package xslices

import (
	"crypto/rand"
	"math/big"
)

func ForEach[T any](items []T, f func(T)) {
	for _, item := range items {
		f(item)
	}
}

func AsMap[T any, U comparable](items []T, f func(T) U) map[U]struct{} {
	out := make(map[U]struct{}, len(items))
	ForEach(items, func(in T) {
		out[f(in)] = struct{}{}
	})
	return out
}

func Shuffle[T any](items []T) {
	maxnum := big.NewInt(int64(len(items)))
	for i := range items {
		swapWith, _ := rand.Int(rand.Reader, maxnum)
		swapWithIdx := int(swapWith.Int64())
		items[i], items[swapWithIdx] = items[swapWithIdx], items[i]
	}
}