<template>
  <div class="kole-mention" v-click-outside="close">
    <div class="kole-mention-area">
      <textarea
        ref="input"
        class="kole-mention-input"
        :value="value"
        rows="3"
        placeholder="输入 @ 提及同事…"
        @input="onInput"
        @keydown.down.prevent="move(1)"
        @keydown.up.prevent="move(-1)"
        @keydown.enter.prevent="enter"
        @keydown.esc="close"
      ></textarea>
      <div v-show="open" class="kole-mention-panel">
        <div
          v-for="(u, i) in users"
          :key="u.name"
          class="kole-mention-item"
          :class="{ 'is-active': i === active }"
          @click="insert(u.name)"
        >
          <span class="kole-mention-avatar">{{ u.name[0] }}</span>
          <span class="kole-mention-name">{{ u.name }}</span>
          <span class="kole-mention-dept">{{ u.dept }}</span>
        </div>
      </div>
    </div>
    <div class="kole-mention-chips">
      <span v-for="n in mentioned" :key="n" class="kole-mention-chip">@{{ n }} <b @click="remove(n)">×</b></span>
    </div>
  </div>
</template>

<script>
export default {
  name: 'KoleMention',
  directives: {
    clickOutside: { bind(el, b) { el.__d = (e) => { if (!el.contains(e.target)) b.value(); }; document.addEventListener('click', el.__d); }, unbind(el) { document.removeEventListener('click', el.__d); } }
  },
  props: {
    value: { type: String, default: '' },
    users: {
      type: Array,
      default: () => [
        { name: '王伟', dept: '华东大区' }, { name: '李娜', dept: '华南大区' }, { name: '张强', dept: '华北大区' },
        { name: '陈静', dept: '研发中心' }, { name: '刘洋', dept: '市场部' }
      ]
    }
  },
  data() {
    return { open: false, active: -1, mentioned: [] };
  },
  methods: {
    onInput(e) {
      var pos = e.target.selectionStart, v = e.target.value;
      this.$emit('input', v);
      var at = v.lastIndexOf('@', pos - 1);
      if (at >= 0 && (at === 0 || /\s/.test(v[at - 1])) && !/\s/.test(v.slice(at + 1, pos))) { this.active = -1; this.open = true; }
      else this.open = false;
    },
    move(d) { this.active = Math.max(-1, Math.min(this.users.length - 1, this.active + d)); },
    enter() { if (this.active >= 0) this.insert(this.users[this.active].name); },
    insert(name) {
      var el = this.$refs.input, pos = el.selectionStart, v = el.value;
      var at = v.lastIndexOf('@', pos - 1);
      if (at >= 0 && (at === 0 || /\s/.test(v[at - 1]))) el.value = v.slice(0, at) + '@' + name + ' ' + v.slice(pos);
      else el.value = v.slice(0, pos) + '@' + name + ' ' + v.slice(pos);
      if (this.mentioned.indexOf(name) < 0) this.mentioned.push(name);
      this.$emit('input', el.value);
      this.close();
      el.focus();
    },
    remove(n) { this.mentioned = this.mentioned.filter((x) => x !== n); },
    close() { this.open = false; }
  }
};
</script>

<style src="./Mention.css"></style>
