<template>
  <el-dialog
    :class="[prefixCls, 'opacity-dialog']"
    :visible.sync="modalIsShow"
    title="图片预览"
    fullscreen
    append-to-body
    :close-on-click-modal="false"
    :close-on-press-escape="false"
  >
    <div slot="title"></div>
    <div slot="footer"></div>
    <div :class="[`${prefixCls}-close`]" @click="cancel">
      <i class="el-icon-circle-close"></i>
    </div>

    <div :class="[`${prefixCls}-body`]" ref="ReviewBody">
      <div
        v-if="!simple"
        :class="[`${prefixCls}-guide`, `${prefixCls}-guide-prev`]"
        @click.stop="showPrev"
      >
        <i class="el-icon-arrow-left"></i>
      </div>
      <div
        v-if="!simple"
        :class="[`${prefixCls}-guide`, `${prefixCls}-guide-next`]"
        @click.stop="showNext"
      >
        <i class="el-icon-arrow-right"></i>
      </div>
      <div
        :class="[
          `${prefixCls}-imgs`,
          { [`${prefixCls}-imgs-nosition`]: nosition }
        ]"
        :style="styles"
        v-if="modalIsShow"
      >
        <img
          :key="curImage.url"
          :src="curImage.url"
          :alt="curImage.filename"
          ref="PreviewImgDetail"
          @load="reizeImage"
        />
      </div>
      <div :class="[`${prefixCls}-none`]" v-if="!curImage.url">
        <i class="el-icon-picture"></i>
        <p>暂无数据</p>
      </div>

      <div :class="[`${prefixCls}-loading`]" v-show="loading">
        <i class="el-icon-loading"></i>
      </div>
    </div>

    <div v-if="!simple" :class="[`${prefixCls}-footer`]">
      <ul>
        <li title="旋转" @click.stop="toRotate">
          <i class="el-icon-refresh-right"></i>
        </li>
      </ul>
    </div>
  </el-dialog>
</template>

<script>
const prefixCls = "cc-image-preview";

export default {
  name: "simple-image-preview",
  props: {
    curImage: {
      type: Object,
      default() {
        return {};
      }
    },
    simple: {
      type: Boolean,
      default: false
    }
  },
  data() {
    return {
      prefixCls,
      modalIsShow: false,
      styles: { width: "", height: "", top: "", left: "", transform: "" },
      initWidth: 500,
      transform: {
        scale: 1,
        rotate: 0
      },
      loading: false,
      loadingSetT: null,
      nosition: false
    };
  },
  watch: {
    "curImage.url": {
      handler(val) {
        if (val) {
          this.loadingSetT = setTimeout(() => {
            this.loading = true;
          }, 300);
          this.styles = {
            width: "",
            height: "",
            top: "",
            left: "",
            transform: ""
          };
        }
      }
    }
  },
  methods: {
    reizeImage() {
      if (this.loadingSetT) clearTimeout(this.loadingSetT);

      const imgDom = this.$refs.PreviewImgDetail;
      const { naturalWidth, naturalHeight } = imgDom;
      const imageSize = this.getImageSizePos({
        win: {
          width: this.$refs.ReviewBody.clientWidth,
          height: this.$refs.ReviewBody.clientHeight
        },
        img: {
          width: naturalWidth,
          height: naturalHeight
        },
        rotate: 0
      });

      this.styles = Object.assign(this.styles, {
        width: imageSize.width + "px",
        height: imageSize.height + "px",
        top: imageSize.top + "px",
        left: imageSize.left + "px",
        marginLeft: "auto",
        transform: "none"
      });
      this.transform = {
        scale: 1,
        rotate: 0
      };
      this.loading = false;
      setTimeout(() => {
        this.nosition = false;
      }, 100);
    },
    getImageSizePos({ win, img, rotate }) {
      const imageSize = {
        width: 0,
        height: 0,
        top: 0,
        left: 0
      };
      const isHorizontal = !!(rotate % 180);

      const rateWin = isHorizontal
        ? win.height / win.width
        : win.width / win.height;
      const hwin = isHorizontal
        ? {
            width: win.height,
            height: win.width
          }
        : win;

      const rateImg = img.width / img.height;

      if (rateImg <= rateWin) {
        imageSize.height = Math.min(hwin.height, img.height);
        imageSize.width = Math.floor(
          (imageSize.height * img.width) / img.height
        );
      } else {
        imageSize.width = Math.min(hwin.width, img.width);
        imageSize.height = Math.floor(
          (imageSize.width * img.height) / img.width
        );
      }
      imageSize.left = (win.width - imageSize.width) / 2;
      imageSize.top = (win.height - imageSize.height) / 2;
      return imageSize;
    },
    cancel() {
      this.modalIsShow = false;
      this.$emit("on-close");
    },
    open() {
      this.modalIsShow = true;
    },
    showPrev() {
      this.$emit("on-prev");
      // this.initData();
    },
    showNext() {
      this.$emit("on-next");
      // this.initData();
    },
    // dome-move
    setStyleTransform() {
      const { scale, rotate } = this.transform;
      this.styles.transform = `scale(${scale}, ${scale}) rotate(${rotate}deg)`;
    },
    toRotate() {
      this.transform.rotate = this.transform.rotate + 90;
      this.setStyleTransform();
      // 调整图片尺寸
      const { naturalWidth, naturalHeight } = this.$refs.PreviewImgDetail;
      const imageSize = this.getImageSizePos({
        win: {
          width: this.$refs.ReviewBody.clientWidth,
          height: this.$refs.ReviewBody.clientHeight
        },
        img: {
          width: naturalWidth,
          height: naturalHeight
        },
        rotate: this.transform.rotate
      });

      this.styles = Object.assign(this.styles, {
        width: imageSize.width + "px",
        height: imageSize.height + "px",
        top: imageSize.top + "px",
        left: imageSize.left + "px"
      });
      // 360度无缝切换到0度
      if (this.transform.rotate >= 360) {
        setTimeout(() => {
          this.nosition = true;
          this.transform.rotate = 0;
          this.setStyleTransform();
          setTimeout(() => {
            this.nosition = false;
          }, 100);
        }, 200);
        // 200ms当次旋转动画持续时间
      }
    }
  }
};
</script>
