const { observable, computed, bundle } = require('../lib/index.js');

describe('bundle', () => {
	const methods = {
		add: (a, b) => a + b,
		square: a => a * a,
		getVal: val => {}
	};

	beforeEach(() => {
		spyOn(methods, 'add').and.callThrough();
		spyOn(methods, 'square').and.callThrough();
		spyOn(methods, 'getVal').and.callThrough();
	});

	it('bundles observable changes together', () => {
		const a = bundle({
			a: observable(0),
			b: observable(10)
		});
		const b = computed(methods.square, [a.a]);
		const c = computed(methods.add, [a.a, a.b]);

		b.subscribe(methods.getVal);
		c.subscribe(methods.getVal);
		expect(methods.getVal).toHaveBeenCalledTimes(0);

		expect(b()).toEqual(0);
		expect(methods.getVal).toHaveBeenCalledTimes(1);
		b();
		expect(methods.getVal).toHaveBeenCalledTimes(1);
		expect(c()).toEqual(10);
		c();
		expect(methods.getVal).toHaveBeenCalledTimes(2);
		expect(methods.add).toHaveBeenCalledTimes(1);
		expect(methods.square).toHaveBeenCalledTimes(1);

		a({ a: 2, b: 20 });
		expect(methods.add).toHaveBeenCalledTimes(2);
		expect(methods.square).toHaveBeenCalledTimes(2);
		expect(methods.getVal).toHaveBeenCalledTimes(4);
		expect(b()).toEqual(4);
		expect(c()).toEqual(22);
		expect(methods.add).toHaveBeenCalledTimes(2);
		expect(methods.square).toHaveBeenCalledTimes(2);
		expect(methods.getVal).toHaveBeenCalledTimes(4);
	});

	it('unbundled changes are less efficient', () => {
		const a = observable(0);
		const _b = observable(10);
		const b = computed(methods.square, [a]);
		const c = computed(methods.add, [a, _b]);

		b.subscribe(methods.getVal);
		c.subscribe(methods.getVal);
		expect(methods.getVal).toHaveBeenCalledTimes(0);

		expect(b()).toEqual(0);
		expect(methods.getVal).toHaveBeenCalledTimes(1);
		b();
		expect(methods.getVal).toHaveBeenCalledTimes(1);
		expect(c()).toEqual(10);
		c();
		expect(methods.getVal).toHaveBeenCalledTimes(2);
		expect(methods.add).toHaveBeenCalledTimes(1);
		expect(methods.square).toHaveBeenCalledTimes(1);

		a(2);
		_b(20);
		expect(methods.add).toHaveBeenCalledTimes(3);
		expect(methods.square).toHaveBeenCalledTimes(2);
		expect(methods.getVal).toHaveBeenCalledTimes(5);
		expect(b()).toEqual(4);
		expect(c()).toEqual(22);
		expect(methods.add).toHaveBeenCalledTimes(3);
		expect(methods.square).toHaveBeenCalledTimes(2);
		expect(methods.getVal).toHaveBeenCalledTimes(5);
	});

	it('allows individual members to be updated', () => {
		const a = bundle({
			a: observable(0),
			b: observable(10)
		});
		const b = computed(methods.square, [a.a]);
		const c = computed(methods.add, [a.a, a.b]);

		b.subscribe(methods.getVal);
		c.subscribe(methods.getVal);
		expect(methods.getVal).toHaveBeenCalledTimes(0);

		expect(b()).toEqual(0);
		expect(methods.getVal).toHaveBeenCalledTimes(1);
		b();
		expect(methods.getVal).toHaveBeenCalledTimes(1);
		expect(c()).toEqual(10);
		c();
		expect(methods.getVal).toHaveBeenCalledTimes(2);
		expect(methods.add).toHaveBeenCalledTimes(1);
		expect(methods.square).toHaveBeenCalledTimes(1);

		a.a(2);
		a.b(20);
		expect(methods.add).toHaveBeenCalledTimes(3);
		expect(methods.square).toHaveBeenCalledTimes(2);
		expect(methods.getVal).toHaveBeenCalledTimes(5);
		expect(b()).toEqual(4);
		expect(c()).toEqual(22);
		expect(methods.add).toHaveBeenCalledTimes(3);
		expect(methods.square).toHaveBeenCalledTimes(2);
		expect(methods.getVal).toHaveBeenCalledTimes(5);
	});
});