import { defineComponent, ref, reactive, PropType, watch } from 'vue'

export default defineComponent({
  name: 'VSelect',
  props: {
    options: {
      type: Array as PropType<ICascadeOptions[]>,
      default: () => []
    },
    value: {
      type: Array as PropType<IBaseOption[]>,
      default: () => []
    },
    fieldNames: {
      type: Object as PropType<IFileOption>,
      default: () => {
        return {
          label: 'name',
          value: 'value',
          children: 'children'
        }
      }
    }
  },
  setup(props, context) {
    const columns = ref<ICascadeOptions[][]>([])
    const selectValue = reactive<ISelectOption>([])
    const trueValue = ref<IBaseOption[]>(props.value || [])
    const fieldNames = ref<IFileOption>(props.fieldNames)
    const options = ref<ICascadeOptions[]>(props.options || [])
    watch(
      trueValue,
      newVal => {
        console.log(newVal)
        context.emit('update:value', newVal)
        context.emit('change', newVal)
      },
      {
        deep: true
      }
    )
    const findColumn = (
      value: IBaseOption,
      index: number,
      options = props.options
    ) => {
      if (options.length) {
        for (const item of options) {
          if (item[fieldNames.value.value] === value) {
            columns.value[index] = options
            selectValue[index] = item
            break
          }
          if (item[fieldNames.value.children]?.length) {
            findColumn(value, index, item[fieldNames.value.children])
          }
        }
      }
    }

    const refreshColumns = (value: IBaseOption[]) => {
      if (value.length) {
        for (let a = 0; a < value.length; a++) {
          findColumn(value[a], a)
        }
      }
    }

    const itemClick = (e: MouseEvent, index: number): void => {
      const target: INewHTMLElement = e.target as INewHTMLElement
      const item: ICascadeOptions = columns.value[index][target.selectedIndex]
      trueValue.value[index] = item[fieldNames.value.value]
      trueValue.value.length = index + 1
      if (item[fieldNames.value['children']]?.length) {
        columns.value[index + 1] = item[fieldNames.value['children']]
        columns.value.length = index + 2
      } else {
        columns.value.length = index + 1
      }
    }
    if (trueValue.value.length) {
      refreshColumns(trueValue.value)
    }

    watch(
      options,
      () => {
        if (options.value?.length) {
          columns.value[0] = options.value
        }
      },
      {
        deep: true
      }
    )

    return {
      columns,
      selectValue,
      itemClick
    }
  }
})