"use client";

import type { AnchorHTMLAttributes } from "react";

type MdLinkProps = AnchorHTMLAttributes<HTMLAnchorElement>;

function isExternalHref(href?: string): boolean {
  if (!href) return false;
  if (href.startsWith("/") || href.startsWith("#") || href.startsWith("?")) {
    return false;
  }
  if (href.startsWith("mailto:") || href.startsWith("tel:")) return false;
  try {
    if (typeof window !== "undefined") {
      const url = new URL(href, window.location.origin);
      return url.origin !== window.location.origin;
    }
  } catch {
    /* 相对或非法 URL 当站内 */
  }
  return /^https?:\/\//i.test(href);
}

/** Markdown 链接：外链新开页 */
export default function MdLink({ href, children, ...rest }: MdLinkProps) {
  const external = isExternalHref(href);
  return (
    <a
      {...rest}
      href={href}
      {...(external
        ? { target: "_blank", rel: "noopener noreferrer" }
        : {})}
    >
      {children}
    </a>
  );
}