<script setup lang="ts">
  import { dragStore } from "./drag";

  const props = defineProps<{
    data: DragItem;
    groupName?: string;
  }>();

  const onDragstart = (e) => dragStore.set(props.groupName, { ...props.data });
  const onDragend = () => dragStore.remove(props.groupName);
</script>
<template>
  <div class="drag-item__el" draggable="true" @dragstart="onDragstart" @dragend="onDragend"></div>
</template>

class DragStore<T extends DragItemData> {
  moveItem = new Map<string, DragItemData>();

  set(key: string, data: T) {
    this.moveItem.set(key, data);
  }

  remove(key: string) {
    this.moveItem.delete(key);
  }

  get(key: string): undefined | DragItemData {
    return this.moveItem.get(key);
  }
}

<script setup lang="ts">
  // 進(jìn)入放置目標(biāo)
  const onDragenter = (e) => {
    e.preventDefault();
  };

  // 在目標(biāo)中移動
  const onDragover = (e) => {
    e.preventDefault();
  };

  // 離開目標(biāo)
  const onDragleave = (e) => {
    e.preventDefault();
  };
</script>
<template>
  <div @dragenter="onDragenter($event)" @dragover="onDragover($event)" @dragleave="onDragleave($event)" @drop="onDrop($event)"></div>
</template>

import { useElementSize } from "@vueuse/core";

/**
 * 容器等分尺寸
 * @param {*} target 容器 HTML
 * @param {*} column 列數(shù)
 * @param {*} row 行數(shù)
 * @param {*} gap 間隔
 * @returns
 */
export const useBoxSize = (target: Ref<HTMLElement | undefined>, column: number, row: number, gap: number) => {
  const { width, height } = useElementSize(target);
  return computed(() => ({
    width: (width.value - (column - 1) * gap) / column,
    height: (height.value - (row - 1) * gap) / row,
  }));
};

<div class="drop-content__drop-container" @dragenter="onDragenter($event)" @dragover="onDragover($event)" @dragleave="onDragleave($event)" @drop="onDrop($event)">
  <template v-for="x in rowCount">
    <div class="bg-column" v-for="y in columnCount" :key="`${x}-${y}`"></div>
  </template>
</div>

.drop-content__drop-container {
  display: grid;
  row-gap: v-bind("gap+'px'");
  column-gap: v-bind("gap+'px'");
  grid-template-columns: repeat(v-bind("columnCount"), v-bind("boxSize.width+'px'"));
  grid-template-rows: repeat(v-bind("rowCount"), v-bind("boxSize.height+'px'"));
  .bg-column {
    background-color: #fff;
    border-radius: 6px;
    pointer-events: none;
  }
}

// 計算 x 坐標(biāo)
const getX = (num) => parseInt(num / (boxSizeWidth + gap));
// 計算 y 坐標(biāo)
const getY = (num) => parseInt(num / (boxSizeHeight + gap));

// 拖拽中的元素
const current = reactive({
  show: <boolean>false,
  id: <undefined | number>undefined,
  column: <number>0, // 寬
  row: <number>0, // 高
  x: <number>0, // 列
  y: <number>0, // 行
});

// 進(jìn)入放置目標(biāo)
const onDragenter = (e) => {
  e.preventDefault();
  const dragData = dragStore.get(props.groupName);
  if (dragData) {
    current.column = dragData.column;
    current.row = dragData.row;
    current.x = getX(e.offsetX);
    current.y = getY(e.offsetY);
    current.show = true;
  }
};

// 在目標(biāo)中移動
const onDragover = (e) => {
  e.preventDefault();
  const dragData = dragStore.get(props.groupName);
  if (dragData) {
    current.x = getX(e.offsetX);
    current.y = getY(e.offsetY);
  }
};

const onDragleave = (e) => {
  e.preventDefault();
  current.show = false;
  current.id = undefined;
};

const list = ref([]);

// 放置在目標(biāo)上
const onDrop = async (e) => {
  e.preventDefault();
  current.show = false;
  const item = dragStore.get(props.groupName);

  list.value.push({
    ...item,
    x: current.x,
    y: current.y,
    id: new Date().getTime(),
  });
};

/**
 * 判斷是否在當(dāng)前四邊形內(nèi)
 * @param {*} p1 父容器
 * @param {*} p2
 *  對應(yīng)是 左上角坐標(biāo) 和 右下角坐標(biāo)
 *  [0,0,1,1]  => 左上角坐標(biāo) 0,0  右下角 1,1
 */
export const booleanWithin = (p1: [number, number, number, number], p2: [number, number, number, number]) => {
  return p1[0] <= p2[0] && p1[1] <= p2[1] && p1[2] >= p2[2] && p1[3] >= p2[3];
};

// 是否可以放置
const isPutDown = computed(() => {
  const currentXy = [current.x, current.y, current.x + current.column, current.y + current.row];
  return (
    booleanWithin([0, 0, columnCount.value, rowCount.value], currentXy) && //
    list.value.every((item) => item.id === current.id || !booleanIntersects([item.x, item.y, item.x + item.column, item.y + item.row], currentXy))
  );
});

grid-area: `${y + 1} / ${x + 1} / ${y + row + 1}/ ${ x + column + 1 }`

.drop-content__preview,
.drop-content__drop-container {
  // ...
}

grid-area: `${y + 1} / ${x + 1} / ${y + row + 1}/ ${ x + column + 1 }`

if (item.id) {
  item.x = current.x;
  item.y = current.y;
} else {
  list.value.push({
    ...item,
    x: current.x,
    y: current.y,
    id: new Date().getTime(),
  });
}

const onDragstart = (e) => {
  const data = props.data;
  data.offsetX = e.offsetX;
  data.offsetY = e.offsetY;
  dragStore.set(props.groupName, data);
};

current.x = getX(e.offsetX) - getX(dragData?.offsetX ?? 0);
current.y = getY(e.offsetY) - getY(dragData?.offsetY ?? 0);

:style="{ pointerEvents: current.show && item.id !== current.id ? 'none' : 'all' }"`

moveing.value
  ? {
      opacity: 0,
      transform: `translate(-999999999px, -9999999999px)`,
    }
  : {};