export const decryptTool = {
  decryptKey: "2019ysapp7527",
  cachedBlobs: {},
  // 并发控制
  maxConcurrency: 10,
  activeCount: 0,
  queue: [],
  /**
   * @description 图片解密
   * @param url 需要解密的url
   * @returns  解密过后的图片链接
   */
  async imgDecypt(url) {
    return new Promise((resolve, reject) => {
      const task = async () => {
        try {
          const r = await fetch(url);
          const rb = await r.arrayBuffer();
          const blobUrl = this.imgEncrypt(rb);
          resolve(blobUrl);
        } catch (e) {
          reject(e);
        } finally {
          // 任务完成，减少计数并尝试启动下一个队列任务
          this.activeCount = Math.max(0, this.activeCount - 1);
          if (this.queue.length > 0) {
            const next = this.queue.shift();
            this.activeCount++;
            next();
          }
        }
      };

      if (this.activeCount < this.maxConcurrency) {
        this.activeCount++;
        task();
      } else {
        this.queue.push(task);
      }
    });
  },
  /**
   * 图片解密
   * @param buffer buffer
   * @returns
   */
  imgEncrypt(buffer) {
    const bytes = new Uint8Array(buffer);
    const encoder = new TextEncoder();
    const KEY = encoder.encode(this.decryptKey);
    for (let i = 0; i < 100; i++) {
      bytes[i] ^= KEY[i % KEY.length];
    }
    const blob = new Blob([bytes], {
      type: "image/png",
    });
    const url = URL.createObjectURL(blob);
    return url;
  },
};