import java.util.Scanner;
public class Calculator{

   private String chooseOperand;
 //  private boolean userAnswer;
   private Scanner userKeyboard;
   private boolean askOperand;
   private boolean runAskNumber;
   private boolean wantsUseCalculate;
   private boolean wantsToRerun;
   private int count;
   private double numbOne;
   private double numbTwo;
   private double operationTotal;

   public Calculator(){
      userKeyboard = new Scanner(System.in);
      askOperand = true;
      runAskNumber = false;

   }

   public void printIntro(){
      System.out.println("Hi, Welcome to Calculator");
      System.out.println("Please input what function you would like to do");
      System.out.println("If you would like to add, type: + ");
      System.out.println("If you would like to subtract, type: - ");
      System.out.println("If you would like to multiply, type: * ");
      System.out.println("If you would like to divide, type: / ");
      System.out.println("Then hit enter");

   }
   public void calculate(){
        System.out.println("In Calculate Method");
        do {
            while (askOperand == true){
               System.out.println("Please input what function you would like the Calculator to perform: ");
               chooseOperand = userKeyboard.nextLine();
               if (chooseOperand.substring(0).equalsIgnoreCase("*")){
                  System.out.println("You want to multiply");
                  askOperand = false; //ends current loop
                  runAskNumber = true; //starts next loop to ask them for a number
               }
               else if(chooseOperand.substring(0).equalsIgnoreCase("/")){
                  System.out.println("You want to divide");
                  askOperand = false;
                  runAskNumber = true;
               }
               else if(chooseOperand.substring(0).equalsIgnoreCase("+")){
                  System.out.println("You Want to add");
                  askOperand = false;
                  runAskNumber = true;
               }

               else if(chooseOperand.substring(0).equalsIgnoreCase("-")){
                  System.out.println("You want to subtract");
                  askOperand = false;
                  runAskNumber = true;
               }
               else{
                  System.out.println("Please input either: * / + -");
                  System.out.println("For example: *");
               }

               while (runAskNumber == true){
                  System.out.println("What's your first number?");
                     try{
                        numbOne = userKeyboard.nextDouble();
                        System.out.println("What's your second number?");
                        numbTwo = userKeyboard.nextDouble();

                        runAskNumber = false;
                     }
                     catch (Exception ex) {
                        System.out.println("Please enter a number:");
                        System.out.println("Example: 98");
                        System.exit(1);
                     }
                     if (chooseOperand.substring(0).equalsIgnoreCase("*")){
                        operationTotal = numbOne * numbTwo;
                        System.out.println("Your Total is: " + operationTotal);
                        wantsToRerun = true;
                     }
                     else if (chooseOperand.substring(0).equalsIgnoreCase("/")){
                        operationTotal = numbOne / numbTwo;
                        System.out.println("Your Total is: " + operationTotal);
                        wantsToRerun = true;
                     }
                     else if (chooseOperand.substring(0).equalsIgnoreCase("+")){
                        operationTotal = numbOne + numbTwo;
                        System.out.println("Your Total is: " + operationTotal);
                        wantsToRerun = true;
                     }
                     else {
                        operationTotal = numbOne - numbTwo;
                        System.out.println(operationTotal);
                        wantsToRerun = true;
                     }
                     System.out.println("Would you like to do another calculation?");
                     System.out.println("To do another calculation type: Yes");
                     System.out.println("Quit the program type: No");
                     System.out.println(" ------ ");
                     userKeyboard.nextLine();
                     /* ^ added because nextInt(); reads only one int and doesn't finish the line. So it reads the call after it asked for the 2nd number.
                     https://stackoverflow.com/questions/7877529/java-string-scanner-input-does-not-wait-for-info-moves-directly-to-next-stateme */
                     while (wantsToRerun == true){
                        String userAnswer = userKeyboard.nextLine();
                         if (userAnswer.contains("yes") || userAnswer.contains("Yes")){
                            askOperand = true;
                            wantsToRerun = false;
                         }
                         else if (userAnswer.contains("no") || userAnswer.contains("No")){
                            wantsUseCalculate = false;
                         }
                         else {
                           System.out.println("Please input either yes or no");
                         }
                     }
               }
            }
        } while(wantsUseCalculate == true);
   }


   public void printReport(){

   }

   public static void main(String args[]){
      Calculator myCalculator = new Calculator();
      myCalculator.printIntro();
      myCalculator.calculate();


   }
}