import { ref, h, reactive, PropType, VNode, watch, computed, nextTick, onMounted, onBeforeUnmount } from 'vue'
import { defineVxeComponent } from '../../ui/src/comp'
import XEUtils from 'xe-utils'
import { getConfig, createEvent, useSize, renderEmptyElement } from '../../ui'
import { toCssUnit } from '../../ui/src/dom'

import type { SegmentedReactData, VxeSegmentedPropTypes, SegmentedPrivateRef, VxeSegmentedEmits, VxeSegmentedPrivateComputed, SegmentedMethods, SegmentedPrivateMethods, VxeSegmentedConstructor, VxeSegmentedPrivateMethods, VxeComponentStyleType, ValueOf } from '../../../types'

function createReactData (): SegmentedReactData {
  return {
    groupName: XEUtils.uniqueId('xe_group_'),
    selectStyle: {
      display: '',
      left: '',
      width: ''
    }
  }
}

export default defineVxeComponent({
  name: 'VxeSegmented',
  props: {
    modelValue: [String, Number] as PropType<VxeSegmentedPropTypes.ModelValue>,
    name: [String, Number] as PropType<VxeSegmentedPropTypes.Name>,
    disabled: Boolean as PropType<VxeSegmentedPropTypes.Disabled>,
    options: Array as PropType<VxeSegmentedPropTypes.Options>,
    type: {
      type: String as PropType<VxeSegmentedPropTypes.Type>,
      default: () => getConfig().segmented.type
    },
    status: String as PropType<VxeSegmentedPropTypes.Status>,
    width: [String, Number] as PropType<VxeSegmentedPropTypes.Width>,
    height: [String, Number] as PropType<VxeSegmentedPropTypes.Height>,
    optionConfig: Object as PropType<VxeSegmentedPropTypes.OptionConfig>,
    size: {
      type: String as PropType<VxeSegmentedPropTypes.Size>,
      default: () => getConfig().segmented.size || getConfig().size
    }
  },
  emits: [
    'update:modelValue',
    'change'
  ] as VxeSegmentedEmits,
  setup (props, context) {
    const { slots, emit } = context

    const xID = XEUtils.uniqueId()

    const { computeSize } = useSize(props)

    const refElem = ref<HTMLDivElement>()
    const refWrapperElem = ref<HTMLDivElement>()
    const refSelectedElem = ref<HTMLDivElement>()

    const reactData = reactive(createReactData())

    const refMaps: SegmentedPrivateRef = {
      refElem
    }

    const computeItemType = computed(() => {
      const { type } = props
      if (type === 'round') {
        return type
      }
      if (type === 'inside') {
        return type
      }
      return 'default'
    })

    const computeWrapperStyle = computed(() => {
      const { width, height } = props
      const stys: VxeComponentStyleType = {}
      if (width) {
        stys.width = toCssUnit(width)
      }
      if (height) {
        stys.height = toCssUnit(height)
      }
      return stys
    })

    const computeOptionOpts = computed(() => {
      return Object.assign({}, getConfig().segmented.optionConfig, props.optionConfig)
    })

    const computeItemList = computed(() => {
      return props.options || []
    })

    const computeSelectIndex = computed(() => {
      const { modelValue } = props
      const itemList = computeItemList.value
      return XEUtils.findIndexOf(itemList, item => item.value === modelValue)
    })

    const comIsFullWidth = computed(() => {
      const wrapperStyle = computeWrapperStyle.value
      return wrapperStyle.width === '100%'
    })

    const computeMaps: VxeSegmentedPrivateComputed = {
    }

    const $xeSegmented = {
      xID,
      props,
      context,
      reactData,

      getRefMaps: () => refMaps,
      getComputeMaps: () => computeMaps
    } as unknown as VxeSegmentedConstructor & VxeSegmentedPrivateMethods

    const dispatchEvent = (type: ValueOf<VxeSegmentedEmits>, params: Record<string, any>, evnt: Event | null) => {
      emit(type, createEvent(evnt, { $segmented: $xeSegmented }, params))
    }

    const emitModel = (value: any) => {
      emit('update:modelValue', value)
    }

    const changeEvent = (evnt: Event, item: VxeSegmentedPropTypes.Option) => {
      const value = item.value
      emitModel(value)
      dispatchEvent('change', { value }, evnt)
      updateStyle()
    }

    const updateStyle = () => {
      nextTick(() => {
        const selectIndex = computeSelectIndex.value
        const wrapperElem = refWrapperElem.value
        const atStyle = {
          display: '',
          left: '',
          width: ''
        }
        if (wrapperElem) {
          const itemEl = wrapperElem.children[selectIndex] as HTMLDivElement
          if (itemEl) {
            atStyle.display = 'block'
            atStyle.left = toCssUnit(itemEl.offsetLeft)
            atStyle.width = toCssUnit(itemEl.clientWidth)
          }
        }
        reactData.selectStyle = atStyle
      })
    }

    const tagMethods: SegmentedMethods = {
      dispatchEvent
    }

    const tagPrivateMethods: SegmentedPrivateMethods = {
    }

    Object.assign($xeSegmented, tagMethods, tagPrivateMethods)

    const renderItems = () => {
      const { modelValue, name } = props
      const { groupName } = reactData
      const optionOpts = computeOptionOpts.value
      const itemList = computeItemList.value
      const isFullWidth = comIsFullWidth.value
      const fullItemWidth = isFullWidth ? Math.max(0, 100 / itemList.length) : 0
      const defaultSlot = slots.default
      const itemVNs: VNode[] = []
      itemList.forEach((item, i) => {
        const { icon, width } = item
        const itemWidth = width || optionOpts.width
        itemVNs.push(
          h('label', {
            key: i,
            class: ['vxe-segmented--item', {
              'is--checked': modelValue === item.value
            }],
            style: isFullWidth || itemWidth
              ? {
                  width: itemWidth ? toCssUnit(itemWidth) : (fullItemWidth ? `${fullItemWidth}%` : '')
                }
              : undefined
          }, [
            h('input', {
              class: 'vxe-segmented--input',
              type: 'radio',
              name: name || groupName,
              onChange (evnt) {
                changeEvent(evnt, item)
              }
            }),
            h('div', {
              class: 'vxe-segmented--content'
            }, [
              icon
                ? h('div', {
                  class: 'vxe-segmented--icon'
                }, [
                  h('i', {
                    class: icon
                  })
                ])
                : renderEmptyElement($xeSegmented),
              h('div', {
                class: 'vxe-segmented--label'
              }, defaultSlot ? defaultSlot({ option: item }) : XEUtils.eqNull(item.label) ? '' : `${item.label}`)
            ])
          ])
        )
      })
      return itemVNs
    }

    const renderVN = () => {
      const { status } = props
      const { selectStyle } = reactData
      const itemType = computeItemType.value
      const wrapperStyle = computeWrapperStyle.value
      const vSize = computeSize.value
      return h('div', {
        ref: refElem,
        class: ['vxe-segmented', `type--${itemType}`, {
          [`size--${vSize}`]: vSize,
          [`theme--${status}`]: status
        }]
      }, [
        h('div', {
          class: 'vxe-segmented--group',
          style: wrapperStyle
        }, [
          h('div', {
            ref: refSelectedElem,
            class: 'vxe-segmented--selected',
            style: selectStyle
          }),
          h('div', {
            ref: refWrapperElem,
            class: 'vxe-segmented--inner'
          }, renderItems())
        ])
      ])
    }

    watch(computeSelectIndex, () => {
      updateStyle()
    })

    onMounted(() => {
      updateStyle()
    })

    onBeforeUnmount(() => {
      XEUtils.assign(reactData, createReactData())
    })

    $xeSegmented.renderVN = renderVN

    return $xeSegmented
  },
  render () {
    return this.renderVN()
  }
})