feat: v0.22.0 — ISS-022/025/027 hover route trace on job list, on-board rows and relocation panel

lib/mapData.test.ts

@@ -1,6 +1,6 @@
 import { describe, expect, it } from 'vitest';
 import type { StateSnapshot } from './game/state';
-import { planesGeoJson, routesGeoJson, greatCircleArc, ROUTE_ARC_SEGMENTS, type AirportCoord } from './mapData';
+import { planesGeoJson, routesGeoJson, hoverRouteGeoJson, greatCircleArc, ROUTE_ARC_SEGMENTS, type AirportCoord } from './mapData';
 import { haversineKm } from './geo';
 
 const AIRPORTS = new Map<string, AirportCoord>([
@@ -140,6 +140,42 @@ describe('routesGeoJson (v0.12.0 — one line per flying plane\'s current leg)',
   });
 });
 
+describe('hoverRouteGeoJson (ISS-022/025/027 v0.22.0 — hover route trace)', () => {
+  it('returns an empty collection for the no-hover "" sentinel', () => {
+    expect(hoverRouteGeoJson('', '', AIRPORTS)).toEqual({ type: 'FeatureCollection', features: [] });
+  });
+
+  it('draws one great-circle line between two known airports with exact endpoints', () => {
+    const fc = hoverRouteGeoJson('EDDF', 'EHAM', AIRPORTS);
+    expect(fc.features).toHaveLength(1);
+    expect(fc.features[0].properties).toEqual({ planeId: '' }); // pure overlay — no owning plane
+    const coords = fc.features[0].geometry.coordinates;
+    expect(coords.length).toBe(ROUTE_ARC_SEGMENTS + 1); // sampled arc, not a 2-point chord
+    expect(coords[0]).toEqual([8.56, 50.03]); // EDDF [lon, lat] — exact endpoint
+    expect(coords[coords.length - 1]).toEqual([4.76, 52.31]); // EHAM — exact endpoint
+  });
+
+  it('draws the same trace reversed (endpoints swapped, arc mirrored)', () => {
+    const ab = hoverRouteGeoJson('EDDF', 'EHAM', AIRPORTS).features[0].geometry.coordinates;
+    const ba = hoverRouteGeoJson('EHAM', 'EDDF', AIRPORTS).features[0].geometry.coordinates;
+    expect(ba.length).toBe(ab.length);
+    // The slerp is symmetric up to floating-point rounding (1 − t ≠ (N−t)/N bit-exactly), so
+    // compare with a tolerance: each reversed point sits on the forward arc within ~1e-9 degrees.
+    for (let i = 0; i < ab.length; i++) {
+      expect(Math.abs(ba[i][0] - ab[ab.length - 1 - i][0])).toBeLessThan(1e-9);
+      expect(Math.abs(ba[i][1] - ab[ab.length - 1 - i][1])).toBeLessThan(1e-9);
+    }
+  });
+
+  it('returns an empty collection when the from airport is missing from the dataset', () => {
+    expect(hoverRouteGeoJson('ZZZZ', 'EDDV', AIRPORTS)).toEqual({ type: 'FeatureCollection', features: [] });
+  });
+
+  it('returns an empty collection when the to airport is missing from the dataset', () => {
+    expect(hoverRouteGeoJson('EDDF', 'ZZZZ', AIRPORTS)).toEqual({ type: 'FeatureCollection', features: [] });
+  });
+});
+
 describe('greatCircleArc (v0.12.2 — curved route traces)', () => {
   it('samples >2 points with the endpoints exactly at the airport coords', () => {
     const arc = greatCircleArc(AIRPORTS.get('EDDF')!, AIRPORTS.get('EHAM')!);

lib/mapData.ts

@@ -85,6 +85,33 @@ export function greatCircleArc(from: AirportCoord, to: AirportCoord): [number, n
   return coords;
 }
 
+// ISS-022/025/027 (v0.22.0): the hover route trace — one great-circle LineString between two
+// airports, drawn top-most while a panel row hovers (job-list rows, on-board cargo rows, the
+// Relocate section). Empty collection when either endpoint is missing from the dataset — never
+// guessed; the '' sentinel (no hovered target) resolves to nothing and yields the same.
+export function hoverRouteGeoJson(
+  fromIcao: string,
+  toIcao: string,
+  airportsByIcao: ReadonlyMap<string, AirportCoord>,
+): FeatureCollection<MapLineFeature> {
+  const from = airportsByIcao.get(fromIcao);
+  const to = airportsByIcao.get(toIcao);
+  if (!from || !to) return EMPTY_LINES;
+  return {
+    type: 'FeatureCollection',
+    features: [
+      {
+        type: 'Feature',
+        geometry: {
+          type: 'LineString',
+          coordinates: greatCircleArc(from, to),
+        },
+        properties: { planeId: '' }, // no owning plane — a pure hover overlay
+      },
+    ],
+  };
+}
+
 // One LineString per FLYING plane — its current leg from locationIcao to dest_icao.
 // Grounded planes draw nothing; a flying plane missing either endpoint from the
 // dataset is skipped, never guessed. The line is sampled along the great circle