<template>
  <div
    ref="floatDrag"
    class="float-position"
    :style="{ left: left + 'px', top: top + 'px', zIndex: zIndex }"
    @touchmove.prevent
    @mousemove.prevent
    @mousedown="mouseDown"
    @mouseup="mouseUp"
  >
    <div id="side-windows">
      <div class="shrink">
      <div class="problem-feedback" @click.stop="showDialog()">
        <img :src="feedback" alt="" />
        <p>問題<br />反饋</p>
      </div>
      </div>
    </div>
  </div>
</template>

<script>
export default {
  name: "DragBall",
  props: {
    distanceRight: { // 初始化定位
      type: Number,
      default: 0
    },
    distanceBottom: { // 初始化定位
      type: Number,
      default: 100
    },
    isScrollHidden: { //滾動是否 隱藏
      type: Boolean,
      default: false
    },
    isCanDraggable: { //是否允許拖拽
      type: Boolean,
      default: true
    },
    zIndex: { // 初始化層級
      type: Number,
      default: 50
    },
    value: {
      type: String,
      default: "懸?。?
    }
  },
  //data 域
  data() {
    return {
      clientWidth: null,
      clientHeight: null,
      left: 0,
      top: 0,
      timer: null,
      currentTop: 0,
      mousedownX: 0,
      mousedownY: 0,
      feedback: require('') // 問題
    };
  },
  created() {
    this.clientWidth = document.documentElement.clientWidth;
    this.clientHeight = document.documentElement.clientHeight;
  },
  mounted() {
    this.isCanDraggable &&
      this.$nextTick(() => {
        this.floatDrag = this.$refs.floatDrag;
        // 獲取元素位置屬性
        this.floatDragDom = this.floatDrag.getBoundingClientRect();
        // 設(shè)置初始位置
        this.left =
          this.clientWidth - this.floatDragDom.width - this.distanceRight;
        this.top =
          this.clientHeight - this.floatDragDom.height - this.distanceBottom;
        this.initDraggable();
      });
    this.isScrollHidden && window.addEventListener("scroll", this.handleScroll);
    window.addEventListener("resize", this.handleResize);
  },
  methods: {
      showDialog() {
        let url
        window.open(url, '_blank')
      },
    /**
     * 設(shè)置滾動時隱藏懸浮按鈕，停止時顯示
     */
    handleScroll() {
      this.timer && clearTimeout(this.timer);
      this.timer = setTimeout(() => {
        this.handleScrollEnd();
      }, 200);
      this.currentTop =
        document.documentElement.scrollTop || document.body.scrollTop;
      if (this.left > this.clientWidth / 2) {
        // 判斷元素位置再左側(cè)還是右側(cè)
        this.left = this.clientWidth + this.floatDragDom.width;
      } else {
        this.left = -this.floatDragDom.width;
      }
    },
    /**
     * 滾動結(jié)束
     */
    handleScrollEnd() {
      let scrollTop =
        document.documentElement.scrollTop || document.body.scrollTop;
      if (scrollTop === this.currentTop) {
        console.log(this.left);
        if (this.left > this.clientWidth / 2) {
          // 判斷元素位置
          this.left = this.clientWidth - this.floatDragDom.width;
        } else {
          this.left = 0;
        }
        clearTimeout(this.timer);
      }
    },
    /**
     * 窗口監(jiān)聽
     */
    handleResize() {
      this.clientWidth = document.documentElement.clientWidth;
      this.clientHeight = document.documentElement.clientHeight;
      this.checkDraggablePosition();
    },
    /**
     * 初始化
     */
    initDraggable() {
      this.floatDrag.addEventListener("touchstart", this.toucheStart);
      this.floatDrag.addEventListener("touchmove", e => this.touchMove(e));
      this.floatDrag.addEventListener("touchend", this.touchEnd);
    },
    mouseDown(e) {
      const event = e || window.event;
      this.mousedownX = event.screenX;
      this.mousedownY = event.screenY;
      const that = this;
      let floatDragWidth = this.floatDragDom.width / 2;
      let floatDragHeight = this.floatDragDom.height / 2;
      if (event.preventDefault) {
        event.preventDefault();
      }
      this.canClick = false;
      this.floatDrag.style.transition = "none";
      setTimeout(() => {
        document.onmousemove = function(e) {
            var event = e || window.event;
            that.left = event.clientX - floatDragWidth;
            that.top = event.clientY - floatDragHeight;
            if (that.left < 0) that.left = 0;
            if (that.top < 0) that.top = 0;
            if (that.left >= that.clientWidth - floatDragWidth * 2) {
                that.left = that.clientWidth - floatDragWidth * 2;
            }
            if (that.top >= that.clientHeight - floatDragHeight * 2) {
                that.top = that.clientHeight - floatDragHeight * 2;
            }
            // 解決鼠標(biāo)移出窗口 松開鼠標(biāo)后 回到窗口內(nèi) 懸浮繼續(xù)跟隨問題
            if(event.clientX<=0 || event.clientY<=0 ||  event.clientY>= that.clientHeight || event.clientX>= that.clientWidth){
                that.mouseUp(event)
            }
        };
      }, 20);
    },
    mouseUp(e) {
      const event = e || window.event;
      //判斷只是單純的點(diǎn)擊，沒有拖拽
      if (
        this.mousedownY == event.screenY &&
        this.mousedownX == event.screenX
      ) {
        this.$emit("handlepaly");
      }
      document.onmousemove = null;
      this.checkDraggablePosition();
      this.floatDrag.style.transition = "all 0.3s";
    },
    toucheStart() {
      this.canClick = false;
      this.floatDrag.style.transition = "none";
    },
    touchMove(e) {
      this.canClick = true;
      if (e.targetTouches.length === 1) {
        let touch = event.targetTouches[0];
        this.left = touch.clientX - this.floatDragDom.width / 2;
        this.top = touch.clientY - this.floatDragDom.height / 2;
      }
    },
    touchEnd() {
      if (!this.canClick) return; // 解決點(diǎn)擊事件和touch事件沖突的問題
      this.floatDrag.style.transition = "all 0.3s";
      this.checkDraggablePosition();
    },
    /**
     * 判斷元素顯示位置
     * 在窗口改變和move end時調(diào)用
     */
    checkDraggablePosition() {
      let details = document.querySelector('.details')
      if (this.left + this.floatDragDom.width / 2 >= this.clientWidth / 2) {
        // 判斷位置是往左往右滑動
        this.left = this.clientWidth - this.floatDragDom.width;
        details.style.right = '56px'
      } else {
        this.left = 0;
        details.style.right = '-233px'
      }
      if (this.top < 0) {
        // 判斷是否超出屏幕上沿
        this.top = 0;
      }
      if (this.top + this.floatDragDom.height >= this.clientHeight) {
        // 判斷是否超出屏幕下沿
        this.top = this.clientHeight - this.floatDragDom.height;
      }
    }
  },
  beforeDestroy() {
    window.removeEventListener("scroll", this.handleScroll);
    window.removeEventListener("resize", this.handleResize);
  }
};
</script>

<style lang="less" scoped>
.float-position{
  font-size: 12px;
  position: fixed;
  z-index: 500!important;
  right: 0;
  top: 50%;
  width: 48px;
  height: 168px;
  display: flex;
  align-items: center;
  justify-content: center;
  user-select: none;
}
</style>