Untitled

import java.util.Scanner;

public class Ja_01_secret_chat {
    public static String ubaciRazmak (String poruka, int indeks){
        StringBuilder sbSaRazmakom = new StringBuilder(poruka);
        sbSaRazmakom.insert(5, " ");

        return sbSaRazmakom.toString();

    } public static String reverse (String poruka, String substring){
        if (!poruka.contains(substring)) {
            System.out.println("Error"); return poruka;
        } else {
                StringBuilder sb = new StringBuilder(substring);
                String obrnutiSubstring = sb.reverse().toString();
                poruka = poruka.replaceFirst(substring, obrnutiSubstring);
        } return poruka;
    } public static String cnangeAll(String poruka, String substring, String zamena) {
        poruka = poruka.replaceAll(substring, zamena);
        return poruka;
        //Reverse:|:?uoy
    }



    public static void main(String[] args) {

        //•	"InsertSpace:|:{index}":
        //o	Inserts a single space at the given index. The given index will always be valid.

        //•	"Reverse:|:{substring}":
        //o	If the message contains the given substring, cut it out, reverse it and add it at the end of the message.
        //o	If not, print "error".
        //o	This operation should replace only the first occurrence of the given substring if there are two or more occurrences.

        //•	"ChangeAll:|:{substring}:|:{replacement}":
        //o	Changes all occurrences of the given substring with the replacement text.

        Scanner sc = new Scanner(System.in);
        String poruka = sc.nextLine();

        while (true) {
            String unos = sc.nextLine();
            if (unos.equals("Reveal")) break;

            String [] nizKomandi = unos.split(":\\|:");
            String komanda = nizKomandi[0];
            if (komanda.equals("InsertSpace")) {
                int indeksZaRazmak = Integer.parseInt(nizKomandi[1]);
                poruka=ubaciRazmak(poruka, indeksZaRazmak);
                System.out.println(poruka);

            } else if (komanda.equals("Reverse")){
                String substring = nizKomandi[1];
                poruka = reverse(poruka, substring);
                System.out.println(poruka);

            } else if (komanda.equals("ChangeAll")){
               //"ChangeAll:|:{substring}:|:{replacement}":
                String substring = nizKomandi[1];
                String zamena = nizKomandi[2];
                poruka = cnangeAll(poruka, substring, zamena);
                System.out.println(poruka);
            }

        }
        System.out.printf("You have a new text message: %s\n", poruka);
    }

}