Preserve leaderboard context in player profiles

tests/unit/leaderboard-navigation.test.ts

@@ -0,0 +1,44 @@
+import { describe, expect, it } from 'vitest';
+import { leaderboardReturnHref, playerContextHref, profileViewHref } from '../../src/lib/leaderboard-navigation.js';
+
+describe('leaderboard profile navigation', () => {
+    it('preserves leaderboard scope, search and page while starting profile history on its first page', () => {
+        const source = '/leaderboard?game=t6&map=t6%3Atown&metric=kills&q=Player+One&offset=50';
+        const profile = new URL(playerContextHref('001/2?#', source), 'http://localhost');
+        expect(profile.pathname).toBe('/leaderboard/players/001%2F2%3F%23');
+        expect(profile.searchParams.get('returnTo')).toBe(source);
+        expect(profile.searchParams.get('game')).toBe('t6');
+        expect(profile.searchParams.get('map')).toBe('t6:town');
+        expect(profile.searchParams.get('metric')).toBe('kills');
+        expect(profile.searchParams.has('q')).toBe(false);
+        expect(profile.searchParams.has('offset')).toBe(false);
+    });
+
+    it('keeps profile filters and return context through pagination and resets history pages on filter changes', () => {
+        const current = new URL('http://localhost/leaderboard/players/101?returnTo=%2Fleaderboard%3Fq%3DAce&game=t5&map=t5%3Atheater&metric=highestRound&offset=25');
+        const next = new URL(profileViewHref(current, { offset: '50' }), current);
+        expect(next.searchParams.get('offset')).toBe('50');
+        expect(next.searchParams.get('returnTo')).toBe('/leaderboard?q=Ace');
+        expect(next.searchParams.get('map')).toBe('t5:theater');
+        const filtered = new URL(profileViewHref(current, { game: 't6', map: '' }), current);
+        expect(filtered.searchParams.has('offset')).toBe(false);
+        expect(filtered.searchParams.has('map')).toBe(false);
+        expect(filtered.searchParams.get('game')).toBe('t6');
+        expect(filtered.searchParams.get('returnTo')).toBe('/leaderboard?q=Ace');
+    });
+
+    it('restricts supplied return destinations to the local leaderboard', () => {
+        for (const value of [null, '', 'https://example.com/leaderboard', '//example.com/leaderboard', '/leaderboard/players/101', '/leaderboard/../settings', '/leaderboard\\@example.com']) {
+            expect(leaderboardReturnHref(value)).toBe('/leaderboard');
+        }
+        expect(leaderboardReturnHref('/leaderboard?q=A%26B&unrelated=drop#fragment')).toBe('/leaderboard?q=A%26B');
+    });
+
+    it('uses the displayed fallback scope when a shared leaderboard URL contains unknown filters', () => {
+        const source = '/leaderboard?game=t7&metric=unknown&q=101';
+        const profile = new URL(playerContextHref('101', source), 'http://localhost');
+        expect(profile.searchParams.get('returnTo')).toBe(source);
+        expect(profile.searchParams.has('game')).toBe(false);
+        expect(profile.searchParams.has('metric')).toBe(false);
+    });
+});