import { Cons, ListZipper } from '../lib/index';

describe('types/collections/cons + zipper', () => {
    test('Cons.from iterates in order', () => {
        const list = Cons.from([1, 2, 3]);
        expect(Array.from(list.get())).toEqual([1, 2, 3]);
    });

    test('Cons.replace replaces head value', () => {
        const list = Cons.from([1, 2]).get();
        expect(Array.from(list.replace(9))).toEqual([9, 2]);
    });

    test('Cons.before prepends a head chain', () => {
        const tail = Cons.from([2, 3]);
        const head = new Cons(1).before(tail);
        expect(Array.from(head)).toEqual([1, 2, 3]);
    });

    test('Cons.addOnto appends onto tail optional', () => {
        const tail = Cons.from([3]);
        const list = Cons.addOnto([1, 2], tail).get();
        expect(Array.from(list)).toEqual([1, 2, 3]);
    });

    test('ListZipper navigation and edits', () => {
        const zipper = ListZipper.from([1, 2, 3]);

        expect(zipper.read().get()).toBe(1);
        const z2 = zipper.next().get() as ListZipper<number>;
        expect(z2.read().get()).toBe(2);

        const z3 = z2.replace(9) as ListZipper<number>;
        expect(z3.collection()).toEqual([1, 9, 3]);

        const z4 = z3.remove() as ListZipper<number>;
        expect(z4.collection()).toEqual([1, 3]);

        const z5 = z4.prependChunk([7, 8]) as ListZipper<number>;
        expect(z5.collection()).toEqual([1, 7, 8, 3]);

        const back = (z2.previous().get() as ListZipper<number>).read().get();
        expect(back).toBe(1);
    });

    test('ListZipper iteration yields full list', () => {
        const zipper = ListZipper.from([1, 2, 3]);
        expect(Array.from(zipper)).toEqual([1, 2, 3]);

        const moved = zipper.next().flatMap((z: any) => z.next());
        expect(moved.present()).toBe(true);
        expect(Array.from(moved.get())).toEqual([1, 2, 3]);

        const empty = ListZipper.from<number>([]);
        expect(empty.read().present()).toBe(false);
        expect(Array.from(empty)).toEqual([]);
    });
});