core/test/container.test.ts

import { describe, expect, test } from "bun:test";
import "reflect-metadata";
import {
	AlveoFactory,
	CircularDependencyError,
	Container,
	forwardRef,
	Inject,
	Injectable,
	Module,
	ProviderNotFoundError,
} from "../index";

describe("Alveo Container & DI", () => {
	test("should resolve a simple singleton service", async () => {
		@Injectable()
		class SimpleService {
			getValue() {
				return "hello";
			}
		}

		@Module({
			providers: [SimpleService],
		})
		class RootModule {}

		const app = await AlveoFactory.create(RootModule);
		const service = await app.get(SimpleService);

		expect(service).toBeInstanceOf(SimpleService);
		expect(service.getValue()).toBe("hello");
	});

	test("should inject dependencies via constructor", async () => {
		@Injectable()
		class Dependency {
			name = "dep";
		}

		@Injectable()
		class MainService {
			constructor(public readonly dep: Dependency) {}
		}

		@Module({
			providers: [Dependency, MainService],
		})
		class RootModule {}

		const app = await AlveoFactory.create(RootModule);
		const main = await app.get(MainService);

		expect(main.dep).toBeInstanceOf(Dependency);
		expect(main.dep.name).toBe("dep");
	});

	test("should support Value Providers", async () => {
		const TOKEN = Symbol("CONFIG");

		@Injectable()
		class Service {
			constructor(
				@Inject(TOKEN) public readonly config: { apiKey: string },
			) {}
		}

		@Module({
			providers: [
				Service,
				{ provide: TOKEN, useValue: { apiKey: "123" } },
			],
		})
		class RootModule {}

		const app = await AlveoFactory.create(RootModule);
		const service = await app.get(Service);

		expect(service.config.apiKey).toBe("123");
	});

	test("should support Factory Providers", async () => {
		const TOKEN = "FACTORY";

		@Module({
			providers: [
				{
					provide: TOKEN,
					useFactory: () => "dynamic_value",
				},
			],
		})
		class RootModule {}

		const app = await AlveoFactory.create(RootModule);
		const value = await app.get(TOKEN);

		expect(value).toBe("dynamic_value");
	});

	test("should support Asynchronous Factory Providers", async () => {
		const TOKEN = "ASYNC_FACTORY";

		@Module({
			providers: [
				{
					provide: TOKEN,
					useFactory: async () => {
						await new Promise((resolve) => setTimeout(resolve, 10));
						return "async_value";
					},
				},
			],
		})
		class RootModule {}

		const app = await AlveoFactory.create(RootModule);
		const value = await app.get(TOKEN);

		expect(value).toBe("async_value");
	});

	test("should handle concurrent resolution of the same async provider", async () => {
		const TOKEN = "CONCURRENT_ASYNC";
		let callCount = 0;

		@Module({
			providers: [
				{
					provide: TOKEN,
					useFactory: async () => {
						callCount++;
						await new Promise((resolve) => setTimeout(resolve, 20));
						return { id: Math.random() };
					},
				},
			],
		})
		class RootModule {}

		// We use a fresh container to test concurrent resolution
		// bypassing the sequential resolveAll() of AlveoFactory.create()
		const container = new Container();
		container.registerRootModule(RootModule);

		const [val1, val2] = await Promise.all([
			container.get(TOKEN),
			container.get(TOKEN),
		]);

		expect(val1).toBe(val2);
		expect(callCount).toBe(1);
	});

	test("should handle Module imports and exports", async () => {
		@Injectable()
		class SharedService {
			identify() {
				return "shared";
			}
		}

		@Module({
			providers: [SharedService],
			exports: [SharedService],
		})
		class LibModule {}

		@Module({
			imports: [LibModule],
		})
		class AppModule {}

		const app = await AlveoFactory.create(AppModule);
		const service = await app.get(SharedService);

		expect(service.identify()).toBe("shared");
	});

	test("should throw ProviderNotFoundError when dependency is missing", async () => {
		@Injectable()
		class MissingDep {}

		@Injectable()
		class Target {
			constructor(_dep: MissingDep) {}
		}

		@Module({
			providers: [Target], // MissingDep is not provided
		})
		class RootModule {}

		expect(AlveoFactory.create(RootModule)).rejects.toThrow(
			ProviderNotFoundError,
		);
	});

	test("should detect circular dependencies without forwardRef", async () => {
		@Injectable()
		class A {
			constructor(_b: unknown) {}
		}
		@Injectable()
		class B {
			constructor(_a: A) {}
		}

		// Manually define metadata to simulate circular dep without forwardRef
		Reflect.defineMetadata("design:paramtypes", [Object], A);
		Reflect.defineMetadata("design:paramtypes", [A], B);
		Reflect.defineMetadata("alveo:inject", [B], A);

		@Module({
			providers: [A, B],
		})
		class RootModule {}

		expect(AlveoFactory.create(RootModule)).rejects.toThrow(
			CircularDependencyError,
		);
	});

	test("should resolve circular dependencies with forwardRef", async () => {
		@Injectable()
		class ServiceA {
			constructor(
				@Inject(forwardRef(() => ServiceB))
				public readonly serviceB: { name: () => string },
			) {}
			name() {
				return "A";
			}
		}

		@Injectable()
		class ServiceB {
			constructor(
				@Inject(forwardRef(() => ServiceA))
				public readonly serviceA: { name: () => string },
			) {}
			name() {
				return "B";
			}
		}

		@Module({
			providers: [ServiceA, ServiceB],
		})
		class RootModule {}

		const app = await AlveoFactory.create(RootModule);
		const a = await app.get(ServiceA);
		const b = await app.get(ServiceB);

		expect(a.serviceB.name()).toBe("B");
		expect(b.serviceA.name()).toBe("A");
	});

	test("should call lifecycle hooks", async () => {
		let initCalled = false;
		let destroyCalled = false;

		@Injectable()
		class LifecycleService {
			async onModuleInit() {
				initCalled = true;
			}
			async onModuleDestroy() {
				destroyCalled = true;
			}
		}

		@Module({
			providers: [LifecycleService],
		})
		class RootModule {}

		const app = await AlveoFactory.create(RootModule);
		expect(initCalled).toBe(true);

		await app.close();
		expect(destroyCalled).toBe(true);
	});

	test("should support existing providers (aliases)", async () => {
		const ALIAS = "ALIAS_TOKEN";

		@Injectable()
		class RealService {
			ok() {
				return true;
			}
		}

		@Module({
			providers: [
				RealService,
				{ provide: ALIAS, useExisting: RealService },
			],
		})
		class RootModule {}

		const app = await AlveoFactory.create(RootModule);
		const real = await app.get(RealService);
		const aliased = await app.get(ALIAS);

		expect(aliased).toBe(real);
		expect((aliased as RealService).ok()).toBe(true);
	});
});