<template>
      <div class="header">
          <!-- 折叠按钮 -->
          <div class="collapse-btn" @click="collapseChage">
              <i v-if="!collapse" class="el-icon-s-fold"></i>
              <i v-else class="el-icon-s-unfold"></i>
          </div>
          <div class="logo">后台管理系统</div>
          <div class="header-right">
              <div class="header-user-con">
                  <!-- 全屏显示 -->
                  <div class="btn-fullscreen" @click="handleFullScreen">
                      <el-tooltip effect="dark" :content="fullscreen?`取消全屏`:`全屏`" placement="bottom">
                          <i class="el-icon-rank"></i>
                      </el-tooltip>
                  </div>
                  <!-- 消息中心 -->
                  <div class="btn-bell">
                      <el-tooltip
                          effect="dark"
                          :content="message?`有${message}条未读消息`:`消息中心`"
                          placement="bottom"
                      >
                          <router-link to="/tabs">
                              <i class="el-icon-bell"></i>
                          </router-link>
                      </el-tooltip>
                      <span class="btn-bell-badge" v-if="message"></span>
                  </div>
                  <!-- 用户头像 -->
                  <div class="user-avator">
                      <img src="../assets/img/img.jpg" />
                  </div>
                  <!-- 用户名下拉菜单 -->
                  <el-dropdown class="user-name" trigger="click" @command="handleCommand">
                      <span class="el-dropdown-link">
                          {{username}}
                          <i class="el-icon-caret-bottom"></i>
                      </span>
                      <el-dropdown-menu slot="dropdown">
                          <a href="https://github.com/lin-xin/vue-manage-system" target="_blank">
                              <el-dropdown-item>项目仓库</el-dropdown-item>
                          </a>
                          <el-dropdown-item divided command="loginout">退出登录</el-dropdown-item>
                      </el-dropdown-menu>
                  </el-dropdown>
              </div>
          </div>
      </div>
  </template>
  <script>
  import bus from './bus';
  export default {
      data() {
          return {
              collapse: false,
              fullscreen: false,
              name: 'linxin',
              message: 2
          };
      },
      computed: {
          username() {
              let username = localStorage.getItem('ms_username');
              return username ? username : this.name;
          }
      },
      methods: {
          // 用户名下拉菜单选择事件
          handleCommand(command) {
              if (command == 'loginout') {
                  localStorage.removeItem('ms_username');
                  this.$router.push('/login');
              }
          },
          // 侧边栏折叠
          collapseChage() {
              this.collapse = !this.collapse;
              bus.$emit('collapse', this.collapse);
          },
          // 全屏事件
          handleFullScreen() {
              let element = document.documentElement;
              if (this.fullscreen) {
                  if (document.exitFullscreen) {
                      document.exitFullscreen();
                  } else if (document.webkitCancelFullScreen) {
                      document.webkitCancelFullScreen();
                  } else if (document.mozCancelFullScreen) {
                      document.mozCancelFullScreen();
                  } else if (document.msExitFullscreen) {
                      document.msExitFullscreen();
                  }
              } else {
                  if (element.requestFullscreen) {
                      element.requestFullscreen();
                  } else if (element.webkitRequestFullScreen) {
                      element.webkitRequestFullScreen();
                  } else if (element.mozRequestFullScreen) {
                      element.mozRequestFullScreen();
                  } else if (element.msRequestFullscreen) {
                      // IE11
                      element.msRequestFullscreen();
                  }
              }
              this.fullscreen = !this.fullscreen;
          }
      },
      mounted() {
          if (document.body.clientWidth < 1500) {
              this.collapseChage();
          }
      }
  };
  </script>
  <style scoped>
  .header {
      position: relative;
      box-sizing: border-box;
      width: 100%;
      height: 70px;
      font-size: 22px;
      color: #fff;
  }
  .collapse-btn {
      float: left;
      padding: 0 21px;
      cursor: pointer;
      line-height: 70px;
  }
  .header .logo {
      float: left;
      width: 250px;
      line-height: 70px;
  }
  .header-right {
      float: right;
      padding-right: 50px;
  }
  .header-user-con {
      display: flex;
      height: 70px;
      align-items: center;
  }
  .btn-fullscreen {
      transform: rotate(45deg);
      margin-right: 5px;
      font-size: 24px;
  }
  .btn-bell,
  .btn-fullscreen {
      position: relative;
      width: 30px;
      height: 30px;
      text-align: center;
      border-radius: 15px;
      cursor: pointer;
  }
  .btn-bell-badge {
      position: absolute;
      right: 0;
      top: -2px;
      width: 8px;
      height: 8px;
      border-radius: 4px;
      background: #f56c6c;
      color: #fff;
  }
  .btn-bell .el-icon-bell {
      color: #fff;
  }
  .user-name {
      margin-left: 10px;
  }
  .user-avator {
      margin-left: 20px;
  }
  .user-avator img {
      display: block;
      width: 40px;
      height: 40px;
      border-radius: 50%;
  }
  .el-dropdown-link {
      color: #fff;
      cursor: pointer;
  }
  .el-dropdown-menu__item {
      text-align: center;
  }
  </style>