import { renderInline } from "../inline/render.js";
import type { BlockHandler } from "./handler.type.js";

/** Generate a URL-friendly heading ID from text. */
export function generateHeadingId(text: string): string {
  return text
    .toLowerCase()
    .replace(/[^\p{L}\p{N}\s-]/gu, "")
    .replace(/\s+/g, "-")
    .replace(/-+/g, "-")
    .replace(/^-|-$/g, "");
}

export const headingHandler = {
  render(raw: string, attrs?: Record<string, string>): string {
    const level = parseInt(attrs?.level ?? "1", 10);
    const tag = `h${Math.min(6, Math.max(1, level))}`;
    const id = generateHeadingId(raw);
    const idAttr = id === "" ? "" : ` id="${id}"`;
    return `<${tag}${idAttr}>${renderInline(raw)}</${tag}>`;
  },

  serialize(raw: string, attrs?: Record<string, string>): string {
    const level = parseInt(attrs?.level ?? "1", 10);
    return `${"#".repeat(Math.min(6, Math.max(1, level)))} ${raw}`;
  },
} satisfies BlockHandler;