<template>
  <!-- 鼠標(biāo)畫(huà)矩形選擇對(duì)象 -->
  <div class="objects" ref="objectsRef" @mousedown="handleMouseDown">
    <!-- 矩形選擇框 -->
    <div
      class="mask"
      ref="maskRef"
      v-show="maskPosition.show"
      :style="
        'width:' +
        maskWidth +
        'left:' +
        maskLeft +
        'height:' +
        maskHeight +
        'top:' +
        maskTop
      "
    />

    <!-- 選擇對(duì)象內(nèi)容的目標(biāo)插槽 -->
    <slot name="selcetObject" />
  </div>
</template>

<script lang="ts" setup>
import { reactive, toRefs, ref, computed } from "vue";

const props = withDefaults(
  defineProps<{
    objectClassName: string; // 選擇對(duì)象的class name，用于定義如何獲取對(duì)象
    objectIdName: string; // 選擇對(duì)象的id name，用于定義如何獲取對(duì)象的id
    selectObjectIds?: Array<string>; // 選中的對(duì)象ID
    selectObjects?: Array<HTMLElement>; // 選中的對(duì)象
    useCtrlSelect?: boolean; // 是否支持按住Ctrl多選
  }>(),
  {
    useCtrlSelect: true // 默認(rèn)支持按住Ctrl多選
  }
);

const objectsRef = ref();
const maskRef = ref();
const emits = defineEmits(["update:selectObjects", "update:selectObjectIds"]);
const state = reactive({
  maskPosition: {
    show: false,
    startX: 0,
    startY: 0,
    endX: 0,
    endY: 0
  }, // 矩形框位置
  isPressCtrlKey: false // 是否按下了Ctrl鍵
});
const { maskPosition, isPressCtrlKey } = toRefs(state);

// 若支持按住Ctrl多選，監(jiān)聽(tīng)Ctrl事件
if (props.useCtrlSelect) {
  // 釋放
  document.addEventListener("keyup", event => {
    if (event.keyCode === 17) {
      isPressCtrlKey.value = false;
    }
  });
  // 按下
  document.addEventListener("keydown", event => {
    if (event.keyCode === 17) {
      isPressCtrlKey.value = true;
    }
  });
}

/** 鼠標(biāo)按下 */
const handleMouseDown = event => {
  // 展示矩形框，通過(guò)坐標(biāo)位置來(lái)畫(huà)出矩形
  maskPosition.value.show = true;
  maskPosition.value.startX = event.clientX;
  maskPosition.value.startY = event.clientY;
  maskPosition.value.endX = event.clientX;
  maskPosition.value.endY = event.clientY;
  // 監(jiān)聽(tīng)鼠標(biāo)移動(dòng)事件和抬起離開(kāi)事件
  objectsRef.value.addEventListener("mousemove", handleMouseMove);
  objectsRef.value.addEventListener("mouseup", handleMouseUp);
};

/** 鼠標(biāo)移動(dòng) */
const handleMouseMove = event => {
  maskPosition.value.endX = event.clientX;
  maskPosition.value.endY = event.clientY;
};

/** 鼠標(biāo)抬起離開(kāi) */
const handleMouseUp = () => {
  // 移除鼠標(biāo)監(jiān)聽(tīng)事件
  objectsRef.value.removeEventListener("mousemove", handleMouseMove);
  objectsRef.value.removeEventListener("mouseup", handleMouseUp);
  maskPosition.value.show = false;
  handleResetMaskPosition();
  handleGetSelectObject();
};

/** 獲取選擇的對(duì)象 */
const handleGetSelectObject = () => {
  // 選中對(duì)象ID和對(duì)象元素
  let tempSelectObjectIds: Array<string> = [];
  let tempSelectObjects: Array<HTMLElement> = [];

  // 如果按下了Ctrl鍵，之前選擇的數(shù)據(jù)不清空
  if (isPressCtrlKey.value) {
    tempSelectObjectIds =
      props.selectObjectIds === undefined ? [] : props.selectObjectIds;
    tempSelectObjects =
      props.selectObjects === undefined ? [] : props.selectObjects;
  }

  // 獲取鼠標(biāo)畫(huà)出的矩形框位置
  const rectanglePosition = maskRef.value.getClientRects()[0];

  // 獲取所有選擇區(qū)域的對(duì)象; 這里獲取的元素的方式定義于父組件的objectClassName
  const selectedObjects = objectsRef.value.querySelectorAll(
    `.${props.objectClassName}`
  );
  // 遍歷對(duì)象，獲取到每個(gè)對(duì)象的坐標(biāo)位置，判斷該位置是否在上面獲取到的鼠標(biāo)畫(huà)矩形的框的位置中
  selectedObjects.forEach(item => {
    const objectPosition = item.getClientRects()[0];

    // 這里獲取的id的方式定義于父組件的objectIdName
    if (compareObjectPosition(objectPosition, rectanglePosition)) {
      const id = item.getAttribute(props.objectIdName);

      // 如果按下了Ctrl鍵
      if (isPressCtrlKey.value) {
        // 已被選中的需要被取消選中
        if (tempSelectObjectIds.includes(id)) {
          tempSelectObjectIds = tempSelectObjectIds.filter(a => a != id);
          tempSelectObjects = tempSelectObjects.filter(a => a != item);
        } else {
          tempSelectObjectIds.push(id);
          tempSelectObjects.push(item);
        }
      } else {
        tempSelectObjectIds.push(id);
        tempSelectObjects.push(item);
      }
    }
  });

  // 回傳到父組件
  emits("update:selectObjects", tempSelectObjects);
  emits("update:selectObjectIds", tempSelectObjectIds);
};

/**
 * 判斷對(duì)象坐標(biāo)是否在鼠標(biāo)畫(huà)出的矩形框坐標(biāo)位置內(nèi)
 * @param objectPosition 對(duì)象坐標(biāo)位置
 * @param rectanglePosition 鼠標(biāo)畫(huà)出的矩形框坐標(biāo)位置
 */
const compareObjectPosition = (objectPosition, rectanglePosition) => {
  const maxX = Math.max(
    objectPosition.x + objectPosition.width,
    rectanglePosition.x + rectanglePosition.width
  );
  const maxY = Math.max(
    objectPosition.y + objectPosition.height,
    rectanglePosition.y + rectanglePosition.height
  );
  const minX = Math.min(objectPosition.x, rectanglePosition.x);
  const minY = Math.min(objectPosition.y, rectanglePosition.y);
  return (
    maxX - minX <= objectPosition.width + rectanglePosition.width &&
    maxY - minY <= objectPosition.height + rectanglePosition.height
  );
};

/** 重置鼠標(biāo)位置 */
const handleResetMaskPosition = () => {
  maskPosition.value.startX = 0;
  maskPosition.value.startY = 0;
  maskPosition.value.endX = 0;
  maskPosition.value.endY = 0;
};

/** 通過(guò)鼠標(biāo)位置實(shí)時(shí)計(jì)算矩形框大小 */
const maskWidth = computed(() => {
  return `${Math.abs(maskPosition.value.endX - maskPosition.value.startX)}px;`;
});
const maskHeight = computed(() => {
  return `${Math.abs(maskPosition.value.endY - maskPosition.value.startY)}px;`;
});
const maskLeft = computed(() => {
  return `${Math.min(maskPosition.value.startX, maskPosition.value.endX)}px;`;
});
const maskTop = computed(() => {
  return `${Math.min(maskPosition.value.startY, maskPosition.value.endY)}px;`;
});
</script>

<style scoped lang="scss">
.objects {
  height: 100%;
  width: 100%;
  overflow-y: auto;

  .mask {
    position: fixed;
    background: #409eff;
    opacity: 0.4;
    z-index: 100;
  }
}
</style>

<template>
  <!------------- 鼠標(biāo)畫(huà)矩形選擇對(duì)象組件DEMO，可以直接拷貝到你的頁(yè)面去運(yùn)行----------------------->
  <div class="content">
    <!-- 
    MouseDrawRectangle說(shuō)明：
    objectClassName綁定到下面對(duì)象class名稱； 
    objectIdName名稱對(duì)應(yīng)object_id；
    useCtrlSelect默認(rèn)是打開(kāi)的，用于按住Ctrl鍵進(jìn)行多選，以及取消已選擇的對(duì)象。
    
    selectObjectIds會(huì)實(shí)時(shí)從子組件更新過(guò)來(lái)，監(jiān)聽(tīng)它的值來(lái)控制頁(yè)面的選擇狀態(tài)即可。
    另外有參數(shù)selectObjects會(huì)實(shí)時(shí)從子組件傳回被選中的對(duì)象Dom信息
    -->
    <MouseDrawRectangle
      objectClassName="select_object"
      objectIdName="object_id"
      :useCtrlSelect="true"
      v-model:selectObjectIds="selectObjectIds"
      v-model:selectObjects="selectObjects"
    >
      <!-- 這個(gè)是插槽，將業(yè)務(wù)內(nèi)容的Dom限制在MouseDrawRectangle組件內(nèi)，
      這樣可以將后面組件所有的監(jiān)聽(tīng)事件綁定到組件上而不是整個(gè)頁(yè)面Dom上，
      鼠標(biāo)滑動(dòng)的區(qū)域也會(huì)限制死在組件內(nèi)，而不是整個(gè)頁(yè)面的范圍 -->
      <template #selcetObject>
        <div class="objects_content">
          <!-- 每一個(gè)選擇的目標(biāo)對(duì)象 -->
          <div
            v-for="item in 50"
            :key="item"
            class="select_object"
            :object_id="item"
            :class="
              selectObjectIds.includes(item.toString()) ? 'is_selected' : ''
            "
          >
            {{ item }}
          </div>
        </div>
      </template>
    </MouseDrawRectangle>
  </div>
</template>

<script lang="ts" setup>
import { reactive, toRefs, watch } from "vue";
import MouseDrawRectangle from "@/components/objectSelect/mouseDrawRectangle.vue";

const state = reactive({
  selectObjectIds: [] as Array<string>, // 選中的對(duì)象ID
  selectObjects: [] as Array<HTMLElement> // 選中的對(duì)象DOM
});
const { selectObjectIds, selectObjects } = toRefs(state);

watch(
  () => [selectObjectIds.value, selectObjects.value],
  () => {
    console.log("選中的ID=>", selectObjectIds);
    console.log("選中的Dom=>", selectObjects);
  }
);
</script>

<style scoped lang="scss">
.content {
  // 因?yàn)槭褂胒lex布局，最下面一行盒子換行只會(huì)出現(xiàn)一半的高度，這里最好減去下每個(gè)盒子的高度
  height: calc(100% - 50px);
  overflow-y: auto;
  padding: 20px;

  .objects_content {
    user-select: none;
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 10px;

    // 盒子樣式
    > div {
      width: 200px;
      height: 100px;
      background-color: #999;
    }

    .is_selected {
      color: #fff;
      box-sizing: border-box;
      border: 3px #317aff solid;
      border-radius: 5px;
    }
  }
}
</style>