<template>
  <el-upload
    :action="uploadUrl"
    :headers="headers"
    :max-size="maxSize"
    :format="format"
    :data="uploadDataDict"
    :before-upload="handleBeforeUpload"
    :on-error="handleError"
    :on-success="handleSuccess"
    :http-request="upload"
    :show-file-list="false"
    style="display:inline-block;margin: 0 18px;"
    ref="UploadComp"
  >
    <el-button :type="btnType" :icon="btnIcon" :loading="loading">{{
      btnContent
    }}</el-button>
  </el-upload>
</template>

<script>
import { fileMD5 } from "../plugins/md5";
import ajax from "../plugins/ajax";

export default {
  name: "upload-button",
  props: {
    btnIcon: {
      type: String
    },
    btnType: {
      type: String,
      default: "default"
    },
    btnContent: {
      type: String
    },
    format: {
      type: Array,
      default() {
        return ["jpg", "jpeg", "png"];
      }
    },
    uploadUrl: {
      type: String,
      required: true
    },
    uploadData: {
      type: Object,
      default() {
        return {};
      }
    },
    maxSize: {
      type: Number,
      default: 20 * 1024 * 1024
    },
    addFilenameParam: {
      type: String,
      default: "filename"
    }
  },
  data() {
    return {
      headers: {
        token: "",
        md5: ""
      },
      res: {},
      loading: false,
      uploadDataDict: {}
    };
  },
  methods: {
    checkFileFormat(fileType) {
      const _file_format = fileType
        .split(".")
        .pop()
        .toLocaleLowerCase();
      return this.format.length
        ? this.format.some(item => item.toLocaleLowerCase() === _file_format)
        : true;
    },
    async handleBeforeUpload(file) {
      this.uploadDataDict = {
        ...this.uploadData
      };
      this.uploadDataDict[this.addFilenameParam] = file.name;

      if (file.size > this.maxSize) {
        this.handleExceededSize();
        return Promise.reject();
      }

      if (!this.checkFileFormat(file.name)) {
        this.handleFormatError();
        return Promise.reject();
      }

      const md5 = await fileMD5(file);
      this.headers["md5"] = md5;
      this.loading = true;

      return true;
    },
    upload(options) {
      return ajax(options);
    },
    handleError(error) {
      this.loading = false;
      this.res = {
        success: false,
        message: error.message
      };
      this.$emit("upload-error", error);
    },
    handleSuccess(response) {
      this.loading = false;
      if (response.code === "200") {
        this.res = {
          success: true,
          message: "导入成功！"
        };
        this.$emit("upload-success", response);
      } else {
        this.handleError(response);
      }
    },
    handleFormatError() {
      const content = "只支持文件格式为" + this.format.join("/");
      this.res = {
        success: false,
        message: content
      };
      this.$emit("upload-error", this.res);
    },
    handleExceededSize() {
      const content =
        "文件大小不能超过" + Math.floor(this.maxSize / (1024 * 1024)) + "M";
      this.res = {
        success: false,
        message: content
      };
      this.$emit("upload-error", this.res);
    }
  }
};
</script>