// 页面导出为pdf格式以及分页隔断处理
//title表示为下载的标题，html表示document.querySelector('#myPrintHtml')
import html2Canvas from 'html2canvas';
import JsPDF from 'jspdf';

let noTableHeight = 0; //table外的元素高度
export function pageToPDF(title, html, lableList, type) {
  return new Promise(function (resolve, reject) {
    let width = html.clientWidth, //获取dom 宽度
      height = html.clientHeight, //获取dom 高度
      canvas = document.createElement('canvas'), //创建一个canvas节点
      scale = 1; //定义任意放大倍数 支持小数
    canvas.width = width * scale; //定义canvas 宽度 * 缩放
    canvas.height = height * scale; //定义canvas高度 *缩放
    canvas.style.width = html.clientWidth * scale + 'px';
    canvas.style.height = html.clientHeight * scale + 'px';
    canvas.getContext('2d').scale(scale, scale); //获取context,设置scale
    let opts = {
      scale: scale, // 添加的scale 参数
      canvas: canvas, //自定义 canvas
      logging: false, //日志开关，便于查看html2canvas的内部执行流程
      width: width, //dom 原始宽度
      height: height,
      useCORS: true, // 【重要】开启跨域配置
    };
    html2Canvas(html, opts).then(() => {
      var contentWidth = canvas.width;
      var contentHeight = canvas.height;
      //一页pdf显示html页面生成的canvas高度;
      var pageHeight = (contentWidth / 592.28) * 841.89;
      //未生成pdf的html页面高度
      var leftHeight = contentHeight;
      //页面偏移
      var position = 0;
      //a4纸的尺寸[595.28,841.89]，html页面生成的canvas在pdf中图片的宽高
      var imgWidth = 595.28;
      var imgHeight = (592.28 / contentWidth) * contentHeight;
      var pageData = canvas.toDataURL('image/jpeg', 1.0);
      var PDF = new JsPDF('', 'pt', 'a4');
      if (leftHeight < pageHeight) {
        PDF.addImage(pageData, 'JPEG', 0, 0, imgWidth, imgHeight);
      } else {
        while (leftHeight > 0) {
          PDF.addImage(pageData, 'JPEG', 0, position, imgWidth, imgHeight);
          leftHeight -= pageHeight;
          position -= 841.89;
          if (leftHeight > 0) {
            PDF.addPage();
          }
        }
      }
      // 保存文件
      if (canvas) {
        PDF.save(title + '.pdf');
        resolve(1);
      } else {
        reject('下载失败');
      }
    });
  });
}
// pdf截断需要一个空白位置来补充
function getFooterElement(remainingHeight, fillingHeight = 0) {
  const newNode = document.createElement('div');
  newNode.style.background = '#ffffff';
  newNode.style.width = 'calc(100% + 8px)';
  newNode.style.marginLeft = '-4px';
  newNode.style.marginBottom = '0px';
  newNode.classList.add('divRemove');
  newNode.style.height = remainingHeight + fillingHeight + 'px';
  return newNode;
}
function isSplit(nodes, index, pageHeight) {
  // 判断是不是tr 如果不是高度存起来
  // 表格里的内容要特殊处理
  // tr.offsetTop 是tr到table表格的高度
  // 所以计算高速时候要把表格外的高度加起来
  // 生成的pdf没有表格了这里可以不做处理 直接计算就行
  if (nodes[index].localName !== 'tr') {
    //判断元素是不是tr
    noTableHeight += nodes[index].clientHeight;
  }

  if (nodes[index].localName !== 'tr') {
    return (
      nodes[index].offsetTop + nodes[index].offsetHeight < pageHeight &&
      nodes[index + 1] &&
      nodes[index + 1].offsetTop + nodes[index + 1].offsetHeight > pageHeight
    );
  } else {
    return (
      nodes[index].offsetTop + nodes[index].offsetHeight + noTableHeight < pageHeight &&
      nodes[index + 1] &&
      nodes[index + 1].offsetTop + nodes[index + 1].offsetHeight + noTableHeight > pageHeight
    );
  }
}