group_Task3

package com.company;

import java.util.*;

public class group_Qnislav_InboxManager {

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

        String input = scanner.nextLine();

        HashMap<String, List<String>> map = new HashMap<>();
        //int counter = 0;

        while (!input.equals("Statistics")) {
            String[] command = input.split("->");
            String action = command[0];
            String username = command[1];
            switch (action) {
                case "Add":
                    if (map.containsKey(username)) {
                        System.out.printf("%s is already registered%n", username);
                    } else {
                        map.put(username, new ArrayList<>());
                        //counter++;
                    }
                    break;
                case "Send":
                    String email = command[2];
                    if (map.containsKey(username)) {
                        map.get(username).add(email);
                    }
                    break;
                case "Delete":
                    if (map.containsKey(username)) {
                        map.remove(username);
                     //   counter--;
                    } else {
                        System.out.printf("%s not found!%n", username);
                    }
                    break;
            }

            input = scanner.nextLine();
        }

        System.out.printf("Users count: %d%n",map.keySet().size());
        map
                .entrySet()
                .stream()
                .sorted((a,b)->{
                    int first = a.getValue().size();
                    int second = b.getValue().size();
                    int compare = second-first;
                    if(compare==0){
                        compare = a.getKey().compareTo(b.getKey());
                    }
                    return compare;
                })
                .forEach(a->{
                    System.out.println(a.getKey());
                    a.getValue()
                            .forEach(b -> System.out.printf("- %s%n",b));
                });


    }
}