ttrpg-tools/src/components/utils/csv-loader.ts

import { parse } from 'csv-parse/browser/esm/sync';
import yaml from 'js-yaml';
import { getIndexedData } from '../../data-loader/file-index';

/**
 * 解析 front matter
 * @param content 包含 front matter 的内容
 * @returns 解析结果，包含 front matter 和剩余内容
 */
function parseFrontMatter(content: string): { frontmatter?: JSONObject; remainingContent: string } {
  // 分割内容
  const parts = content.trim().split(/(?:^|\n)---\s*\n/g);

  // 至少需要三个部分：空字符串、front matter、剩余内容
  if (parts.length !== 3 || parts[0] !== '') {
    return { remainingContent: content };
  }

  try {
    // 解析 YAML front matter
    const frontmatterStr = parts[1].trim();
    const frontmatter = yaml.load(frontmatterStr) as JSONObject;

    // 剩余内容是第三部分及之后的所有内容
    const remainingContent = parts.slice(2).join('---\n').trimStart();

    return { frontmatter, remainingContent };
  } catch (error) {
    console.warn('Failed to parse front matter:', error);
    return { remainingContent: content };
  }
}

/**
 * 检测字符串是否是 CSV 格式
 * @param str 待检测的字符串
 * @returns 如果是 CSV 格式返回 true
 */
export function isCSV(str: string): boolean {
  const trimmed = str.trim();
  
  // 检查是否以 YAML front matter 开头
  if (trimmed.startsWith('---\n') || trimmed.startsWith('---\r\n')) {
    return true;
  }
  
  // 检查是否包含 CSV 特征：多行且有分隔符
  const lines = trimmed.split(/\r?\n/).filter(line => line.trim() !== '');
  if (lines.length < 2) {
    return false;
  }
  
  // 检测常见 CSV 分隔符
  const separators = [',', '\t', ';', '|'];
  const firstLine = lines[0];
  
  for (const sep of separators) {
    if (firstLine.includes(sep)) {
      // 检查其他行是否也有相同的分隔符
      const hasSeparatorInOtherLines = lines.slice(1).some(line => line.includes(sep));
      if (hasSeparatorInOtherLines) {
        return true;
      }
    }
  }
  
  return false;
}

/**
 * 解析 CSV 字符串
 * @template T 返回数据的类型，默认为 Record<string, string>
 * @param csvString CSV 字符串内容
 * @param sourcePath 源路径标识（用于标记数据来源）
 * @returns 解析后的 CSV 数据
 */
export function parseCSVString<T = Record<string, string>>(csvString: string, sourcePath: string = 'inline'): CSV<T> {
  // 解析 front matter
  const { frontmatter, remainingContent } = parseFrontMatter(csvString);

  const records = parse(remainingContent, {
    columns: true,
    comment: '#',
    trim: true,
    skipEmptyLines: true
  });

  const result = records as Record<string, string>[];
  // 添加 front matter 到结果中
  const csvResult = result as CSV<T>;
  if (frontmatter) {
    csvResult.frontmatter = frontmatter;
    for(const each of result){
      Object.assign(each, frontmatter);
    }
  }
  csvResult.sourcePath = sourcePath;
  return csvResult;
}

/**
 * 加载 CSV 文件
 * @template T 返回数据的类型，默认为 Record<string, string>
 * @param pathOrContent 文件路径或 inline CSV 字符串
 * @returns 解析后的 CSV 数据
 */
export async function loadCSV<T = Record<string, string>>(pathOrContent: string): Promise<CSV<T>> {
  // 检测是否是 inline CSV 数据
  if (isCSV(pathOrContent)) {
    return parseCSVString<T>(pathOrContent, 'inline');
  }
  
  // 从索引获取文件内容
  const content = await getIndexedData(pathOrContent);

  // 解析 front matter
  const { frontmatter, remainingContent } = parseFrontMatter(content);

  const records = parse(remainingContent, {
    columns: true,
    comment: '#',
    trim: true,
    skipEmptyLines: true
  });

  const result = records as Record<string, string>[];
  // 添加 front matter 到结果中
  const csvResult = result as CSV<T>;
  if (frontmatter) {
    csvResult.frontmatter = frontmatter;
    for(const each of result){
      Object.assign(each, frontmatter);
    }
  }
  csvResult.sourcePath = pathOrContent;
  return csvResult;
}

type JSONData = JSONArray | JSONObject | string | number | boolean | null;
interface JSONArray extends Array<JSONData> {}
interface JSONObject extends Record<string, JSONData> {}

export type CSV<T> = T[] & {
  frontmatter?: JSONObject;
  sourcePath: string;
}

export function processVariables<T extends JSONObject> (body: string, currentRow: T, csv: CSV<T>, filtered?: T[], remix?: boolean): string {
  const rolled = filtered || csv;

  function replaceProp(key: string) {
    const row = remix ?
        rolled[Math.floor(Math.random() * rolled.length)] :
        currentRow;
    const frontMatter = csv.frontmatter;
    if(key in row) return row[key];
    if(frontMatter && key in frontMatter) return frontMatter[key];
    return `{{${key}}}`;
  }

  return body?.replace(/\{\{(\w+)\}\}/g, (_, key) => `${replaceProp(key)}`) || '';
}