import { promises as fsPromises } from 'fs';
import path from 'path';
import { byteConvert } from './common';
import { printError } from './print';
import {
  getFileHeadData, getFileMiddleData, getFileRowsNumber, getFileTailData,
} from './shell';

interface FileInfo {
  name: string
  fullPath: string
  size: string
  rowCount: number
}

interface SampledData {
  head: string[]
  middle: string[]
  tail: string[]
}

/**
 * 新建文件
 * @param filePath 文件路径
 * @param contents 文件内容，数组里的一项就是文件里的一行
 */
export function createFile(filePath: string, contents: string[]): Promise<void> {
  const data = contents.join('\n');
  return fsPromises.writeFile(filePath, data, 'utf-8').catch((err) => {
    printError(err);
    throw err;
  });
}

/**
 * 读取文件
 * @param filePath 文件路径
 */
export function readFile(filePath: string): Promise<string[]> {
  return new Promise((resolve, reject) => {
    fsPromises.readFile(filePath, 'utf-8')
      .then((data) => {
        resolve(data.split('\n'));
      })
      .catch((err) => {
        printError(err);
        throw err;
      });
  });
}

/**
 * 获取文件信息
 * @param filePath 文件路径
 */
export async function getFileStats(filePath: string): Promise<FileInfo> {
  const { size } = await fsPromises.stat(filePath);
  const rowCount = await getFileRowsNumber(filePath);

  return Promise.resolve({
    name: path.basename(filePath),
    fullPath: filePath,
    size: byteConvert(size),
    rowCount,
  });
}

export async function getSampledData(filePath: string, rowCount = 3): Promise<SampledData> {
  return Promise.resolve({
    head: await getFileHeadData(filePath, rowCount),
    middle: await getFileMiddleData(filePath, rowCount),
    tail: await getFileTailData(filePath, rowCount),
  });
}