import {
	getRandomFromArray,
	getRandomInt
} from '~/utilities/random';

const MOCK_RANDOM_STARTING_VALUE = 0.123456789;

describe('Random Utility functions', () => {
	// eslint-disable-next-line @typescript-eslint/init-declarations
	let mockRandomValue: number;

	beforeAll(() => {
		const mockMath = Object.create(global.Math) as Math;
		mockMath.random = (): number => mockRandomValue;
		global.Math = mockMath;
	});

	beforeEach(() => {
		mockRandomValue = MOCK_RANDOM_STARTING_VALUE;
	});

	describe('getRandomInt', () => {
		test('No min, no max', () => {
			const int = getRandomInt();

			// eslint-disable-next-line no-mixed-operators,max-len
			const expected = Math.floor(mockRandomValue * (Number.MAX_SAFE_INTEGER - Number.MIN_SAFE_INTEGER + 1) + Number.MIN_SAFE_INTEGER);

			expect(int).toStrictEqual(expected);
		});

		test('Min, no max', () => {
			const min = 50;

			const int = getRandomInt(min);

			expect(int).toBeGreaterThanOrEqual(min);
		});

		test('No min, max', () => {
			const max = 50;

			const int = getRandomInt(Number.MIN_SAFE_INTEGER, max);

			expect(int).toBeLessThanOrEqual(max);
		});
	});

	describe('getRandomFromArray', () => {
		test('Returns "random" item from array', () => {
			const arr = ['cornelius', 'zira', 'lucius', 'maximus', 'caesar'];

			const expectedIndex = Math.floor(mockRandomValue * arr.length);

			const item = getRandomFromArray(arr);

			expect(item).toStrictEqual(arr[expectedIndex]);
		});
	});
});