import type { MarkedExtension, Tokens } from "marked";
import Slugger from "github-slugger";

/**
 * 将表格数据转换为 CSV 格式字符串
 * @param headers 表头数组
 * @param rows 表格数据行
 * @returns CSV 格式字符串
 */
function tableToCSV(headers: string[], rows: string[][]): string {
  const escapeCell = (cell: string) => {
    // 如果单元格包含逗号、换行或引号，需要转义
    if (
      cell.includes(",") ||
      cell.includes("\n") ||
      cell.includes('"') ||
      cell.includes("#")
    ) {
      return `"${cell.replace(/"/g, '""')}"`;
    }
    return cell;
  };

  const headerLine = headers.map(escapeCell).join(",");
  const dataLines = rows.map((row) => row.map(escapeCell).join(","));

  return [headerLine, ...dataLines].join("\n");
}

/** Spark table: first column header is a pure dice formula (d6, d20, etc.) */
const SPARK_DICE_RE = /^\d*d\d+$/i;

export default function markedTable(): MarkedExtension {
  return {
    renderer: {
      table(token: Tokens.Table) {
        // 检查表头是否包含 md-table-label
        const header = token.header;
        let roll = "";
        let spark = "";
        const labelIndex = header.findIndex((cell) => {
          if (cell.text === "md-roll-label" || cell.text.match(/(\d+)?d\d+/)) {
            roll = " roll=true";
            // If this is a spark table (first column is a pure dice formula),
            // compute the data-column slug for DOM injection
            if (SPARK_DICE_RE.test(cell.text)) {
              const slugger = new Slugger();
              const dataHeaders = header
                .filter((_, i) => i !== 0)
                .map((h) => h.text);
              const slug = dataHeaders
                .map((h) => slugger.slug(h.toLowerCase()))
                .join("-");
              spark = ` data-spark="${slug}"`;
            }
            return true;
          } else if (cell.text === "md-remix-label") {
            roll = " roll=true remix=true";
            return true;
          }
          return cell.text === "md-table-label" || cell.text === "label";
        });

        // 默认表格渲染 - 使用 marked 默认行为
        if (labelIndex === -1) return false;

        const headers = token.header.map((cell) => cell.text);
        headers[labelIndex] = "label";
        const rows = token.rows.map((row) => row.map((cell) => cell.text));

        if (header.findIndex((header) => header.text === "body") < 0) {
          // 收集所有非 label 列的表头
          const bodyColumns = headers.filter((cell) => cell !== "label");

          // 构建 body 列的模板：**列名**：{{列名}}\n\n
          const bodyTemplate = bodyColumns
            .map((col) => `**${col}**：{{${col}}}`)
            .join("\n\n");

          headers.push("body");
          rows.forEach((row) => {
            row.push(bodyTemplate);
          });
        }

        // 生成 CSV 数据
        const csvData = tableToCSV(headers, rows);

        // 渲染为 md-table 组件，内联 CSV 数据
        return `<md-table ${roll}${spark}>${csvData}</md-table>\n`;
      },
    },
  };
}