import html2canvas from "html2canvas";
import jsPDF from "jspdf";
import { pdfToText } from "pdf-ts";

export async function htmlToPdf2(htmlCode: string) {
  const container = document.createElement("div");
  container.style.cssText = `
    position: fixed;
    left: -9999px;
    top: -9999px;
    width: 210mm; // 固定 A4 宽度
    background: white;
  `;
  container.innerHTML = htmlCode;
  document.body.appendChild(container);

  try {
    // 关键修改 1: 确保所有图片加载完成
    await waitForImages(container);

    // 关键修改 2: 强制触发布局计算
    void container.offsetHeight;

    const canvas = await html2canvas(container, {
      scale: 2,
      useCORS: true,
      logging: true,
      scrollY: -window.scrollY, // 消除滚动偏移
      windowWidth: container.scrollWidth,
      windowHeight: container.scrollHeight,
    });

    const pdf = new jsPDF("p", "mm", "a4");
    const pageWidth = pdf.internal.pageSize.getWidth();
    const imgRatio = canvas.width / canvas.height;

    // 关键修改 3: 动态计算高度
    const imgHeight = (pageWidth * canvas.height) / canvas.width;
    pdf.addImage(
      canvas.toDataURL("image/png"),
      "PNG",
      0,
      0,
      pageWidth,
      imgHeight,
    );

    // 关键修改 4: 处理多页内容
    if (imgHeight > pdf.internal.pageSize.getHeight()) {
      pdf.addPage();
      pdf.addImage(
        canvas.toDataURL("image/png"),
        "PNG",
        0,
        -pdf.internal.pageSize.getHeight(),
        pageWidth,
        imgHeight,
      );
    }

    pdf.save("document.pdf");
  } catch (error) {
    console.error("生成失败:", error);
  } finally {
    document.body.removeChild(container);
  }
}

// 图片加载等待函数
const waitForImages = (element: HTMLElement) => {
  return new Promise<void>((resolve) => {
    const images = element.getElementsByTagName("img");
    let loaded = 0;

    const checkDone = () => {
      if (loaded >= images.length) resolve();
    };

    if (images.length === 0) return resolve();

    Array.from(images).forEach((img) => {
      if (img.complete) {
        loaded++;
        checkDone();
      } else {
        img.onload = () => {
          loaded++;
          checkDone();
        };
        img.onerror = checkDone;
      }
    });
  });
};

export function htmlToPdf(htmlCode: string) {
  // 1. 动态创建一个 div 元素，并配置为隐藏（display: none）
  const container = document.createElement("div");
  container.innerHTML = htmlCode;
  container.style.display = "none";
  document.body.appendChild(container);
  // 2. 为了让 html2canvas 能捕获内容，将 display 修改为 block，并移至视野之外
  container.style.display = "block";
  container.style.position = "absolute";
  container.style.top = "-9999px";
  container.style.left = "-9999px";
  window.pageYOffset = 0;
  document.documentElement.scrollTop = 0;
  document.body.scrollTop = 0;
  setTimeout(() => {
    html2canvas(container, {
      allowTaint: true,
      useCORS: true,
      scale: 2, // 提升画面质量，但是会增加文件大小
      height: container.scrollHeight, // 需要注意，element的 高度 宽度一定要在这里定义一下，不然会存在只下载了当前你能看到的页面   避雷避雷！！！
      windowHeight: container.scrollHeight,
    }).then(function (canvas) {
      var contentWidth = canvas.width;
      var contentHeight = canvas.height;
      // console.log('contentWidth', contentWidth)
      // console.log('contentHeight', contentHeight)
      // 一页pdf显示html页面生成的canvas高度;
      var pageHeight = (contentWidth * 841.89) / 592.28;
      // 未生成pdf的html页面高度
      var leftHeight = contentHeight;
      // console.log('pageHeight', pageHeight)
      // console.log('leftHeight', leftHeight)
      // 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  //40是左右页边距
      var imgWidth = 595.28 - 40;
      var imgHeight = (592.28 / contentWidth) * contentHeight;
      var pageData = canvas.toDataURL("image/jpeg", 1.0);
      var pdf = new jsPDF("p", "pt", "a4");
      // 有两个高度需要区分，一个是html页面的实际高度，和生成pdf的页面高度(841.89)
      // 当内容未超过pdf一页显示的范围，无需分页
      if (leftHeight < pageHeight) {
        // console.log('没超过1页')
        pdf.addImage(pageData, "JPEG", 20, 20, imgWidth, imgHeight);
      } else {
        while (leftHeight > 0) {
          // console.log('超过1页')
          pdf.addImage(pageData, "JPEG", 20, position, imgWidth, imgHeight);
          leftHeight -= pageHeight;
          position -= 841.89;
          // 避免添加空白页
          if (leftHeight > 0) {
            pdf.addPage();
          }
        }
      }
      pdf.save("out.pdf");
    });
  }, 1000);
}

export async function getPdfData(file: File) {
  try {
    const arrayBuffer = await file.arrayBuffer();
    const text = await pdfToText(new Uint8Array(arrayBuffer));
    return text;
  } catch (error) {
    console.error("Error extracting PDF content:", error);
    throw error;
  }
}