なんかもうめっちゃ変えた

packages/backend/src/core/FederatedInstanceService.ts

@@ -0,0 +1,46 @@
+import { Inject, Injectable } from '@nestjs/common';
+import { InstancesRepository } from '@/models/index.js';
+import type { Instance } from '@/models/entities/Instance.js';
+import { Cache } from '@/misc/cache.js';
+import { IdService } from '@/core/IdService.js';
+import { DI } from '@/di-symbols.js';
+import { UtilityService } from './UtilityService.js';
+
+@Injectable()
+export class FederatedInstanceService {
+	#cache: Cache<Instance>;
+
+	constructor(
+		@Inject(DI.instancesRepository)
+		private instancesRepository: InstancesRepository,
+
+		private utilityService: UtilityService,
+		private idService: IdService,
+	) {
+		this.#cache = new Cache<Instance>(1000 * 60 * 60);
+	}
+
+	public async registerOrFetchInstanceDoc(host: string): Promise<Instance> {
+		host = this.utilityService.toPuny(host);
+	
+		const cached = this.#cache.get(host);
+		if (cached) return cached;
+	
+		const index = await this.instancesRepository.findOneBy({ host });
+	
+		if (index == null) {
+			const i = await this.instancesRepository.insert({
+				id: this.idService.genId(),
+				host,
+				caughtAt: new Date(),
+				lastCommunicatedAt: new Date(),
+			}).then(x => this.instancesRepository.findOneByOrFail(x.identifiers[0]));
+	
+			this.#cache.set(host, i);
+			return i;
+		} else {
+			this.#cache.set(host, index);
+			return index;
+		}
+	}
+}