feat(記憶與情緒快取): 記憶與情緒狀態加入 Redis 快取層,連不到時自動退回原行為

apps/api/src/emotion/emotion.service.ts

@@ -5,6 +5,9 @@ import { RuleBasedEmotionTagger } from "./emotion-tagger.js";
 import { nextEmotionState, type TransitionContext } from "./emotion-state-machine.js";
 import { toResponseStyle, type ResponseStyle } from "./response-style.js";
 import { getArchetypeParams } from "../personality/archetype-params.js";
+import { getRedisClient } from "../cache/redis-client.js";
+
+const REDIS_KEY_PREFIX = "kokorone:emotion-state:";
 
 // D-2 時間衰減：預設半衰期 2 小時，實際速度由角色參數（G 群組）覆寫。
 const DEFAULT_HALF_LIFE_MS = 2 * 60 * 60 * 1000;
@@ -133,11 +136,45 @@ export class EmotionService {
     return { state: toDomain(characterId, updated, now), style: toResponseStyle(next) };
   }
 
+  // R-2：情緒狀態機的即時讀寫改走 Redis 當熱路徑快取，Prisma／SQLite（未來 Postgres）
+  // 仍是唯一的持久真實來源——快取只省掉命中時的資料庫往返，Redis 不可用或未命中都直接退回原本
+  // 讀 Prisma 的行為，因此「重啟 api 後情緒狀態不遺失」這件事完全不受快取層是否存在影響。
+  private async readCached(characterId: string): Promise<{ dims: Dimensions; updatedAt: Date } | null> {
+    try {
+      const raw = await getRedisClient().get(REDIS_KEY_PREFIX + characterId);
+      if (!raw) return null;
+      const parsed = JSON.parse(raw) as Dimensions & { updatedAt: string };
+      const { updatedAt, ...dims } = parsed;
+      return { dims, updatedAt: new Date(updatedAt) };
+    } catch {
+      return null;
+    }
+  }
+
+  private async writeCache(characterId: string, dims: Dimensions, updatedAt: Date): Promise<void> {
+    try {
+      await getRedisClient().set(
+        REDIS_KEY_PREFIX + characterId,
+        JSON.stringify({ ...dims, updatedAt: updatedAt.toISOString() }),
+        "EX",
+        60 * 60 * 24,
+      );
+    } catch {
+      // Redis 不可用時，Prisma 仍是持久真實來源，快取寫入失敗不影響正確性。
+    }
+  }
+
   private async decayedDimensions(
     characterId: string,
     now: Date,
     halfLifeMs = DEFAULT_HALF_LIFE_MS,
   ): Promise<{ dims: Dimensions; updatedAt: Date }> {
+    const cached = await this.readCached(characterId);
+    if (cached) {
+      const elapsedMs = now.getTime() - cached.updatedAt.getTime();
+      return { dims: decayDimensions(cached.dims, elapsedMs, halfLifeMs), updatedAt: cached.updatedAt };
+    }
+
     const row = await this.prisma.client.emotionState.upsert({
       where: { characterId },
       update: {},
@@ -154,6 +191,7 @@ export class EmotionService {
       where: { characterId },
       data: { ...dims, updatedAt: now },
     });
+    await this.writeCache(characterId, dims, now);
   }
 }