using System;

namespace productlist
{
	public static class UI
	{
		private enum inputType {
			create,
			delete,
			list,
			help
		}
		private static inputType decodeInputType(string input) {
			string command = input.Split (null, 1)[0];
			switch (command.ToLower()) {
			case "create":
				return inputType.create;
			case "delete":
				return inputType.delete;
			case "list":
				return inputType.list;
			default:
			case "help":
				return inputType.help;
			}
		}

		public static bool validateInt(string input) {
			int result;
			return Int32.TryParse (input, out result);
		}

		public static bool validateString (object input) {
			return input is string;
		}

		public static string getAnswer(string prompt, Func<string, bool> validator) {
			string input;
			do {
				Console.Write(prompt + ": ");
				input = Console.ReadLine();
			} while (!validator (input));
			return input;
		}

		public static void promptForCommand() {
			while (true) {
				Console.Write ("Enter command: ");
				string command = Console.ReadLine ();
				inputType type = decodeInputType (command);
				switch (type) {
				case inputType.create:
					Product p = Product.fromPrompt ();
					Storage.Add (p);
					break;
				case inputType.list:
					Storage.List ();
					break;
				}
			}
		}
	}
}