using System.Text.RegularExpressions;
using System.ComponentModel.DataAnnotations;
using System.Globalization;

namespace Ophelias.Expressions
{
    internal static class Expressions
    {
        /*
         * These are a collection of regular expressions used in the validation class.
         * They exist in their own class to better isolate them and make it easier to
         * find.
         * 
         *      CardRx
         *          Regular expression to check for 16 digit credit cards
         *      
         *      ExpirationRx
         *          Ensures that a card expires sometime in past 2021
         *          
         *      CCVRx
         *          Checks to make sure the input is 3 digits
         *          
         *      MoneyRx
         *          Basic check to make sure money is in US format. 300.20/ 0.00 etc.
         */
        internal static Regex CardRx = new(@"^[0-9]{16}$", RegexOptions.Compiled);
        internal static Regex ExpriationRx = new(@"^(0?[1-9]|1[012])/[2-9][0-9]{1}$", RegexOptions.Compiled);
        internal static Regex CCVRx = new(@"^[0-9]{3}$", RegexOptions.Compiled);
        internal static Regex MoneyRx = new(@"^(\d+\.\d{2}|\d+)$", RegexOptions.Compiled);
    }
    internal static class Validation
    {
        internal static bool ValidateCreditCard(string CreditCard) // Returns if the regex evaluates true or false
        {
            return Expressions.CardRx.IsMatch(CreditCard);
        }
        internal static bool ValidateExpirationDate(string Expiration) // Returns if the regex evaluates true or false
        {
            if (Expressions.ExpriationRx.IsMatch(Expiration))
            {
                DateTime dt = DateTime.ParseExact(Expiration, "MM/yy", CultureInfo.InvariantCulture); // Converts to date time for comparison
                if (dt.Date >= DateTime.Now.Date)
                    return true;
            }
            return false;
        }
        internal static bool ValidateEmail(string email) // Returns if the regex evaluates true or false
        {
            EmailAddressAttribute EmailChecker = new(); // Creates an email checker based off the EmailAddressAttribute class
            return EmailChecker.IsValid(email);
        }
        internal static bool ValidateCCV(string CCV) // Returns if the regex evaluates true or false
        {
            if (Expressions.CCVRx.IsMatch(CCV))
                return true;
            return false;
        }
        internal static bool ValidateMoney(string Money) // Returns if the regex evaluates true or false
        {
            return Expressions.MoneyRx.IsMatch(Money);
        }

    }
}