import { Fragment } from "react";

// Render a small, safe subset of Discord Markdown; React escapes raw HTML.
function inline(text: string) {
  return text
    .split(/(\*\*[^*]+\*\*|`[^`]+`|\[[^\]]+\]\(https?:\/\/[^\s)]+\))/g)
    .map((part, i) => {
      if (part.startsWith("**") && part.endsWith("**"))
        return <strong key={i}>{part.slice(2, -2)}</strong>;
      if (part.startsWith("`") && part.endsWith("`"))
        return <code key={i}>{part.slice(1, -1)}</code>;
      const link = /^\[([^\]]+)\]\((https?:\/\/[^\s)]+)\)$/.exec(part);
      if (link)
        return (
          <a key={i} href={link[2]} target="_blank" rel="noopener noreferrer">
            {link[1]}
          </a>
        );
      return <Fragment key={i}>{part}</Fragment>;
    });
}

export function ReleaseNotes({ body }: { body: string }) {
  const blocks: { list: boolean; lines: string[] }[] = [];
  let current: (typeof blocks)[number] | undefined;
  for (const line of body.split(/\r?\n/)) {
    if (!line.trim()) {
      current = undefined;
      continue;
    }
    const bullet = /^\s*[-*]\s+(.+)$/.exec(line);
    if (!bullet && current?.list && /^\s{2,}\S/.test(line)) {
      current.lines[current.lines.length - 1] += ` ${line.trim()}`;
      continue;
    }
    const list = !!bullet;
    if (!current || current.list !== list) {
      current = { list, lines: [] };
      blocks.push(current);
    }
    current.lines.push(bullet ? bullet[1] : line);
  }
  return blocks.map(({ list, lines }, i) => {
    if (list)
      return (
        <ul key={i}>
          {lines.map((line, j) => (
            <li key={j}>{inline(line)}</li>
          ))}
        </ul>
      );
    return (
      <p key={i}>
        {lines.map((line, j) => (
          <Fragment key={j}>
            {j > 0 && <br />}
            {inline(line)}
          </Fragment>
        ))}
      </p>
    );
  });
}