feat(game): Pathfinder BFS over visited rooms (locks + light aware)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Semesterprojekt/src/test/java/thb/jeanluc/adventure/game/PathfinderTest.java

@@ -0,0 +1,88 @@
+package thb.jeanluc.adventure.game;
+
+import org.junit.jupiter.api.Test;
+import thb.jeanluc.adventure.io.TestIO;
+import thb.jeanluc.adventure.model.Condition;
+import thb.jeanluc.adventure.model.Direction;
+import thb.jeanluc.adventure.model.ExitLock;
+import thb.jeanluc.adventure.model.Player;
+import thb.jeanluc.adventure.model.Room;
+import thb.jeanluc.adventure.model.World;
+import thb.jeanluc.adventure.model.item.Item;
+import thb.jeanluc.adventure.model.item.PlainItem;
+
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class PathfinderTest {
+
+    private Room room(String id) {
+        return new Room(id, id, "d");
+    }
+
+    private GameContext ctx(Room start, List<Room> all, Set<String> visited) {
+        Map<String, Room> rooms = new LinkedHashMap<>();
+        for (Room r : all) {
+            rooms.put(r.getId(), r);
+        }
+        World w = new World(rooms, Map.of(), Map.of(), "t", "w");
+        Player p = new Player(start, 0);
+        p.getVisitedRoomIds().addAll(visited);
+        return new GameContext(w, p, new TestIO());
+    }
+
+    @Test
+    void findsShortestPathOverVisitedRooms() {
+        Room a = room("a"), b = room("b"), c = room("c");
+        a.addExit(Direction.NORTH, b);
+        b.addExit(Direction.NORTH, c);
+        GameContext ctx = ctx(a, List.of(a, b, c), Set.of("a", "b", "c"));
+        assertThat(Pathfinder.findPath(ctx, c)).containsExactly(b, c);
+    }
+
+    @Test
+    void willNotRouteThroughUnvisitedRoom() {
+        Room a = room("a"), b = room("b"), c = room("c");
+        a.addExit(Direction.NORTH, b);
+        b.addExit(Direction.NORTH, c);
+        GameContext ctx = ctx(a, List.of(a, b, c), Set.of("a", "c")); // b not visited
+        assertThat(Pathfinder.findPath(ctx, c)).isEmpty();
+    }
+
+    @Test
+    void respectsLockedExit() {
+        Room a = room("a"), b = room("b");
+        a.addExit(Direction.NORTH, b);
+        a.addExitLock(Direction.NORTH,
+                new ExitLock(List.of(new Condition(Condition.Type.FLAG, "open")), "locked"));
+        GameContext ctx = ctx(a, List.of(a, b), Set.of("a", "b"));
+        assertThat(Pathfinder.findPath(ctx, b)).isEmpty();
+        ctx.getState().set("open");
+        assertThat(Pathfinder.findPath(ctx, b)).containsExactly(b);
+    }
+
+    @Test
+    void respectsDarkness() {
+        Room a = room("a");
+        Room dark = room("dark");
+        dark.setDark(true);
+        a.addExit(Direction.NORTH, dark);
+        GameContext ctx = ctx(a, List.of(a, dark), Set.of("a", "dark"));
+        assertThat(Pathfinder.findPath(ctx, dark)).isEmpty();
+        Item torch = PlainItem.builder().id("lit").name("Lit").description("d").light(true).build();
+        ctx.getPlayer().addItem(torch);
+        assertThat(Pathfinder.findPath(ctx, dark)).containsExactly(dark);
+    }
+
+    @Test
+    void unreachableTargetReturnsEmpty() {
+        Room a = room("a");
+        Room island = room("island"); // no connecting exits
+        GameContext ctx = ctx(a, List.of(a, island), Set.of("a", "island"));
+        assertThat(Pathfinder.findPath(ctx, island)).isEmpty();
+    }
+}