1 files changed, 168 insertions, 0 deletions
diff --git a/packages/backend/src/core/NoteDeleteService.ts b/packages/backend/src/core/NoteDeleteService.ts
new file mode 100644
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+++ b/packages/backend/src/core/NoteDeleteService.ts
@@ -0,0 +1,168 @@
+import { Brackets, In } from 'typeorm';
+import { Injectable, Inject } from '@nestjs/common';
+import type { User, ILocalUser, IRemoteUser } from '@/models/entities/User.js';
+import type { Note, IMentionedRemoteUsers } from '@/models/entities/Note.js';
+import { InstancesRepository, NotesRepository, UsersRepository } from '@/models/index.js';
+import { RelayService } from '@/core/RelayService.js';
+import { FederatedInstanceService } from '@/core/FederatedInstanceService.js';
+import { DI } from '@/di-symbols.js';
+import { Config } from '@/config.js';
+import NotesChart from '@/core/chart/charts/notes.js';
+import PerUserNotesChart from '@/core/chart/charts/per-user-notes.js';
+import InstanceChart from '@/core/chart/charts/instance.js';
+import { GlobalEventService } from '@/core/GlobalEventService.js';
+import { ApRendererService } from './remote/activitypub/ApRendererService.js';
+import { ApDeliverManagerService } from './remote/activitypub/ApDeliverManagerService.js';
+import { UserEntityService } from './entities/UserEntityService.js';
+
+@Injectable()
+export class NoteDeleteService {
+	constructor(
+		@Inject(DI.config)
+		private config: Config,
+
+		@Inject(DI.usersRepository)
+		private usersRepository: UsersRepository,
+
+		@Inject(DI.notesRepository)
+		private notesRepository: NotesRepository,
+
+		@Inject(DI.instancesRepository)
+		private instancesRepository: InstancesRepository,
+
+		private userEntityService: UserEntityService,
+		private globalEventServie: GlobalEventService,
+		private relayService: RelayService,
+		private federatedInstanceService: FederatedInstanceService,
+		private apRendererService: ApRendererService,
+		private apDeliverManagerService: ApDeliverManagerService,
+		private notesChart: NotesChart,
+		private perUserNotesChart: PerUserNotesChart,
+		private instanceChart: InstanceChart,
+	) {}
+	
+	/**
+ * 投稿を削除します。
+ * @param user 投稿者
+ * @param note 投稿
+ */
+	async delete(user: { id: User['id']; uri: User['uri']; host: User['host']; }, note: Note, quiet = false) {
+		const deletedAt = new Date();
+
+		// この投稿を除く指定したユーザーによる指定したノートのリノートが存在しないとき
+		if (note.renoteId && (await this.noteEntityService.countSameRenotes(user.id, note.renoteId, note.id)) === 0) {
+			this.notesRepository.decrement({ id: note.renoteId }, 'renoteCount', 1);
+			this.notesRepository.decrement({ id: note.renoteId }, 'score', 1);
+		}
+
+		if (note.replyId) {
+			await this.notesRepository.decrement({ id: note.replyId }, 'repliesCount', 1);
+		}
+
+		if (!quiet) {
+			this.globalEventServie.publishNoteStream(note.id, 'deleted', {
+				deletedAt: deletedAt,
+			});
+
+			//#region ローカルの投稿なら削除アクティビティを配送
+			if (this.userEntityService.isLocalUser(user) && !note.localOnly) {
+				let renote: Note | null = null;
+
+				// if deletd note is renote
+				if (note.renoteId && note.text == null && !note.hasPoll && (note.fileIds == null || note.fileIds.length === 0)) {
+					renote = await this.notesRepository.findOneBy({
+						id: note.renoteId,
+					});
+				}
+
+				const content = this.apRendererService.renderActivity(renote
+					? this.apRendererService.renderUndo(this.apRendererService.renderAnnounce(renote.uri ?? `${this.config.url}/notes/${renote.id}`, note), user)
+					: this.apRendererService.renderDelete(this.apRendererService.renderTombstone(`${this.config.url}/notes/${note.id}`), user));
+
+				this.#deliverToConcerned(user, note, content);
+			}
+
+			// also deliever delete activity to cascaded notes
+			const cascadingNotes = (await this.#findCascadingNotes(note)).filter(note => !note.localOnly); // filter out local-only notes
+			for (const cascadingNote of cascadingNotes) {
+				if (!cascadingNote.user) continue;
+				if (!this.userEntityService.isLocalUser(cascadingNote.user)) continue;
+				const content = this.apRendererService.renderActivity(this.apRendererService.renderDelete(this.apRendererService.renderTombstone(`${this.config.url}/notes/${cascadingNote.id}`), cascadingNote.user));
+				this.#deliverToConcerned(cascadingNote.user, cascadingNote, content);
+			}
+			//#endregion
+
+			// 統計を更新
+			this.notesChart.update(note, false);
+			this.perUserNotesChart.update(user, note, false);
+
+			if (this.userEntityService.isRemoteUser(user)) {
+				this.federatedInstanceService.registerOrFetchInstanceDoc(user.host).then(i => {
+					this.instancesRepository.decrement({ id: i.id }, 'notesCount', 1);
+					this.instanceChart.updateNote(i.host, note, false);
+				});
+			}
+		}
+
+		await this.notesRepository.delete({
+			id: note.id,
+			userId: user.id,
+		});
+	}
+
+	async #findCascadingNotes(note: Note) {
+		const cascadingNotes: Note[] = [];
+
+		const recursive = async (noteId: string) => {
+			const query = this.notesRepository.createQueryBuilder('note')
+				.where('note.replyId = :noteId', { noteId })
+				.orWhere(new Brackets(q => {
+					q.where('note.renoteId = :noteId', { noteId })
+						.andWhere('note.text IS NOT NULL');
+				}))
+				.leftJoinAndSelect('note.user', 'user');
+			const replies = await query.getMany();
+			for (const reply of replies) {
+				cascadingNotes.push(reply);
+				await recursive(reply.id);
+			}
+		};
+		await recursive(note.id);
+
+		return cascadingNotes.filter(note => note.userHost === null); // filter out non-local users
+	}
+
+	async #getMentionedRemoteUsers(note: Note) {
+		const where = [] as any[];
+
+		// mention / reply / dm
+		const uris = (JSON.parse(note.mentionedRemoteUsers) as IMentionedRemoteUsers).map(x => x.uri);
+		if (uris.length > 0) {
+			where.push(
+				{ uri: In(uris) },
+			);
+		}
+
+		// renote / quote
+		if (note.renoteUserId) {
+			where.push({
+				id: note.renoteUserId,
+			});
+		}
+
+		if (where.length === 0) return [];
+
+		return await this.usersRepository.find({
+			where,
+		}) as IRemoteUser[];
+	}
+
+	async #deliverToConcerned(user: { id: ILocalUser['id']; host: null; }, note: Note, content: any) {
+		this.apDeliverManagerService.deliverToFollowers(user, content);
+		this.relayService.deliverToRelays(user, content);
+		const remoteUsers = await this.#getMentionedRemoteUsers(note);
+		for (const remoteUser of remoteUsers) {
+			this.apDeliverManagerService.deliverToUser(user, content, remoteUser);
+		}
+	}
+}