using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace CustomerMaintenance
{
	public static class Validator
	{
		private static string lineEnd = "\n";

		public static string LineEnd
		{
			get
			{
				return lineEnd;
			}
			set
			{
				lineEnd = value;
			}
		}

		public static string IsPresent(string value, string name)
		{
			string msg = "";
			if (value == "")
			{
				msg += name + " is a required field." + LineEnd;
			}
			return msg;
		}

		public static string IsDecimal(string value, string name)
		{
			string msg = "";
			if (!Decimal.TryParse(value, out _))
			{
				msg += name + " must be a valid decimal value." + LineEnd;
			}
			return msg;
		}

		 public static string IsInt32(string value, string name)
		{
			string msg = "";
			if (!Int32.TryParse(value, out _))
			{
				msg += name + " must be a valid integer value." + LineEnd;
			}
			return msg;
		}

		public static string IsWithinRange(string value, string name, decimal min,
			decimal max)
		{
			string msg = "";
			if (Decimal.TryParse(value, out decimal number))
			{
				if (number < min || number > max)
				{
					msg += name + " must be between " + min + " and " + max + "." + LineEnd;
				}
			}
			return msg;
		}

		public static string IsValidEmail(string value, string name)
		{
			string msg = "";
			if (value.IndexOf("@") == -1 ||
				 value.IndexOf(".") == -1)
			{
				msg += name + " must be a valid email address." + LineEnd;
			}
			return msg;
		}
	}
}