Fix X-Ray for multi-hex movement previews

src/__tests__/utility/hexgrid-xray.ts

@@ -0,0 +1,42 @@
+import { describe, expect, jest, test } from '@jest/globals';
+
+jest.mock('phaser-ce', () => ({}));
+jest.mock('../../creature', () => ({
+	Creature: class Creature {},
+}));
+
+import { Creature } from '../../creature';
+import { HexGrid } from '../../utility/hexgrid';
+
+/* eslint-disable @typescript-eslint/no-explicit-any */
+
+function makeCreature(hexagons: Array<{ ghostOverlap: jest.Mock }>) {
+	const CreatureCtor = Creature as unknown as { new (): Creature };
+	const creature = new CreatureCtor() as any;
+	creature.hexagons = hexagons;
+	creature.xray = jest.fn();
+	return creature;
+}
+
+describe('HexGrid.xray', () => {
+	test('checks every preview footprint hex for obstructing creatures', () => {
+		const activeHex = { ghostOverlap: jest.fn() };
+		const activeCreature = makeCreature([activeHex]);
+		const otherCreature = makeCreature([]);
+		const frontPreviewHex = { creature: undefined, ghostOverlap: jest.fn() };
+		const backPreviewHex = { creature: undefined, ghostOverlap: jest.fn() };
+
+		const grid = Object.create(HexGrid.prototype) as any;
+		grid.game = {
+			creatures: [activeCreature, otherCreature],
+			activeCreature,
+		};
+
+		grid.xray(frontPreviewHex as never, [frontPreviewHex as never, backPreviewHex as never]);
+
+		expect(frontPreviewHex.ghostOverlap).toHaveBeenCalledTimes(1);
+		expect(backPreviewHex.ghostOverlap).toHaveBeenCalledTimes(1);
+		expect(activeHex.ghostOverlap).toHaveBeenCalledWith(activeCreature);
+		expect(activeCreature.xray).toHaveBeenLastCalledWith(false);
+	});
+});

src/__tests__/utility/query_footprint.ts

@@ -0,0 +1,58 @@
+import { describe, expect, jest, test } from '@jest/globals';
+import { getQueryFootprintHexes } from '../../utility/query_footprint';
+
+type TestHex = {
+	x: number;
+	y: number;
+	isWalkable: jest.Mock;
+};
+
+function buildGrid(width: number, height = 1) {
+	const hexes: TestHex[][] = [];
+
+	for (let y = 0; y < height; y++) {
+		const row: TestHex[] = [];
+		for (let x = 0; x < width; x++) {
+			row.push({
+				x,
+				y,
+				isWalkable: jest.fn((size: number) => x - size + 1 >= 0),
+			});
+		}
+		hexes.push(row);
+	}
+
+	return { hexes };
+}
+
+describe('getQueryFootprintHexes', () => {
+	test('returns every occupied hex for a non-flipped multi-hex preview', () => {
+		const grid = buildGrid(10);
+		const footprint = getQueryFootprintHexes(
+			grid as never,
+			grid.hexes[0][6] as never,
+			3,
+			false,
+			12,
+		);
+
+		expect(footprint.map(({ x, y }) => [x, y])).toEqual([
+			[6, 0],
+			[5, 0],
+			[4, 0],
+		]);
+		expect(grid.hexes[0][6].isWalkable).toHaveBeenCalledWith(3, 12);
+	});
+
+	test('offsets the footprint when the active player is flipped', () => {
+		const grid = buildGrid(10);
+		const footprint = getQueryFootprintHexes(grid as never, grid.hexes[0][6] as never, 3, true, 12);
+
+		expect(footprint.map(({ x, y }) => [x, y])).toEqual([
+			[8, 0],
+			[7, 0],
+			[6, 0],
+		]);
+		expect(grid.hexes[0][8].isWalkable).toHaveBeenCalledWith(3, 12);
+	});
+});