import { ReplyDocumentIR, ReplyNode, ReplyInline } from '../../types/replyExport';

/**
 * 将 Reply Document IR 序列化为规范化 GFM Markdown
 */
export function serializeMarkdown(ir: ReplyDocumentIR): string {
  return ir.nodes.map(renderNodeToMarkdown).join('\n\n');
}

function renderNodeToMarkdown(node: ReplyNode): string {
  switch (node.type) {
    case 'heading': {
      const hashes = '#'.repeat(node.level);
      return `${hashes} ${node.children.map(renderInlineToMarkdown).join('')}`;
    }
    case 'paragraph': {
      return node.children.map(renderInlineToMarkdown).join('');
    }
    case 'list': {
      return node.items
        .map((item, idx) => {
          const prefix = node.ordered ? `${idx + 1}. ` : '- ';
          return `${prefix}${item.map(renderInlineToMarkdown).join('')}`;
        })
        .join('\n');
    }
    case 'table': {
      const headerLine = `| ${node.header.map((c) => c.map(renderInlineToMarkdown).join('')).join(' | ')} |`;
      const sepLine = `| ${node.header.map(() => '---').join(' | ')} |`;
      const rowLines = node.rows.map(
        (row) => `| ${row.map((c) => c.map(renderInlineToMarkdown).join('')).join(' | ')} |`
      );
      return [headerLine, sepLine, ...rowLines].join('\n');
    }
    case 'blockquote': {
      const inner = node.children.map(renderNodeToMarkdown).join('\n\n');
      return inner
        .split('\n')
        .map((l) => `> ${l}`)
        .join('\n');
    }
    case 'code': {
      const lang = node.language || '';
      return `\`\`\`${lang}\n${node.value}\n\`\`\``;
    }
    case 'math': {
      if (node.display) {
        return `$$\n${node.latex}\n$$`;
      }
      return `$${node.latex}$`;
    }
    case 'mermaid': {
      return `\`\`\`mermaid\n${node.source}\n\`\`\``;
    }
    case 'divider': {
      return '---';
    }
    default:
      return '';
  }
}

function renderInlineToMarkdown(inline: ReplyInline): string {
  switch (inline.type) {
    case 'text': {
      let val = inline.value;
      if (inline.bold) val = `**${val}**`;
      if (inline.italic) val = `*${val}*`;
      if (inline.strike) val = `~~${val}~~`;
      return val;
    }
    case 'code':
      return `\`${inline.value}\``;
    case 'math':
      return `$${inline.latex}$`;
    case 'link': {
      const text = inline.children.map(renderInlineToMarkdown).join('');
      return `[${text}](${inline.href})`;
    }
    case 'hardBreak':
      return '\n';
    default:
      return '';
  }
}