package util

import (
	"cmp"
	"slices"
)

// Keys returns a slice of keys from any map.
func Keys[M ~map[K]V, K comparable, V any](m M) []K {
	r := make([]K, 0, len(m))
	for k := range m {
		r = append(r, k)
	}
	return r
}

// KeysSorted returns a slice of keys from any map, sorted in ascending order.
func KeysSorted[M ~map[K]V, K cmp.Ordered, V any](m M) []K {
	return Sorted(Keys(m))
}

// KeysSortedFunc returns a slice of keys from any map, sorted by cmp.
func KeysSortedFunc[M ~map[K]V, K comparable, V any](m M, cmp func(K, K) int) []K {
	keys := Keys(m)
	slices.SortFunc(keys, cmp)
	return keys
}

// MapKeys returns a slice of keys from m, transformed by f.
func MapKeys[M ~map[K]V, K comparable, V, R any](m M, f func(K) R) []R {
	r := make([]R, 0, len(m))
	for k := range m {
		r = append(r, f(k))
	}
	return r
}

// Values returns a slice of values from any map. Copied from golang.org/x/exp/maps.
func Values[M ~map[K]V, K comparable, V any](m M) []V {
	r := make([]V, 0, len(m))
	for _, v := range m {
		r = append(r, v)
	}
	return r
}