feat: add announcement channels, publishing and following (#3090)

fluxer_api/src/api/channel/services/message/CrosspostSourceService.ts

@@ -0,0 +1,104 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+import {createGuildID, type GuildID} from '@app/api/BrandedTypes';
+import {Config} from '@app/api/Config';
+import {mapGuildToPartialResponse} from '@app/api/guild/GuildModel';
+import type {IGuildDiscoveryRepository} from '@app/api/guild/repositories/GuildDiscoveryRepository';
+import type {IGuildDataRepository} from '@app/api/guild/repositories/IGuildDataRepository';
+import type {IGatewayService} from '@app/api/infrastructure/IGatewayService';
+import {Logger} from '@app/api/Logger';
+import {MessageFlags, MessageTypes} from '@fluxer/constants/src/ChannelConstants';
+import {DiscoveryApplicationStatus} from '@fluxer/constants/src/DiscoveryConstants';
+import {GuildFeatures} from '@fluxer/constants/src/GuildConstants';
+import {UnknownMessageError} from '@fluxer/errors/src/domains/channel/UnknownMessageError';
+import {UnknownGuildError} from '@fluxer/errors/src/domains/guild/UnknownGuildError';
+import type {CrosspostSourceResponse} from '@fluxer/schema/src/domains/message/CrosspostSourceSchemas';
+import type {MessageResponse} from '@fluxer/schema/src/domains/message/MessageResponseSchemas';
+import type {ICacheService} from '@pkgs/cache/src/ICacheService';
+
+const CROSSPOST_SOURCE_COUNTS_TTL_SECONDS = 60;
+
+const CROSSPOST_SOURCE_PUBLIC_FEATURES = new Set<string>([
+	GuildFeatures.VERIFIED,
+	GuildFeatures.PARTNERED,
+	GuildFeatures.DISCOVERABLE,
+]);
+
+interface CrosspostSourceCounts {
+	memberCount: number;
+	presenceCount: number;
+}
+
+export function crosspostSourceCountsCacheKey(guildId: GuildID): string {
+	return `crosspost-source:counts:${guildId.toString()}`;
+}
+
+export function getCrosspostSourceGuildId(message: MessageResponse): GuildID | null {
+	const isCopy = (message.flags & MessageFlags.IS_CROSSPOST) !== 0;
+	const isFollowNotice = message.type === MessageTypes.CHANNEL_FOLLOW_ADD;
+	if (!isCopy && !isFollowNotice) {
+		return null;
+	}
+	const guildId = message.message_reference?.guild_id;
+	return guildId ? createGuildID(BigInt(guildId)) : null;
+}
+
+export class CrosspostSourceService {
+	constructor(
+		private readonly guildRepository: IGuildDataRepository,
+		private readonly discoveryRepository: IGuildDiscoveryRepository,
+		private readonly gatewayService: IGatewayService,
+		private readonly cacheService: ICacheService,
+	) {}
+
+	async getSource(message: MessageResponse): Promise<CrosspostSourceResponse> {
+		const guildId = getCrosspostSourceGuildId(message);
+		if (guildId === null) {
+			throw new UnknownMessageError();
+		}
+		const guild = await this.guildRepository.findUnique(guildId);
+		if (!guild) {
+			throw new UnknownGuildError();
+		}
+		const partial = mapGuildToPartialResponse(guild);
+		const isListed = Config.discovery.enabled && guild.features.has(GuildFeatures.DISCOVERABLE);
+		const [counts, description] = await Promise.all([
+			this.getCounts(guildId),
+			isListed ? this.getListedDescription(guildId) : null,
+		]);
+		return {
+			guild: {
+				id: partial.id,
+				name: partial.name,
+				icon: partial.icon ?? null,
+				banner: partial.banner ?? null,
+				features: partial.features.filter((feature) => CROSSPOST_SOURCE_PUBLIC_FEATURES.has(feature)),
+				approximate_member_count: counts?.memberCount ?? null,
+				approximate_presence_count: counts?.presenceCount ?? null,
+				description,
+				discoverable: isListed && !guild.features.has(GuildFeatures.INVITES_DISABLED),
+			},
+		};
+	}
+
+	private async getListedDescription(guildId: GuildID): Promise<string | null> {
+		const row = await this.discoveryRepository.findByGuildId(guildId);
+		if (row?.status !== DiscoveryApplicationStatus.APPROVED) {
+			return null;
+		}
+		return row.description || null;
+	}
+
+	private async getCounts(guildId: GuildID): Promise<CrosspostSourceCounts | null> {
+		try {
+			return await this.cacheService.getOrSet<CrosspostSourceCounts>(
+				crosspostSourceCountsCacheKey(guildId),
+				() => this.gatewayService.getGuildCounts(guildId),
+				CROSSPOST_SOURCE_COUNTS_TTL_SECONDS,
+			);
+		} catch (error) {
+			Logger.warn({error, guildId: guildId.toString()}, 'Failed to load crosspost source community counts');
+			return null;
+		}
+	}
+}