/**
 * Minimal Kodi/Jellyfin-style .nfo parser. Operates on a string that contains
 * an XML document and extracts the fields we map onto cover metadata.
 *
 * No XML library dependency — small, regex-based, deliberately lenient.
 * Returns null if the buffer doesn't look like a movie .nfo.
 */

export interface NfoMetadata {
  title?: string;
  code?: string;
  releaseDate?: string;
  runtimeMin?: number;
  director?: string;
  studio?: string;
  series?: string;
  actresses?: string[];
  genres?: string[];
  notes?: string;
}

const TAG_RE = (tag: string) =>
  new RegExp(`<${tag}\\b[^>]*>([\\s\\S]*?)<\\/${tag}>`, "gi");

function firstMatch(xml: string, tag: string): string | undefined {
  const re = TAG_RE(tag);
  const m = re.exec(xml);
  if (!m) return undefined;
  return decodeEntities(m[1].trim());
}

function allMatches(xml: string, tag: string): string[] {
  const re = TAG_RE(tag);
  const out: string[] = [];
  let m: RegExpExecArray | null;
  while ((m = re.exec(xml)) !== null) {
    const text = decodeEntities(m[1].trim());
    if (text) out.push(text);
  }
  return out;
}

function decodeEntities(s: string): string {
  return s
    .replace(/<!\[CDATA\[([\s\S]*?)]]>/g, "$1")
    .replace(/&amp;/g, "&")
    .replace(/&lt;/g, "<")
    .replace(/&gt;/g, ">")
    .replace(/&quot;/g, '"')
    .replace(/&apos;/g, "'");
}

export function parseNfo(xml: string): NfoMetadata | null {
  if (!/<movie\b|<id\b|<title\b/i.test(xml)) return null;

  const runtimeRaw = firstMatch(xml, "runtime");
  const runtime = runtimeRaw ? parseInt(runtimeRaw, 10) : NaN;

  return strip({
    title: firstMatch(xml, "title") ?? firstMatch(xml, "originaltitle"),
    code: firstMatch(xml, "id") ?? firstMatch(xml, "num"),
    releaseDate: firstMatch(xml, "premiered") ?? firstMatch(xml, "releasedate") ?? firstMatch(xml, "year"),
    runtimeMin: Number.isFinite(runtime) ? runtime : undefined,
    director: firstMatch(xml, "director"),
    studio: firstMatch(xml, "studio") ?? firstMatch(xml, "maker"),
    series: firstMatch(xml, "set") ?? firstMatch(xml, "series"),
    actresses: allMatches(xml, "actor").map((block) => {
      const name = block.match(/<name>([\s\S]*?)<\/name>/i);
      return decodeEntities(name ? name[1].trim() : block.trim());
    }).filter(Boolean),
    genres: [...allMatches(xml, "genre"), ...allMatches(xml, "tag")],
    notes: firstMatch(xml, "plot") ?? firstMatch(xml, "outline"),
  });
}

function strip(o: NfoMetadata): NfoMetadata {
  const out: NfoMetadata = {};
  for (const [k, v] of Object.entries(o)) {
    if (v == null) continue;
    if (Array.isArray(v) && v.length === 0) continue;
    if (typeof v === "string" && v === "") continue;
    (out as Record<string, unknown>)[k] = v;
  }
  return out;
}