From 077391919da06f05cfda722d8612df1bd43f4f3c Mon Sep 17 00:00:00 2001
From: Ross Keenan <rossk29@gmail.com>
Date: Sun, 15 Aug 2021 18:23:12 +0200
Subject: [PATCH] feat(Vis View): :sparkles: Force Directed Graph: Highlight
 path from current note to hovered node

---
 src/Visualisations/ForceDirectedG.ts | 63 ++++++++++++++++++++++++----
 1 file changed, 56 insertions(+), 7 deletions(-)

diff --git a/src/Visualisations/ForceDirectedG.ts b/src/Visualisations/ForceDirectedG.ts
index ae14f73d..dedea21a 100644
--- a/src/Visualisations/ForceDirectedG.ts
+++ b/src/Visualisations/ForceDirectedG.ts
@@ -1,5 +1,6 @@
 import * as d3 from "d3";
 import type { Graph } from "graphlib";
+import * as graphlib from "graphlib";
 import { openOrSwitch } from "src/sharedFunctions";
 import type { d3Node } from "src/interfaces";
 import { graphlibToD3, VisModal } from "src/VisModal";
@@ -13,6 +14,11 @@ export const forceDirectedG = (
   width: number,
   height: number
 ) => {
+  const pathsFromCurrNode = graphlib.alg.dijkstra(graph, currFile.basename);
+
+  const nodeColour = getComputedStyle(document.body).getPropertyValue(
+    "--text-accent"
+  );
   const colourChange = d3
     .select(".d3-graph")
     .append("input")
@@ -41,11 +47,14 @@ export const forceDirectedG = (
 
   const links: {
     index: number;
-    source: { index: number };
-    target: { index: number };
+    source: { index: number; x: number; y: number };
+    target: { index: number; x: number; y: number };
   }[] = data.links.map((d) => Object.create(d));
 
   const nodes = data.nodes.map((d) => Object.create(d));
+  const currNodeIndex = data.nodes.find(
+    (node) => node.name === currFile.basename
+  ).id;
 
   const simulation = d3
     .forceSimulation(nodes)
@@ -126,9 +135,11 @@ export const forceDirectedG = (
     .append("svg:path")
     .attr("d", "M0,-5L10,0L0,5");
 
-  const nodeColour = getComputedStyle(document.body).getPropertyValue(
-    "--text-accent"
-  );
+  const nameFromIndex = (d: { index: number }) =>
+    data.nodes.find((node) => node.id === d.index).name;
+
+  const indexFromName = (name: string): number =>
+    data.nodes.find((node) => node.name === name).id;
 
   const node: d3.Selection<
     d3.BaseType | SVGCircleElement,
@@ -137,7 +148,6 @@ export const forceDirectedG = (
     unknown
   > = svg
     .append("g")
-    .attr("stroke", nodeColour)
     .attr("stroke-width", 1.5)
     .selectAll("circle")
     .data(nodes)
@@ -168,6 +178,29 @@ export const forceDirectedG = (
     return !!linkedArr;
   }
 
+  function walkDijkstraPaths(
+    paths: { [node: string]: graphlib.Path },
+    startNode: string
+  ) {
+    if (
+      startNode === currFile.basename ||
+      paths[startNode].distance === Infinity
+    )
+      return [];
+    let step = startNode;
+
+    const path: string[] = [startNode];
+    let i = 0;
+    while (paths[step].distance > 1 && i < 200) {
+      i++;
+      step = paths[startNode].predecessor;
+      path.push(step);
+    }
+    if (i >= 200) return [];
+    path.push(currFile.basename);
+    return path;
+  }
+
   node
     .on("mouseover", (event: MouseEvent, d: { index: number }) => {
       node.style("opacity", (o) => {
@@ -178,6 +211,22 @@ export const forceDirectedG = (
           ? 1
           : 0.1;
       });
+
+      // Highlight path from hovered node to currNode
+      const hoveredNode = nameFromIndex(d);
+      const path = walkDijkstraPaths(pathsFromCurrNode, hoveredNode);
+      if (path.length) {
+        link
+          .transition()
+          .duration(150)
+          .style("stroke", function (link) {
+            if (
+              path.includes(nameFromIndex(link.source)) &&
+              path.includes(nameFromIndex(link.target))
+            )
+              return nodeColour;
+          });
+      }
     })
     .on("mouseout", unfocus);
 
@@ -186,7 +235,7 @@ export const forceDirectedG = (
   function unfocus() {
     // labelNode.attr("display", "block");
     node.style("opacity", 1);
-    link.style("opacity", 1);
+    link.style("opacity", 1).style("stroke", "#868282");
   }
 
   simulation.on("tick", () => {