<template>
  <div class="upload-file">
    <el-upload
      multiple
      :action="uploadFileUrl"
      :before-upload="handleBeforeUpload"
      :file-list="fileList"
      :limit="limit"
      :on-error="handleUploadError"
      :on-exceed="handleExceed"
      :on-success="handleUploadSuccess"
      :show-file-list="false"
      :headers="headers"
      class="upload-file-uploader"
      ref="fileUpload"
    >
      <!-- 上传按钮 -->
      <el-button type="primary">选取文件</el-button>
    </el-upload>
    <!-- 上传提示 -->
    <div class="el-upload__tip" v-if="showTip">
      请上传
      <template v-if="fileSize"> 大小不超过 <b style="color: #f56c6c">{{ fileSize }}MB</b> </template>
      <template v-if="fileType"> 格式为 <b style="color: #f56c6c">{{ fileType.join("/") }}</b> </template>
      的文件
    </div>
    <!-- 文件列表 -->
    <transition-group 
      class="upload-file-list el-upload-list el-upload-list--text" 
      name="el-fade-in-linear" 
      tag="ul"
      ref="fileListWrapper"
      @update="handleSortUpdate"
    >
      <li 
        :key="file.uid" 
        class="el-upload-list__item ele-upload-list__item-content draggable"
        v-for="(file, index) in fileList"
        :draggable="true"
        :title="limit > 1 ? '可拖动文件进行调序' : ''"
      >
        <el-link :href="`${file.url}`" :underline="false" target="_blank">
          <span class="el-icon-document"> {{ getFileName(file.name) }} </span>
        </el-link>
        <div class="ele-upload-list__item-content-action">
          <el-link :underline="false" @click="handleDelete(index)" type="danger">删除</el-link>
        </div>
      </li>
    </transition-group>
  </div>
</template>

<script setup>
import { getToken } from "@/utils/auth";
import { listByIds, delOss } from "@/api/system/oss";
import Sortable from 'sortablejs';

const props = defineProps({
  modelValue: [String, Object, Array],
  // 数量限制
  limit: {
    type: Number,
    default: 5,
  },
  // 大小限制(MB)
  fileSize: {
    type: Number,
    default: 100,
  },
  // 文件类型, 例如['png', 'jpg', 'jpeg']
  fileType: {
    type: Array,
    default: () => ["doc", "xls", "ppt", "txt", "pdf"],
  },
  // 是否显示提示
  isShowTip: {
    type: Boolean,
    default: true
  }
});

const { proxy } = getCurrentInstance();
const emit = defineEmits();
const number = ref(0);
const uploadList = ref([]);
const baseUrl = import.meta.env.VITE_APP_BASE_API || '';
const uploadFileUrl = ref(baseUrl + "/system/oss/upload"); // 上传文件服务器地址
const headers = ref({ Authorization: "Bearer " + getToken() });
const fileList = ref([]);
const showTip = computed(
  () => props.isShowTip && (props.fileType || props.fileSize)
);
// 初始化拖拽排序
onMounted(() => {
  const el = proxy.$refs.fileListWrapper.$el; // 确保transition-group添加ref="fileListWrapper"
  if (el) {
    new Sortable(el, {
      animation: 150, // 过渡动画时长
      draggable: '.draggable', // 可拖拽的元素
      onUpdate: (evt) => {
        // 拖拽结束时更新列表顺序
        const oldIndex = evt.oldIndex;
        const newIndex = evt.newIndex;
        
        // 移动元素位置
        fileList.value.splice(newIndex, 0, fileList.value.splice(oldIndex, 1)[0]);
        
        // 触发排序更新事件
        handleSortUpdate();
      }
    });
  }
});
// 排序更新处理
function handleSortUpdate() {
  // 更新父组件modelValue
  emit("update:modelValue", listToString(fileList.value));
  
  // 输出排序后的列表（可选）
  console.log('排序后的文件列表:', fileList.value);
}


watch(() => props.modelValue, async val => {
  if (val) {
    let temp = 1;
    // 首先将值转为数组
    let list;
    if (Array.isArray(val)) {
      list = val;
    } else {
      await listByIds(val).then(res => {
        list = res.data.map(oss => {
          oss = { name: oss.originalName, url: oss.url, ossId: oss.ossId };
          return oss;
        });
      })
    }
    // 然后将数组转为对象数组
    fileList.value = list.map(item => {
      item = {name: item.name, url: item.url, ossId: item.ossId};
      item.uid = item.uid || new Date().getTime() + temp++;
      return item;
    });
  } else {
    fileList.value = [];
    return [];
  }
},{ deep: true, immediate: true });

// 上传前校检格式和大小
function handleBeforeUpload(file) {
  // 校检文件类型
  if (props.fileType.length) {
    const fileName = file.name.split('.');
    const fileExt = fileName[fileName.length - 1];
    const isTypeOk = props.fileType.indexOf(fileExt) >= 0;
    if (!isTypeOk) {
      proxy.$modal.msgError(`文件格式不正确, 请上传${props.fileType.join("/")}格式文件!`);
      return false;
    }
  }
  // 校检文件大小
  if (props.fileSize) {
    const isLt = file.size / 1024 / 1024 < props.fileSize;
    if (!isLt) {
      proxy.$modal.msgError(`上传文件大小不能超过 ${props.fileSize} MB!`);
      return false;
    }
  }
  proxy.$modal.loading("正在上传文件，请稍候...");
  number.value++;
  return true;
}

// 文件个数超出
function handleExceed() {
  proxy.$modal.msgError(`上传文件数量不能超过 ${props.limit} 个!`);
}

// 上传失败
function handleUploadError(err) {
  proxy.$modal.msgError("上传文件失败");
}

// 上传成功回调
function handleUploadSuccess(res, file) {
  if (res.code === 200) {
    uploadList.value.push({ name: res.data.fileName, url: res.data.url, ossId: res.data.ossId });
    uploadedSuccessfully();
  } else {
    number.value--;
    proxy.$modal.closeLoading();
    proxy.$modal.msgError(res.msg);
    proxy.$refs.fileUpload.handleRemove(file);
    uploadedSuccessfully();
  }
}

// 删除文件
function handleDelete(index) {
  let ossId = fileList.value[index].ossId;
  delOss(ossId);
  fileList.value.splice(index, 1);
  emit("update:modelValue", listToString(fileList.value));
}

// 上传结束处理
function uploadedSuccessfully() {
  if (number.value > 0 && uploadList.value.length === number.value) {
    fileList.value = fileList.value.filter(f => f.url !== undefined).concat(uploadList.value);
    uploadList.value = [];
    number.value = 0;
    console.log(fileList.value);
    emit("update:modelValue", listToString(fileList.value));
    proxy.$modal.closeLoading();
  }
}

// 获取文件名称
function getFileName(name) {
  // 如果是url那么取最后的名字 如果不是直接返回
  if (name.lastIndexOf("/") > -1) {
    return name.slice(name.lastIndexOf("/") + 1);
  } else {
    return name;
  }
}

// 对象转成指定字符串分隔
function listToString(list, separator) {
  let strs = "";
  separator = separator || ",";
  for (let i in list) {
    if(list[i].ossId) {
      strs += list[i].ossId + separator;
    }
  }
  return strs != "" ? strs.substr(0, strs.length - 1) : "";
}
</script>

<style scoped lang="scss">
.upload-file-uploader {
  margin-bottom: 5px;
}
.upload-file-list .el-upload-list__item {
  border: 1px solid #e4e7ed;
  line-height: 2;
  margin-bottom: 10px;
  position: relative;
}
.upload-file-list .ele-upload-list__item-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: inherit;
}
.ele-upload-list__item-content-action .el-link {
  margin-right: 10px;
}
.draggable {
  cursor: move;
}
</style>