package two

import (
	"errors"
	"fmt"
)

type queue struct {
	elements []point
}

func newQueue() *queue {
	return &queue{}
}

func (q *queue) Enqueue(elem point) {
	q.elements = append(q.elements, elem)
}

func (q *queue) Dequeue() interface{} {
	if q.IsEmpty() {
		fmt.Println("UnderFlow")
		return point{}
	}
	element := q.elements[0]
	if q.Len() == 1 {
		q.elements = nil
		return element
	}
	q.elements = q.elements[1:]
	return element
}

func (q *queue) Len() int {
	return len(q.elements)
}

func (q *queue) IsEmpty() bool {
	return len(q.elements) == 0
}

func (q *queue) Peek() (point, error) {
	if q.IsEmpty() {
		return point{}, errors.New("empty queue")
	}
	return q.elements[0], nil
}