package utils

// Queue implementation

type Node struct {
	Value interface{}
	Next  *Node
}

type Queue struct {
	Head *Node
	Tail *Node
}

func (q *Queue) Enqueue(value interface{}) {
	node := &Node{Value: value}

	if q.Head == nil {
		q.Head = node
		q.Tail = node
		return
	}

	q.Tail.Next = node
	q.Tail = node
}

func (q *Queue) Dequeue() interface{} {
	if q.Head == nil {
		return nil
	}

	node := q.Head
	q.Head = node.Next

	if q.Head == nil {
		q.Tail = nil
	}

	return node.Value
}

func (q *Queue) Peek() interface{} {
	if q.Head == nil {
		return nil
	}

	return q.Head.Value
}

func (q *Queue) IsEmpty() bool {
	return q.Head == nil
}