优化房间点赞同步为增量更新策略

PROJECT_AUDIT_2026-03-03.md

@@ -211,12 +211,14 @@
 - 证据：
   - `src/lib/planQueries.ts` 已由“逐条房间查询”改为“单次查询带房间关系”。
 
-### R2 `atomicUpdateRoom` 对 likes 的“全删全建”策略成本较高
+### R2 `atomicUpdateRoom` 对 likes 的“全删全建”策略成本较高【已完成】
+- 修复状态：✅ 已完成（2026-03-03）
+- 修复内容：
+  - 在 `roomRepository` 中新增 `diffRoomLikes`，按差集计算 `toCreate/toDelete`；
+  - `atomicUpdateRoom` 改为 likes 增量更新（`deleteMany + createMany` 仅处理变更项），替代全量重建；
+  - 补充 `src/lib/roomRepository.test.ts` 验证增量 diff 行为与去重逻辑。
 - 证据：
-  - `src/lib/roomRepository.ts:185-195`
-- 建议：
-  - 按增量 diff 更新（新增/删除差集）替代全量重建；
-  - 对高频路径（swipe/undo）优先优化。
+  - `src/lib/roomRepository.ts` 已移除 likes 全删全建逻辑，改为差量同步。
 
 ### R3 请求参数契约不统一（前端仍大量发送已废弃 `userId`）
 - 证据：

src/lib/roomRepository.test.ts

@@ -0,0 +1,58 @@
+import { describe, it, expect } from "vitest";
+import { diffRoomLikes } from "@/lib/roomRepository";
+
+describe("diffRoomLikes", () => {
+  it("returns incremental create/delete changes", () => {
+    const current = {
+      r1: ["u1", "u2"],
+      r2: ["u3"],
+    };
+    const updated = {
+      r1: ["u1", "u3"],
+      r3: ["u2"],
+    };
+
+    const result = diffRoomLikes(current, updated);
+
+    expect(result.toDelete).toEqual(
+      expect.arrayContaining([
+        { userId: "u2", restaurantId: "r1" },
+        { userId: "u3", restaurantId: "r2" },
+      ]),
+    );
+    expect(result.toCreate).toEqual(
+      expect.arrayContaining([
+        { userId: "u3", restaurantId: "r1" },
+        { userId: "u2", restaurantId: "r3" },
+      ]),
+    );
+  });
+
+  it("deduplicates repeated user likes", () => {
+    const current = {
+      r1: ["u1", "u1", "u1"],
+    };
+    const updated = {
+      r1: ["u1"],
+    };
+
+    const result = diffRoomLikes(current, updated);
+
+    expect(result.toCreate).toEqual([]);
+    expect(result.toDelete).toEqual([]);
+  });
+
+  it("returns empty arrays when likes are unchanged", () => {
+    const current = {
+      r1: ["u1", "u2"],
+    };
+    const updated = {
+      r1: ["u1", "u2"],
+    };
+
+    const result = diffRoomLikes(current, updated);
+
+    expect(result.toCreate).toEqual([]);
+    expect(result.toDelete).toEqual([]);
+  });
+});

src/lib/roomRepository.ts

@@ -16,8 +16,56 @@ export interface RoomData {
   scene: SceneType;
 }
 
+interface RoomLikeRow {
+  userId: string;
+  restaurantId: string;
+}
+
 const ROOM_ID_CHARS = "ABCDEFGHJKLMNPQRSTUVWXYZ23456789";
 
+function normalizeLikeRows(likes: Record<string, string[]>): RoomLikeRow[] {
+  const rows: RoomLikeRow[] = [];
+  const seen = new Set<string>();
+
+  for (const [restaurantId, userIds] of Object.entries(likes)) {
+    for (const userId of userIds) {
+      const key = `${userId}::${restaurantId}`;
+      if (seen.has(key)) continue;
+      seen.add(key);
+      rows.push({ userId, restaurantId });
+    }
+  }
+
+  return rows;
+}
+
+export function diffRoomLikes(
+  currentLikes: Record<string, string[]>,
+  updatedLikes: Record<string, string[]>,
+): { toCreate: RoomLikeRow[]; toDelete: RoomLikeRow[] } {
+  const currentRows = normalizeLikeRows(currentLikes);
+  const updatedRows = normalizeLikeRows(updatedLikes);
+
+  const currentMap = new Map(
+    currentRows.map((row) => [`${row.userId}::${row.restaurantId}`, row]),
+  );
+  const updatedMap = new Map(
+    updatedRows.map((row) => [`${row.userId}::${row.restaurantId}`, row]),
+  );
+
+  const toCreate: RoomLikeRow[] = [];
+  const toDelete: RoomLikeRow[] = [];
+
+  for (const [key, row] of updatedMap) {
+    if (!currentMap.has(key)) toCreate.push(row);
+  }
+  for (const [key, row] of currentMap) {
+    if (!updatedMap.has(key)) toDelete.push(row);
+  }
+
+  return { toCreate, toDelete };
+}
+
 function generateRoomId(): string {
   let id = "";
   for (let i = 0; i < 6; i++) {
@@ -181,18 +229,27 @@ export async function atomicUpdateRoom(
         });
       }
 
-      // Sync likes: rebuild from updated data
-      if (JSON.stringify(current.likes) !== JSON.stringify(updated.likes)) {
-        await tx.roomLike.deleteMany({ where: { roomId } });
-        const likeRows: { roomId: string; userId: string; restaurantId: string }[] = [];
-        for (const [restaurantId, userIds] of Object.entries(updated.likes)) {
-          for (const userId of userIds) {
-            likeRows.push({ roomId, userId, restaurantId });
-          }
-        }
-        if (likeRows.length > 0) {
-          await tx.roomLike.createMany({ data: likeRows });
-        }
+      // Sync likes incrementally to avoid full delete + rebuild on every change.
+      const { toCreate, toDelete } = diffRoomLikes(current.likes, updated.likes);
+      if (toDelete.length > 0) {
+        await tx.roomLike.deleteMany({
+          where: {
+            roomId,
+            OR: toDelete.map((row) => ({
+              userId: row.userId,
+              restaurantId: row.restaurantId,
+            })),
+          },
+        });
+      }
+      if (toCreate.length > 0) {
+        await tx.roomLike.createMany({
+          data: toCreate.map((row) => ({
+            roomId,
+            userId: row.userId,
+            restaurantId: row.restaurantId,
+          })),
+        });
       }
 
       // Sync swipes