const TEXT_NODE = "text";

function textNode(text: string) {
  return {
    type: TEXT_NODE,
    text,
  };
}

function paragraphNode(lines: string[]) {
  const content: Array<{ type: string; text?: string }> = [];

  lines.forEach((line, index) => {
    if (index > 0) {
      content.push({ type: "hardBreak" });
    }

    if (line.length > 0) {
      content.push(textNode(line));
    }
  });

  return {
    type: "paragraph",
    ...(content.length > 0 ? { content } : {}),
  };
}

export function markdownToAdf(input: string) {
  const lines = input.replace(/\r\n/g, "\n").split("\n");
  const content: Array<Record<string, unknown>> = [];
  let index = 0;

  while (index < lines.length) {
    const current = lines[index]?.trimEnd() ?? "";

    if (current.trim().length === 0) {
      index += 1;
      continue;
    }

    const heading = current.match(/^(#{1,6})\s+(.*)$/);

    if (heading) {
      content.push({
        type: "heading",
        attrs: { level: heading[1].length },
        content: [textNode(heading[2])],
      });
      index += 1;
      continue;
    }

    if (/^[-*]\s+/.test(current)) {
      const items: Array<Record<string, unknown>> = [];

      while (index < lines.length && /^[-*]\s+/.test(lines[index] ?? "")) {
        items.push({
          type: "listItem",
          content: [
            {
              type: "paragraph",
              content: [textNode((lines[index] ?? "").replace(/^[-*]\s+/, ""))],
            },
          ],
        });
        index += 1;
      }

      content.push({
        type: "bulletList",
        content: items,
      });
      continue;
    }

    const paragraphLines: string[] = [];

    while (index < lines.length && (lines[index]?.trim().length ?? 0) > 0) {
      paragraphLines.push(lines[index] ?? "");
      index += 1;
    }

    content.push(paragraphNode(paragraphLines));
  }

  return {
    type: "doc",
    version: 1,
    content,
  };
}