import java.util.ArrayList;

public class Calculations
{
    public static Console console = new Console();
    public static ArrayList<String> library = new ArrayList<String>();
    
    public Calculations(){
   
    library.add("multiply");
    library.add("divide");
    library.add("subtract");
    library.add("add");
    library.add("COS");
    library.add("SIN");
    library.add("TAN");
    library.add("invertS");
    library.add("invertN");
    library.add("factorial");
    library.add("switchunit");
    library.add("clear");
    library.add("storeM");
    library.add("resetM");
    library.add("recallM");
    library.add("displayM");
        
    }

    public static void getCommand(String userInput)
    {
        boolean foundCommand = false;
        String command = "";
        String result = "";
        
        String[] inputArr = userInput.split(" ");
        for(int i = 0; i < library.size(); i ++)
        {
            String currCommand = library.get(i);
            if(currCommand.equalsIgnoreCase(inputArr[0]))
            {
                command = currCommand;
                foundCommand = true;
                break;
            }
        }
        
        switch(command)
        {
            case "multiply":
                result = Multiply(userInput);
            break;
            
            case "divide":
                result = Divide(userInput);
            break;
            
            case "add":
                result = Add(userInput);
            break;
            
            case "subtract":
                result = Subtract(userInput);
            break;
            
            case "invertS":
                result = InvertSign(userInput);
            break;
            
            case "invertN":
                result = InvertNumber(userInput);
            break;   
            
            case "clear":
                Clear();
            break;
        }
        System.out.println(result);
        //return result;
    }
    
    public static ArrayList<Double> getNumbers(String userInput){
        ArrayList<Double> results = new ArrayList<Double>();
        //takes in a string
        //finds the first occurence of a number
        //store it as a double ( left )
        //add this to the arraylist
        //find the second occurence of a number
        //store it as a double (right)
        //add this to the array list
        //if the size of the arraylist is 2
            //return the array list
        //else return null
        return results;
    }
    
    public static String Multiply(String userInput)
    {
        //perform the operation
        //convert to string
        //return string
        return null;
    }

    public static String Divide(String userInput)
    {
        //perform the operation
        //convert to string
        //return string
        return null;
    } 

        public static String Add(String userInput)
    {
        //perform the operation
        //convert to string
        //return string
        return null;
    }
    
    public static String Subtract(String userInput)
    {
        //perform the operation
        //convert to string
        //return string
        return null;
    }
 
    public static String InvertSign(String userInput)
    {
        //perform the operation
        //convert to string
        //return string
        return null;
    }  
    
    public static String InvertNumber(String userInput)
    {
        //perform the operation
        //convert to string
        //return string
        return null;
    } 

    public static void Clear()
    {
        //reset the default value to 0
    }
}