✨Feature: implement room entry flow with encounter resolution and logging

src/rules/roomEntry.ts

@@ -0,0 +1,164 @@
+import { findRoomTemplateById } from "@/data/contentHelpers";
+import type { ContentPack } from "@/types/content";
+import type { DungeonLevelState, RoomState } from "@/types/state";
+import type { LogEntry } from "@/types/rules";
+
+import type { DiceRoller } from "./dice";
+import { resolveRoomEncounter } from "./encounters";
+import type { TableLookupResult } from "./tables";
+
+export type EnterRoomOptions = {
+  content: ContentPack;
+  levelState: DungeonLevelState;
+  roomId: string;
+  roller?: DiceRoller;
+  at?: string;
+};
+
+export type EnterRoomResult = {
+  levelState: DungeonLevelState;
+  room: RoomState;
+  logEntries: LogEntry[];
+  lookup?: TableLookupResult;
+  firstEntry: boolean;
+  encounterResolved: boolean;
+};
+
+function cloneRoom(room: RoomState): RoomState {
+  return {
+    ...room,
+    position: { ...room.position },
+    dimensions: { ...room.dimensions },
+    exits: room.exits.map((exit) => ({ ...exit })),
+    discovery: { ...room.discovery },
+    encounter: room.encounter
+      ? {
+          ...room.encounter,
+          creatureIds: [...room.encounter.creatureIds],
+          creatureNames: room.encounter.creatureNames
+            ? [...room.encounter.creatureNames]
+            : undefined,
+        }
+      : undefined,
+    objects: room.objects.map((object) => ({
+      ...object,
+      effects: object.effects ? [...object.effects] : undefined,
+    })),
+    notes: [...room.notes],
+    flags: [...room.flags],
+  };
+}
+
+function cloneLevel(levelState: DungeonLevelState): DungeonLevelState {
+  return {
+    ...levelState,
+    rooms: Object.fromEntries(
+      Object.entries(levelState.rooms).map(([roomId, room]) => [roomId, cloneRoom(room)]),
+    ),
+    discoveredRoomOrder: [...levelState.discoveredRoomOrder],
+  };
+}
+
+function getRoomLabel(content: ContentPack, room: RoomState) {
+  if (room.templateId) {
+    return findRoomTemplateById(content, room.templateId).title;
+  }
+
+  return room.notes[0] ?? room.id;
+}
+
+function createLogEntry(
+  id: string,
+  at: string,
+  type: LogEntry["type"],
+  text: string,
+  relatedIds: string[],
+): LogEntry {
+  return {
+    id,
+    at,
+    type,
+    text,
+    relatedIds,
+  };
+}
+
+function formatRollText(lookup: TableLookupResult) {
+  const total = lookup.roll.modifiedTotal ?? lookup.roll.total;
+  const rolledValues = lookup.roll.rolls.join(", ");
+
+  return `Rolled ${lookup.roll.diceKind} [${rolledValues}] on ${lookup.tableId} for ${total}: ${lookup.entry.label}.`;
+}
+
+export function enterRoom(options: EnterRoomOptions): EnterRoomResult {
+  const levelState = cloneLevel(options.levelState);
+  const room = levelState.rooms[options.roomId];
+
+  if (!room) {
+    throw new Error(`Unknown room id: ${options.roomId}`);
+  }
+
+  const at = options.at ?? new Date().toISOString();
+  const roomLabel = getRoomLabel(options.content, room);
+  const firstEntry = !room.discovery.entered;
+  room.discovery.entered = true;
+
+  const resolution = resolveRoomEncounter(options.content, room, options.roller);
+  const nextRoom = resolution.room;
+  const encounterResolved = Boolean(resolution.encounter);
+
+  if (resolution.encounter && resolution.encounter.creatureIds.length === 0) {
+    nextRoom.discovery.cleared = true;
+  }
+
+  levelState.rooms[nextRoom.id] = nextRoom;
+
+  const entryVerb = firstEntry ? "Entered" : "Re-entered";
+  const logEntries: LogEntry[] = [
+    createLogEntry(
+      `${nextRoom.id}.entry.${firstEntry ? "first" : "repeat"}`,
+      at,
+      "room",
+      `${entryVerb} ${roomLabel}.`,
+      [nextRoom.id],
+    ),
+  ];
+
+  if (resolution.lookup) {
+    logEntries.push(
+      createLogEntry(
+        `${nextRoom.id}.entry.roll`,
+        at,
+        "roll",
+        formatRollText(resolution.lookup),
+        [nextRoom.id, resolution.lookup.tableId],
+      ),
+    );
+  }
+
+  if (resolution.encounter) {
+    const encounterText =
+      resolution.encounter.creatureIds.length === 0
+        ? `${roomLabel} is quiet.`
+        : `Encounter in ${roomLabel}: ${resolution.encounter.resultLabel ?? "Unknown threat"}.`;
+
+    logEntries.push(
+      createLogEntry(
+        `${nextRoom.id}.entry.encounter`,
+        at,
+        "room",
+        encounterText,
+        [nextRoom.id, resolution.encounter.id],
+      ),
+    );
+  }
+
+  return {
+    levelState,
+    room: nextRoom,
+    logEntries,
+    lookup: resolution.lookup,
+    firstEntry,
+    encounterResolved,
+  };
+}