import html2canvas from 'html2canvas';
import jsPDF from 'jspdf';
import caseApi from "@/api/lawenforcement/Case.js";
import {ElMessage} from "element-plus";

/**
 * 用Vue组件设计HTML模板
 * 将HTML转换为Canvas
 * 将Canvas插入PDF并下载
 * @param pdfTemplate 导出区域div ref
 * @param fileName 导出的pdf文件名
 * @returns {Promise<void>}
 */
const exportPDF = async (pdfTemplate,fileName) => {
  try {
    const element = pdfTemplate.value;
    const canvas = await html2canvas(element, { scale: 2, onclone: (clonedDoc) => {
        clonedDoc.querySelectorAll('*').forEach(el => {
          el.style.transform = 'translateZ(0)'; // 强制 GPU 渲染
        });
      } }); // 提高分辨率
    const imgData = canvas.toDataURL('image/jpeg', 0.8);

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

    // 添加图片到PDF（自动分页）
    let heightLeft = imgHeight;
    let position = 0;

    pdf.addImage(imgData, 'JPEG', 0, position, pageWidth, imgHeight);
    heightLeft -= pageHeight;

    while (heightLeft >= 0) {
      position = heightLeft - imgHeight;
      pdf.addPage();
      pdf.addImage(imgData, 'JPEG', 0, position, pageWidth, imgHeight);
      heightLeft -= pageHeight;
    }

    // 返回 Promise 包装的导出结果
    return new Promise((resolve, reject) => {
      try {
        pdf.save(fileName);
        // 假设浏览器在 500ms 内触发下载（根据实际情况调整时间）
        setTimeout(() => {
          resolve({ success: true, message: 'PDF导出成功！' });
        }, 500);
      } catch (error) {
        reject({ success: false, message: '导出失败：' + error.message });
      }
    });
  } catch (error) {
    return Promise.reject({ success: false, message: '生成PDF出错：' + error.message });
  }
}
export { exportPDF }