package container

type Vector[T any] []T

// PushBack adds an element to the end of the vector.
// Complexity O(1) + array extesnion
func (v *Vector[T]) PushBack(e T) {
	*v = append(*v, e)
}

// PopBack removes and returns the last element from the vector.
// If the vector is empty, it will panic.
// Complexity O(1)
func (v *Vector[T]) PopBack() T {
	if !v.HasElement() {
		panic("called PopBack() on an empty vector")
	}

	value := (*v)[len(*v)-1]
	*v = (*v)[0 : len(*v)-1]
	return value
}

// Len returns the length of the vector.
// It returns an integer representing the number of elements in the vector.
func (v Vector[T]) Len() int {
	return len(v)
}

// HasElement returns true if the vector v contains at least one element.
func (v Vector[T]) HasElement() bool {
	return v.Len() > 0
}

// PushFront adds an element to the front of the vector.
// Complexity O(n)
func (v *Vector[T]) PushFront(e T) {
	newVect := make([]T, v.Len()+1)
	copy(newVect[1:], *v)
	newVect[0] = e
	*v = newVect
}

// PopFront removes and returns the element at the front of the vector.
// It panics if the vector is empty.
// Complexity O(1)
func (v *Vector[T]) PopFront() T {
	if !v.HasElement() {
		panic("called PopFront() on an empty vector")
	}

	value := (*v)[0]
	var zeroValue T
	(*v)[0] = zeroValue
	*v = (*v)[1:]

	return value
}