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fluxer_api/src/unfurler/resolvers/BaseResolver.ts

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+/*
+ * Copyright (C) 2026 Fluxer Contributors
+ *
+ * This file is part of Fluxer.
+ *
+ * Fluxer is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Fluxer is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with Fluxer. If not, see <https://www.gnu.org/licenses/>.
+ */
+
+import type {MessageEmbedResponse} from '~/channel/EmbedTypes';
+import type {IMediaService} from '~/infrastructure/IMediaService';
+import {Logger} from '~/Logger';
+import {URLType} from '~/Schema';
+import {buildEmbedMediaPayload} from '~/unfurler/resolvers/media/MediaMetadataHelpers';
+
+export abstract class BaseResolver {
+	constructor(protected mediaService: IMediaService) {}
+
+	abstract match(url: URL, mimeType: string, content: Uint8Array): boolean;
+	abstract resolve(url: URL, content: Uint8Array, isNSFWAllowed?: boolean): Promise<Array<MessageEmbedResponse>>;
+
+	protected resolveRelativeURL(baseUrl: string, relativeUrl?: string): string | null {
+		if (!relativeUrl) {
+			return null;
+		}
+		try {
+			return new URL(relativeUrl, baseUrl).href;
+		} catch (error) {
+			Logger.error({error}, 'Failed to resolve relative URL');
+			return relativeUrl;
+		}
+	}
+
+	protected async resolveMediaURL(
+		url: URL,
+		mediaUrl?: string | null,
+		isNSFWAllowed: boolean = false,
+	): Promise<MessageEmbedResponse['image']> {
+		if (!mediaUrl) {
+			return null;
+		}
+
+		const resolvedUrl = this.resolveRelativeURL(url.href, mediaUrl);
+		if (resolvedUrl && URLType.safeParse(resolvedUrl).success) {
+			try {
+				const metadata = await this.mediaService.getMetadata({
+					type: 'external',
+					url: resolvedUrl,
+					isNSFWAllowed,
+				});
+				return buildEmbedMediaPayload(resolvedUrl, metadata);
+			} catch (error) {
+				Logger.error({error}, 'Failed to resolve media URL metadata');
+				return null;
+			}
+		}
+
+		return null;
+	}
+}