<template>
  <div class="la-panel" :class="panelClass" :tabindex="1">
    <div class="la-panel__header" v-if="!hideTitle" @dblclick="handleDblClick">
      <i class="la-panel__icon" :class="panelIcon"></i>

      <div v-if="!collapse" style="display: inline-block;">
        <slot v-if="$slots.title" name="title"/>
        <span v-else>{{title}}</span>
      </div>


      <span v-if="collapse" class="la-panel__colbtn" @click="handleCollapse">
        <i class="la-panel__colbtn__icon el-icon-d-arrow-right"/>
        <span>{{title}}</span>
      </span>

      <el-popover v-if="$slots.help" placement="top" v-model="showHelp" popper-class="la-panel-help-popper">
        <div>
          <slot name="help"/>
        </div>
        <template slot="reference">
          <i style="color:#2d8cf0;cursor:pointer;margin-left:4px" class="el-icon-question"/>
        </template>
      </el-popover>

      <div class="la-panel__buttons">
        <slot name="buttons"/>
        <el-button v-if="maxable"
                   :icon="state!=='maximize'?'el-icon-fa-window-maximize':'el-icon-fa-window-minimize'"
                   type="text"
                   title="点击最大化" @click="handleDblClick"/>
      </div>

      <div style="clear:both"></div>
    </div>

    <div class="la-panel__body ">
      <slot/>
      <div style="clear:both"></div>
    </div>

    <div style="clear:both"></div>

  </div>

</template>

<script>
  const panelManager = {
    idx: 0,
    next() {
      ++this.idx;
    }
  };

  export default {
    name: "panel",
    props: {
      maxable: {type: Boolean, default: false},
      collapse: {type: Boolean, default: false},
      light: {type: Boolean, default: false},
      icon: {type: String},
      full: {type: Boolean, default: false},
      title: {type: String},
      hideTitle: {type: Boolean, default: false},
    },
    computed: {
      panelIcon() {
        return this.light && !this.collapse ? "el-icon-d-arrow-right" : this.icon;
      },
      panelClass() {
        return [
          {
            "la-panel--full": this.full,
            "la-panel--collapse": this.collapse,
            "la-panel--light": this.light,
            "la-panel--icon": !!this.icon
          },
          "la-panel--" + this.state
        ];
      }
    },
    data() {
      return {
        showHelp: false,
        state: "opened"
      };
    },
    beforeMount() {
      if (this.collapse) {
        this.state = "closed";
      }
    },
    mounted() {
      this.$el.tabindex = panelManager.next();
      this.$el.addEventListener("keydown", e => {
        if (e.keyCode == 112) {
          if (this.$slots.help) {
            this.showHelp = !this.showHelp;
          }
          e.preventDefault();
        }
      });

      this.$el.addEventListener("mousedown", e => {
        // document
        //   .querySelectorAll(".la-panel")
        //   .forEach(i => i.classList.remove("la-panel--focus"));
        // e.currentTarget.classList.add("la-panel-focus");
      });
    },
    methods: {
      handleCollapse() {
        if (this.state === "closed") {
          this.state = "opened";
          this.$emit('opened');
        } else {
          this.state = "closed";
          this.$emit('closed');
        }
      },
      handleDblClick() {
        if (!this.maxable) {
          return;
        }
        this.state = this.state === "maximize" ? "" : "maximize";
      }
    }
  };
</script>
