// 公共文件
'use strict';
const Service = require('egg').Service;
const fs = require('fs');
const path = require('path');
class FileService extends Service {
  // 文件下载
  async download({ filePath }) {
    const target = path.join(filePath);
    this.ctx.attachment(target);
    this.ctx.set('Content-Type', 'application/octet-stream');
    const msg = fs.createReadStream(target);
    return msg;
  }
  // 文件上传
  async upload({ name, stream }) {
    return new Promise((resolve, reject) => {
      const target = path.join(`${name}`);
      const remoteFileStream = fs.createWriteStream(target);
      stream.pipe(remoteFileStream);
      let errFlag;
      remoteFileStream.on('error', err => {
        errFlag = true;
        remoteFileStream.destroy();
        reject(err);
      });

      remoteFileStream.on('finish', async () => {
        if (errFlag) return;
        resolve({ errcode: 0, errmsg: '' });
      });
    });
  }
  // 文件写入
  async write({ filePath, str }) {
    return new Promise((resolve, reject) => {
      fs.writeFile(path.resolve(filePath), str, {}, function(err) {
        if (err) {
          reject(err);
        }
        resolve({ errmsg: '', errcode: 0 });
      });
    });
  }
  // 文件删除
  async filesDel(filePath) {
    const cafile = path.join(filePath);
    return new Promise((resolve, reject) => {
      fs.unlink(cafile, function(err) {
        if (err) {
          reject(err);
        }
        resolve({ errmsg: '', errcode: 0 });
      });
    });
  }
  // 文件读取
  async fileread(filePath) {
    return new Promise((resolve, reject) => {
      fs.readFile(filePath, (err, data) => {
        if (err) {
          reject(err);
        }
        resolve({ errmsg: '', errcode: 0, data });
      });
    });
  }
}
module.exports = FileService;