<template>
  <div
    class="demo-block"
    :class="[blockClass, { 'hover': hovering }]"
    @mouseenter="hovering = true"
    @mouseleave="hovering = false"
  >
    <div class="source">
      <slot name="source"></slot>
    </div>
    <div ref="meta" class="meta">
      <div v-if="$slots.default" class="description">
        <slot></slot>
      </div>
      <div class="highlight">
        <slot name="highlight"></slot>
      </div>
    </div>
    <div
      ref="control"
      class="demo-block-control"
      :class="{ 'is-fixed': fixedControl }"
      @click="isExpanded = !isExpanded"
    >
      <transition name="arrow-slide">
        <i :class="[iconClass, { 'hovering': hovering }]"></i>
      </transition>
      <transition name="text-slide">
        <span v-show="hovering">{{ controlText }}</span>
      </transition>
      <el-tooltip effect="dark" :content="langConfig['tooltip-text']" placement="right">
        <transition name="text-slide">
          <el-button
            v-show="hovering || isExpanded"
            size="small"
            type="text"
            class="control-button"
            @click.stop="goCodepen"
          >
            {{ langConfig['button-text'] }}
          </el-button>
        </transition>
      </el-tooltip>
    </div>
  </div>
</template>
<script>
import { nextTick } from 'vue'
import hljs from 'highlight.js'
import compoLang from '../i18n/component.json'
import { stripScript, stripStyle, stripTemplate } from '../util'
const version = '1.0.0' // element version

export default {
  data() {
    return {
      codepen: {
        script: '',
        html: '',
        style: '',
      },
      hovering: false,
      isExpanded: false,
      fixedControl: false,
      scrollParent: null,
    }
  },

  computed: {
    lang() {
      return this.$route.path.split('/')[1]
    },

    langConfig() {
      return compoLang.filter(config => config.lang === this.lang)[0]['demo-block']
    },

    blockClass() {
      return `demo-${ this.lang } demo-${ this.$router.currentRoute.value.path.split('/').pop() }`
    },

    iconClass() {
      return this.isExpanded ? 'el-icon-caret-top' : 'el-icon-caret-bottom'
    },

    controlText() {
      return this.isExpanded ? this.langConfig['hide-text'] : this.langConfig['show-text']
    },

    codeArea() {
      return this.$el.getElementsByClassName('meta')[0]
    },

    codeAreaHeight() {
      if (this.$el.getElementsByClassName('description').length > 0) {
        return this.$el.getElementsByClassName('description')[0].clientHeight +
            this.$el.getElementsByClassName('highlight')[0].clientHeight + 20
      }
      return this.$el.getElementsByClassName('highlight')[0].clientHeight
    },
  },

  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.querySelector('.page-component__scroll > .el-scrollbar__wrap')
        this.scrollParent && this.scrollParent.addEventListener('scroll', this.scrollHandler)
        this.scrollHandler()
      }, 200)
    },
  },

  created() {
    const highlight = this.$slots.highlight()
    if (highlight && highlight[0]) {
      let code = ''
      let cur = highlight[0]
      if (cur.tag === 'pre' && (cur.children && cur.children[0])) {
        cur = cur.children[0]
        if (cur.tag === 'code') {
          code = cur.children[0].text
        }
      }
      if (code) {
        this.codepen.html = stripTemplate(code)
        this.codepen.script = stripScript(code)
        this.codepen.style = stripStyle(code)
      }
    }
  },

  mounted() {
    nextTick(() => {
      let highlight = this.$el.getElementsByClassName('highlight')[0]
      if (this.$el.getElementsByClassName('description').length === 0) {
        highlight.style.width = '100%'
        highlight.borderRight = 'none'
      }

      try {
        hljs.highlightBlock(highlight.querySelector('code'))
      } catch (error) {
        console.log(error)
      }
    })
  },

  beforeUnmount() {
    this.removeScrollHandler()
  },

  methods: {
    goCodepen() {
      // since 2.6.2 use code rather than jsfiddle https://blog.codepen.io/documentation/api/prefill/
      const { script, html, style } = this.codepen
      const resourcesTpl = '<scr' + 'ipt src="//unpkg.com/vue/dist/vue.js"></scr' + 'ipt>' +
        '\n<scr' + `ipt src="//unpkg.com/element-ui@${ version }/lib/index.js"></scr` + 'ipt>'
      let jsTpl = (script || '').replace(/export default/, 'var Main =').trim()
      let htmlTpl = `${resourcesTpl}\n<div id="app">\n${html.trim()}\n</div>`
      let cssTpl = `@import url("//unpkg.com/element-ui@${ version }/lib/theme-chalk/index.css");\n${(style || '').trim()}\n`
      jsTpl = jsTpl
        ? jsTpl + '\nvar Ctor = Vue.extend(Main)\nnew Ctor().$mount(\'#app\')'
        : 'new Vue().$mount(\'#app\')'
      const data = {
        js: jsTpl,
        css: cssTpl,
        html: htmlTpl,
      }
      const form = document.getElementById('fiddle-form') || document.createElement('form')
      while (form.firstChild) {
        form.removeChild(form.firstChild)
      }
      form.method = 'POST'
      form.action = 'https://codepen.io/pen/define/'
      form.target = '_blank'
      form.style.display = 'none'

      const input = document.createElement('input')
      input.setAttribute('name', 'data')
      input.setAttribute('type', 'hidden')
      input.setAttribute('value', JSON.stringify(data))

      form.appendChild(input)
      document.body.appendChild(form)

      form.submit()
    },

    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)
    },
  },
}
</script>
<style lang="scss" scoped>
  .demo-block {
    border: solid 1px #ebebeb;
    border-radius: 3px;
    transition: .2s;

    &.hover {
      box-shadow: 0 0 8px 0 rgba(232, 237, 250, .6), 0 2px 4px 0 rgba(232, 237, 250, .5);
    }

    code {
      font-family: Menlo, Monaco, Consolas, Courier, monospace;
    }

    .demo-button {
      float: right;
    }

    .source {
      padding: 24px;
    }

    .meta {
      background-color: #fafafa;
      border-top: solid 1px #eaeefb;
      overflow: hidden;
      height: 0;
      transition: height .2s;
    }

    .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: #fff;

      p {
        margin: 0;
        line-height: 26px;
      }

      code {
        color: #5e6d82;
        background-color: #e6effb;
        margin: 0 4px;
        display: inline-block;
        padding: 1px 5px;
        font-size: 12px;
        border-radius: 3px;
        height: 18px;
        line-height: 18px;
      }
    }

    .highlight {
      pre {
        margin: 0;
      }

      code.hljs {
        margin: 0;
        border: none;
        max-height: none;
        border-radius: 0;

        &::before {
          content: none;
        }
      }
    }

    .demo-block-control {
      border-top: solid 1px #eaeefb;
      height: 44px;
      box-sizing: border-box;
      background-color: #fff;
      border-bottom-left-radius: 4px;
      border-bottom-right-radius: 4px;
      text-align: center;
      margin-top: -1px;
      color: #d3dce6;
      cursor: pointer;
      position: relative;

      &.is-fixed {
        position: fixed;
        bottom: 0;
        width: 868px;
      }

      i {
        font-size: 16px;
        line-height: 44px;
        transition: .3s;
        &.hovering {
          transform: translateX(-40px);
        }
      }

      > span {
        position: absolute;
        transform: translateX(-30px);
        font-size: 14px;
        line-height: 44px;
        transition: .3s;
        display: inline-block;
      }

      &:hover {
        color: #409EFF;
        background-color: #f9fafc;
      }

      & .text-slide-enter,
      & .text-slide-leave-active {
        opacity: 0;
        transform: translateX(10px);
      }

      .control-button {
        line-height: 26px;
        position: absolute;
        top: 0;
        right: 0;
        font-size: 14px;
        padding-left: 5px;
        padding-right: 25px;
      }
    }
  }
</style>
