package lifo

import "fmt"

type LIFO[T any] []T

func New[T any](items ...T) *LIFO[T] {
	l := LIFO[T](items)
	return &l
}

func (l *LIFO[T]) Push(item T) {
	*l = append(*l, item)
}

func (l *LIFO[T]) Empty() bool {
	return len(*l) == 0
}

func (l *LIFO[T]) MustPop() T {
	var item T

	*l, item = (*l)[:len(*l)-1], (*l)[len(*l)-1]
	return item
}

func (l *LIFO[T]) Pop() (T, error) {
	var item T

	if l.Empty() {
		return item, fmt.Errorf("stack is exhausted")
	}

	return l.MustPop(), nil
}