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/users/users.service.spec.ts

@@ -12,61 +12,46 @@ jest.mock("jose", () => ({
 }));
 
 import { Test, TestingModule } from "@nestjs/testing";
-import { CryptoService } from "../crypto/crypto.service";
-import { DatabaseService } from "../database/database.service";
+import { CACHE_MANAGER } from "@nestjs/cache-manager";
 import { UsersService } from "./users.service";
+import { UsersRepository } from "./repositories/users.repository";
 
 describe("UsersService", () => {
 	let service: UsersService;
+	let repository: UsersRepository;
 
-	const mockDb = {
-		insert: jest.fn(),
-		select: jest.fn(),
+	const mockUsersRepository = {
+		create: jest.fn(),
+		findOne: jest.fn(),
+		findByEmailHash: jest.fn(),
+		findOneWithPrivateData: jest.fn(),
+		countAll: jest.fn(),
+		findAll: jest.fn(),
+		findByUsername: jest.fn(),
 		update: jest.fn(),
-		transaction: jest.fn().mockImplementation((cb) => cb(mockDb)),
+		getTwoFactorSecret: jest.fn(),
+		getUserContents: jest.fn(),
+		getUserFavorites: jest.fn(),
+		softDeleteUserAndContents: jest.fn(),
 	};
 
-	const mockCryptoService = {
-		getPgpEncryptionKey: jest.fn().mockReturnValue("mock-pgp-key"),
+	const mockCacheManager = {
+		del: jest.fn(),
 	};
 
 	beforeEach(async () => {
 		jest.clearAllMocks();
 
-		const chain = {
-			insert: jest.fn().mockReturnThis(),
-			values: jest.fn().mockReturnThis(),
-			returning: jest.fn().mockReturnThis(),
-			select: jest.fn().mockReturnThis(),
-			from: jest.fn().mockReturnThis(),
-			where: jest.fn().mockReturnThis(),
-			limit: jest.fn().mockReturnThis(),
-			offset: jest.fn().mockReturnThis(),
-			update: jest.fn().mockReturnThis(),
-			set: jest.fn().mockReturnThis(),
-			// biome-ignore lint/suspicious/noThenProperty: Fine for testing purposes
-			then: jest.fn().mockImplementation(function (cb) {
-				return Promise.resolve(this).then(cb);
-			}),
-		};
-
-		const mockImplementation = () => Object.assign(Promise.resolve([]), chain);
-		for (const mock of Object.values(chain)) {
-			if (mock !== chain.then) {
-				mock.mockImplementation(mockImplementation);
-			}
-		}
-		Object.assign(mockDb, chain);
-
 		const module: TestingModule = await Test.createTestingModule({
 			providers: [
 				UsersService,
-				{ provide: DatabaseService, useValue: { db: mockDb } },
-				{ provide: CryptoService, useValue: mockCryptoService },
+				{ provide: UsersRepository, useValue: mockUsersRepository },
+				{ provide: CACHE_MANAGER, useValue: mockCacheManager },
 			],
 		}).compile();
 
 		service = module.get<UsersService>(UsersService);
+		repository = module.get<UsersRepository>(UsersRepository);
 	});
 
 	it("should be defined", () => {
@@ -81,24 +66,24 @@ describe("UsersService", () => {
 				passwordHash: "p1",
 				emailHash: "eh1",
 			};
-			mockDb.returning.mockResolvedValue([{ uuid: "uuid1", ...data }]);
+			mockUsersRepository.create.mockResolvedValue({ uuid: "uuid1", ...data });
 
 			const result = await service.create(data);
 
 			expect(result.uuid).toBe("uuid1");
-			expect(mockDb.insert).toHaveBeenCalled();
+			expect(repository.create).toHaveBeenCalledWith(data);
 		});
 	});
 
 	describe("findOne", () => {
 		it("should find a user", async () => {
-			mockDb.limit.mockResolvedValue([{ uuid: "uuid1" }]);
+			mockUsersRepository.findOne.mockResolvedValue({ uuid: "uuid1" });
 			const result = await service.findOne("uuid1");
 			expect(result.uuid).toBe("uuid1");
 		});
 
 		it("should return null if not found", async () => {
-			mockDb.limit.mockResolvedValue([]);
+			mockUsersRepository.findOne.mockResolvedValue(null);
 			const result = await service.findOne("uuid1");
 			expect(result).toBeNull();
 		});
@@ -106,7 +91,7 @@ describe("UsersService", () => {
 
 	describe("update", () => {
 		it("should update a user", async () => {
-			mockDb.returning.mockResolvedValue([{ uuid: "uuid1", displayName: "New" }]);
+			mockUsersRepository.update.mockResolvedValue([{ uuid: "uuid1", displayName: "New" }]);
 			const result = await service.update("uuid1", { displayName: "New" });
 			expect(result[0].displayName).toBe("New");
 		});