Update to Roll and Created EightBall

Added more use to the Roll command, can now do basic math in addition to rolling dice.
Created Eightball, a command to output a standard eightball saying.

src/commands/CommandRoll.java

@@ -1,5 +1,7 @@
 package commands;
 
+import java.util.Stack;
+
 import core.*;
 import dataStructures.KittyChannel;
 import dataStructures.KittyGuild;
@@ -19,71 +21,157 @@ public class CommandRoll extends Command
 	@Override
 	public void OnRun(KittyGuild guild, KittyChannel channel, KittyUser user, UserInput input, Response res)
 	{
-		int dice;
-		int sides;
-		String dicenum [] = input.args.split("d");
-		
 		try 
 		{
-			dice = Integer.parseInt(dicenum[0]);
-			sides = Integer.parseInt(dicenum[1]);
+			res.Call(rollDice(input.args));
 		}
-		catch (NumberFormatException e)
+		catch(Exception e)
 		{
-			res.Call("Rude.");
-			return;
+			res.Call("Didn't work ;3;");
 		}
-		
-		res.Call(rollDice(dice,sides));
 	}
 	
-	private String rollDice(int dice, int sides)
+	private String rollDice(String thing)
+	{
+		Stack<Integer> values = new Stack<Integer>();
+		Stack<Character> operators = new Stack<Character>();
+		for(int i = 0; i < thing.length(); i ++)
+		{
+			char current = thing.charAt(i);
+			
+			switch(current)
+			{
+				case '+':
+				case '-':
+				case '*':
+				case '/':
+					if(operators.isEmpty() || !hasPrecendence(operators.peek(), current) || operators.peek() == '(')
+						operators.add(current);
+					else
+					{
+						calculate(values, operators);
+						operators.add(current); 
+					}
+						
+					continue;
+					
+				case '(':
+					operators.add(current);
+					continue;
+					
+				case ')':
+					if(operators.peek() == '(')
+						operators.pop(); 
+					else
+					{
+						i --;
+						calculate(values, operators);
+					}
+					continue;
+					
+				case 'd':
+					if(operators.isEmpty() || operators.peek() == '(' || !hasPrecendence(operators.peek(), current))
+						operators.add(current);
+					else
+						calculate(values, operators);
+					continue;
+					
+				case ' ':
+					continue; 
+					
+				default:
+					try
+					{
+					    // Accumulate valid characters
+					    String accumulated = "";
+					    for(int j = i; j < thing.length(); ++j)
+					    {
+					        char parse = thing.charAt(j);
+					        if(Character.isDigit(parse))
+					        {
+					            accumulated += parse; // Keep tabs on our character
+					            ++i;                  // Offset overall loop
+					            continue;
+					        }
+					        
+					        // Default leave
+					        break;
+					    }
+					    
+					    if(accumulated.length() <= 0)
+					        throw new Exception("Error! Invalid character!");
+					        
+					    values.add(Integer.parseInt(accumulated));
+					    i--;
+					}
+					catch (Exception e)
+					{
+					    System.out.print("Something went wrong");
+					    i = thing.length();
+					}
+			}
+		}
+		
+		while(operators.size() > 0)
+		{
+			calculate(values, operators);
+		}
+		
+		return "" + values.pop();
+	}
+	
+	private void calculate(Stack<Integer> nums, Stack<Character> operators)
+	{
+		int second = nums.pop();
+		int first = nums.pop();
+		int value = 0;
+		
+		switch(operators.pop())
+		{
+			case '+':
+				value = first + second;
+				break;
+			case '-':
+				value = first - second;
+				break;
+			case '*':
+				value = first * second;
+				break;
+			case '/':
+				value = first / second;
+				break;
+			case 'd': 
+				value = roll(first, second);
+		}
+		
+		nums.add(value);
+	}
+
+	private int roll(int first, int second) 
 	{
 		int total = 0;
 		int roll = 0;
-		String nums = "";
-		
-		//checks for lower than 1 dice or dice size 
-		if(dice > 100 || sides > 100)
-		{
-			return ("*drowns in dice*");
-		}
-		
-		if(dice < 1 || sides < 1)
-		{
-			return("I can't do that!");
-		}
+		int dice = first;
+		int sides = second;
 		
+		if(dice < 1)
+			return 0; 
 		for(int i = 0; dice > i; i ++)
 		{
 			roll = (int)(Math.random() * sides) + 1;
-			nums += roll + " ";
 			total += roll;
 		}
-		
-		//makes output look nicer
-		String prettyNums = "";
-		String[] splitNums = nums.split(" ");
-		if(splitNums.length > 10)
-		{
-			final int len = 5;
-			for(int i = 0; i < splitNums.length; i += len)
-			{
-				prettyNums += "\n";
-				for(int j = 0; j < len; ++j)
-				{
-					if(j != 0)
-						prettyNums += " ";
-					
-					prettyNums += splitNums[i + j];
-				}
-			}
-		}
-		else
-		{
-			prettyNums = nums;
-		}
-		
-		return ("Rolls are\n" + prettyNums + "\n" + "Total is: " + total);
+		return total;
+	}
+
+	private boolean hasPrecendence(char op1, char op2)
+	{
+		 if ((op1 == '*' || op1 == '/') && (op2 == '+' || op2 == '-')) 
+	         return false;
+	     else
+	    	 if ((op2 == 'd') && (op1 == '+' || op1 == '-' || op1 == '*' || op1 == '/')) 
+	    		 return false;
+	    	 else
+	    		 return true; 
 	}
 }