/** Parsed YAML scalar from minimal frontmatter parser. */
export type FrontmatterScalar = string | number | boolean | string[];

export function parseScalar(value: string): FrontmatterScalar {
  const trimmed = value.trim();
  if (trimmed === "true") return true;
  if (trimmed === "false") return false;
  if (/^-?\d+(\.\d+)?$/.test(trimmed)) return Number(trimmed);
  if (trimmed.startsWith("[") && trimmed.endsWith("]")) {
    return trimmed
      .slice(1, -1)
      .split(",")
      .map((item) => item.trim().replace(/^['"]|['"]$/g, ""))
      .filter(Boolean);
  }
  return trimmed.replace(/^['"]|['"]$/g, "");
}

export function toStringArray(
  value: FrontmatterScalar | FrontmatterScalar[] | undefined,
): string[] {
  if (Array.isArray(value)) {
    return value.flatMap((item) => (typeof item === "string" ? [item] : []));
  }
  if (typeof value === "string")
    return value
      .split(",")
      .map((item) => item.trim())
      .filter(Boolean);
  return [];
}