<template>
  <div
    @click="togglePaneMode"
    :class="['toolbar-button', { disabled: panes.length < 2 }]"
    v-tooltip.right="label"
  >
    <font-awesome-icon icon="redo" />
  </div>
</template>

<script>
/* This is Free Software under GNU Affero General Public License v >= 3.0
 * without warranty, see README.md and license for details.
 *
 * SPDX-License-Identifier: AGPL-3.0-or-later
 * License-Filename: LICENSES/AGPL-3.0.txt
 *
 * Copyright (C) 2018 by via donau
 *   – Österreichische Wasserstraßen-Gesellschaft mbH
 * Software engineering by Intevation GmbH
 *
 * Author(s):
 * Markus Kottländer <markus.kottlaender@intevation.de>
 */
import { mapState } from "vuex";

export default {
  data() {
    return {
      // This is needed to accomplish a true rotation of components/panes with
      // two panes. On every second "rotation" the components are fliped. This way
      // toggling between horizontal and vertical mode feels like the components
      // are actually rotating. See: togglePaneMode()
      rotations: 0
    };
  },
  computed: {
    ...mapState("application", ["panes", "paneMode"]),
    label() {
      return this.$gettext("Rotate Panes");
    }
  },
  watch: {
    panes(panes) {
      if (panes.length !== 2) this.rotations = 0;
    }
  },
  methods: {
    rotateComponents() {
      this.panes.unshift(this.panes.pop());
    },
    togglePaneMode() {
      if (this.panes.length === 2) {
        this.$store.commit(
          "application/paneMode",
          this.paneMode === "horizontal" ? "vertical" : "horizontal"
        );
        if (++this.rotations % 2) {
          this.rotateComponents();
        }
      }
      if (this.panes.length === 3) {
        let next;
        if (this.paneMode === "top") {
          next = "right";
        }
        if (this.paneMode === "right") {
          next = "bottom";
        }
        if (this.paneMode === "bottom") {
          next = "left";
        }
        if (this.paneMode === "left") {
          next = "top";
        }
        this.$store.commit("application/paneMode", next);
      }
      if (this.panes.length === 4) {
        this.rotateComponents();
      }
    }
  }
};
</script>