feat: add modular services and repositories for improved code organization

Introduce repository pattern across multiple services, including `favorites`, `tags`, `sessions`, `reports`, `auth`, and more. Decouple crypto functionalities into modular services like `HashingService`, `JwtService`, and `EncryptionService`. Improve testability and maintainability by simplifying dependencies and consolidating utility logic.

backend/src/media/media.module.ts

@@ -1,8 +1,10 @@
 import { Module } from "@nestjs/common";
 import { MediaService } from "./media.service";
+import { ImageProcessorStrategy } from "./strategies/image-processor.strategy";
+import { VideoProcessorStrategy } from "./strategies/video-processor.strategy";
 
 @Module({
-	providers: [MediaService],
+	providers: [MediaService, ImageProcessorStrategy, VideoProcessorStrategy],
 	exports: [MediaService],
 })
 export class MediaModule {}

backend/src/media/media.service.spec.ts

@@ -6,6 +6,9 @@ import ffmpeg from "fluent-ffmpeg";
 import sharp from "sharp";
 import { MediaService } from "./media.service";
 
+import { ImageProcessorStrategy } from "./strategies/image-processor.strategy";
+import { VideoProcessorStrategy } from "./strategies/video-processor.strategy";
+
 jest.mock("sharp");
 jest.mock("fluent-ffmpeg");
 jest.mock("node:fs/promises");
@@ -29,6 +32,8 @@ describe("MediaService", () => {
 		const module: TestingModule = await Test.createTestingModule({
 			providers: [
 				MediaService,
+				ImageProcessorStrategy,
+				VideoProcessorStrategy,
 				{
 					provide: ConfigService,
 					useValue: {

backend/src/media/media.service.ts

@@ -1,22 +1,18 @@
-import { readFile, unlink, writeFile } from "node:fs/promises";
-import { tmpdir } from "node:os";
-import { join } from "node:path";
 import { Readable } from "node:stream";
 import {
-	BadRequestException,
 	Injectable,
 	InternalServerErrorException,
 	Logger,
 } from "@nestjs/common";
 import { ConfigService } from "@nestjs/config";
 import * as NodeClam from "clamscan";
-import ffmpeg from "fluent-ffmpeg";
-import sharp from "sharp";
-import { v4 as uuidv4 } from "uuid";
 import type {
+	IMediaService,
 	MediaProcessingResult,
 	ScanResult,
-} from "./interfaces/media.interface";
+} from "../common/interfaces/media.interface";
+import { ImageProcessorStrategy } from "./strategies/image-processor.strategy";
+import { VideoProcessorStrategy } from "./strategies/video-processor.strategy";
 
 interface ClamScanner {
 	scanStream(
@@ -25,12 +21,16 @@ interface ClamScanner {
 }
 
 @Injectable()
-export class MediaService {
+export class MediaService implements IMediaService {
 	private readonly logger = new Logger(MediaService.name);
 	private clamscan: ClamScanner | null = null;
 	private isClamAvInitialized = false;
 
-	constructor(private readonly configService: ConfigService) {
+	constructor(
+		private readonly configService: ConfigService,
+		private readonly imageProcessor: ImageProcessorStrategy,
+		private readonly videoProcessor: VideoProcessorStrategy,
+	) {
 		this.initClamScan();
 	}
 
@@ -84,82 +84,13 @@ export class MediaService {
 		buffer: Buffer,
 		format: "webp" | "avif" = "webp",
 	): Promise<MediaProcessingResult> {
-		try {
-			let pipeline = sharp(buffer);
-			const metadata = await pipeline.metadata();
-
-			if (format === "webp") {
-				pipeline = pipeline.webp({ quality: 80, effort: 6 });
-			} else {
-				pipeline = pipeline.avif({ quality: 65, effort: 6 });
-			}
-
-			const processedBuffer = await pipeline.toBuffer();
-
-			return {
-				buffer: processedBuffer,
-				mimeType: `image/${format}`,
-				extension: format,
-				width: metadata.width,
-				height: metadata.height,
-				size: processedBuffer.length,
-			};
-		} catch (error) {
-			this.logger.error(`Error processing image: ${error.message}`);
-			throw new BadRequestException("Failed to process image");
-		}
+		return this.imageProcessor.process(buffer, { format });
 	}
 
 	async processVideo(
 		buffer: Buffer,
 		format: "webm" | "av1" = "webm",
 	): Promise<MediaProcessingResult> {
-		const tempInput = join(tmpdir(), `${uuidv4()}.tmp`);
-		const tempOutput = join(
-			tmpdir(),
-			`${uuidv4()}.${format === "av1" ? "mp4" : "webm"}`,
-		);
-
-		try {
-			await writeFile(tempInput, buffer);
-
-			await new Promise<void>((resolve, reject) => {
-				let command = ffmpeg(tempInput);
-
-				if (format === "webm") {
-					command = command
-						.toFormat("webm")
-						.videoCodec("libvpx-vp9")
-						.audioCodec("libopus")
-						.outputOptions("-crf 30", "-b:v 0");
-				} else {
-					command = command
-						.toFormat("mp4")
-						.videoCodec("libaom-av1")
-						.audioCodec("libopus")
-						.outputOptions("-crf 34", "-b:v 0", "-strict experimental");
-				}
-
-				command
-					.on("end", () => resolve())
-					.on("error", (err) => reject(err))
-					.save(tempOutput);
-			});
-
-			const processedBuffer = await readFile(tempOutput);
-
-			return {
-				buffer: processedBuffer,
-				mimeType: format === "av1" ? "video/mp4" : "video/webm",
-				extension: format === "av1" ? "mp4" : "webm",
-				size: processedBuffer.length,
-			};
-		} catch (error) {
-			this.logger.error(`Error processing video: ${error.message}`);
-			throw new BadRequestException("Failed to process video");
-		} finally {
-			await unlink(tempInput).catch(() => {});
-			await unlink(tempOutput).catch(() => {});
-		}
+		return this.videoProcessor.process(buffer, { format });
 	}
 }

backend/src/media/strategies/image-processor.strategy.ts

@@ -0,0 +1,44 @@
+import { BadRequestException, Injectable, Logger } from "@nestjs/common";
+import sharp from "sharp";
+import type { MediaProcessingResult } from "../../common/interfaces/media.interface";
+import type { IMediaProcessorStrategy } from "./media-processor.strategy";
+
+@Injectable()
+export class ImageProcessorStrategy implements IMediaProcessorStrategy {
+	private readonly logger = new Logger(ImageProcessorStrategy.name);
+
+	canHandle(mimeType: string): boolean {
+		return mimeType.startsWith("image/");
+	}
+
+	async process(
+		buffer: Buffer,
+		options: { format: "webp" | "avif" } = { format: "webp" },
+	): Promise<MediaProcessingResult> {
+		try {
+			const { format } = options;
+			let pipeline = sharp(buffer);
+			const metadata = await pipeline.metadata();
+
+			if (format === "webp") {
+				pipeline = pipeline.webp({ quality: 80, effort: 6 });
+			} else {
+				pipeline = pipeline.avif({ quality: 65, effort: 6 });
+			}
+
+			const processedBuffer = await pipeline.toBuffer();
+
+			return {
+				buffer: processedBuffer,
+				mimeType: `image/${format}`,
+				extension: format,
+				width: metadata.width,
+				height: metadata.height,
+				size: processedBuffer.length,
+			};
+		} catch (error) {
+			this.logger.error(`Error processing image: ${error.message}`);
+			throw new BadRequestException("Failed to process image");
+		}
+	}
+}

backend/src/media/strategies/media-processor.strategy.ts

@@ -0,0 +1,6 @@
+import type { MediaProcessingResult } from "../../common/interfaces/media.interface";
+
+export interface IMediaProcessorStrategy {
+	canHandle(mimeType: string): boolean;
+	process(buffer: Buffer, options?: any): Promise<MediaProcessingResult>;
+}

backend/src/media/strategies/video-processor.strategy.ts

@@ -0,0 +1,71 @@
+import { readFile, unlink, writeFile } from "node:fs/promises";
+import { tmpdir } from "node:os";
+import { join } from "node:path";
+import { BadRequestException, Injectable, Logger } from "@nestjs/common";
+import ffmpeg from "fluent-ffmpeg";
+import { v4 as uuidv4 } from "uuid";
+import type { MediaProcessingResult } from "../../common/interfaces/media.interface";
+import type { IMediaProcessorStrategy } from "./media-processor.strategy";
+
+@Injectable()
+export class VideoProcessorStrategy implements IMediaProcessorStrategy {
+	private readonly logger = new Logger(VideoProcessorStrategy.name);
+
+	canHandle(mimeType: string): boolean {
+		return mimeType.startsWith("video/");
+	}
+
+	async process(
+		buffer: Buffer,
+		options: { format: "webm" | "av1" } = { format: "webm" },
+	): Promise<MediaProcessingResult> {
+		const { format } = options;
+		const tempInput = join(tmpdir(), `${uuidv4()}.tmp`);
+		const tempOutput = join(
+			tmpdir(),
+			`${uuidv4()}.${format === "av1" ? "mp4" : "webm"}`,
+		);
+
+		try {
+			await writeFile(tempInput, buffer);
+
+			await new Promise<void>((resolve, reject) => {
+				let command = ffmpeg(tempInput);
+
+				if (format === "webm") {
+					command = command
+						.toFormat("webm")
+						.videoCodec("libvpx-vp9")
+						.audioCodec("libopus")
+						.outputOptions("-crf 30", "-b:v 0");
+				} else {
+					command = command
+						.toFormat("mp4")
+						.videoCodec("libaom-av1")
+						.audioCodec("libopus")
+						.outputOptions("-crf 34", "-b:v 0", "-strict experimental");
+				}
+
+				command
+					.on("end", () => resolve())
+					.on("error", (err) => reject(err))
+					.save(tempOutput);
+			});
+
+			const processedBuffer = await readFile(tempOutput);
+
+			return {
+				buffer: processedBuffer,
+				mimeType: format === "av1" ? "video/mp4" : "video/webm",
+				extension: format === "av1" ? "mp4" : "webm",
+				size: processedBuffer.length,
+			};
+		} catch (error) {
+			this.logger.error(`Error processing video: ${error.message}`);
+			throw new BadRequestException("Failed to process video");
+		} finally {
+			await unlink(tempInput).catch(() => {});
+			await unlink(tempOutput).catch(() => {});
+		}
+	}
+}