type LexicalNode = { text?: string; children?: LexicalNode[] };

function collectText(node: LexicalNode, out: string[]): void {
  if (typeof node.text === "string" && node.text) out.push(node.text);
  if (Array.isArray(node.children)) {
    for (const child of node.children) collectText(child, out);
  }
}

/** Walks a Lexical richText field's JSON (any node shape) and extracts plain text, regardless of formatting/links/lists used. */
export function plainTextFromRichText(data: unknown): string {
  if (!data || typeof data !== "object") return "";
  const root = (data as { root?: LexicalNode }).root;
  if (!root) return "";
  const parts: string[] = [];
  collectText(root, parts);
  return parts.join(" ").replace(/\s+/g, " ").trim();
}

/** Truncates at a word boundary rather than mid-word, for a natural-reading meta description fallback. */
export function excerpt(text: string, maxLength = 160): string {
  const clean = text.replace(/\s+/g, " ").trim();
  if (clean.length <= maxLength) return clean;
  const truncated = clean.slice(0, maxLength);
  const lastSpace = truncated.lastIndexOf(" ");
  const safe = lastSpace > maxLength * 0.6 ? truncated.slice(0, lastSpace) : truncated;
  return `${safe.trim()}…`;
}

export function excerptFromRichText(data: unknown, maxLength = 160): string {
  return excerpt(plainTextFromRichText(data), maxLength);
}