import java.util.Scanner;
import java.io.BufferedWriter;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;

public class Guerra {

  private static final String FILENAME = "db.txt";
  public static void main(String args[]){

    //Variables supplied by the user
    String firstName;
    String lastName;
    String address;
    String dob;
    String phoneNumber;
    String cprNumber;

    //Variables the program will generate based on user input.
    //They will then be stored in the database along with all user data.
    String username;
    //first 3 letters of last name
    //last 4 digits of the cpr number
    String password;
    //this boolean will allow us to stop normal program execution
    //in order to make certain format checks on user-supplied input.
    boolean validityCheck = true;
    //Number of tries the user has to log in should he or she choose this option.
    int validityCounter = 2;
    //A string which will be used to guide the switch statement.
    //The user can either log in, create an account, or exit.
    //The input string is formatted into caps, following conventions.
    String decision = "";


    Scanner input = new Scanner(System.in);
    //***************************************
    //Program Start Here
    System.out.println("Welcome to Java Bikes!");
    System.out.println("-----------*-----------");
    System.out.println("----------***----------");
    System.out.println("---------*****---------");
    System.out.println("--------*******--------");
    System.out.println("-------*********-------");
    System.out.println("-----------------------");
    System.out.println("Please enter one of the following options using your keyboard(login, create account, exit)");
    decision = input.nextLine().toUpperCase();
    decision = decision.replaceAll("\\s", "");

    switch (decision) {
      case "LOGIN":
        System.out.println("LOGIN");
        System.out.println("-----------------------");
        System.out.println("-----------------------");
        System.out.println("-----------------------");

        //The username the user inputs into the keyboard
        String enteredUserName = "";
        //This variable will hold the line from our text file if that line contains the username.
        String userDetails = "";
        //This variable will contain the "password" part of the userDetails line. We will use it to compare against what the user entered.
        String correctPassword = "";
        //The password the user inputs into the keyboard. We will compare this against the enteredPassword variable.
        String enteredPassword = "";

        //we set up our file reading variables
        //we also set validityCheck to true. This will ensure that the login loop only breaks if the user has succesfully logged in within 3 tries.
        validityCheck = true;
        FileReader fr = null;
        BufferedReader br = null;

        while(validityCheck){
          System.out.println("Please enter your username");

          //We do this in upper case to compare against what is in the file, which is in upper case
          //Design consideration: I decided to NOT make the username case sensitive.
          enteredUserName = input.nextLine().toUpperCase();

          //This is where we open our text file database to extract the required information.
          //Step 1: Open the file and begin reading line by line
          //Step 2: If the entered username is found in a particular file line, store that entire line in the userDetails variable as a string
          //Step 3: Break out of the while loop.

          try {
            String currentLine = "";
            fr = new FileReader(FILENAME);
			      br = new BufferedReader(fr);
            while((currentLine = br.readLine()) != null){
              if(currentLine.indexOf(enteredUserName) != -1){
                userDetails = currentLine;
                //found the user. we exit the loop.
                break;
              }
            }
          } catch(IOException e) {
            e.printStackTrace();
          } finally {
            try {
              if(br != null){
                br.close();
              }
              if(fr != null){
                fr.close();
              }
            } catch (IOException ex){
              ex.printStackTrace();
            }
          }

          //If the userDetails string remains empty after we've combed the file line by line, we assume the username is either incorrect or does not exist.
          //Thus, we maintain the correctPassword variable empty.

          if(userDetails.length() > 0){
            correctPassword = userDetails.split("\\s")[1];
          } else {
            correctPassword = "";
          }

          System.out.println("Please enter your password");
          enteredPassword = input.nextLine();

          // Step 1: Compare the correctPassword and the enteredPassword for equality
          // Step 2: Ensure the correctPassword variable is of length more than 6.
          //         This is because we know that our auto-generated passwords are of 7 characters
          // Step 3: We only allow a succesfull login if the conditions in Step 1 and Step 2 check out.
          // Step 4: Otherwise, we subtract 1 from the validityCounter and allow the user to try inputting his/her credentials again.
          // Step 5: If the user fails to correctly input his/her details, and the validityCounter is -1, the application exits for expired tries.

          if(correctPassword.equals(enteredPassword) && correctPassword.length() > 6){
            System.out.println("You are now logged in...");
            validityCheck = false;
          } else if(validityCounter > -1){
            System.out.println("You pressed wrong password and/or username");
            validityCounter--;
          } else {
            System.out.println("Sorry. You have exceeded the number of tries. Please try again after a few hours");
            validityCheck = false;
          }
        }

        break;

      case "CREATEACCOUNT":
        System.out.println("CREATE ACCOUNT");
        System.out.println("-----------------------");
        System.out.println("-----------------------");
        System.out.println("-----------------------");


        System.out.println("Please enter your first name");
        firstName = input.nextLine().toUpperCase();

        System.out.println("Please enter your last name");
        lastName = input.nextLine().toUpperCase();

        // ZIP CODE
        //Step 1: Validate if the zip code supplied is 4 digits and below 2500.
        //Step 2. Validate the zip code only contains numbers and not letters or special characters
        System.out.println("Please enter your zipcode");
        address = input.nextLine();
        while(validityCheck){
          if(Integer.parseInt(address) > 2500 || Integer.parseInt(address) < 1000){
            System.out.println("Your address must be located in Copenhagen. Try again");
            address = input.nextLine();
          } else if(address.matches(".*[a-zA-Z].*")) {
            System.out.println("Your address must not contain letters. Try again");
            address = input.nextLine();
          } else if (address.matches(".*[!@#$%^&*()_~].*")) {
            System.out.println("Your address must not contain special characters. Try again");
            address = input.nextLine();
          } else {
            validityCheck = false;
          }
        }

        // DATE OF BIRTH
        //Step 1: Validate if the date of birth is of length 8.
        //Step 2. Validate the input string contains only numbers.
        //Step 3. Validate the last 4 digits correspond to a year after 1900.
        System.out.println("Please enter your date of birth in the format ddmmyyyy");
        dob = input.nextLine();
        validityCheck = true;
        while(validityCheck){
          if(dob.length() > 8 || dob.length() < 8){
            System.out.println("Your DOB must be exactly 9 characters. Try again");
            dob = input.nextLine();
          } else if (dob.matches(".*[a-zA-Z].*")){
            System.out.println("Your DOB must not contain letters. Try again.");
            dob = input.nextLine();
          } else if(dob.matches(".*[!@#$%^&*()_~].*")){
            System.out.println("Your DOB must not contain illegal characters. Try again.");
            dob = input.nextLine();
          } else if (Integer.parseInt(dob.substring(4)) < 1900 ) {
            System.out.println("Your DOB must have a year after 1900 to be valid. Try again");
            System.out.println(Integer.parseInt(dob.substring(4)));
            dob = input.nextLine();
          } else {
            validityCheck = false;
          }
        }

        //PHONE NUMBER
        //Step 1: Validate the phone number is of length 8.
        //Step 2. Validate the input string contains only numbers.
        //Step 3. Confirm the phone number has no special characters or letters.
        System.out.println("Please enter your phone number in the format XXXXXXXX");
        phoneNumber = input.nextLine();
        validityCheck = true;
        while(validityCheck){
          if(phoneNumber.length() < 8 || phoneNumber.length() > 8){
            System.out.println("Your phone number has to be exactly 8 digits");
            phoneNumber = input.nextLine();
          } else if(phoneNumber.matches(".*[a-zA-Z].*")){
            System.out.println("Your phone number cannot contain letters. Please try again.");
            phoneNumber = input.nextLine();
          } else if(phoneNumber.matches(".*[!@#$%^&*()_~].*")) {
            System.out.println("Your phone number cannot contain illegal characters. Please try again.");
            phoneNumber = input.nextLine();
          } else {
            validityCheck = false;
          }
        }

        //CPR NUMBER
        //Step 1: Validate the user input contains the -.
        //Step 2. Validate the input string contains only numbers.
        //Step 3. Confirm the phone number has no special characters or letters.
        //Step 4. Validate the length of the CPR number is exactly 11 including the -
        //Step 5. We ensure the - is located just before the last 4 numbers.
        System.out.println("Please enter your CPR number in the format XXXXXX-XXXX");
        cprNumber = input.nextLine();
        validityCheck = true;
        while(validityCheck){
          if(!cprNumber.matches(".*[-].*")){
            System.out.println("Your CPR number must contain an -");
            cprNumber = input.nextLine();
          } else if(cprNumber.matches(".*[a-zA-Z].*")){
            System.out.println("Your CPR number cannot contain any letters");
            cprNumber = input.nextLine();

          } else if(cprNumber.length() > 11 || cprNumber.length() < 11){
            System.out.println("Your CPR number must contain exactly 11 characters. This includes the -");
            cprNumber = input.nextLine();

          } else if(cprNumber.indexOf("-") != 6){
            System.out.println("the - in your CPR must precede the last 4 digits of your CPR");
            cprNumber = input.nextLine();
          } else if(cprNumber.matches(".*[!@#$%^&*()_~].*")) {
            System.out.println("Your CPR number cannot contain illegal characters. Please try again.");
            cprNumber = input.nextLine();
          } else {
            validityCheck = false;
          }
        }

        //PROGRAMMERS JUDGMENT CALL
        // I am assuming some people have last names with less than 3 characters.
        // I have thus implemented the following conditionals to cover this case.
        // This way usernames and passwords can be created for everyone.

        if(lastName.length() > 3) {
          username = firstName.charAt(0) + lastName.substring(0, 3);
          password = lastName.substring(0,3) + cprNumber.substring(7);
        } else {
          username = firstName.charAt(0) + lastName;
          password = lastName + cprNumber.substring(7);
        }

        //WRITING TO OUR DATABASE
        //For the purpose of this exercise, I decided to use a text file as my "database"
        //When the user creation process is completed, all information is recorded on a single line in a file, separated by whitespace.
        //The login functionality will read from this file.
        try (BufferedWriter bw = new BufferedWriter(new FileWriter(FILENAME, true))){

          String content = username + " " + password + " " + firstName + " " + lastName + " " + address + " " + dob + " " + phoneNumber + " " + cprNumber + "\n";

          bw.write(content);
          bw.close();
          System.out.println("New user has been created");
        } catch (IOException e){
          e.printStackTrace();
        }

        break;
      case "EXIT":
        System.out.println("Bye Bye!");
        break;
      default:
        System.out.println("That is not a viable option");
        break;
    }
  }
}