//Convertor
//Kelsey Godwin
//Converts C to F and F to C (degree of temperatures :) )

import javax.swing.*;

public class Convertor {

    public static void main(String[] args) {
		//declare needed variables
		String starterString;
		char tempType = 'N';
		double startTemp = 0;
		double endTemp = 0;
		boolean correctString = false;
		char[] arrayStarterString;
		String split;
		char convertTempType;


		do{
			//grab the input
			starterString = JOptionPane.showInputDialog("Enter your value followed by temp type (C or F) or EXIT to exit program. ");

			//what if they hit cancle?  What jerks.
			if(starterString == null)
			{
				JOptionPane.showMessageDialog(null,"Please make sure to enter input!");
				continue;
			}

			//let's nix any spaces before and after
			starterString = starterString.trim();

			//let's make everything uppercase just to trim out half of the error handling we'd need to do!
			starterString = starterString.toUpperCase();

			//if they want to get the hell out of this loop, let's let them
			if (starterString.contentEquals("EXIT"))
				System.exit(0);

			try{
				if ((starterString.charAt(0) >= 58) || (starterString.charAt(0) <= 44) || (starterString.charAt(0) == 47) ){
					JOptionPane.showMessageDialog(null,"Please make sure to start your input with a number.");
					continue;
				}//end of if statement

			}//end of try
			catch(StringIndexOutOfBoundsException e){
				//they just hit enter when putting in input, resulting in nothing.  Handle dat error
				JOptionPane.showMessageDialog(null,"Please make sure to enter input!");
				continue;

			}//end of catch

			//if the second to last char is not a space nor a numeral, then the user is a jerk and boot him out
			try {
				if (starterString.charAt(starterString.length() - 2 ) == ' '){
					split = starterString.substring(0,starterString.length() - 2);

					//they were jerks and put a letter somewhere in the number
					try{
						startTemp = Double.valueOf(split);
					}
					catch(NumberFormatException e){
						JOptionPane.showMessageDialog(null,"Please make sure you have a number followed by F or C");
						continue;
					}
				}
				else if ((starterString.charAt(starterString.length() -2) > '9') || (starterString.charAt(starterString.length() -2) < '0')){
					JOptionPane.showMessageDialog(null,"Please make sure to only use C or F for temperature type.");
					continue;
				}
				else{
					split = starterString.substring(0,starterString.length() - 1);

					//they were jerks and put a letter somewhere in the number
					try{
						startTemp = Double.valueOf(split);
					}
					catch(NumberFormatException e){
						JOptionPane.showMessageDialog(null,"Please make sure you have a number followed by F or C");
						continue;
					}
				}
			}//end of try
			catch(StringIndexOutOfBoundsException e){
				//grr, they just entered one number
				JOptionPane.showMessageDialog(null,"Please input a C or F for temperature type at end of input");
				continue;
			}//end of catch


			//finally, convert
			if (starterString.charAt(starterString.length() -1) == 'F'){
				endTemp = convertFtoC(startTemp);
				convertTempType = 'C';
			}
			else if (starterString.charAt(starterString.length() -1) == 'C'){
				endTemp = convertCtoF(startTemp);
				convertTempType = 'F';
			}
			else
			{	JOptionPane.showMessageDialog(null,"Please make sure to use C or F for temperature type.");
				continue;
			}

			JOptionPane.showMessageDialog(null, "Converted Temp is " + endTemp + convertTempType);
		}//end of do
		while(correctString == false);

    }//end of main method

    public static double convertFtoC(double startTemp)
    {
    	double convertTemp;

    	//after you get all the stuff cleaned up, you have a wonderful number to work with
    	//so let's convert it FINALLY!
    	return convertTemp = (5.0/9.0) * (startTemp - 32);

    }
    public static double convertCtoF(double startTemp)
    {
    	double convertTemp;

    	//after you get all the stuff cleaned up, you have a wonderful number to work with
    	//so let's convert it FINALLY!
    	return convertTemp = ((9.0/5.0) * startTemp) + 32;

    }

}