<template>
  <div ref="outerWrapper" :class="wrapperClasses" v-loading="loading" :element-loading-text="loadingText" :element-loading-background="loadingBackground" :element-loading-spinner="loadingSpinner">
    <div v-if="isHorizontal" :class="`${prefix}-horizontal`">
      <div :style="{ right: `${anotherOffset}%` }" class="left-pane" :class="paneClasses">
        <slot name="left" />
      </div>
      <div :class="`${prefix}-trigger-con`" :style="{ left: `${offset}%` }" @mousedown="handleMousedown">
        <slot name="trigger">
          <trigger mode="vertical" />
        </slot>
      </div>
      <div :style="{ left: `${offset}%` }" class="right-pane" :class="paneClasses">
        <slot name="right" />
      </div>
    </div>
    <div v-else :class="`${prefix}-vertical`">
      <div :style="{ bottom: `${anotherOffset}%` }" class="top-pane" :class="paneClasses">
        <slot name="top" />
      </div>
      <div :class="`${prefix}-trigger-con`" :style="{ top: `${offset}%` }" @mousedown="handleMousedown">
        <slot name="trigger">
          <trigger mode="horizontal" />
        </slot>
      </div>
      <div :style="{ top: `${offset}%` }" class="bottom-pane" :class="paneClasses">
        <slot name="bottom" />
      </div>
    </div>
  </div>
</template>

<script>
// 从iView迁移
import { mapState } from 'vuex'
import Trigger from './trigger.vue'
export default {
  name: 'Split',
  components: {
    Trigger
  },
  props: {
    value: {
      type: [Number, String],
      default: 0.5
    },
    mode: {
      validator(value) {
        return value === 'horizontal' || value === 'vertical'
      },
      default: 'horizontal'
    },
    min: {
      type: [Number, String],
      default: '40px'
    },
    max: {
      type: [Number, String],
      default: '40px'
    },
    /** loading */
    loading: Boolean
  },
  /**
   * Events
   * @on-move-start
   * @on-moving 返回值：事件对象，但是在事件对象中加入了两个参数：atMin(当前是否在最小值处), atMax(当前是否在最大值处)
   * @on-move-end
   */
  data() {
    return {
      prefix: 'nm-split',
      offset: 0,
      oldOffset: 0,
      isMoving: false
    }
  },
  computed: {
    ...mapState('app/loading', { loadingText: 'text', loadingBackground: 'background', loadingSpinner: 'spinner' }),
    wrapperClasses() {
      return [`${this.prefix}-wrapper`, this.isMoving ? 'no-select' : '']
    },
    paneClasses() {
      return [
        `${this.prefix}-pane`,
        {
          [`${this.prefix}-pane-moving`]: this.isMoving
        }
      ]
    },
    isHorizontal() {
      return this.mode === 'horizontal'
    },
    anotherOffset() {
      return 100 - this.offset
    },
    valueIsPx() {
      return typeof this.value === 'string'
    },
    offsetSize() {
      return this.isHorizontal ? 'offsetWidth' : 'offsetHeight'
    },
    computedMin() {
      return this.getComputedThresholdValue('min')
    },
    computedMax() {
      return this.getComputedThresholdValue('max')
    }
  },
  methods: {
    px2percent(numerator, denominator) {
      return parseFloat(numerator) / parseFloat(denominator)
    },
    getComputedThresholdValue(type) {
      let size = this.$refs.outerWrapper[this.offsetSize]
      if (this.valueIsPx) return typeof this[type] === 'string' ? this[type] : size * this[type]
      else return typeof this[type] === 'string' ? this.px2percent(this[type], size) : this[type]
    },
    getMin(value1, value2) {
      if (this.valueIsPx) return `${Math.min(parseFloat(value1), parseFloat(value2))}px`
      else return Math.min(value1, value2)
    },
    getMax(value1, value2) {
      if (this.valueIsPx) return `${Math.max(parseFloat(value1), parseFloat(value2))}px`
      else return Math.max(value1, value2)
    },
    getAnotherOffset(value) {
      let res = 0
      if (this.valueIsPx) res = `${this.$refs.outerWrapper[this.offsetSize] - parseFloat(value)}px`
      else res = 1 - value
      return res
    },
    handleMove(e) {
      let pageOffset = this.isHorizontal ? e.pageX : e.pageY
      let offset = pageOffset - this.initOffset
      let outerWidth = this.$refs.outerWrapper[this.offsetSize]
      let value = this.valueIsPx ? `${parseFloat(this.oldOffset) + offset}px` : this.px2percent(outerWidth * this.oldOffset + offset, outerWidth)
      let anotherValue = this.getAnotherOffset(value)
      if (parseFloat(value) <= parseFloat(this.computedMin)) value = this.getMax(value, this.computedMin)
      if (parseFloat(anotherValue) <= parseFloat(this.computedMax)) value = this.getAnotherOffset(this.getMax(anotherValue, this.computedMax))
      e.atMin = this.value === this.computedMin
      e.atMax = this.valueIsPx ? this.getAnotherOffset(this.value) === this.computedMax : this.getAnotherOffset(this.value).toFixed(5) === this.computedMax.toFixed(5)
      this.$emit('input', value)
      this.$emit('on-moving', e)
    },
    handleUp() {
      this.isMoving = false
      document.removeEventListener('mousemove', this.handleMove, false)
      document.removeEventListener('mouseup', this.handleUp, false)
      this.$emit('on-move-end')
    },
    handleMousedown(e) {
      this.initOffset = this.isHorizontal ? e.pageX : e.pageY
      this.oldOffset = this.value
      this.isMoving = true
      document.addEventListener('mousemove', this.handleMove, false)
      document.addEventListener('mouseup', this.handleUp, false)
      this.$emit('on-move-start')
    },
    computeOffset() {
      this.offset = ((this.valueIsPx ? this.px2percent(this.value, this.$refs.outerWrapper[this.offsetSize]) : this.value) * 10000) / 100
    }
  },
  watch: {
    value() {
      this.computeOffset()
    }
  },
  mounted() {
    this.$nextTick(() => {
      this.computeOffset()
    })

    window.addEventListener('resize', () => {
      this.computeOffset()
    })
  }
}
</script>
