openmct/src/ui/layout/Pane.vue

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 Open MCT, Copyright (c) 2014-2023, United States Government
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 Open MCT is licensed under the Apache License, Version 2.0 (the
 "License"); you may not use this file except in compliance with the License.
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-->
<template>
  <div class="l-pane" :class="paneClasses">
    <div v-if="handle" class="l-pane__handle" @mousedown.prevent="startResizing"></div>
    <div class="l-pane__header">
      <span v-if="label" class="l-pane__label">{{ label }}</span>
      <slot name="controls"></slot>
      <button
        v-if="isCollapsable"
        class="l-pane__collapse-button c-icon-button"
        :name="collapseTitle"
        :title="collapseTitle"
        @click="toggleCollapse"
      ></button>
    </div>
    <button
      class="l-pane__expand-button"
      :name="expandTitle"
      :title="expandTitle"
      @click="toggleCollapse"
    >
      <span class="l-pane__expand-button__label">{{ label }}</span>
    </button>
    <div class="l-pane__contents">
      <slot></slot>
    </div>
  </div>
</template>

<script>
const COLLAPSE_THRESHOLD_PX = 40;
const LOCAL_STORAGE_KEY__PANE_POSITIONS = 'mct-pane-positions';

export default {
  inject: ['openmct'],
  props: {
    handle: {
      type: String,
      default: '',
      validator: function (value) {
        return ['', 'before', 'after'].indexOf(value) !== -1;
      }
    },
    label: {
      type: String,
      default: ''
    },
    hideParam: {
      type: String,
      default: ''
    },
    persistPosition: {
      type: Boolean,
      default: false
    }
  },
  data() {
    return {
      collapsed: false,
      resizing: false
    };
  },
  computed: {
    isCollapsable() {
      return this.hideParam?.length > 0;
    },
    collapseTitle() {
      return `Collapse ${this.label} Pane`;
    },
    expandTitle() {
      return `Expand ${this.label} Pane`;
    },
    localStorageKey() {
      if (!this.label) {
        return null;
      }

      return this.label.toLowerCase().replace(/ /g, '-');
    },
    paneClasses() {
      return {
        'l-pane--horizontal-handle-before': this.type === 'horizontal' && this.handle === 'before',
        'l-pane--horizontal-handle-after': this.type === 'horizontal' && this.handle === 'after',
        'l-pane--vertical-handle-before': this.type === 'vertical' && this.handle === 'before',
        'l-pane--vertical-handle-after': this.type === 'vertical' && this.handle === 'after',
        'l-pane--collapsed': this.collapsed,
        'l-pane--reacts': !this.handle,
        'l-pane--resizing': this.resizing === true
      };
    }
  },
  beforeMount() {
    this.type = this.$parent.type;
    this.styleProp = this.type === 'horizontal' ? 'width' : 'height';
  },
  created() {
    this.handleHideUrl = this.handleHideUrl.bind(this);
    // Hide tree and/or inspector pane if specified in URL
    this.openmct.router.on('change:params', this.handleHideUrl);
  },
  async mounted() {
    if (this.persistPosition) {
      const savedPosition = this.getSavedPosition();
      if (savedPosition) {
        this.$el.style[this.styleProp] = savedPosition;
      }
    }

    await this.$nextTick();
    if (this.isCollapsable) {
      this.handleHideUrl();
    }
  },
  beforeUnmount() {
    this.openmct.router.off('change:params', this.handleHideUrl);
  },
  methods: {
    addHideParam(target) {
      this.openmct.router.setSearchParam(target, 'true');
    },
    endResizing(_event) {
      document.body.removeEventListener('mousemove', this.updatePosition);
      document.body.removeEventListener('mouseup', this.endResizing);
      this.resizing = false;
      this.$emit('end-resizing');
      this.trackSize();
    },
    getNewSize(event) {
      const delta = this.startPosition - this.getPosition(event);
      if (this.handle === 'before') {
        return `${this.initial + delta}px`;
      }

      if (this.handle === 'after') {
        return `${this.initial - delta}px`;
      }
    },
    getSavedPosition() {
      if (!this.localStorageKey) {
        return null;
      }

      const savedPositionsString = localStorage.getItem(LOCAL_STORAGE_KEY__PANE_POSITIONS);
      const savedPositions = savedPositionsString ? JSON.parse(savedPositionsString) : {};

      return savedPositions[this.localStorageKey];
    },
    getPosition(event) {
      return this.type === 'horizontal' ? event.pageX : event.pageY;
    },
    handleCollapse() {
      this.currentSize = this.dragCollapse === true ? this.initial : this.$el.style[this.styleProp];
      this.$el.style[this.styleProp] = '';
      this.collapsed = true;
    },
    handleExpand() {
      this.$el.style[this.styleProp] = this.currentSize;
      delete this.currentSize;
      delete this.dragCollapse;
      this.collapsed = false;
    },
    handleHideUrl() {
      const hideParam = this.openmct.router.getSearchParam(this.hideParam);

      if (hideParam === 'true') {
        this.handleCollapse();
      }
    },
    removeHideParam(target) {
      this.openmct.router.deleteSearchParam(target);
    },
    setSavedPosition(panePosition) {
      const panePositionsString = localStorage.getItem(LOCAL_STORAGE_KEY__PANE_POSITIONS);
      const panePositions = panePositionsString ? JSON.parse(panePositionsString) : {};
      panePositions[this.localStorageKey] = panePosition;
      localStorage.setItem(LOCAL_STORAGE_KEY__PANE_POSITIONS, JSON.stringify(panePositions));
    },
    startResizing(event) {
      this.startPosition = this.getPosition(event);
      document.body.addEventListener('mousemove', this.updatePosition);
      document.body.addEventListener('mouseup', this.endResizing);
      this.resizing = true;
      this.$emit('start-resizing');
      this.trackSize();
    },
    toggleCollapse(_event) {
      if (this.collapsed) {
        this.handleExpand();
        this.removeHideParam(this.hideParam);
      } else {
        this.handleCollapse();
        this.addHideParam(this.hideParam);
      }
    },
    trackSize() {
      if (!this.dragCollapse) {
        if (this.type === 'vertical') {
          this.initial = this.$el.offsetHeight;
        } else if (this.type === 'horizontal') {
          this.initial = this.$el.offsetWidth;
        }

        if (this.persistPosition) {
          this.setSavedPosition(`${this.initial}px`);
        }
      }
    },
    updatePosition(event) {
      const size = this.getNewSize(event);
      const intSize = parseInt(size.substr(0, size.length - 2), 10);
      if (intSize < COLLAPSE_THRESHOLD_PX && this.isCollapsable === true) {
        this.dragCollapse = true;
        this.endResizing();
        this.toggleCollapse();
      } else {
        this.$el.style[this.styleProp] = size;
      }
    }
  }
};
</script>