From b5fd8ea09ba6bb0a897f5e56313fd92242b714b4 Mon Sep 17 00:00:00 2001
From: vcoppe <vianney.coppe@gmail.com>
Date: Thu, 22 Aug 2024 10:41:04 +0200
Subject: [PATCH] refine routing controls interactions

---
 gpx/src/gpx.ts                                    |  8 +++++++-
 .../toolbar/tools/routing/RoutingControls.ts      | 15 ++++++++++++---
 website/src/lib/utils.ts                          | 13 +++++++++----
 3 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/gpx/src/gpx.ts b/gpx/src/gpx.ts
index 54612f18..cb11066a 100644
--- a/gpx/src/gpx.ts
+++ b/gpx/src/gpx.ts
@@ -1360,7 +1360,13 @@ export class GPXStatistics {
 }
 
 const earthRadius = 6371008.8;
-export function distance(coord1: Coordinates, coord2: Coordinates): number {
+export function distance(coord1: TrackPoint | Coordinates, coord2: TrackPoint | Coordinates): number {
+    if (coord1 instanceof TrackPoint) {
+        coord1 = coord1.getCoordinates();
+    }
+    if (coord2 instanceof TrackPoint) {
+        coord2 = coord2.getCoordinates();
+    }
     const rad = Math.PI / 180;
     const lat1 = coord1.lat * rad;
     const lat2 = coord2.lat * rad;
diff --git a/website/src/lib/components/toolbar/tools/routing/RoutingControls.ts b/website/src/lib/components/toolbar/tools/routing/RoutingControls.ts
index ec118d16..08b21755 100644
--- a/website/src/lib/components/toolbar/tools/routing/RoutingControls.ts
+++ b/website/src/lib/components/toolbar/tools/routing/RoutingControls.ts
@@ -334,14 +334,14 @@ export class RoutingControls {
         let file = get(this.file)?.file;
 
         // Find the point closest to the temporary anchor
-        let minDistance = Number.MAX_VALUE;
+        let minDetails: any = { distance: Number.MAX_VALUE };
         let minAnchor = this.temporaryAnchor as Anchor;
         file?.forEachSegment((segment, trackIndex, segmentIndex) => {
             if (get(selection).hasAnyParent(new ListTrackSegmentItem(this.fileId, trackIndex, segmentIndex))) {
                 let details: any = {};
                 let closest = getClosestLinePoint(segment.trkpt, this.temporaryAnchor.point, details);
-                if (details.distance < minDistance) {
-                    minDistance = details.distance;
+                if (details.distance < minDetails.distance) {
+                    minDetails = details;
                     minAnchor = {
                         point: closest,
                         segment,
@@ -352,6 +352,15 @@ export class RoutingControls {
             }
         });
 
+        if (minAnchor.point._data.anchor) {
+            minAnchor.point = minAnchor.point.clone();
+            if (minDetails.before) {
+                minAnchor.point._data.index = minAnchor.point._data.index + 0.5;
+            } else {
+                minAnchor.point._data.index = minAnchor.point._data.index - 0.5;
+            }
+        }
+
         return minAnchor;
     }
 
diff --git a/website/src/lib/utils.ts b/website/src/lib/utils.ts
index 3542aae4..1e0d6e40 100644
--- a/website/src/lib/utils.ts
+++ b/website/src/lib/utils.ts
@@ -5,11 +5,10 @@ import type { TransitionConfig } from "svelte/transition";
 import { get } from "svelte/store";
 import { map } from "./stores";
 import { base } from "$app/paths";
-import { browser } from "$app/environment";
 import { languages } from "$lib/languages";
-import { locale } from "svelte-i18n";
+import { locale, t } from "svelte-i18n";
 import type mapboxgl from "mapbox-gl";
-import { type TrackPoint, type Coordinates, crossarcDistance } from "gpx";
+import { type TrackPoint, type Coordinates, crossarcDistance, distance } from "gpx";
 
 export function cn(...inputs: ClassValue[]) {
     return twMerge(clsx(inputs));
@@ -75,8 +74,14 @@ export function getClosestLinePoint(points: TrackPoint[], point: TrackPoint | Co
     for (let i = 0; i < points.length - 1; i++) {
         let dist = crossarcDistance(points[i], points[i + 1], point);
         if (dist < closestDist) {
-            closest = points[i];
             closestDist = dist;
+            if (distance(points[i], point) <= distance(points[i + 1], point)) {
+                closest = points[i];
+                details['before'] = true;
+            } else {
+                closest = points[i + 1];
+                details['before'] = false;
+            }
         }
     }
     details['distance'] = closestDist;