import { readdir } from 'fs/promises';
import { join } from 'path';
import { csvStr2arr } from '../utils/csv';
import { getFileHeadData } from '../utils/shell';

export interface GenerateCsvConf {
  outputDirPath: string;
  inputDirPath: string;
}

export interface ColObj {
  filePath: string;
  columnCount: number;
}

export async function getColCount(filePath: string): Promise<ColObj> {
  const firstRow = await getFileHeadData(filePath, 1);
  const rowArr = await csvStr2arr(firstRow.join('\n'));
  return Promise.resolve({
    filePath,
    columnCount: rowArr[0].length,
  });
}
export async function getFilesColCount(dirPath: string): Promise<ColObj[]> {
  const filePaths = await readdir(dirPath);
  const res = filePaths.map((filePath) => getColCount(join(dirPath, filePath)));
  return Promise.all(res);
}

export function getConfByColObjList(colObjs: ColObj[], outputDirPath: string): string {
  const conf = [
    'module.exports = {',
  ];
  conf.push(`  outputDirPath: '${outputDirPath}',`);
  conf.push('  files: [');
  colObjs.forEach((item) => {
    conf.push('    {');
    conf.push(`      filePath: '${item.filePath}',`);
    conf.push(`      columnCount: ${item.columnCount},`);
    conf.push('    },');
  });
  conf.push('  ],');
  conf.push('};');
  return conf.join('\n');
}

export async function generateCsvConf(conf: GenerateCsvConf): Promise<string> {
  const { outputDirPath, inputDirPath } = conf;
  return getConfByColObjList(await getFilesColCount(inputDirPath), outputDirPath);
}