(function(require) {
    'use strict';

    require(
        ['video/00_iterator.js'],
        function(Iterator) {
            describe('Iterator', function() {
                var list = ['a', 'b', 'c', 'd', 'e'],
                    iterator;

                beforeEach(function() {
                    iterator = new Iterator(list);
                });

                it('size contains correct list length', function() {
                    expect(iterator.size).toBe(list.length);
                    expect(iterator.lastIndex).toBe(list.length - 1);
                });

                describe('next', function() {
                    describe('with passed `index`', function() {
                        it('returns next item in the list', function() {
                            expect(iterator.next(2)).toBe('d');
                            expect(iterator.next(0)).toBe('b');
                        });

                        it('returns first item if index equal last item', function() {
                            expect(iterator.next(4)).toBe('a');
                        });

                        it('returns next item if index is not valid', function() {
                            expect(iterator.next(-4)).toBe('b'); // index < 0
                            expect(iterator.next(100)).toBe('c'); // index > size
                            expect(iterator.next('99')).toBe('d'); // incorrect Type
                        });
                    });

                    describe('without passed `index`', function() {
                        it('returns next item in the list', function() {
                            expect(iterator.next()).toBe('b');
                            expect(iterator.next()).toBe('c');
                        });

                        it('returns first item if index equal last item', function() {
                            expect(iterator.next()).toBe('b');
                            expect(iterator.next()).toBe('c');
                            expect(iterator.next()).toBe('d');
                            expect(iterator.next()).toBe('e');
                            expect(iterator.next()).toBe('a');
                        });
                    });
                });

                describe('prev', function() {
                    describe('with passed `index`', function() {
                        it('returns previous item in the list', function() {
                            expect(iterator.prev(3)).toBe('c');
                            expect(iterator.prev(1)).toBe('a');
                        });

                        it('returns last item if index equal first item', function() {
                            expect(iterator.prev(0)).toBe('e');
                        });

                        it('returns previous item if index is not valid', function() {
                            expect(iterator.prev(-4)).toBe('e'); // index < 0
                            expect(iterator.prev(100)).toBe('d'); // index > size
                            expect(iterator.prev('99')).toBe('c'); // incorrect Type
                        });
                    });

                    describe('without passed `index`', function() {
                        it('returns previous item in the list', function() {
                            expect(iterator.prev()).toBe('e');
                            expect(iterator.prev()).toBe('d');
                        });

                        it('returns last item if index equal first item', function() {
                            expect(iterator.prev()).toBe('e');
                        });
                    });
                });

                it('returns last item in the list', function() {
                    expect(iterator.last()).toBe('e');
                });

                it('returns first item in the list', function() {
                    expect(iterator.first()).toBe('a');
                });

                it('isEnd works correctly', function() {
                    expect(iterator.isEnd()).toBeFalsy();
                    iterator.next(); // => index 1
                    expect(iterator.isEnd()).toBeFalsy();
                    iterator.next(); // => index 2
                    expect(iterator.isEnd()).toBeFalsy();
                    iterator.next(); // => index 3
                    expect(iterator.isEnd()).toBeFalsy();
                    iterator.next(); // => index 4 == last
                    expect(iterator.isEnd()).toBeTruthy();
                });
            });
        });
}(require));