<!--
  - Copyright 2014-2018 the original author or authors.
  -
  - Licensed under the Apache License, Version 2.0 (the "License");
  - you may not use this file except in compliance with the License.
  - You may obtain a copy of the License at
  -
  -     http://www.apache.org/licenses/LICENSE-2.0
  -
  - Unless required by applicable law or agreed to in writing, software
  - distributed under the License is distributed on an "AS IS" BASIS,
  - WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  - See the License for the specific language governing permissions and
  - limitations under the License.
  -->

<template>
  <div class="section">
    <div class="container">
      <h1 class="title">Event Journal</h1>
      <div v-if="error" class="message is-warning">
        <div class="message-body">
          <strong>
            <font-awesome-icon class="has-text-warning" icon="exclamation-triangle"/>
            Server connection failed.
          </strong>
          <p v-text="error.message"/>
        </div>
      </div>
      <table class="table is-fullwidth">
        <thead>
          <tr>
            <th>Application</th>
            <th>Instance</th>
            <th>Time</th>
            <th>Event</th>
          </tr>
        </thead>
        <tbody>
          <template v-for="event in events">
            <tr class="is-selectable" :key="event.key"
                @click="showPayload[event.key] ? $delete(showPayload, event.key) : $set(showPayload, event.key, true)">
              <td v-text="instanceNames[event.instance] || '?'"/>
              <td v-text="event.instance"/>
              <td v-text="event.timestamp.format('L HH:mm:ss.SSS')"/>
              <td>
                <span v-text="event.type"/> <span v-if="event.type === 'STATUS_CHANGED'"
                                                  v-text="`(${event.payload.statusInfo.status})`"/>
              </td>
            </tr>
            <tr :key="`${event.key}-detail`" v-if="showPayload[event.key]">
              <td colspan="4">
                <pre v-text="toJson(event.payload)"/>
              </td>
            </tr>
          </template>
        </tbody>
      </table>
    </div>
  </div>
</template>

<script>
  import subscribing from '@/mixins/subscribing';
  import Instance from '@/services/instance';
  import {compareBy} from '@/utils/collections';
  import _ from 'lodash';
  import moment from 'moment';

  class Event {
    constructor(event) {
      this.instance = event.instance;
      this.version = event.version;
      this.type = event.type;
      this.timestamp = moment(event.timestamp);
      this.payload = _.omit(event, ['instance', 'version', 'timestamp', 'type']);
    }

    get key() {
      return `${this.instance}-${this.version}`;
    }
  }

  export default {
    mixins: [subscribing],
    data: () => ({
      events: [],
      showPayload: {},
      instanceNames: {},
      error: null
    }),
    methods: {
      toJson(obj) {
        return JSON.stringify(obj, null, 4);
      },
      addEvents(data) {
        const converted = data.map(event => new Event(event));
        converted.reverse();
        this.events = converted.concat(this.events);

        const newInstanceNames = converted.filter(event => event.type === 'REGISTERED').reduce((names, event) => ({
          ...names,
          [event.instance]: event.payload.registration.name
        }), {});
        _.assign(this.instanceNames, newInstanceNames);
      },
      createSubscription() {
        return Instance.getEventStream().subscribe({
          next: message => {
            this.error = null;
            this.addEvents([message.data])
          },
          error: error => {
            console.warn('Listening for events failed:', error);
            this.error = error;
          }
        });
      }
    },
    async created() {
      try {
        const response = await Instance.fetchEvents();
        this.addEvents(response.data.sort(compareBy(v => v.timestamp)));
        this.error = null;
      } catch (error) {
        console.warn('Fetching events failed:', error);
        this.error = error;
      }
    },
    install({viewRegistry}) {
      viewRegistry.addView({
        path: '/journal',
        name: 'journal',
        label: 'Journal',
        order: 100,
        component: this
      });
    }
  };
</script>
