using System.Text.RegularExpressions;

namespace Dungeoneer {

	public sealed class Command {

		public static void Roll(IList<string> args) {
			//	don't do anything with empty expressions
			if(args.Count == 0)
				return;
			var expression = "";

			var diePattern = new Regex(@"\d+d\d+");

			//	reassemble split args and substitute die notation
			foreach(string arg in args) {
				string part;

				var dieCheck = diePattern.Match(arg);
				if(dieCheck.Success) {
					var parts = arg.Split('d');
					var first = parts[0];
					var second = parts[1];

					int count;
					int sides;
					try {
						count = int.Parse(first);
						sides = int.Parse(second);
					} catch {
						Console.WriteLine("'{arg}' is not a valid dice expression");
						return;
					}

					var rolls = "( ";
					for(int i = 0; i < count; i++) {
						string result;
						var roll = Util.Roll(sides);
						if(i < count - 1)
							result = $"{roll} + ";
						else
							result = $"{roll} ";
						rolls += result;
					}
					rolls += ")";
					part = rolls;
				} else
					part = arg;
				expression += $"{part} ";
			}

			dynamic output;
			try { output = Scripting.Expr($"eval('{expression}')"); }
			catch {
				Console.WriteLine("invalid expression");
				return;
			}
			Console.WriteLine($"{expression}\n=> {output}");
		}



	}

}