✨Feature: implement dungeon state management with room expansion and exit handling

src/rules/dungeon.test.ts

@@ -0,0 +1,87 @@
+import { describe, expect, it } from "vitest";
+
+import { sampleContentPack } from "@/data/sampleContentPack";
+
+import {
+  expandLevelFromExit,
+  getUnresolvedExits,
+  initializeDungeonLevel,
+} from "./dungeon";
+
+function createSequenceRoller(values: number[]) {
+  let index = 0;
+
+  return () => {
+    const next = values[index];
+    index += 1;
+    return next;
+  };
+}
+
+describe("dungeon state", () => {
+  it("initializes level 1 with a generated start room", () => {
+    const levelState = initializeDungeonLevel({ content: sampleContentPack });
+
+    expect(levelState.level).toBe(1);
+    expect(levelState.discoveredRoomOrder).toEqual(["room.level1.start"]);
+    expect(levelState.rooms["room.level1.start"]?.roomClass).toBe("start");
+  });
+
+  it("lists unresolved traversable exits in discovery order", () => {
+    const levelState = initializeDungeonLevel({ content: sampleContentPack });
+
+    expect(getUnresolvedExits(levelState)).toEqual([
+      expect.objectContaining({
+        roomId: "room.level1.start",
+        direction: "north",
+      }),
+    ]);
+  });
+
+  it("expands the dungeon from a chosen exit and links both rooms", () => {
+    const levelState = initializeDungeonLevel({ content: sampleContentPack });
+    const result = expandLevelFromExit({
+      content: sampleContentPack,
+      levelState,
+      fromRoomId: "room.level1.start",
+      exitDirection: "north",
+      roomTableCode: "L1SR",
+      roller: createSequenceRoller([3, 3]),
+    });
+
+    expect(result.createdRoom.position).toEqual({ x: 0, y: -1 });
+    expect(result.levelState.discoveredRoomOrder).toEqual([
+      "room.level1.start",
+      "room.level1.small.002",
+    ]);
+    expect(result.fromRoom.exits[0]?.leadsToRoomId).toBe("room.level1.small.002");
+    expect(result.createdRoom.exits.some((exit) => exit.leadsToRoomId === "room.level1.start")).toBe(
+      true,
+    );
+  });
+
+  it("rejects placement into an occupied coordinate", () => {
+    const levelState = initializeDungeonLevel({ content: sampleContentPack });
+    const expanded = expandLevelFromExit({
+      content: sampleContentPack,
+      levelState,
+      fromRoomId: "room.level1.start",
+      exitDirection: "north",
+      roomTableCode: "L1SR",
+      roomId: "room.level1.small.a",
+      roller: createSequenceRoller([3, 3]),
+    });
+
+    expect(() =>
+      expandLevelFromExit({
+        content: sampleContentPack,
+        levelState: expanded.levelState,
+        fromRoomId: "room.level1.start",
+        exitDirection: "north",
+        roomTableCode: "L1SR",
+        roomId: "room.level1.small.b",
+        roller: createSequenceRoller([4, 4]),
+      }),
+    ).toThrow("already connected");
+  });
+});