import java.util.*;
import java.io.*;
 
public class Main {
    static Scanner scanner;
    static Map<String, String> cardToDefinition;
    static Map<String, String> definitionToCard;
 
    public static void main(String[] args) {
            scanner = new Scanner(System.in);
            cardToDefinition = new HashMap<>();
            definitionToCard = new HashMap<>();
           
            while (true) {
            System.out.println("Input the action (add, remove, import, export, ask, exit):");
            String input = scanner.nextLine();
            switch(input) {
            case "add":
            add();
            break;
            case "remove":
            remove();
            break;
            case "import":
            importCards();
            break;
            case "export":
            exportCards();
            break;
            case "ask":
            ask();
            break;
            case "exit":
            System.out.println("Bye bye!");
            System.exit(0);
            break;
       
    }
    }
    }
 
 
    public static void add() {
        System.out.println("The card:");
        String userCard = scanner.nextLine();
        if (cardToDefinition.containsKey(userCard)) {
            System.out.println("The card "+ "\"" + userCard + "\"" +" already exists.");
            return;
        }
        System.out.println("The definition of the card:");
        String userDefinition = scanner.nextLine();
        if (cardToDefinition.containsValue(userDefinition)) {
            System.out.println("The definition " + "\"" + userDefinition + "\"" + " already exists.");
        } else {
            cardToDefinition.put(userCard, userDefinition);
            definitionToCard.put(userDefinition, userCard);
            System.out.println("The pair (" + "\"" + userCard + "\"" + ":" + "\"" + userDefinition + "\"" + ") has been added.");
        }
    }
    public static void remove() {
        System.out.println("The card:");
        String userCard = scanner.nextLine();
        if (cardToDefinition.containsKey(userCard)) {
            definitionToCard.remove(cardToDefinition.get(userCard));
            cardToDefinition.remove(userCard);
            System.out.println("The card has been removed.");
        } else {
            System.out.println("Can't remove " + "\"" +userCard + "\"" + ": there is no such card.");
        }
    }
 
    public static void ask() {
        System.out.println("How many times to ask?");
        int numOfAsk = Integer.parseInt(scanner.nextLine());
        int numb = 0;
        for (Map.Entry<String, String> card : cardToDefinition.entrySet()) {
			if(numb == numOfAsk) {
				break;
			} 
           
            System.out.println("Print the definition of " + "\"" + card.getKey() + "\"" + ":");
            String answer = scanner.nextLine();
            if (answer.equals(card.getValue())) {
                System.out.println("Correct answer.");
            } else if (cardToDefinition.containsValue(answer)) {
           
                System.out.println("Wrong answer . The correct one is " + "\"" + card.getValue() + "\"" + ", you've just written a definition of " + "\"" + definitionToCard.get(answer) + "\"" + " card.");
            } else {
                System.out.println("Wrong answer . The correct one is " + "\"" + card.getValue() + "\"" + ".");
            }
           numb++;
        }
        
           
       
    }
 
 
    public static void importCards() {
        System.out.println("File name:");
        String pathToFile = scanner.nextLine();
        File file = new File(pathToFile);
        int counter=0;
        try (Scanner reader = new Scanner(file)) {
            while (reader.hasNext()) {
                String userCard = reader.next();
                String userDefinition = reader.next();
                counter++;
                if (cardToDefinition.containsKey(userCard) || cardToDefinition.containsValue(userDefinition)) {
                    System.out.println("Don't use a duplicated card or a definition");
                    counter--;
                } else {
                    cardToDefinition.put(userCard, userDefinition);
                    definitionToCard.put(userDefinition, userCard);
                }
            }
            System.out.println(counter + " cards have been loaded.");
        } catch (FileNotFoundException e) {
            System.out.println("File not found.");
        }
    }
 
    public static void exportCards() {
        System.out.println("File name:");
        String pathToFile = scanner.nextLine();
        File file = new File(pathToFile);
        try (PrintWriter printWriter = new PrintWriter(file)) {
            for (Map.Entry<String, String> card : cardToDefinition.entrySet()) {
                printWriter.println(card.getKey());
                printWriter.println(card.getValue());
            }
            System.out.println(cardToDefinition.size() + " cards have been saved.");
        } catch (IOException e) {
            System.out.printf("An exception occurs %s", e.getMessage());
        }
    }
   
   
       
 
   
   
   
}