import crypto from "crypto";
import fs from "node:fs";
import SparkMD5 from "spark-md5";
import environment from "#environment";

export function createMD5(filePath) {
  return new Promise((res, rej) => {
    const hash = crypto.createHash("md5");
    const rStream = fs.createReadStream(filePath);
    rStream.on("data", (data) => {
      hash.update(data);
    });
    rStream.on("end", () => {
      res(hash.digest("hex"));
    });
  });
}

/**
 * 作者：起一个可以中奖的名字
 * 链接：https://juejin.cn/post/7142831050052665381
 * 来源：稀土掘金
 * 著作权归作者所有。商业转载请联系作者获得授权，非商业转载请注明出处。
 * 计算文件Md5
 * 将文件分片逐步计算最终合并得出整个文件md5, 提升计算速度
 * @param {*} file
 */

// export function computeFileMD5(file) {
//   return new Promise((resolve, reject) => {
//     let blobSlice = File.prototype.slice || File.prototype.mozSlice || File.prototype.webkitSlice;
//     let chunkSize = 2097152;  // 按照一片 2MB 分片
//     let chunks = Math.ceil(file.size / chunkSize); // 片数
//     let currentChunk = 0;
//     let spark = new SparkMD5.ArrayBuffer();
//     let fileReader = new FileReader();

//     fileReader.onload = function (e) {
//       console.log('read chunk nr', currentChunk + 1, 'of', chunks);
//       spark.append(e.target.result);
//       currentChunk++;

//       if (currentChunk < chunks) {
//         loadNext();
//       } else {
//         console.log('finished loading');
//         let md5 = spark.end(); //最终md5值
//         spark.destroy(); //释放缓存
//         resolve(md5);
//       }
//     };

//     fileReader.onerror = function (e) {
//       console.warn('oops, something went wrong.');
//       reject(e);
//     };

//     function loadNext() {
//       let start = currentChunk * chunkSize;
//       const end = ((start + chunkSize) >= file.size) ? file.size : start + chunkSize;
//       fileReader.readAsArrayBuffer(blobSlice.call(file, start, end));
//     }

//     loadNext();
//   })
// }
//

export function computeFileMD5(file) {
  return new Promise((resolve, reject) => {
    const hash = crypto.createHash("md5");

    // 直接将整个 Buffer 更新到 hash
    hash.update(file.data);

    // 计算哈希值
    const md5 = hash.digest("hex");
    resolve(md5);
  });
}


// 加密
export function aes_encrypt(msg) {
  const aesInfo = environment.aes_info();
  const cipher = crypto.createCipheriv("aes-256-cbc", aesInfo.key, aesInfo.iv);
  // input encoding: utf8
  // output encoding: hex
  let encrypted = cipher.update(msg, "utf8", "hex");
  encrypted += cipher.final("hex");
  return encrypted;
}

// 解谜
export function aes_decrypt(encrypted) {
  const aesInfo = environment.aes_info();
  const decipher = crypto.createDecipheriv(
    "aes-256-cbc",
    aesInfo.key,
    aesInfo.iv,
  );
  let decrypted = decipher.update(encrypted, "hex", "utf8");
  decrypted += decipher.final("utf8");
  return decrypted;
}