<!-- 多图上传组件 -->
<template>
  <el-upload
    v-model:file-list="fileList"
    list-type="picture-card"
    :class="
      fileList.length >= props.limit || !props.showUploadBtn ? 'hide' : 'show'
    "
    :before-upload="handleBeforeUpload"
    :http-request="handleUpload"
    :on-remove="handleRemove"
    :accept="accept"
    :limit="props.limit"
  >
    <i-ep-plus />
    <template #file="{ file }">
      <div>
        <img class="el-upload-list__item-thumbnail" :src="file.url" alt="" />
        <span class="el-upload-list__item-actions">
          <span class="el-upload-list__item-preview" @click="previewImg(file)">
            <el-icon><zoom-in /></el-icon>
          </span>
          <span
            v-if="props.showDelBtn"
            class="el-upload-list__item-delete"
            @click="handleRemove(file)"
          >
            <el-icon><Delete /></el-icon>
          </span>
        </span>
      </div>
    </template>
  </el-upload>

  <el-image-viewer
    v-if="viewVisible"
    :zoom-rate="1.2"
    @close="closePreview"
    :initialIndex="initialIndex"
    :url-list="viewFileList"
  />
</template>
<script setup lang="ts">
import {
  UploadRawFile,
  UploadRequestOptions,
  UploadUserFile,
  UploadFile,
  UploadProps,
} from "element-plus";
import FileAPI from "@/api/file";

const emit = defineEmits(["update:modelValue"]);

const props = defineProps({
  /**
   * 文件路径集合
   */
  modelValue: {
    type: Array<string>,
    default: () => [],
  },
  /**
   * 文件上传数量限制
   */
  limit: {
    type: Number,
    default: 10,
  },
  /**
   * 是否显示删除按钮
   */
  showDelBtn: {
    type: Boolean,
    default: true,
  },
  /**
   * 是否显示上传按钮
   */
  showUploadBtn: {
    type: Boolean,
    default: true,
  },
  /**
   * 单张图片最大大小
   */
  uploadMaxSize: {
    type: Number,
    default: 2 * 1048 * 1048,
  },
  /**
   * 上传文件类型
   */
  accept: {
    type: String,
    default: "image/*",
  },
});

const viewVisible = ref(false);
const initialIndex = ref(0);

const fileList = ref([] as UploadUserFile[]);
const viewFileList = ref([] as string[]);

watch(
  () => props.modelValue,
  (newVal: string[]) => {
    const filePaths = fileList.value.map((file) => file.url);
    // 监听modelValue文件集合值未变化时，跳过赋值
    if (
      filePaths.length > 0 &&
      filePaths.length === newVal.length &&
      filePaths.every((x) => newVal.some((y) => y === x)) &&
      newVal.every((y) => filePaths.some((x) => x === y))
    ) {
      return;
    }

    if (newVal.length <= 0) {
      fileList.value = [];
      return;
    }

    fileList.value = newVal.map((filePath) => {
      return { url: filePath } as UploadUserFile;
    });
  },
  { immediate: true }
);

/**
 * 自定义图片上传
 *
 * @param options
 */
async function handleUpload(options: UploadRequestOptions): Promise<any> {
  // 上传API调用
  const data = await FileAPI.upload(options.file);

  // 上传成功需手动替换文件路径为远程URL，否则图片地址为预览地址 blob:http://
  const fileIndex = fileList.value.findIndex(
    (file) => file.uid == (options.file as any).uid
  );
  fileList.value.splice(fileIndex, 1, {
    name: data.name,
    url: data.url,
  } as UploadUserFile);
  emit(
    "update:modelValue",
    fileList.value.map((file) => file.url)
  );
}

/**
 * 删除图片
 */
function handleRemove(removeFile: UploadFile) {
  const filePath = removeFile.url;

  if (filePath) {
    FileAPI.deleteByPath(filePath).then(() => {
      // 删除成功回调
      emit(
        "update:modelValue",
        fileList.value.map((file) => file.url)
      );
    });
  }
}

/**
 * 限制用户上传文件的格式和大小
 */
function handleBeforeUpload(file: UploadRawFile) {
  if (file.size > props.uploadMaxSize) {
    let mUploadMaxSize = props.uploadMaxSize / 1048 / 1048;
    ElMessage.warning("上传图片不能大于" + mUploadMaxSize + "M");
    return false;
  }
  return true;
}

/**
 * 预览图片
 */
const previewImg: UploadProps["onPreview"] = (uploadFile: UploadFile) => {
  viewFileList.value = fileList.value.map((file) => file.url!);
  initialIndex.value = fileList.value.findIndex(
    (file) => file.url === uploadFile.url
  );
  viewVisible.value = true;
};

/**
 * 关闭预览
 */
const closePreview = () => {
  viewVisible.value = false;
};
</script>
<style lang="scss" scoped>
.hide {
  :deep(.el-upload--picture-card) {
    display: none;
  }
}

.show {
  :deep(.el-upload--picture-card) {
    display: flex;
  }
}
</style>
