package collections

type Set[T comparable] struct {
	items []T
	index map[T]bool
}

func SetOf[T comparable](items ...T) Set[T] {
	index := make(map[T]bool, len(items))
	uniqueItems := make([]T, 0, len(items))

	for _, item := range items {
		if index[item] {
			continue
		}
		index[item] = true
		uniqueItems = append(uniqueItems, item)
	}

	return Set[T]{
		items: uniqueItems,
		index: index,
	}
}

func (set Set[T]) Contains(item T) bool {
	return set.index[item]
}

func (set Set[T]) All() []T {
	copied := make([]T, len(set.items))
	copy(copied, set.items)
	return copied
}

func (set Set[T]) Len() int {
	return len(set.items)
}