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

<script setup lang="ts" name="Grid">
import { ref, watch, useSlots, computed, provide, onBeforeMount, onMounted, onUnmounted, onDeactivated, onActivated, VNodeArrayChildren, VNode } from 'vue';
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>
