import { attachUrlProtocol, getBasename } from './file';
import { isImage } from './is-image';

/**
 * 下载图片
 */
export const downloadImg = (url: string, _fileName?: string) => {
  const fileName = _fileName || getBasename(url);

  const image = new Image();
  image.setAttribute('crossOrigin', 'Anonymous');
  image.onload = function () {
    const canvas = document.createElement('canvas');
    const context = canvas.getContext('2d');
    canvas.width = image.width;
    canvas.height = image.height;
    context?.drawImage(image, 0, 0, image.width, image.height);
    const canvasUrl = canvas.toDataURL('images/png');
    const a = document.createElement('a');
    a.download = fileName;
    a.href = canvasUrl;
    a.click();
  };
  const tempUrl = new URL(attachUrlProtocol(url));
  if (tempUrl.search) {
    image.src = `${url}&v=${Date.now()}`;
  } else {
    image.src = `${url}?v=${Date.now()}`;
  }
};

/**
 * 通用下载
 */
export const commonDownload = (fileUrl: string, _fileName?: string) => {
  const fileName = _fileName || getBasename(fileUrl);
  const a = document.createElement('a');
  a.target = '_blank';
  a.href = fileUrl;
  a.download = fileName;
  document.body.appendChild(a);
  a.click();
  document.body.removeChild(a);
};

/**
 * 下载文件
 * @param fileUrl 下载的文件路径
 * @param fileName 重命名下载文件
 */
export const downloadFile = (fileUrl: string, fileName?: string) => {
  // 防护代码
  if (!fileUrl) return;
  fileName = fileName || '';

  if (isImage(fileUrl) || isImage(fileName)) {
    downloadImg(fileUrl, fileName);
  } else {
    commonDownload(fileUrl, fileName);
  }
};