02_Friendlist_Maintenance_ProgramFundMidExam_2Nov2019_Group2

import java.util.List;
import java.util.Arrays;
import java.util.Scanner;
import java.util.stream.Collectors;

public class FriendlistMaintenance {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        List<String> friends = Arrays.stream(scanner.nextLine().split(", "))
                .collect(Collectors.toList());

        String command = scanner.nextLine();

        int blacklistedCount = 0;
        int lostNamesCount = 0;

        while(!command.equals("Report")) {
            String[] tokens = command.split(" ");
            String subCommand = tokens[0];
            int index = 0;

            switch (subCommand) {

                case "Blacklist":
                    String name = tokens[1];

                        if (friends.contains(name)) {
                            System.out.printf("%s was blacklisted.%n", name);
                            friends.set(friends.indexOf(name), "Blacklisted");
                            blacklistedCount++;
                            break;
                        } else {
                            System.out.printf("%s was not found.%n", name);
                        }
                    break;
                case "Error":
                    index = Integer.parseInt(tokens[1]);

                    if (checkIfIndexExists(friends, index)) {
                        if (!(friends.get(index)).equals("Blacklisted") && !(friends.get(index)).equals("Lost")) {
                            System.out.printf("%s was lost due to an error.%n", friends.get(index));
                            friends.set(index, "Lost");
                            lostNamesCount++;
                        }
                    }
                    break;

                case "Change":
                    index = Integer.parseInt(tokens[1]);
                    String newName = tokens[2];

                    if (checkIfIndexExists(friends, index)) {
                        System.out.printf("%s changed his username to %s.%n", friends.get(index), newName);
                        friends.set(index, newName);
                    }
                    break;
            }
            command = scanner.nextLine();
        }
        System.out.printf("Blacklisted names: %d%n", blacklistedCount);
        System.out.printf("Lost names: %d%n", lostNamesCount);
        System.out.print(String.join(" ", friends));
    }

    private static boolean checkIfIndexExists(List<String> friends, int index) {
        return index >= 0 && index < friends.size();
    }
}