package sliceutils

// MapS applies a given function to every element of a slice.
// The return type may be different from the initial type of the slice.
func Map[T any, M any](arr []T, apply func(T) M) []M {
	n := make([]M, len(arr))
	for i, e := range arr {
		n[i] = apply(e)
	}
	return n
}

// Filter filters a slice using a given function.
// If the filter function returns true, the element stays, otherwise it gets removed.
func Filter[T any](arr []T, filter func(T) bool) []T {
	n := make([]T, 0)
	for _, e := range arr {
		if filter(e) {
			n = append(n, e)
		}
	}
	return n
}

// RemoveDuplicate removes all duplicates inside a slice.
func RemoveDuplicate[T comparable](sliceList []T) []T {
	allKeys := make(map[T]bool)
	list := []T{}
	for _, item := range sliceList {
		if _, value := allKeys[item]; !value {
			allKeys[item] = true
			list = append(list, item)
		}
	}
	return list
}

// Reverse reverses a given slice.
func Reverse[E any](s []E) {
	for i, j := 0, len(s)-1; i < j; i, j = i+1, j-1 {
		s[i], s[j] = s[j], s[i]
	}
}

// CompareOrdered compares two slices for both element equality and element order.
func CompareOrdered[T comparable](a, b []T) bool {
	if len(a) != len(b) {
		return false
	}
	for i, v := range a {
		if b[i] != v {
			return false
		}
	}
	return true
}

// CompareUnorderedS compares two slices for element equality.
// The order of those elements does not matter.
func CompareUnordered[T comparable](a, b []T) bool {
	if len(a) != len(b) {
		return false
	}
	hits := 0
	for _, v := range a {
		for _, o := range b {
			if o == v {
				hits += 1
			}
		}
	}
	return hits == len(a)
}

func Contains[T comparable](a []T, b T) bool {
	for _, v := range a {
		if v == b {
			return true
		}
	}
	return false
}