import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

import javax.swing.JOptionPane;

public class hasher{

    public static String hashString(String password){

        MessageDigest md = null;

        try {
            md = MessageDigest.getInstance("SHA-256");
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }

        byte[] byteData = null;

        for(int i = 0; i <= 999; i++){
            md.update(password.getBytes());
            byteData = md.digest();
        }

        StringBuffer sb = new StringBuffer();

        for(int i = 0; i < byteData.length; i++){
            String hex = Integer.toHexString(0xff & byteData[i]);
            if(hex.length() == 1){
                sb.append('0');
            }

            sb.append(hex);
        }

        String finalHash = sb.toString();

        return finalHash;
    }

    public static void main(String args[]){

        fileReadWrite frw= new fileReadWrite();
        //Scanner scanner = new Scanner(System.in);

        int menuOption = 0;
        String tempUser;
        String tempPassword;
        String tempHash;
        boolean outcome;

        String localUsers[];
        String localHashes[];

        System.out.println("--SHA-256 Hasher---");
        System.out.println("===MAIN MENU===");

        System.out.println("1) Create new password hash");
        System.out.println("2) Compare existing password");
        System.out.println("3) Print hash database");
        System.out.println("4) Quit");

        System.out.println("Input: ");
        String SmenuOption = JOptionPane.showInputDialog(null, "Menu Choice..");
        menuOption = Integer.parseInt(SmenuOption);


    switch(menuOption){
        case 1:
                System.out.println("Enter a username for the password");
                tempUser = JOptionPane.showInputDialog(null, "Enter a username");

                System.out.println("Enter a password for the above username");
                tempPassword = JOptionPane.showInputDialog(null, "Enter a password");
                tempHash = hashString(tempPassword);
                outcome = frw.writeHash(tempUser, tempHash);
                if(outcome == true){
                    System.out.println("Operation Successful");
                } else {
                    System.out.println("Operation Failed!");
                }

        case 2:
                System.out.println("Enter a username..");
                tempUser = JOptionPane.showInputDialog(null, "Enter a username..");

                System.out.println("Enter the password for the username");
                tempPassword = JOptionPane.showInputDialog(null, "Enter a password");
                tempHash = hashString(tempPassword);
                frw.readHash();
                outcome = frw.compareHashes(tempUser, tempHash);
                if(outcome == true){
                    System.out.println("Password for Username: " + tempUser + " matches!");
                } else {
                    System.out.println("No match found! Username of password invalid");
                }

                break;

        case 3:
                //PRINT USERNAME AND HASH DATABASE
                localUsers = frw.getUsers();
                localHashes = frw.getHashes();
                System.out.println(localHashes[0]);
                for(int i = 0; i <= localUsers.length+1; i++){
                    System.out.println("Username: " + localUsers[i] + "\nHash: " + localHashes[i] + "\n---------------------\n");
                }
                break;

        case 4:
                break;

        default:
                System.out.println("Invalid entry");
                break;
    }
    }
}