import {
	assertEquals,
	assertThrows,
} from 'https://deno.land/std@0.224.0/assert/mod.ts';

import { DependencyManager, Provider } from './dependency-manager.ts';

Deno.test('should register and resolve a simple dependency', () => {
	const manager = new DependencyManager();

	const dependency = () => 'test';
	manager.register(dependency);

	const resolved = manager.resolve(dependency);
	assertEquals(resolved, 'test');
});

Deno.test('should register and resolve a module with multiple dependencies', () => {
	const manager = new DependencyManager();

	const module = {
		a: () => 'test1',
		b: () => 42,
	};

	manager.register(module);

	const a = manager.resolve(module.a);
	const b = manager.resolve(module.b);

	assertEquals(a, 'test1');
	assertEquals(b, 42);
});

Deno.test('should throw error when registering the same dependency twice', () => {
	const manager = new DependencyManager();

	const dependency = () => 'test';
	manager.register(dependency);

	assertThrows(
		() => manager.register(dependency),
		Error,
		'This dependency or module has already been registered',
	);
});

Deno.test('should throw error when resolving a non-registered dependency', () => {
	const manager = new DependencyManager();

	const dependency = () => 'test';

	assertThrows(
		() => manager.resolve(dependency),
		Error,
		'This key has not (yet ?) been used to register something',
	);
});

Deno.test('should resolve dependency recursively (when not circular)', () => {
	const manager = new DependencyManager();

	const dependencyA = () => 'A';
	const dependencyB = (manager: DependencyManager) =>
		manager.resolve(dependencyA);

	manager.register(dependencyA);
	manager.register(dependencyB);

	const b = manager.resolve(dependencyB);

	assertEquals(b, 'A');
});

Deno.test('should throw error when detecting a circular dependency', () => {
	const manager = new DependencyManager();

	const dependencyA: Provider<string> = (manager) =>
		manager.resolve(dependencyB);
	const dependencyB: Provider<string> = (manager) =>
		manager.resolve(dependencyA);

	manager.register(dependencyA);
	manager.register(dependencyB);

	assertThrows(
		() => manager.resolve(dependencyA),
		Error,
		'Circular dependency detected',
	);
});