import type { BlockHandler } from "./handler.type.js";
import { ITEM_SEPARATOR } from "./identify.js";
import { isLooseList, renderItemContent, serializeItemTail, splitItemHead } from "./list-item.js";

export const listHandler = {
  render(raw: string, attrs?: Record<string, string>): string {
    const ordered = attrs?.["list-type"] === "ordered";
    const tag = ordered ? "ol" : "ul";
    // A non-numeric `start` previously emitted `start="NaN"`.
    const parsedStart = parseInt(attrs?.start ?? "1", 10);
    const startNum = Number.isNaN(parsedStart) ? 1 : parsedStart;
    const startAttr = ordered && startNum !== 1 ? ` start="${startNum}"` : "";

    const items = raw.split(ITEM_SEPARATOR);
    const loose = isLooseList(items);
    const inner = items.map((itemRaw) => `<li>${renderItemContent(itemRaw, loose)}</li>`).join("");

    return `<${tag}${startAttr}>${inner}</${tag}>`;
  },

  serialize(raw: string, attrs?: Record<string, string>): string {
    const ordered = attrs?.["list-type"] === "ordered";
    const startNum = parseInt(attrs?.start ?? "1", 10);
    const items = raw.split(ITEM_SEPARATOR);
    const lines: string[] = [];
    let num = startNum;

    for (const itemRaw of items) {
      const marker = ordered ? `${num++}. ` : "- ";
      const [head, tail] = splitItemHead(itemRaw);
      lines.push(marker + head);
      lines.push(...serializeItemTail(tail, head));
    }

    return lines.join("\n");
  },
} satisfies BlockHandler;