/**
 * 压缩图片
 * @param img 被压缩的img对象
 * @param type 压缩后转换的文件类型
 * @param mx 触发压缩的图片最大宽度限制
 * @param mh 触发压缩的图片最大高度限制
 * @param quality 图片质量
 */
function compressImg(
  img: any,
  type: string,
  mx: number,
  mh: number,
  quality = 1,
) {
  return new Promise((resolve) => {
    const canvas = document.createElement('canvas');
    const context = canvas.getContext('2d');
    const { width: originWidth, height: originHeight } = img;
    // 最大尺寸限制
    const maxWidth = mx;
    const maxHeight = mh;
    // 目标尺寸
    let targetWidth = originWidth;
    let targetHeight = originHeight;
    if (originWidth > maxWidth || originHeight > maxHeight) {
      if (originWidth / originHeight > 1) {
        // 宽图片
        targetWidth = maxWidth;
        targetHeight = Math.round(maxWidth * (originHeight / originWidth));
      } else {
        // 高图片
        targetHeight = maxHeight;
        targetWidth = Math.round(maxHeight * (originWidth / originHeight));
      }
    }
    canvas.width = targetWidth;
    canvas.height = targetHeight;
    context?.clearRect(0, 0, targetWidth, targetHeight);
    // 图片绘制
    context?.drawImage(img, 0, 0, targetWidth, targetHeight);
    canvas.toBlob(
      function (blob) {
        resolve(blob);
      },
      type || 'image/png',
      quality,
    );
  });
}

export default compressImg;