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

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

Deno.test('provide: should throw error when an identifier is reused', () => {
	const value = 'test';
	const identifier = Symbol() as Identifier<typeof value>;

	const manager = new Manager();
	manager.register(identifier, () => value);

	assertThrows(
		() => manager.register(identifier, () => value),
		Error,
	);
});

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

	assertThrows(
		() => manager.inject(identifier),
		Error,
	);
});

Deno.test('inject: should return the provided value (stand-alone injectable)', () => {
	const value = 'foo';
	const identifier = Symbol() as Identifier<typeof value>;

	const manager = new Manager();
	manager.register(identifier, () => value);

	const resolved = manager.inject(identifier);
	assertEquals(resolved, 'foo');
});

Deno.test('inject: should return the expected value (injectable with dependencies)', () => {
	const providerA = () => 'a';
	const identifierA = Symbol() as Identifier<ReturnType<typeof providerA>>;

	const providerB = (m: Manager) => {
		const a = manager.inject(identifierA);

		return `-${a}-`;
	};
	const identifierB = Symbol() as Identifier<ReturnType<typeof providerB>>;

	const manager = new Manager();
	manager.register(identifierA, providerA);
	manager.register(identifierB, providerB);

	const b = manager.inject(identifierB);

	assertEquals(b, '-a-');
});

Deno.test('inject: should throw error when detecting a circular dependency', () => {
	const identifierA = Symbol();
	const identifierB = Symbol();

	const providerA = (manager: Manager) => manager.inject(identifierB);
	const providerB = (manager: Manager) => manager.inject(identifierA);

	const manager = new Manager();
	manager.register(identifierA, providerA);
	manager.register(identifierB, providerB);

	assertThrows(
		() => manager.inject(identifierA),
		Error,
	);
});