<template>
  <div
    class="demo-block"
    :class="[blockClass, { hover: hovering }]"
    @mouseenter="hovering = true"
    @mouseleave="hovering = false"
  >
    <div class="demo-content">
      <slot name="demo"></slot>
    </div>
    <div class="meta" ref="meta">
      <div class="description" v-if="$slots.description">
        <slot name="description"></slot>
      </div>
      <div class="code-content">
        <slot name="source"></slot>
      </div>
    </div>
    <div
      class="demo-block-control"
      :class="{ 'is-fixed': fixedControl }"
      :style="{ width: fixedControl ? `${codeContentWidth}px` : 'unset' }"
      ref="control"
      @click="isExpanded = !isExpanded"
    >
      <transition name="arrow-slide">
        <i :class="[iconClass, { hovering: hovering }, 'icon']"></i>
      </transition>
      <transition name="text-slide">
        <span v-show="hovering">{{ controlText }}</span>
      </transition>
      <span
        v-show="!copied"
        :class="['copy-action', { 'copying ': copied }]"
        @click.stop="copyCode"
        >{{ copiedText }}</span
      >
      <transition name="bounce">
        <span v-show="copied" class="copy-action copy-action-success">{{ copiedText }}</span>
      </transition>
    </div>
  </div>
</template>

<script type="text/babel">
  export default {
    name: 'DemoBlock',
    data() {
      return {
        hovering: false,
        copied: false,
        isExpanded: false,
        fixedControl: false,
        codeContentWidth: 0,
        scrollParent: null
      };
    },
    props: {
      options: {
        type: Object,
        default: () => {
          return {};
        }
      }
    },
    computed: {
      compoLang() {
        return this.options.locales;
      },
      langConfig() {
        return this.compoLang.filter((config) => config.lang === this.$lang)[0]['demo-block'];
      },
      blockClass() {
        return `demo-${this.$lang} demo-${this.$router.currentRoute.path.split('/').pop()}`;
      },
      iconClass() {
        return this.isExpanded ? 'caret-top' : 'caret-bottom';
      },
      controlText() {
        return this.isExpanded ? this.langConfig['hide-text'] : this.langConfig['show-text'];
      },
      copiedText() {
        return this.copied ? this.langConfig['copy-success'] : this.langConfig['copy-text'];
      },
      codeArea() {
        return this.$el.getElementsByClassName('meta')[0];
      },
      codeAreaHeight() {
        if (this.$el.getElementsByClassName('description').length > 0) {
          return (
            this.$el.getElementsByClassName('description')[0].clientHeight +
            this.$el.getElementsByClassName('code-content')[0].clientHeight +
            20
          );
        }
        return this.$el.getElementsByClassName('code-content')[0].clientHeight;
      }
    },
    methods: {
      copyCode() {
        if (this.copied) {
          return;
        }
        const pre = this.$el.querySelectorAll('pre')[0];
        pre.setAttribute('contenteditable', 'true');
        pre.focus();
        document.execCommand('selectAll', false, null);
        this.copied = document.execCommand('copy');
        pre.removeAttribute('contenteditable');
        setTimeout(() => {
          this.copied = false;
        }, 1500);
      },
      scrollHandler() {
        const { top, bottom, left } = this.$refs.meta.getBoundingClientRect();
        this.fixedControl =
          bottom > document.documentElement.clientHeight &&
          top + 44 <= document.documentElement.clientHeight;
        this.$refs.control.style.left = this.fixedControl ? `${left}px` : '0';
      },
      removeScrollHandler() {
        this.scrollParent && this.scrollParent.removeEventListener('scroll', this.scrollHandler);
      }
    },
    watch: {
      isExpanded(val) {
        this.codeArea.style.height = val ? `${this.codeAreaHeight + 1}px` : '0';
        if (!val) {
          this.fixedControl = false;
          this.$refs.control.style.left = '0';
          this.removeScrollHandler();
          return;
        }
        setTimeout(() => {
          this.scrollParent = document;
          this.scrollParent && this.scrollParent.addEventListener('scroll', this.scrollHandler);
          this.scrollHandler();
        }, 200);
      }
    },
    mounted() {
      this.$nextTick(() => {
        let codeContent = this.$el.getElementsByClassName('code-content')[0];
        this.codeContentWidth = this.$el.offsetWidth;
        if (this.$el.getElementsByClassName('description').length === 0) {
          codeContent.style.width = '100%';
          codeContent.borderRight = 'none';
        }
      });
    },
    beforeDestroy() {
      this.removeScrollHandler();
    }
  };
</script>
<style scoped>
  .demo-block {
    border: solid 1px #ebebeb;
    border-radius: 3px;
    transition: 0.2s;
    margin-top: 15px;
    margin-bottom: 15px;
  }
  .demo-block.hover {
    box-shadow: 0 0 8px 0 rgba(232, 237, 250, 0.6), 0 2px 4px 0 rgba(232, 237, 250, 0.5);
  }
  .demo-block code {
    font-family: Menlo, Monaco, Consolas, Courier, monospace;
  }
  .demo-block .demo-button {
    float: right;
  }
  .demo-block .demo-content {
    padding: 24px;
  }
  .demo-block .meta {
    background-color: #282c34;
    border: solid 1px #ebebeb;
    border-radius: 3px;
    overflow: hidden;
    height: 0;
    transition: height 0.2s;
  }
  .demo-block .description {
    padding: 20px;
    box-sizing: border-box;
    border: solid 1px #ebebeb;
    border-radius: 3px;
    font-size: 14px;
    line-height: 22px;
    color: #666;
    word-break: break-word;
    margin: 10px;
    background-color: #fafafa;
  }
  .demo-block .demo-block-control {
    border-top: solid 1px #eaeefb;
    height: 44px;
    box-sizing: border-box;
    background-color: #fafafa;
    border-bottom-left-radius: 4px;
    border-bottom-right-radius: 4px;
    text-align: center;
    margin-top: -1px;
    color: #d3dce6;
    cursor: pointer;
    position: relative;
  }
  .demo-block .demo-block-control.is-fixed {
    position: fixed;
    bottom: 0;
    width: 660px;
    z-index: 999;
  }
  .demo-block .demo-block-control .icon {
    font-family: element-icons !important;
    font-style: normal;
    font-weight: 400;
    font-variant: normal;
    text-transform: none;
    line-height: 1;
    vertical-align: baseline;
    display: inline-block;
    -webkit-font-smoothing: antialiased;
  }
  .demo-block .demo-block-control .caret-top::before {
    content: '';
    position: absolute;
    right: 50%;
    width: 0;
    height: 0;
    border-bottom: 6px solid #ccc;
    border-right: 6px solid transparent;
    border-left: 6px solid transparent;
  }
  .demo-block .demo-block-control .caret-bottom::before {
    content: '';
    position: absolute;
    right: 50%;
    width: 0;
    height: 0;
    border-top: 6px solid #ccc;
    border-right: 6px solid transparent;
    border-left: 6px solid transparent;
  }
  .demo-block .demo-block-control i {
    font-size: 16px;
    line-height: 44px;
    transition: 0.3s;
  }
  .demo-block .demo-block-control i.hovering {
    transform: translateX(-40px);
  }
  .demo-block .demo-block-control > span {
    position: absolute;
    transform: translateX(-30px);
    font-size: 14px;
    line-height: 44px;
    transition: 0.3s;
    display: inline-block;
  }
  .demo-block .demo-block-control .copy-action {
    right: 0px;
    color: #409eff;
  }
  .demo-block .demo-block-control.copying {
    transform: translateX(-44px);
  }
  .demo-block .demo-block-control .copy-action-success {
    color: #f5222d;
  }
  .demo-block .demo-block-control:hover {
    color: #409eff;
    background-color: #f9fafc;
  }
  .demo-block .demo-block-control .text-slide-enter,
  .demo-block .demo-block-control .text-slide-leave-active {
    opacity: 0;
    transform: translateX(10px);
  }
  .demo-block .demo-block-control .bounce-enter-active {
    animation: bounce-in 0.5s;
  }
  @keyframes bounce-in {
    0% {
      transform: scale(0);
    }
    50% {
      transform: scale(1.5);
    }
    100% {
      transform: scale(1);
    }
  }
  .demo-block .demo-block-control .control-button {
    line-height: 26px;
    position: absolute;
    top: 0;
    right: 0;
    font-size: 14px;
    padding-left: 5px;
    padding-right: 25px;
  }
</style>
