feat(map): MapLayout BFS grid layout with fog of war

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Semesterprojekt/src/main/java/thb/jeanluc/adventure/map/MapLayout.java

@@ -0,0 +1,137 @@
+package thb.jeanluc.adventure.map;
+
+import lombok.extern.slf4j.Slf4j;
+import thb.jeanluc.adventure.io.text.CellState;
+import thb.jeanluc.adventure.io.text.Connection;
+import thb.jeanluc.adventure.io.text.MapView;
+import thb.jeanluc.adventure.io.text.RoomCell;
+import thb.jeanluc.adventure.model.Direction;
+import thb.jeanluc.adventure.model.Room;
+import thb.jeanluc.adventure.model.World;
+
+import java.util.ArrayDeque;
+import java.util.ArrayList;
+import java.util.Deque;
+import java.util.HashMap;
+import java.util.HashSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Set;
+
+/**
+ * Computes a {@link MapView} from the room graph: BFS assigns grid coordinates
+ * from exit directions, then fog-of-war keeps only visited rooms and their
+ * directly-reachable (but unentered) neighbours.
+ */
+@Slf4j
+public final class MapLayout {
+
+    private MapLayout() {
+    }
+
+    public static MapView compute(World world, Set<String> visited, Room current) {
+        if (visited.isEmpty()) {
+            return new MapView(List.of(), List.of());
+        }
+        String anchorId = visited.iterator().next();
+        Room anchor = world.getRooms().get(anchorId);
+        if (anchor == null) {
+            return new MapView(List.of(), List.of());
+        }
+
+        Map<String, int[]> coords = bfs(anchor);
+
+        // Determine which rooms are placed: visited (with coords) + their unentered neighbours.
+        Map<String, CellState> placed = new LinkedHashMap<>();
+        for (String id : visited) {
+            if (coords.containsKey(id)) {
+                placed.put(id, id.equals(current.getId()) ? CellState.CURRENT : CellState.VISITED);
+            }
+        }
+        for (String id : visited) {
+            Room r = world.getRooms().get(id);
+            if (r == null) {
+                continue;
+            }
+            for (Room nb : r.getExits().values()) {
+                if (!placed.containsKey(nb.getId()) && coords.containsKey(nb.getId())) {
+                    placed.put(nb.getId(), CellState.KNOWN);
+                }
+            }
+        }
+
+        // Normalise coordinates to non-negative.
+        int minX = Integer.MAX_VALUE;
+        int minY = Integer.MAX_VALUE;
+        for (String id : placed.keySet()) {
+            int[] c = coords.get(id);
+            minX = Math.min(minX, c[0]);
+            minY = Math.min(minY, c[1]);
+        }
+
+        Map<String, RoomCell> cells = new LinkedHashMap<>();
+        for (Map.Entry<String, CellState> e : placed.entrySet()) {
+            int[] c = coords.get(e.getKey());
+            String name = e.getValue() == CellState.KNOWN ? "?" : world.getRooms().get(e.getKey()).getName();
+            cells.put(e.getKey(), new RoomCell(e.getKey(), name, c[0] - minX, c[1] - minY, e.getValue()));
+        }
+
+        // Connections: from each visited room to any placed neighbour, de-duplicated.
+        List<Connection> connections = new ArrayList<>();
+        Set<String> seen = new HashSet<>();
+        for (String id : visited) {
+            Room r = world.getRooms().get(id);
+            RoomCell from = cells.get(id);
+            if (r == null || from == null) {
+                continue;
+            }
+            for (Room nb : r.getExits().values()) {
+                RoomCell to = cells.get(nb.getId());
+                if (to == null) {
+                    continue;
+                }
+                String key = id.compareTo(nb.getId()) < 0 ? id + "|" + nb.getId() : nb.getId() + "|" + id;
+                if (seen.add(key)) {
+                    connections.add(new Connection(from, to));
+                }
+            }
+        }
+
+        return new MapView(List.copyOf(cells.values()), connections);
+    }
+
+    private static Map<String, int[]> bfs(Room anchor) {
+        Map<String, int[]> coords = new HashMap<>();
+        Deque<Room> queue = new ArrayDeque<>();
+        coords.put(anchor.getId(), new int[]{0, 0});
+        queue.add(anchor);
+        while (!queue.isEmpty()) {
+            Room r = queue.poll();
+            int[] c = coords.get(r.getId());
+            for (Map.Entry<Direction, Room> e : r.getExits().entrySet()) {
+                Room nb = e.getValue();
+                int[] d = delta(e.getKey());
+                int[] nc = {c[0] + d[0], c[1] + d[1]};
+                int[] existing = coords.get(nb.getId());
+                if (existing == null) {
+                    coords.put(nb.getId(), nc);
+                    queue.add(nb);
+                } else if (existing[0] != nc[0] || existing[1] != nc[1]) {
+                    log.warn("Map layout collision at room '{}' ({} vs {},{}); keeping first placement",
+                            nb.getId(), java.util.Arrays.toString(existing), nc[0], nc[1]);
+                }
+            }
+        }
+        return coords;
+    }
+
+    private static int[] delta(Direction d) {
+        return switch (d) {
+            case NORTH -> new int[]{0, -1};
+            case SOUTH -> new int[]{0, 1};
+            case EAST -> new int[]{1, 0};
+            case WEST -> new int[]{-1, 0};
+        };
+    }
+}