From 6a2752ef7346568679347e0cec1da7c84fe5d5c8 Mon Sep 17 00:00:00 2001
From: Namekuji <nmkj@mx.kazuno.co>
Date: Sat, 15 Apr 2023 03:37:26 -0400
Subject: [PATCH] adjust following and followers counts when unfollowing

---
 .../backend/src/core/UserFollowingService.ts  | 104 ++++++++++++------
 1 file changed, 68 insertions(+), 36 deletions(-)

diff --git a/packages/backend/src/core/UserFollowingService.ts b/packages/backend/src/core/UserFollowingService.ts
index d979974996..b7c7536651 100644
--- a/packages/backend/src/core/UserFollowingService.ts
+++ b/packages/backend/src/core/UserFollowingService.ts
@@ -23,6 +23,7 @@ import { CacheService } from '@/core/CacheService.js';
 import type { Config } from '@/config.js';
 import Logger from '../logger.js';
 import { ApPersonService } from '@/core/activitypub/models/ApPersonService.js';
+import { IsNull } from 'typeorm';
 
 const logger = new Logger('following/create');
 
@@ -330,7 +331,7 @@ export class UserFollowingService implements OnModuleInit {
 			}
 		});
 
-		if (following === null) {
+		if (following === null || !following.follower || !following.followee) {
 			logger.warn('フォロー解除がリクエストされましたがフォローしていませんでした');
 			return;
 		}
@@ -339,10 +340,7 @@ export class UserFollowingService implements OnModuleInit {
 
 		this.cacheService.userFollowingsCache.refresh(follower.id);
 
-		// Neither followee nor follower has moved.
-		if (!following.followee?.movedToUri && !following.follower?.movedToUri) {
-			this.decrementFollowing(follower, followee);
-		}
+		this.decrementFollowing(following.follower, following.followee);
 
 		// Publish unfollow event
 		if (!silent && this.userEntityService.isLocalUser(follower)) {
@@ -374,37 +372,74 @@ export class UserFollowingService implements OnModuleInit {
 
 	@bindThis
 	private async decrementFollowing(
-		follower: { id: User['id']; host: User['host']; },
-		followee: { id: User['id']; host: User['host']; },
+		follower: User,
+		followee: User,
 	): Promise<void> {
 		this.globalEventService.publishInternalEvent('unfollow', { followerId: follower.id, followeeId: followee.id });
 
-		//#region Decrement following / followers counts
-		await Promise.all([
-			this.usersRepository.decrement({ id: follower.id }, 'followingCount', 1),
-			this.usersRepository.decrement({ id: followee.id }, 'followersCount', 1),
-		]);
-		//#endregion
+		// Neither followee nor follower has moved.
+		if (!follower.movedToUri && !followee.movedToUri) {
+			//#region Decrement following / followers counts
+			await Promise.all([
+				this.usersRepository.decrement({ id: follower.id }, 'followingCount', 1),
+				this.usersRepository.decrement({ id: followee.id }, 'followersCount', 1),
+			]);
+			//#endregion
 
-		//#region Update instance stats
-		if (this.userEntityService.isRemoteUser(follower) && this.userEntityService.isLocalUser(followee)) {
-			this.federatedInstanceService.fetch(follower.host).then(async i => {
-				this.instancesRepository.decrement({ id: i.id }, 'followingCount', 1);
-				if ((await this.metaService.fetch()).enableChartsForFederatedInstances) {
-					this.instanceChart.updateFollowing(i.host, false);
-				}
-			});
-		} else if (this.userEntityService.isLocalUser(follower) && this.userEntityService.isRemoteUser(followee)) {
-			this.federatedInstanceService.fetch(followee.host).then(async i => {
-				this.instancesRepository.decrement({ id: i.id }, 'followersCount', 1);
-				if ((await this.metaService.fetch()).enableChartsForFederatedInstances) {
-					this.instanceChart.updateFollowers(i.host, false);
-				}
-			});
+			//#region Update instance stats
+			if (this.userEntityService.isRemoteUser(follower) && this.userEntityService.isLocalUser(followee)) {
+				this.federatedInstanceService.fetch(follower.host).then(async i => {
+					this.instancesRepository.decrement({ id: i.id }, 'followingCount', 1);
+					if ((await this.metaService.fetch()).enableChartsForFederatedInstances) {
+						this.instanceChart.updateFollowing(i.host, false);
+					}
+				});
+			} else if (this.userEntityService.isLocalUser(follower) && this.userEntityService.isRemoteUser(followee)) {
+				this.federatedInstanceService.fetch(followee.host).then(async i => {
+					this.instancesRepository.decrement({ id: i.id }, 'followersCount', 1);
+					if ((await this.metaService.fetch()).enableChartsForFederatedInstances) {
+						this.instanceChart.updateFollowers(i.host, false);
+					}
+				});
+			}
+			//#endregion
+
+			this.perUserFollowingChart.update(follower, followee, false);
+		} else {
+			// Adjust following/followers counts
+			for (const user of [follower, followee]) {
+				if (user.movedToUri) continue; // No need to update if the user has already moved.
+
+				const nonMovedFollowees = await this.followingsRepository.count({
+					relations: {
+						followee: true,
+					},
+					where: {
+						followerId: user.id,
+						followee: {
+							movedToUri: IsNull(),
+						}
+					}
+				});
+				const nonMovedFollowers = await this.followingsRepository.count({
+					relations: {
+						follower: true,
+					},
+					where: {
+						followeeId: user.id,
+						follower: {
+							movedToUri: IsNull(),
+						}
+					}
+				});
+				await this.usersRepository.update(
+					{ id: user.id },
+					{ followingCount: nonMovedFollowees, followersCount: nonMovedFollowers },
+				);
+			}
+
+			// TODO: adjust charts
 		}
-		//#endregion
-
-		this.perUserFollowingChart.update(follower, followee, false);
 	}
 
 	@bindThis
@@ -618,14 +653,11 @@ export class UserFollowingService implements OnModuleInit {
 			}
 		});
 
-		if (!following) return;
+		if (!following || !following.followee || !following.follower) return;
 
 		await this.followingsRepository.delete(following.id);
 
-		// Neither followee nor follower has moved.
-		if (!following.followee?.movedToUri && !following.follower?.movedToUri) {
-			this.decrementFollowing(follower, followee);
-		}
+		this.decrementFollowing(following.follower, following.followee);
 	}
 
 	/**