<template>
  <div class="label-render-container">
    <!-- 标签预览容器 -->
    <div class="preview-container" id="label-preview-container" ref="labelRef">
      <ProductionTagPreview
        v-if="labelType === '2'"
        :content="content"
        :paperWidthMm="100"
        :paperHeightMm="80"
      />
      <OuterTagPreview
        v-if="labelType === '3'"
        :content="content"
        :paperWidthMm="180"
        :paperHeightMm="100"
      />
      <SampleTagPreview v-if="labelType === '4'" :content="content" />
      <ForgeTagPreview v-if="labelType === '5'" :content="content" />
      <SaltSprayTagPreview v-if="labelType === '6'" :content="content" />
    </div>
    <div class="action-buttons">
      <el-button type="primary" @click="downloadLabelAsImage">下载标签图片</el-button>
      <el-button type="primary" @click="printLabel" style="margin-left: 10px;">打印标签</el-button>
    </div>
  </div>
</template>

<script>
import domToImage from 'dom-to-image';
// import printJS from 'print-js'; // 改为自建 iframe 打印，避免多余空白页
import html2canvas from 'html2canvas'; // 新增：引入高清渲染库
import { Message } from 'element-ui';

import ProductionTagPreview from './ProductionTagPreview.vue';
import OuterTagPreview from './OuterTagPreview.vue';
import SampleTagPreview from './SampleTagPreview.vue';
import ForgeTagPreview from './ForgeTagPreview.vue';
import SaltSprayTagPreview from './SaltSprayTagPreview.vue';

export default {
  name: 'LabelRender',
  components: {
    ProductionTagPreview,
    OuterTagPreview,
    SampleTagPreview,
    ForgeTagPreview,
    SaltSprayTagPreview,
  },
  props: {
    labelType: {
      type: String,
      required: true,
    },
    content: {
      type: Object,
      required: true,
    },
  },
  methods: {
    // -------- 图片下载方法（保留，可按需替换为html2canvas） --------
    async downloadLabelAsImage() {
      const labelContainer = document.getElementById('label-preview-container');
      if (!labelContainer) {
        Message.error('未找到标签容器，无法下载');
        return;
      }

      try {
        // 可选：也替换为html2canvas提升下载清晰度
        // const canvas = await html2canvas(labelContainer, { scale: 3, backgroundColor: '#ffffff', allowTaint: true, taintTest: false });
        // const dataUrl = canvas.toDataURL('image/png', 1.0);
        const dataUrl = await domToImage.toPng(labelContainer);
        
        const downloadLink = document.createElement('a');
        downloadLink.href = dataUrl;
        downloadLink.download = `标签_${new Date().getTime()}.png`;
        document.body.appendChild(downloadLink);
        downloadLink.click();
        document.body.removeChild(downloadLink);
      } catch (error) {
        console.error('标签图片下载失败：', error);
        Message.error('标签图片下载失败，请重试');
      }
    },

    // -------- 重构后的打印方法（核心优化） --------
    async printLabel() {
      // 1. 获取标签容器DOM
      const labelContainer = document.querySelector('.label-container') || 
                            document.querySelector('.material-label-container');
      if (!labelContainer) {
        Message.error('未找到标签容器，无法打印');
        return;
      }

      try {
        Message.info('正在准备打印内容，请稍等...');
        
        // 2. 等待二维码/字体等资源加载完成（复用之前的等待逻辑）
        await this.waitForAllResources(labelContainer);

        // 3. 计算纸张尺寸和缩放比例
        // 根据标签类型设置纸张尺寸：
        // 产品码：100mm x 180mm（横向，原先180x100）
        // 原料码：80mm x 100mm（竖向）
        const isMaterial = labelContainer.classList.contains('material-label-container');
        const paperWidthMm = isMaterial ? 100 : 180;
        const paperHeightMm = isMaterial ? 80 : 100;
        const dpi = 96;
        const mmToPx = dpi / 25.4;
        const paperWidthPx = paperWidthMm * mmToPx;
        const paperHeightPx = paperHeightMm * mmToPx;

        // 获取标签容器的实际尺寸
        const containerRect = labelContainer.getBoundingClientRect();
        const containerWidth = containerRect.width;
        const containerHeight = containerRect.height;

        // 计算缩放比例，确保内容适配到纸张（留出2mm边距）
        const marginMm = 2;
        const marginPx = marginMm * mmToPx;
        const availableWidth = paperWidthPx - marginPx * 2;
        const availableHeight = paperHeightPx - marginPx * 2;
        
        const scaleX = containerWidth > 0 ? availableWidth / containerWidth : 1;
        const scaleY = containerHeight > 0 ? availableHeight / containerHeight : 1;
        const printScale = Math.min(scaleX, scaleY, 1); // 不超过1，不放大

        // 计算最终Canvas尺寸（适配纸张）
        const finalCanvasWidth = containerWidth * printScale;
        const finalCanvasHeight = containerHeight * printScale;
        
        // 使用合适的scale值生成高清Canvas（但不超过纸张尺寸）
        const canvasScale = Math.min(1.5, printScale * 1.5); // 确保不超过纸张

        // 4. 用html2canvas生成高清Canvas（解决文字模糊+二维码丢失）
        const canvas = await html2canvas(labelContainer, {
          scale: canvasScale,
          backgroundColor: '#ffffff', // 强制白色背景，避免打印时背景透明
          useCORS: true, // 支持跨域图片
          allowTaint: true, // 允许渲染canvas（二维码）
          taintTest: false, // 关闭canvas污染检测
          width: containerWidth,
          height: containerHeight,
          logging: false,
        });

        // 5. 如果Canvas尺寸超出纸张，需要缩放Canvas
        let finalCanvas = canvas;
        if (canvas.width > paperWidthPx || canvas.height > paperHeightPx) {
          // 创建新的Canvas，尺寸适配纸张
          const scaledCanvas = document.createElement('canvas');
          scaledCanvas.width = Math.min(canvas.width, paperWidthPx);
          scaledCanvas.height = Math.min(canvas.height, paperHeightPx);
          const ctx = scaledCanvas.getContext('2d');
          ctx.drawImage(canvas, 0, 0, scaledCanvas.width, scaledCanvas.height);
          finalCanvas = scaledCanvas;
        }

        // 6. 生成 DataURL，使用 printJS 的 image 模式（单图），并减少额外样式以避免隐藏内容
        const dataUrl = finalCanvas.toDataURL('image/png');

        // 6. 创建隐藏 iframe 进行打印，避免 printJS 的分页行为
        const iframe = document.createElement('iframe');
        iframe.style.position = 'fixed';
        iframe.style.right = '0';
        iframe.style.bottom = '0';
        iframe.style.width = '0';
        iframe.style.height = '0';
        iframe.style.border = '0';
        document.body.appendChild(iframe);

        const doc = iframe.contentWindow.document;
        doc.open();
        doc.write(`
          <!doctype html>
          <html>
            <head>
              <style>
                @page {
                  size: ${paperWidthMm}mm ${paperHeightMm}mm;
                  margin: 2mm;
                }
                * {
                  -webkit-print-color-adjust: exact;
                  print-color-adjust: exact;
                  box-sizing: border-box;
                }
                html, body {
                  margin: 0;
                  padding: 0;
                  width: 100%;
                  height: 100%;
                  overflow: hidden;
                }
                body {
                  display: flex;
                  align-items: center;
                  justify-content: center;
                }
                img {
                  width: calc(100% - 4mm);
                  height: calc(100% - 4mm);
                  object-fit: contain;
                  display: block;
                  page-break-after: avoid;
                  page-break-before: avoid;
                  page-break-inside: avoid;
                }
              </style>
            </head>
            <body>
              <img src="${dataUrl}" />
            </body>
          </html>
        `);
        doc.close();

        iframe.onload = () => {
          setTimeout(() => {
            iframe.contentWindow.focus();
            iframe.contentWindow.print();
            setTimeout(() => {
              document.body.removeChild(iframe);
            }, 1000);
          }, 300);
        };
      } catch (error) {
        console.error('打印准备失败:', error);
        Message.error('打印内容准备失败，请重试');
      }
    },

    // -------- 辅助方法：等待所有资源加载（图片+字体+二维码） --------
    async waitForAllResources(element) {
      // 等待图片加载
      const images = element.querySelectorAll('img');
      const imgPromises = Array.from(images).map(img => 
        img.complete ? Promise.resolve() : new Promise(resolve => {
          img.onload = resolve;
          img.onerror = resolve;
        })
      );
      await Promise.all(imgPromises);

      // 等待字体加载
      await document.fonts.ready;

      // 等待二维码Canvas渲染
      await this.waitForQRCodeRender(element);

      // 最终等待样式稳定
      await new Promise(resolve => setTimeout(resolve, 300));
    },

    // -------- 辅助方法：等待二维码Canvas渲染完成 --------
    async waitForQRCodeRender(element) {
      const qrCanvasList = element.querySelectorAll('canvas');
      if (qrCanvasList.length === 0) return;

      const qrLoadPromises = Array.from(qrCanvasList).map(canvas => {
        return new Promise(resolve => {
          const checkInterval = setInterval(() => {
            const ctx = canvas.getContext('2d');
            if (!ctx) {
              clearInterval(checkInterval);
              resolve();
              return;
            }
            const imageData = ctx.getImageData(0, 0, canvas.width, canvas.height);
            const hasContent = imageData.data.some(value => value !== 0);
            if (hasContent || Date.now() - (ctx.startTime || 0) > 2000) {
              clearInterval(checkInterval);
              resolve();
            }
          }, 100);
        });
      });
      await Promise.all(qrLoadPromises);
    }
  },
};
</script>

<style scoped>
.label-render-container {
  width: 100%;
  display: flex;
  flex-direction: column;
  justify-content: flex-start;
  align-items: center;
  /* padding: 1rem; */
  box-sizing: border-box;
}

.action-buttons {
  margin-top: 1rem;
}

.preview-container {
  background-color: #fff;
  color: #000;
  /* padding: 1.5rem; */
  width: fit-content;
  /* min-width: 200px; */
  box-shadow: 0 0 60px rgba(255, 255, 255, 0.2);
  /* border: 1px solid rgba(255, 255, 255, 0.1); */
  overflow: hidden;
  transition: all 0.3s ease;
}

.preview-container:hover {
  box-shadow: 0 0 80px rgba(255, 255, 255, 0.3);
  transform: translateY(-2px);
}

/* 强制二维码Canvas可见，避免渲染丢失 */
:deep(canvas) {
  display: block;
  visibility: visible;
  opacity: 1;
}

/* 字体平滑，提升文字清晰度 */
:deep(.preview-container) {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-smooth: always;
}
</style>