/**
 * 校验文件是否已上传
 * @param md5 
 * @param chunks 
 */
const verifyFile = (md5: string, chunks: Blob[], file: File) => {
  let chunsNames = [] as string[]
  chunks.forEach((item, index) => chunsNames.push(md5 + separator + index))
  return $fetch(`${config?.baseUrl}/upload/verifyFile`,
    {
      method: 'POST',
      query: {
        chunksObj: { name: md5, chunsNames },
        extName: file.name.split(".").slice(-1)[0],
        fileName: md5 + '.' + file.name.split(".").slice(-1)[0]
      }
    })
}

/**
 * 文件分片
 * @param file 文件对象
 * @param chunksize 分片大小
 */
const createChunks = (file: File, chunksize: number) => {
  const chunks = [];
  for (let i = 0; i < file.size; i += chunksize) {
    chunks.push(file.slice(i, i + chunksize));
  }
  return chunks;
};

/**
 * 创建MD5 加密串
 * @param chunks 
 */
import SparkMD5 from "spark-md5";

const createMd5 = (chunks: Blob[]) => {
  const spark = new SparkMD5();
  return new Promise((reslove) => {
    function _read(i: number) {
      if (i >= chunks.length) {
        const md5 = spark.end();
        reslove(md5);
        return;
      }
      const blob = chunks[i];
      const reader = new FileReader();

      reader.onload = (e) => {
        const bytes = e?.target?.result;
        spark.append(bytes);
        _read(i + 1);
      };
      reader.readAsArrayBuffer(blob);
    }
    _read(0);
  });
};

/**
 * 上传chunk
 * @param item chunks
 * @param md5 加密串
 * @param fileName 文件名
 * @param index 下标：失败辅助标识
 */
const uploadLargeFile = (item, md5 = '', fileName = '', index = -1) => {
  const formData = new FormData();
  formData.append("file", item);
  return useFetch(`${config?.baseUrl}/upload/largeFile`, {
    method: "POST",
    headers: {
      authorization: "authorization-text",
    },
    body: formData,
    query: {
      filename: md5 + separator + index,
      name: md5,
      fileName,
      index,
    },
  });
}

/**
 * 循环上传chunks
 * @param chunks 
 * @param md5 加密串
 * @param fileName 文件名
 */
const uploadChunks = (chunks = [], md5 = '', fileName = '') => {
  const allRequest = chunks.map((item, index) => {
    return uploadLargeFile(item, md5, fileName, index)
  });
  return allRequest 
}

/**
 * 合并chunks
 * @param md5 
 * @param file 
 */
const mergeFile = async (md5 = '', file: File) => {
  const {
    url = "",
    fileType = "",
    fileName: _fileName,
  } = await $fetch(`${config?.baseUrl}/upload/mergeFile`, {
    method: "POST",
    query: {
      fileName: md5,
      filename: file.name,
      extName: file.name.split(".").slice(-1)[0],
    },
  });
}

// md5Worker.js
self.importScripts('park-md5.js');

self.addEventListener('message', async (event) => {
  const chunks = event.data;
  const md5 = await createMd5(chunks);
  self.postMessage( md5);
})

const createMd5 = (chunks) => {
  const spark = new self.SparkMD5();

  return new Promise((resolve) => {
    function _read(i) {
      if (i >= chunks.length) {
        const md5 = spark.end();
        resolve(md5);
        return;
      }

      const blob = chunks[i];
      const reader = new FileReader();

      reader.onload = (e) => {
        const bytes = e?.target?.result;
        spark.append(bytes);
        _read(i + 1);
      };
      reader.readAsArrayBuffer(blob);
    }
    _read(0);
  });
};

// 在主线程中创建 Web Worker
import("./md5Worker?worker").then((worker) => {
    const md5Worker = new worker.default();
    // 发送消息
    md5Worker.postMessage('发送的消息')
    // 报错监听
    md5Worker.onerror = err => {
        }
    // 接收消息
    md5Worker.onmessage = function (e) {}
    // 关闭联系
    md5Worker.terminate()
})

// ----------------------或者-----------------------
const worker = new Worker('worker-script.js');
worker.postMessage('Hello from main thread');
worker.onmessage = function(event) {
  console.log('Main thread received message from Worker:', event.data);
};

const express = require('express');
const router = express.Router();
const fs = require('fs');
const path = require('path');
/**
 * 合并分片
 */
router.post('/mergeFile', async (req, res) => {
  const { fileName, extName, filename } = req.query
  thunkStreamMerge(
    '../public/file/thunk/' + fileName,
    '../public/file/' + fileName + '.' + extName
  );
  let fileType = extName
  if (imageFormats.includes(extName)) {
    fileType = 'img'
  } else if (videoFormats.includes(extName)) {
    fileType = 'video'
  }

  res.json({
    code: 1,
    url: '/static/file/' + fileName,
    fileType,
    fileName
  });
})

/**
 * 文件合并
 * @param {string} sourceFiles 源文件目录
 * @param {string} targetFile 目标文件路径
 */
function thunkStreamMerge(sourceFiles, targetFile) {
  const sourceFilesDir = path.join(__dirname, sourceFiles);
  targetFile = path.join(__dirname, targetFile);

  const fileList = fs
    .readdirSync(sourceFilesDir)
    .filter((file) => fs.lstatSync(path.join(sourceFilesDir, file)).isFile())
    .sort((a, b) => parseInt(a.split('@')[1]) - parseInt(b.split('@')[1]))
    .map((name) => ({
      name,
      filePath: path.join(sourceFilesDir, name),
    }));

  const fileWriteStream = fs.createWriteStream(targetFile);

  thunkStreamMergeProgress(fileList, fileWriteStream, sourceFilesDir);
}

/**
 * 合并每一个切片
 * @param {Array} fileList 文件数据列表
 * @param {WritableStream} fileWriteStream 最终的写入结果流
 * @param {string} sourceFilesDir 源文件目录
 */
function thunkStreamMergeProgress(fileList, fileWriteStream, sourceFilesDir) {
  if (!fileList.length) {
    fileWriteStream.end('完成了');
    // 删除临时目录
    fs.rmdirSync(sourceFilesDir, { recursive: true, force: true });
    return;
  }

  const { filePath: chunkFilePath } = fileList.shift();
  const currentReadStream = fs.createReadStream(chunkFilePath);

  // 把结果往最终的生成文件上进行拼接
  currentReadStream.pipe(fileWriteStream, { end: false });

  currentReadStream.on('end', () => {
    // 拼接完之后进入下一次循环
    thunkStreamMergeProgress(fileList, fileWriteStream, sourceFilesDir);
  });
}

import md5Worker from "./md5Worker";
const worker = new Worker('./md5Worker.js')
worker.onerror= (err) => {
  console.log(err)
}

import("./md5Worker?worker").then((worker) => {
const md5Worker = new worker.default();
md5Worker.postMessage(chunks)
md5Worker.onerror = err => {
    console.log(err)
}
md5Worker.onmessage = async function (e) {}
})

const allRequest = uploadChunks(chunks, md5, fileName, notUploadedChunks, uploadedChunks)
console.log(allRequest, 'allRequest')
const successArr: any[] = [] // 纪录成功上传的chunks
Promise.allSettled(allRequest).then(res => {
    res?.forEach(item => {
    if (item.status == 'fulfilled' && item.value?.data?.value?.code == 0) {
        const failIndex = item.value.data.value?.index
        successArr.push(failIndex)
    }
    })
}).finally(async () => {
    // const isAllSuccess = successArr.length === chunks.length // 你小子让我徘徊半小时是吧，看完不揍死你
    const isAllSuccess = successArr.length === allRequest.length
    if (!isAllSuccess) {
        const tryAllRequest = chunks.map((item, index) => {
            if (!successArr.includes('' + index)) {
                return uploadLargeFile(item, md5, fileName, index)
            }
        })
        // 失败重试一次
        await Promise.all(tryAllRequest)
    }
    mergeFile(md5, file)
    loading.value = false;
    showUploadList.value = false
})