import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.FileInputStream;
import java.io.InputStreamReader;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Scanner;
// Import necessary classes

public class AuthenticationSystem{
    // Define the class AuthenticationSystem

    public static void main(String[] args) throws IOException{

    }

public class ValidateCredentials{

    private boolean isValid;
    private String filePath;
    private String credentialsFileName;

    public ValidateCredentials(){
        isValid = false;
        filePath = "C:\\Users\\Owner\\My Documents\\NetBeansProjects\\AuthenticationSystem\\";
        credentialsFileName = "credentials";
    }

    public boolean isCredentialsValid() throws Exception{
        int flag = 0;
        // Declare the variables
        int unsuccessfulattempts = 3;
        // Declare and initialize the unsuccessfulattempts to 3
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        //Create object 'br' to read the input from the user
        System.out.println("Authentication System");
        // Display the Header of the program

            do{
                if(unsuccessfulattempts == 0){
                // Checks if the user enters more then 3 attempts.
                    System.out.println("You are attempting to login more than three times");
                    System.out.println("You are out of attempts " + "Exiting!");
                    System.exit(1);
                }
                else{
                    // If condition is false, have user try submitting credentials again
                    System.out.println("Invalid Username or Password.");
                    System.out.println("Please try again.");
                    System.out.println(unsuccessfulattempts + " more attemptes left.\n");
                }
            }
        while(unsuccessfulattempts>0);

        unsuccessfulattempts--;
        System.out.println("Username:");
        String name = br.readLine();
        System.out.println("Password:");
        String pwd = br.readLine();
        String original = pwd;
        MessageDigest md = MessageDigest.getInstance("MD5");
        md.update(original.getBytes());
        byte[] digest = md.digest();
        StringBuffer sb = new StringBuffer();
        for (byte b : digest) {
            sb.append(String.format("%02x", b & 0xff));
        }
        System.out.println("");
        System.out.println("original:" + original);
        System.out.println("digested:" + sb.toString()); //sb.toString() is what you'll need to compare password strings

        isValid = readDataFiles(name, sb.toString());

        return isValid;
    }

    public boolean readDataFiles(String userName, String passWord) throws IOException{
        FileInputStream fileByteStream1 = null; // File input stream
        FileInputStream fileByteStream2 = null; // File input stream

        Scanner inFS1 = null;                   // Scanner object
        Scanner inFS2 = null;                   // Scanner object

        String textLine = null;
        boolean foundCredentials = false;

        // Try to open file
        System.out.println("");
        System.out.println("Opening file " + credentialsFileName + ".txt");
        fileByteStream1 = new FileInputStream(filePath + "credentials.txt");
        inFS1 = new Scanner(fileByteStream1);

        System.out.println("");
        System.out.println("Reading lines of text.");

        while (inFS1.hasNextLine()){
            textLine = inFS1.nextLine();
            System.out.println(textLine);

            if (textLine.contains(userName) && textLine.contains(passWord)){
                foundCredentials = true;
                break;
            }
        }
        // Done with file, so try to close it
        System.out.println("");
        System.out.println("Closing file " + credentialsFileName + ".txt");

        if (textLine != null) {
            fileByteStream1.close(); // close() may throw IOException if fails
        }
        if (foundCredentials == true) {
            // Try to open file
            System.out.println("");
            System.out.println("Opening file " + userName + ".txt");
            fileByteStream2 = new FileInputStream(filePath + userName + ".txt");
            inFS2 = new Scanner(fileByteStream2);

            System.out.println("");

            while (inFS2.hasNextLine()) {
                textLine = inFS2.nextLine();
                System.out.println(textLine);
            }

            // Done with file, so try to close it
            System.out.println("");
            System.out.println("Closing file " + userName + ".txt");

            if (textLine != null) {
                fileByteStream2.close(); // close() may throw IOException if fails
            }
        }

        return foundCredentials;

    }

}

public class Authorization{

    public Authorization(){
    // Create authorization() method
        String userLogOut;
        Scanner scnr = new Scanner(System.in);
        // Get a string from the user to logout by creating Scanner object
        System.out.println("\n\tWelcome Admin\t");
        System.out.println("Press EXIT for logout\n");

            do{
                userLogOut = scnr.nextLine();
                // Take input from the user until they enter EXIT
            }

        while(!userLogOut.equals("EXIT"));

            if(userLogOut.equals("EXIT")){
            // If user enters EXIT to logout
                System.exit(1);
            }
        }
    }
}