<template>
  <view class="easy-scancode" v-if="show">
    <view id="reader"></view>
	<view class="scan-back">
		<button class="action-btn" @tap="stop">返回</button>
	</view>
    <!-- 扫码提示区域 -->
    <view class="scan-tip-overlay">
      <view class="scan-tip"> 请将二维码放入框内 </view>
    </view>
  </view>
</template>

<script>
import { Html5Qrcode } from "html5-qrcode";
export default {
  name: "easy-scancode",
  data() {
    return {
      options: {
        success: () => {},
        fail: () => {},
      },
      show: false,
      html5QrCode: null,
    };
  },
  methods: {
    start(options) {
      this.options = options;
      // #ifdef H5
      // 检查摄像头权限
      if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
        navigator.mediaDevices
          .getUserMedia({
            video: true,
          })
          .then((stream) => {
            // 获得权限后关闭流
            stream.getTracks().forEach((track) => track.stop());
            this.show = true;
            // 有权限后调用扫码
            this.getCameras();
          })
          .catch((err) => {
            // 用户拒绝了权限
            uni.showToast({
              title: "请允许使用摄像头权限！",
              icon: "none",
            });
            this.options.fail("未获得摄像头权限");
          });
      } else {
        uni.showToast({
          title: "您的浏览器不支持访问摄像头",
          icon: "none",
        });
        this.options.fail("浏览器不支持访问摄像头");
      }
      return;
      // #endif
      // 其他环境
      uni.scanCode({
        onlyFromCamera: true,
        success: (res) => {
          this.options.success(res.result, res);
        },
        fail: (rej) => {
          this.options.fail("扫码失败");
        },
      });
    },
    stop() {
      this.show = false;
      let that = this;
	  if(this.html5QrCode){
		  this.html5QrCode
		    .stop()
		    .then((ignore) => {
		      // 二维码扫描已停止
		      console.log("二维码扫描已停止");
		    })
		    .catch((err) => {
		      // 停止失败，处理错误
		      console.log("无法停止扫描");
		    });
	  }
       
    },
    getCameras() {
      let that = this;
      Html5Qrcode.getCameras()
        .then((devices) => {
          // console.log(devices)
          that.html5QrCode = new Html5Qrcode("reader");

          let windowInfo = uni.getWindowInfo();
          // console.log(windowInfo);
          const width = windowInfo&&windowInfo.windowWidth?windowInfo.windowWidth:375;
          const height = windowInfo&&windowInfo.windowHeight?windowInfo.windowHeight:720; 
		  
          // 横屏
          const aspectRatio = width / height;
          // 竖屏
          const reverseAspectRatio = height / width;

          const mobileAspectRatio =
            reverseAspectRatio > 1.5
              ? reverseAspectRatio + (reverseAspectRatio * 12) / 100
              : reverseAspectRatio;

          if (devices && devices.length) {
            let cameraId = "";
            if (devices.length > 1) {
              cameraId = devices[1].id;
            } else {
              cameraId = devices[0].id;
            }
            // 计算二维码扫描框大小 - 使用宽度/高度中较小的值来确保方框适合屏幕
            // 并在扫描区域周围留出一些边距
            const qrboxSize = Math.min(width, height) * 0.7;
            console.log(qrboxSize);
            // 使用这个来开始扫描
            that.html5QrCode
              .start(
                {
                  facingMode: "environment",
                },
                {
                  fps: 10, // 可选，二维码扫描的每秒帧数
                  aspectRatio: aspectRatio,
                  qrbox: { width: qrboxSize, height: qrboxSize }, // 可选，如果你想要边界框UI
                  videoConstraints: {
                    facingMode: "environment",
                    aspectRatio: width < 600 ? mobileAspectRatio : aspectRatio,
                  },
				  autofocus:true,  //自动对焦  但使用的时候没有体会到
				                  colorDark: '#0000ff',  //加深二维码黑色部分的颜色提高识别度
				                  colorLight: '#ffffff',//这个应该是提高非黑即白部分的亮度  提高识别度
				                  visualFeedback:true, //开启视觉反馈  没有体会到
				                  halfSample:true,//缩小二维码提高识别精度吧
                },
                (decodedText, decodedResult) => {
                  // 当码被读取时执行操作
                  console.log("decodedText", decodedText);
                  that.options.success(decodedText.replace('\r','').replace('\n',''), decodedResult);
                  that.stop();
                },
                (errorMessage) => {
                  // 解析错误，忽略它
                  // console.log('解析错误，忽略它', errorMessage)
                }
              )
              .catch((err) => {
                // 启动失败，处理它
                console.log("启动失败，需要处理");
                that.options.fail(err);
                this.show = false;
              });
          }
        })
        .catch((err) => {
          // 处理错误
          console.log(err);
          that.options.fail(err);
          this.show = false;
        });
    },
  },
  // beforeDestroy() {
  // 	this.stop();
  // }
};
</script>
<style lang="scss" scoped>
.easy-scancode {
  width: 100vw;
  height: 100vh;
  position: fixed;
  z-index: 1000;
  top: 0;
  left: 0;
  background-color: rgba(0, 0, 0, 0.5);
}

#reader {
  top: 50%;
  left: 0;
  transform: translateY(-50%);
  width: 100vw;
  height: 100vh;
}

.scan-tip-overlay {
	position: absolute;
	top: 0;
	left: 0;
	width: 100%;
	height: 100%;
	z-index: 10000;
	background: rgba(0, 0, 0, 0.1);
	pointer-events: none; /* 不阻挡摄像头画面 */
}

.scan-tip {
	position: absolute;
	top: 74%;
	left: 50%;
	transform: translateX(-50%);
	color: #fff;
	font-size: 16px;
	text-align: center;
	z-index: 10001;
	background: rgba(0, 0, 0, 0.5);
	padding: 10px 20px;
	border-radius: 5px;
}
.scan-back{
	position: absolute;
	top: calc(100vh - 100px );
	left: 50%;
	transform: translateX(-50%);
	color: #fff;
	font-size: 16px;
	text-align: center;
	z-index: 10001;
	padding: 10px;
	border-radius: 5px;
}
</style>
