshu.com" ||
    hostname.endsWith(".xiaohongshu.com") ||
    hostname === "xhslink.cn" ||
    hostname.endsWith(".xhslink.cn")
  );
}

export function extractPublishUrl(
  input: string,
  platform: SupportedPlatform = "小红书",
) {
  const candidates =
    input.match(/https?:\/\/[^\s<>"'，。！？；：、【】（）]+/gi) ?? [];
  for (const candidate of candidates) {
    const cleaned = candidate.replace(/[.,!?;:~)\]}]+$/g, "");
    const url = safeHttpUrl(cleaned);
    if (url && platformMatches(url, platform)) return url.toString();
  }
  return "";
}

export function extractAnyPublishUrl(input: string) {
  return extractPublishUrl(input, "小红书") || extractPublishUrl(input, "抖音");
}

export function platformFromPublishUrl(input: string): SupportedPlatform | "" {
  const url = safeHttpUrl(input);
  if (!url) return "";
  if (platformMatches(url, "小红书")) return "小红书";
  if (platformMatches(url, "抖音")) return "抖音";
  return "";
}