1 files changed, 84 insertions, 0 deletions
diff --git a/packages/backend/src/server/api/mastodon/MastodonDataService.ts b/packages/backend/src/server/api/mastodon/MastodonDataService.ts
new file mode 100644
index 0000000000..671ecdcbed
--- /dev/null
+++ b/packages/backend/src/server/api/mastodon/MastodonDataService.ts
@@ -0,0 +1,84 @@
+/*
+ * SPDX-FileCopyrightText: hazelnoot and other Sharkey contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+import { Inject, Injectable } from '@nestjs/common';
+import { IsNull } from 'typeorm';
+import { DI } from '@/di-symbols.js';
+import { QueryService } from '@/core/QueryService.js';
+import type { MiNote, NotesRepository } from '@/models/_.js';
+import type { MiLocalUser } from '@/models/User.js';
+import { ApiError } from '../error.js';
+
+/**
+ * Utility service for accessing data with Mastodon semantics
+ */
+@Injectable()
+export class MastodonDataService {
+	constructor(
+		@Inject(DI.notesRepository)
+		private readonly notesRepository: NotesRepository,
+
+		@Inject(QueryService)
+		private readonly queryService: QueryService,
+	) {}
+
+	/**
+	 * Fetches a note in the context of the current user, and throws an exception if not found.
+	 */
+	public async requireNote(noteId: string, me?: MiLocalUser | null): Promise<MiNote> {
+		const note = await this.getNote(noteId, me);
+
+		if (!note) {
+			throw new ApiError({
+				message: 'No such note.',
+				code: 'NO_SUCH_NOTE',
+				id: '24fcbfc6-2e37-42b6-8388-c29b3861a08d',
+				kind: 'client',
+				httpStatusCode: 404,
+			});
+		}
+
+		return note;
+	}
+
+	/**
+	 * Fetches a note in the context of the current user.
+	 */
+	public async getNote(noteId: string, me?: MiLocalUser | null): Promise<MiNote | null> {
+		// Root query: note + required dependencies
+		const query = this.notesRepository
+			.createQueryBuilder('note')
+			.where('note.id = :noteId', { noteId })
+			.innerJoinAndSelect('note.user', 'user');
+
+		// Restrict visibility
+		this.queryService.generateVisibilityQuery(query, me);
+		if (me) {
+			this.queryService.generateBlockedUserQuery(query, me);
+		}
+
+		return await query.getOne();
+	}
+
+	/**
+	 * Checks where the current user has made a reblog / boost / pure renote of a given target note.
+	 */
+	public async hasReblog(noteId: string, me: MiLocalUser | null | undefined): Promise<boolean> {
+		if (!me) return false;
+
+		return await this.notesRepository.existsBy({
+			// Reblog of the target note by me
+			userId: me.id,
+			renoteId: noteId,
+
+			// That is pure (not a quote)
+			text: IsNull(),
+			cw: IsNull(),
+			replyId: IsNull(),
+			hasPoll: false,
+			fileIds: '{}',
+		});
+	}
+}