<template>
  <div :style='style'>
    <slot></slot>
  </div>
</template>

<script setup lang='ts' name='Grid'>
import type { BreakPoint } from './interface/index'

type Props = {
  cols?: number | Record<BreakPoint, number>;
  collapsed?: boolean;
  collapsedRows?: number;
  gap?: [number, number] | number;
};

const props = withDefaults(defineProps<Props>(), {
  cols: () => ({ xs: 1, sm: 2, md: 2, lg: 3, xl: 4 }),
  collapsed: false,
  collapsedRows: 1,
  gap: 0,
})

onBeforeMount(() => props.collapsed && findIndex())
onMounted(() => {
  resize({ target: { innerWidth: window.innerWidth } } as unknown as UIEvent)
  window.addEventListener('resize', resize)
})
onActivated(() => {
  resize({ target: { innerWidth: window.innerWidth } } as unknown as UIEvent)
  window.addEventListener('resize', resize)
})
onUnmounted(() => {
  window.removeEventListener('resize', resize)
})
onDeactivated(() => {
  window.removeEventListener('resize', resize)
})

// 监听屏幕变化
const resize = (e: UIEvent) => {
  let width = (e.target as Window).innerWidth
  switch (!!width) {
    case width < 768:
      breakPoint.value = 'xs'
      break
    case width >= 768 && width < 992:
      breakPoint.value = 'sm'
      break
    case width >= 992 && width < 1200:
      breakPoint.value = 'md'
      break
    case width >= 1200 && width < 1920:
      breakPoint.value = 'lg'
      break
    case width >= 1920:
      breakPoint.value = 'xl'
      break
  }
}

// 注入 gap 间距
provide('gap', Array.isArray(props.gap) ? props.gap[0] : props.gap)

// 注入响应式断点
let breakPoint = ref<BreakPoint>('xl')
provide('breakPoint', breakPoint)

// 注入要开始折叠的 index
const hiddenIndex = ref(-1)
provide('shouldHiddenIndex', hiddenIndex)

// 注入 cols
const gridCols = computed(() => {
  if (typeof props.cols === 'object') return props.cols[breakPoint.value] ?? props.cols
  return props.cols
})
provide('cols', gridCols)

// 寻找需要开始折叠的字段 index
const slots = useSlots().default!()

const findIndex = () => {
  let fields: VNodeArrayChildren = []
  let suffix: VNode | null = null
  slots.forEach((slot: any) => {
    // suffix
    if (typeof slot.type === 'object' && slot.type.name === 'GridItem' && slot.props?.suffix !== undefined) suffix = slot
    // slot children
    if (typeof slot.type === 'symbol' && Array.isArray(slot.children)) fields.push(...slot.children)
  })

  // 计算 suffix 所占用的列
  let suffixCols = 0
  if (suffix) {
    suffixCols =
      ((suffix as VNode).props![breakPoint.value]?.span ?? (suffix as VNode).props?.span ?? 1) +
      ((suffix as VNode).props![breakPoint.value]?.offset ?? (suffix as VNode).props?.offset ?? 0)
  }
  try {
    let find = false
    fields.reduce((prev = 0, current, index) => {
      prev +=
        ((current as VNode)!.props![breakPoint.value]?.span ?? (current as VNode)!.props?.span ?? 1) +
        ((current as VNode)!.props![breakPoint.value]?.offset ?? (current as VNode)!.props?.offset ?? 0)
      if (Number(prev) >= props.collapsedRows * gridCols.value - suffixCols) {
        hiddenIndex.value = index
        find = true
        throw 'find it'
      }
      return prev
    }, 0)
    if (!find) hiddenIndex.value = -1
  } catch (e) {
    // console.warn(e);
  }
}

// 断点变化时执行 findIndex
watch(
  () => breakPoint.value,
  () => {
    if (props.collapsed) findIndex()
  },
)

// 监听 collapsed
watch(
  () => props.collapsed,
  value => {
    if (value) return findIndex()
    hiddenIndex.value = -1
  },
)

// 设置间距
const gridGap = computed(() => {
  if (typeof props.gap === 'number') return `${props.gap}px`
  if (Array.isArray(props.gap)) return `${props.gap[1]}px ${props.gap[0]}px`
  return 'unset'
})

// 设置 style
const style = computed(() => {
  return {
    display: 'grid',
    gridGap: gridGap.value,
    gridTemplateColumns: `repeat(${gridCols.value}, minmax(0, 1fr))`,
  }
})

defineExpose({ breakPoint })
</script>
