<!--
import verifyCode from '@/components/common/verify-code.vue';
<verifyCode></verifyCode>
components: {
  verifyCode
}
-->
<template>
  <div class="verify-canvas" @click="getVerifyCode">
    <canvas id="verify-canvas" :width="contentWidth" :height="contentHeight"></canvas>
  </div>
</template>
<script>
import { getRequest } from '@/api/api';
import errMsg from '@/common/js/error';
export default {
  name: 'verify-code',
  props: {
    fontSizeMin: {
      type: Number,
      default: 16
    },
    fontSizeMax: {
      type: Number,
      default: 40
    },
    backgroundColorMin: {
      type: Number,
      default: 180
    },
    backgroundColorMax: {
      type: Number,
      default: 240
    },
    colorMin: {
      type: Number,
      default: 50
    },
    colorMax: {
      type: Number,
      default: 160
    },
    lineColorMin: {
      type: Number,
      default: 40
    },
    lineColorMax: {
      type: Number,
      default: 180
    },
    dotColorMin: {
      type: Number,
      default: 0
    },
    dotColorMax: {
      type: Number,
      default: 255
    },
    contentWidth: {
      type: Number,
      default: 112
    },
    contentHeight: {
      type: Number,
      default: 38
    }
  },
  data() {
    return {
      identifyCode: ''
    };
  },
  methods: {
    // 生成一个随机数
    randomNum(min, max) {
      return Math.floor(Math.random() * (max - min) + min);
    },
    // 生成一个随机的颜色
    randomColor(min, max) {
      let r = this.randomNum(min, max);
      let g = this.randomNum(min, max);
      let b = this.randomNum(min, max);
      return 'rgb(' + r + ',' + g + ',' + b + ')';
    },
    drawPic() {
      let canvas = document.getElementById('verify-canvas');
      let ctx = canvas.getContext('2d');
      ctx.textBaseline = 'bottom';
      // 绘制背景
      ctx.fillStyle = this.randomColor(this.backgroundColorMin, this.backgroundColorMax);
      ctx.fillRect(0, 0, this.contentWidth, this.contentHeight);
      // 绘制文字
      for (let i = 0; i < this.identifyCode.length; i++) {
        this.drawText(ctx, this.identifyCode[i], i);
      }
      this.drawLine(ctx);
      this.drawDot(ctx);
    },
    drawText(ctx, txt, i) {
      ctx.fillStyle = this.randomColor(this.colorMin, this.colorMax);
      ctx.font = this.randomNum(this.fontSizeMin, this.fontSizeMax) + 'px SimHei';
      let x = (i + 1) * (this.contentWidth / (this.identifyCode.length + 1));
      let y = this.randomNum(this.fontSizeMax, this.contentHeight - 5);
      var deg = this.randomNum(-45, 45);
      // 修改坐标原点和旋转角度
      ctx.translate(x, y);
      ctx.rotate((deg * Math.PI) / 180);
      ctx.fillText(txt, 0, 0);
      // 恢复坐标原点和旋转角度
      ctx.rotate((-deg * Math.PI) / 180);
      ctx.translate(-x, -y);
    },
    drawLine(ctx) {
      // 绘制干扰线
      for (let i = 0; i < 8; i++) {
        ctx.strokeStyle = this.randomColor(this.lineColorMin, this.lineColorMax);
        ctx.beginPath();
        ctx.moveTo(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight));
        ctx.lineTo(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight));
        ctx.stroke();
      }
    },
    drawDot(ctx) {
      // 绘制干扰点
      for (let i = 0; i < 100; i++) {
        ctx.fillStyle = this.randomColor(0, 255);
        ctx.beginPath();
        ctx.arc(this.randomNum(0, this.contentWidth), this.randomNum(0, this.contentHeight), 1, 0, 2 * Math.PI);
        ctx.fill();
      }
    },

    /**
     * 获取验证码
     */
    getVerifyCode() {
      const that = this;
      getRequest('/haoban-manage-web/get-pic-code', {})
        .then(res => {
          let resData = res.data;
          if (resData.errorCode == 1) {
            that.identifyCode = resData.result;
            that.$emit('changeCode', that.identifyCode);
            that.drawPic();
            return;
          }
          errMsg.errorMsg(resData);
        })
        .catch(function(error) {
          that.$message.error({
            duration: 1000,
            message: error.message
          });
        });
    }
  },
  mounted() {
    this.getVerifyCode();
  }
};
</script>
<style lang="less" scoped>
.verify-canvas {
  display: inline-block;
  vertical-align: top;
  padding-left: 10px;
  cursor: pointer;
  canvas {
    border-radius: 4px;
  }
}
</style>
