package u

func Filter[T any](v []T, f func(T) bool) []T {
	var result []T

	for _, s := range v {
		if f(s) {
			result = append(result, s)
		}
	}

	return result
}

func First[T any](v []T) (T, bool) {
	if len(v) == 0 {
		var zero T
		return zero, false
	}
	return v[0], true
}

func FirstOrZero[T any](v []T) T {
	if len(v) == 0 {
		var zero T
		return zero
	}
	return v[0]
}

func LastOrZero[T any](v []T) T {
	if len(v) == 0 {
		var zero T
		return zero
	}
	return v[len(v)-1]
}

func ChunkBy[T any](items []T, chunkSize int) [][]T {
	chunks := make([][]T, 0, (len(items)/chunkSize)+1)
	for chunkSize < len(items) {
		items, chunks = items[chunkSize:], append(chunks, items[0:chunkSize:chunkSize])
	}
	return append(chunks, items)
}