import java.io.*;

import java.util.*;

class PhoneDirectory {
    private Hashtable<String, String> phoneBook;

    private ArrayDeque<String> callingHistory;
    public static ArrayDeque<String> operationHistory;
    private static final String FILE_NAME = "phone_directory.txt";

    private static final String CALLING_HISTORY_FILE_NAME = "callinghistory.txt";

    public PhoneDirectory() {

        phoneBook = new Hashtable();
        callingHistory = new ArrayDeque();
        operationHistory = new ArrayDeque();
    }

    public void addContact(String name, String phoneNumber) {
        phoneBook.put(name, phoneNumber);
        operationHistory.addFirst("add" + name);
    }

    public void removeContact(String name) {
        if (phoneBook.containsKey(name)) {
            phoneBook.remove(name);

            operationHistory.addFirst("remove" + name);
            System.out.println(name + " removed successfully");

        }

    }

    public void searchContact(String name) {
        String phoneNumber = phoneBook.get(name);
        if (phoneNumber != null) {
            System.out.println("Contact found:");
            System.out.println("Name: " + name);
            System.out.println("Phone Number: " + phoneNumber);
            operationHistory.addFirst("search" + name);

        } else {

            System.out.println("Contact not found.");

        }
    }
    
    public void displayAllContacts() {

        if (phoneBook.isEmpty()) {

            System.out.println("Phone Directory is empty.");
            return;
        }
        System.out.println("Phone Directory:");
        for (String name : phoneBook.keySet()) {

            System.out.println("Name:" + name + ", Phone Number:" + phoneBook.get(name));
        }
        operationHistory.addFirst("displayed all contacts");

    }

    public void renameContact(String oldName, String newName) {

        if (phoneBook.containsKey(oldName)) {

            String phoneNumber = phoneBook.get(oldName);

            phoneBook.remove(oldName);

            phoneBook.put(newName, phoneNumber);

            operationHistory.addFirst("rename " + oldName + "to" + newName);

            System.out.println("rename of " + oldName + " is successful");

        }

    }

    public void callContact(String name) {

        String phoneNumber = phoneBook.get(name);

        if (phoneNumber != null) {

            callingHistory.add(name);

            operationHistory.addFirst("call " + name);

            System.out.println("Calling..." + name);

        } else {

            System.out.println("Contact not found. Cannot call.");

        }

    }

    public void savePhoneDirectoryToFile() {

        try (BufferedWriter writer = new BufferedWriter(new FileWriter(FILE_NAME))) {
            for (String name : phoneBook.keySet()) {

                writer.write(name + "," + phoneBook.get(name));
                writer.newLine();

            }

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

    public void saveCallingHistoryToFile() {

        try (BufferedWriter writer = new BufferedWriter(new FileWriter(CALLING_HISTORY_FILE_NAME))) {

            for (String calledContact : callingHistory) {
                writer.write(calledContact);
                writer.newLine();
            }

        } catch (IOException e) {

            e.printStackTrace();
        }
    }

    public void loadPhoneDirectoryFromFile() {

        try (BufferedReader reader = new BufferedReader(new FileReader(FILE_NAME))) {

            String line;

            while ((line = reader.readLine()) != null) {

                String[] parts = line.split(",");

                if (parts.length == 2) {

                    phoneBook.put(parts[0], parts[1]);

                }

            }
        } catch (IOException e) {

            e.printStackTrace();

        }

    }

    public static void main(String[] args) throws IOException {
        PhoneDirectory phoneDirectory = new PhoneDirectory();

        phoneDirectory.loadPhoneDirectoryFromFile();

        File fl = new File(FILE_NAME);

        fl.createNewFile();

        File f2 = new File(CALLING_HISTORY_FILE_NAME);
        f2.createNewFile();

        Scanner scanner = new Scanner(System.in);

        int choice;

        String name, phoneNumber, newName;

        do {

            System.out.println("\nPhone Directory Management System");

            System.out.println("1. Add a Contact");

            System.out.println("2. Remove a Contact");

            System.out.println("3. Search for a Contact");

            System.out.println("4. Display All Contacts");

            System.out.println("5. Rename a Contact");

            System.out.println("6. Call a Contact");

            System.out.println("7. Exit");

            System.out.print("Enter your choice: ");

            choice = scanner.nextInt();

            scanner.nextLine(); // Clear the newline character from the buffer
            switch (choice) {

                case 1:

                    System.out.print("Enter the name of the contact: ");
                    name = scanner.nextLine();
                    System.out.print("Enter the phone number: ");
                    phoneNumber = scanner.nextLine();
                    phoneDirectory.addContact(name, phoneNumber);
                    phoneDirectory.savePhoneDirectoryToFile();
                    break;

                case 2:

                    System.out.print("Enter the name of the contact to remove: ");
                    name = scanner.nextLine();
                    phoneDirectory.removeContact(name);
                    phoneDirectory.savePhoneDirectoryToFile();
                    break;

                case 3:

                    System.out.print("Enter the name of the contact to search: ");
                    name = scanner.nextLine();
                    phoneDirectory.searchContact(name);
                    break;

                case 4:

                    phoneDirectory.displayAllContacts();
                    break;

                case 5:

                    System.out.print("Enter the name of the contact to rename: ");
                    name = scanner.nextLine();
                    System.out.print("Enter the new name: ");
                    newName = scanner.nextLine();
                    phoneDirectory.renameContact(name, newName);
                    phoneDirectory.savePhoneDirectoryToFile();
                    break;

                case 6:

                    System.out.print("Enter the name of the contact to call: ");
                    name = scanner.nextLine();
                    phoneDirectory.callContact(name);
                    phoneDirectory.saveCallingHistoryToFile();
                    break;

                case 7:

                    System.out.println("Exiting Phone Directory Management System.");
                    break;

                default:

                    System.out.println("Invalid choice. Please try again.");

                    break;

            }

        } while (choice != 7);

        System.out.println("Recent Operations History: ");
        for (String s : operationHistory) {

            System.out.println(s);

        }

        scanner.close();

    }

}