From 39ce53f561a73421cca195c955a44bb48c9c776c Mon Sep 17 00:00:00 2001
From: Shefali <simplyrender@gmail.com>
Date: Tue, 18 Mar 2025 11:32:09 -0700
Subject: [PATCH] Use composable instead of using event emitters for extended
 lines overlays

---
 .../events/components/EventTimelineView.vue   |  90 +++++----
 src/plugins/timeline/ExtendedLinesOverlay.vue |  60 +++---
 src/plugins/timeline/TimelineObjectView.vue   |  18 +-
 src/plugins/timeline/TimelineViewLayout.vue   |  12 --
 src/ui/composables/extendedLines.js           | 177 ++++++++++++++++++
 5 files changed, 273 insertions(+), 84 deletions(-)
 create mode 100644 src/ui/composables/extendedLines.js

diff --git a/src/plugins/events/components/EventTimelineView.vue b/src/plugins/events/components/EventTimelineView.vue
index 49a626f651..478bde8525 100644
--- a/src/plugins/events/components/EventTimelineView.vue
+++ b/src/plugins/events/components/EventTimelineView.vue
@@ -34,8 +34,8 @@
             class="c-events-tsv__event-line"
             :class="event.limitClass || ''"
             :style="`left: ${event.left}px`"
-            @mouseover="showToolTip(event)"
-            @mouseleave="dismissToolTip()"
+            @mouseenter="showToolTip(event)"
+            @mouseleave="dismissToolTip(event)"
             @click.stop="createSelectionForInspector(event)"
           ></div>
         </div>
@@ -54,6 +54,7 @@ import SwimLane from '@/ui/components/swim-lane/SwimLane.vue';
 
 import tooltipHelpers from '../../../api/tooltips/tooltipMixins';
 import { useAlignment } from '../../../ui/composables/alignmentContext.js';
+import { useExtendedLines } from '../../../ui/composables/extendedLines';
 import eventData from '../mixins/eventData.js';
 
 const PADDING = 1;
@@ -68,7 +69,21 @@ export default {
     const objectPath = inject('objectPath');
     const openmct = inject('openmct');
     const { alignment: alignmentData } = useAlignment(domainObject, objectPath, openmct);
-    return { alignmentData };
+
+    const {
+      extendedLines: extendedLines,
+      update: updateExtendedLines,
+      updateLineHover: updateExtendedLineHover,
+      remove: removeLinesForObject
+    } = useExtendedLines(domainObject, objectPath, openmct);
+
+    return {
+      alignmentData,
+      extendedLines,
+      updateExtendedLineHover,
+      updateExtendedLines,
+      removeLinesForObject
+    };
   },
   data() {
     return {
@@ -107,13 +122,23 @@ export default {
         this.setScaleAndPlotEvents(this.timeSystem);
       },
       deep: true
+    },
+    extendedLines: {
+      handler() {
+        const { enabled = false } = this.extendedLines[this.keyString];
+        if (this.extendedLinesEnabled !== enabled) {
+          this.extendedLinesEnabled = enabled === true;
+          this.updateLines();
+        }
+      },
+      deep: true
     }
   },
   created() {
     this.valueMetadata = {};
     this.height = 0;
     this.timeSystem = this.openmct.time.getTimeSystem();
-    this.extendLines = false;
+    this.extendedLinesEnabled = false;
   },
   mounted() {
     this.setDimensions();
@@ -136,8 +161,6 @@ export default {
     this.resize = _.debounce(this.resize, 400);
     this.eventStripResizeObserver = new ResizeObserver(this.resize);
     this.eventStripResizeObserver.observe(this.$refs.events);
-    this.extendedLinesBus.addEventListener('disable-extended-lines', this.disableExtendEventLines);
-    this.extendedLinesBus.addEventListener('enable-extended-lines', this.enableExtendEventLines);
   },
   beforeUnmount() {
     if (this.eventStripResizeObserver) {
@@ -148,15 +171,6 @@ export default {
     if (this.unlisten) {
       this.unlisten();
     }
-    if (this.destroyEventContainer) {
-      this.destroyEventContainer();
-    }
-
-    this.extendedLinesBus.removeEventListener(
-      'disable-extended-lines',
-      this.disableExtendEventLines
-    );
-    this.extendedLinesBus.removeEventListener('enable-extended-lines', this.enableExtendEventLines);
   },
   methods: {
     setTimeContext() {
@@ -165,20 +179,6 @@ export default {
       this.timeContext.on('timeSystem', this.setScaleAndPlotEvents);
       this.timeContext.on('boundsChanged', this.updateViewBounds);
     },
-    enableExtendEventLines(event) {
-      const keyStringToEnable = event.detail;
-      if (this.keyString === keyStringToEnable) {
-        this.extendLines = true;
-        this.emitExtendedLines();
-      }
-    },
-    disableExtendEventLines(event) {
-      const keyStringToDisable = event.detail;
-      if (this.keyString === keyStringToDisable) {
-        this.extendLines = false;
-        this.emitExtendedLines();
-      }
-    },
     firstNonDomainAttribute(metadata) {
       return metadata
         .values()
@@ -242,12 +242,11 @@ export default {
           return {
             ...eventHistoryItem,
             left: this.xScale(eventHistoryItem.time),
-            limitClass
+            limitClass,
+            hoverEnabled: false
           };
         });
-        if (this.extendLines) {
-          this.emitExtendedLines();
-        }
+        this.updateLines();
       }
     },
     setDimensions() {
@@ -354,22 +353,33 @@ export default {
         `wrapper-${event.time}`,
         [aClasses.join(' ')]
       );
-      this.extendedLinesBus.updateHoverExtendEventLine(this.keyString, event.time);
+      this.updateExtendedLineHover({
+        keyString: this.keyString,
+        id: event.time,
+        hoverEnabled: true
+      });
     },
-    dismissToolTip() {
+    dismissToolTip(event) {
       this.hideToolTip();
-      this.extendedLinesBus.updateHoverExtendEventLine(this.keyString, null);
+      this.updateExtendedLineHover({
+        keyString: this.keyString,
+        id: event.time
+      });
     },
-    emitExtendedLines() {
+    updateLines() {
       let lines = [];
-      if (this.extendLines) {
+      if (this.extendedLinesEnabled) {
         lines = this.eventItems.map((e) => ({
           x: e.left,
           limitClass: e.limitClass,
-          id: e.time
+          id: e.time,
+          hoverEnabled: false
         }));
       }
-      this.extendedLinesBus.updateExtendedLines(this.keyString, lines);
+      this.updateExtendedLines({
+        lines,
+        keyString: this.keyString
+      });
     }
   }
 };
diff --git a/src/plugins/timeline/ExtendedLinesOverlay.vue b/src/plugins/timeline/ExtendedLinesOverlay.vue
index 27daa8219e..0b2c6f1f17 100644
--- a/src/plugins/timeline/ExtendedLinesOverlay.vue
+++ b/src/plugins/timeline/ExtendedLinesOverlay.vue
@@ -22,37 +22,39 @@
 <template>
   <div class="c-timeline__overlay-lines">
     <div
-      v-for="(lines, key) in extendedLinesPerKey"
+      v-for="(lineData, key) in extendedLines"
       :key="key"
       class="c-timeline__event-line--extended-container"
     >
-      <div
-        v-for="(line, index) in lines"
-        :id="line.id"
-        :key="`${index - line.id}`"
-        class="c-timeline__event-line--extended"
-        :class="[
-          line.limitClass,
-          {
-            '--hilite':
-              (hoveredLineId && hoveredKeyString === key && line.id === hoveredLineId) ||
-              (selectedLineId && selectedKeyString === key && line.id === selectedLineId)
-          }
-        ]"
-        :style="{ left: `${line.x + leftOffset}px`, height: `${height}px` }"
-      ></div>
+      <template v-if="lineData.enabled">
+        <div
+          v-for="(line, index) in lineData.lines"
+          :id="line.id"
+          :key="`${index - line.id}`"
+          class="c-timeline__event-line--extended"
+          :class="[
+            line.limitClass,
+            {
+              '--hilite':
+                line.hoverEnabled === true ||
+                (selectedLineId && selectedKeyString === key && line.id === selectedLineId)
+            }
+          ]"
+          :style="{ left: `${line.x + leftOffset}px`, height: `${height}px` }"
+        ></div>
+      </template>
     </div>
   </div>
 </template>
 
 <script>
+import { inject } from 'vue';
+
+import { useExtendedLines } from '../../ui/composables/extendedLines';
+
 export default {
   name: 'ExtendedLinesOverlay',
   props: {
-    extendedLinesPerKey: {
-      type: Object,
-      required: true
-    },
     height: {
       type: Number,
       required: true
@@ -61,22 +63,20 @@ export default {
       type: Number,
       default: 0
     },
-    extendedLineHover: {
-      type: Object,
-      required: true
-    },
     extendedLineSelection: {
       type: Object,
       required: true
     }
   },
+  setup() {
+    const domainObject = inject('domainObject');
+    const path = inject('path');
+    const openmct = inject('openmct');
+    const { extendedLines: extendedLines } = useExtendedLines(domainObject, path, openmct);
+
+    return { extendedLines };
+  },
   computed: {
-    hoveredLineId() {
-      return this.extendedLineHover.id || null;
-    },
-    hoveredKeyString() {
-      return this.extendedLineHover.keyString || null;
-    },
     selectedLineId() {
       return this.extendedLineSelection.id || null;
     },
diff --git a/src/plugins/timeline/TimelineObjectView.vue b/src/plugins/timeline/TimelineObjectView.vue
index cc6cce7442..3c0743187a 100644
--- a/src/plugins/timeline/TimelineObjectView.vue
+++ b/src/plugins/timeline/TimelineObjectView.vue
@@ -50,9 +50,13 @@
 </template>
 
 <script>
+import { inject } from 'vue';
+
 import ObjectView from '@/ui/components/ObjectView.vue';
 import SwimLane from '@/ui/components/swim-lane/SwimLane.vue';
 
+import { useExtendedLines } from '../../ui/composables/extendedLines';
+
 export default {
   components: {
     ObjectView,
@@ -69,6 +73,16 @@ export default {
       required: true
     }
   },
+  setup() {
+    const domainObject = inject('domainObject');
+    const objectPath = inject('path');
+    const openmct = inject('openmct');
+
+    const { disable: disableExetendedLinesForObject, enable: enableExtendedLinesForObject } =
+      useExtendedLines(domainObject, objectPath, openmct);
+
+    return { disableExetendedLinesForObject, enableExtendedLinesForObject };
+  },
   data() {
     return {
       domainObject: null,
@@ -141,11 +155,11 @@ export default {
     },
     enableExtendEventLines() {
       const keyString = this.openmct.objects.makeKeyString(this.item.domainObject.identifier);
-      this.extendedLinesBus.enableExtendEventLines(keyString);
+      this.enableExtendedLinesForObject(keyString);
     },
     disableExtendEventLines() {
       const keyString = this.openmct.objects.makeKeyString(this.item.domainObject.identifier);
-      this.extendedLinesBus.disableExtendEventLines(keyString);
+      this.disableExetendedLinesForObject(keyString);
     },
     setActionCollection(actionCollection) {
       this.openmct.menus.actionsToMenuItems(
diff --git a/src/plugins/timeline/TimelineViewLayout.vue b/src/plugins/timeline/TimelineViewLayout.vue
index c9a1b573aa..7f19cf5566 100644
--- a/src/plugins/timeline/TimelineViewLayout.vue
+++ b/src/plugins/timeline/TimelineViewLayout.vue
@@ -47,10 +47,8 @@
     </div>
 
     <ExtendedLinesOverlay
-      :extended-lines-per-key="extendedLinesPerKey"
       :height="height"
       :left-offset="extendedLinesLeftOffset"
-      :extended-line-hover="extendedLineHover"
       :extended-line-selection="extendedLineSelection"
     />
   </div>
@@ -105,8 +103,6 @@ export default {
       height: 0,
       useIndependentTime: this.domainObject.configuration.useIndependentTime === true,
       timeOptions: this.domainObject.configuration.timeOptions,
-      extendedLinesPerKey: {},
-      extendedLineHover: {},
       extendedLineSelection: {},
       extendedLinesLeftOffset: 0
     };
@@ -128,15 +124,11 @@ export default {
     this.handleContentResize.cancel();
     this.contentResizeObserver.disconnect();
     this.openmct.selection.off('change', this.checkForLineSelection);
-    this.extendedLinesBus.removeEventListener('update-extended-lines', this.updateExtendedLines);
-    this.extendedLinesBus.removeEventListener('update-extended-hover', this.updateExtendedHover);
   },
   mounted() {
     this.items = [];
     this.setTimeContext();
 
-    this.extendedLinesBus.addEventListener('update-extended-lines', this.updateExtendedLines);
-    this.extendedLinesBus.addEventListener('update-extended-hover', this.updateExtendedHover);
     this.openmct.selection.on('change', this.checkForLineSelection);
 
     if (this.composition) {
@@ -275,10 +267,6 @@ export default {
       const { keyString, lines } = event.detail;
       this.extendedLinesPerKey[keyString] = lines;
     },
-    updateExtendedHover(event) {
-      const { keyString, id } = event.detail;
-      this.extendedLineHover = { keyString, id };
-    },
     checkForLineSelection(selection) {
       const selectionContext = selection?.[0]?.[0]?.context;
       const eventType = selectionContext?.type;
diff --git a/src/ui/composables/extendedLines.js b/src/ui/composables/extendedLines.js
new file mode 100644
index 0000000000..64544a13cf
--- /dev/null
+++ b/src/ui/composables/extendedLines.js
@@ -0,0 +1,177 @@
+/*****************************************************************************
+ * Open MCT, Copyright (c) 2014-2024, United States Government
+ * as represented by the Administrator of the National Aeronautics and Space
+ * Administration. All rights reserved.
+ *
+ * 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.
+ * 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.
+ *
+ * Open MCT includes source code licensed under additional open source
+ * licenses. See the Open Source Licenses file (LICENSES.md) included with
+ * this source code distribution or the Licensing information page available
+ * at runtime from the About dialog for additional information.
+ *****************************************************************************/
+/* eslint-disable func-style */
+
+import { reactive } from 'vue';
+
+/** @type {Map<string, LineData> | null} */
+const extendedLineMap = new Map();
+/**
+ * Manages line data given an timeline object.
+ * This is a Vue composition API utility function.
+ * @param {Object} targetObject - The target to that's consuming the useExtendedLines composable.
+ * @param {ObjectPath} objectPath - The path of the target object.
+ * @param {import('../../../openmct.js').OpenMCT} openmct - The open mct API.
+ * @returns {Object} An object containing line data and methods to update, enable/disable, and reset extended line data.
+ */
+export function useExtendedLines(targetObject, objectPath, openmct) {
+  /**
+   * Get the key for the extended line given a path.
+   * @returns {string|undefined} The key of the extended line if found, otherwise undefined.
+   */
+  const getTargetObjectKeyForPath = () => {
+    const keys = Array.from(extendedLineMap.keys());
+    return objectPath
+      .map((domainObject) => openmct.objects.makeKeyString(domainObject.identifier))
+      .reverse()
+      .find((keyString) => keys.includes(keyString));
+  };
+
+  // Use the furthest ancestor's lineData if it exists, otherwise, use your own
+  let targetObjectKey =
+    getTargetObjectKeyForPath() || openmct.objects.makeKeyString(targetObject.identifier);
+
+  if (!extendedLineMap.has(targetObjectKey)) {
+    extendedLineMap.set(targetObjectKey, reactive({}));
+  }
+
+  /**
+   * Reset any data for the given target object.
+   */
+  const reset = () => {
+    const key = getTargetObjectKeyForPath();
+    if (key && extendedLineMap.has(key)) {
+      extendedLineMap.delete(key);
+    }
+  };
+
+  /**
+   * @typedef {Object} UpdateParams
+   * @property {Array} lines - The line data to be updated.
+   * @property {string} keyString - The domain object identifier of the telemetry object.
+   */
+
+  /**
+   * Update line data given the keyString and path. The path is used to determine which ancestor should hold the lineData.
+   * @param {UpdateParams} param0 - The array of lines, keyString.
+   */
+  const update = ({ lines, keyString } = {}) => {
+    const key = getTargetObjectKeyForPath();
+    if (key) {
+      const lineData = extendedLineMap.get(key);
+      if (lineData[keyString] === undefined) {
+        lineData[keyString] = {};
+      }
+      lineData[keyString].lines = lines;
+    }
+  };
+
+  /**
+   * @typedef {Object} UpdateParams
+   * @property {string} keyString - The domain object identifier of the telemetry object.
+   * @property {string} id - The identifier of the line
+   */
+
+  /**
+   * Update line data given the keyString and path. The path is used to determine which ancestor should hold the lineData.
+   * @param {UpdateParams} param0 - The keyString and id.
+   */
+  const updateLineHover = ({ keyString, id, hoverEnabled } = {}) => {
+    const key = getTargetObjectKeyForPath();
+    if (key) {
+      const lineData = extendedLineMap.get(key);
+      if (lineData[keyString] !== undefined) {
+        const lines = lineData[keyString].lines || [];
+        let line = lines.find((lineItem) => {
+          return lineItem.id === id;
+        });
+        if (line) {
+          line.hoverEnabled = hoverEnabled === true;
+        }
+      }
+    }
+  };
+
+  /**
+   * @typedef {Object} RemoveParams
+   * @property {string} keyString - The domain object identifier of the telemetry object.
+   */
+
+  /**
+   * Unregister a telemetry object from line data.
+   * @param keyString
+   */
+  const disable = (keyString) => {
+    const key = getTargetObjectKeyForPath();
+    if (key) {
+      const lineData = extendedLineMap.get(key);
+      if (lineData[keyString] !== undefined) {
+        lineData[keyString].enabled = false;
+      }
+    }
+  };
+
+  /**
+   * @typedef {Object} AddParams
+   * @property {string} keyString - The domain object identifier of the telemetry object.
+   */
+
+  /**
+   * Register a telemetry object to line data.
+   * @param keyString
+   */
+  const enable = (keyString) => {
+    const key = getTargetObjectKeyForPath();
+    if (key) {
+      const lineData = extendedLineMap.get(key);
+      if (lineData[keyString] === undefined) {
+        lineData[keyString] = {};
+      }
+      lineData[keyString].enabled = true;
+    }
+  };
+
+  return {
+    extendedLines: extendedLineMap.get(targetObjectKey),
+    update,
+    updateLineHover,
+    enable,
+    disable,
+    reset
+  };
+}
+
+/**
+ * @typedef {import('../../api/objects/ObjectAPI.js').DomainObject[]} ObjectPath
+ */
+
+/**
+ * @typedef {Object} LineData
+ * @property {Map<string, {Object} boolean, Array.<Line>> keyString - The domain object identifier of the telemetry object (typically an event or command)
+ */
+
+/**
+ * @typedef {Object} Line
+ * @property {Number} x - the left offset
+ * @property {string} limitClass - the class to apply to the line overlay
+ * @property {string} id - the id of the line (typically a timestamp)
+ * @property {boolean} hoverEnabled - whether the line is currently hovered on */