gehgassi_app/gehGassiApp/gehGassiApp.Domain/Payment/BankAccount.cs

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.Linq;
using System.Numerics;
using System.Text;
using System.Text.RegularExpressions;
using System.Threading.Tasks;
using CommunityToolkit.Mvvm.ComponentModel;
using gehGassiApp.Domain.Common;
using static System.Net.Mime.MediaTypeNames;

namespace gehGassiApp.Domain.Payment
{
    /// <summary>
    /// Repräsentiert eine Bankverbindung eines App-Users
    /// </summary>
    public class BankAccount : ObservableObject
    {
        private string _ownerName;
        private string _iban;
        private string _bic;

        /// <summary>
        /// ID des AppUsers
        /// </summary>
        [Required]
        [MaxLength(128)]
        public string AppUserId { get; set; }

        /// <summary>
        /// ID des AppUsers bei MangoPay
        /// </summary>
        [MaxLength(128)]
        public string PaymentId { get; set; }

        /// <summary>
        /// ID der Bankverbindung bei MangoPay
        /// </summary>
        [MaxLength(128)]
        public string BankId { get; set; }

        /// <summary>
        /// Name des Inhabers der Bankverbindung
        /// </summary>
        [Required]
        [MaxLength(255)]
        public string OwnerName
        {
            get => _ownerName;
            set
            {
                _ownerName = value;
                OnPropertyChanged();
            }
        }

        /// <summary>
        /// Adresse des Inhabers der Bankverbindung
        /// </summary>
        [Required]
        public Address Address { get; set; }

        /// <summary>
        /// Iban der Bankverbindung
        /// </summary>
        [Required]
        [MaxLength(255)]
        public string Iban
        {
            get => _iban;
            set
            {
                _iban = value;
                OnPropertyChanged();
            }
        }

        /// <summary>
        /// Bic der Bankverbindung
        /// </summary>
        [MaxLength(255)]
        public string Bic
        {
            get => _bic;
            set
            {
                _bic = value;
                OnPropertyChanged();
            }
        }

        /// <summary>
        /// Erstellt eine Instanz
        /// </summary>
        public BankAccount()
        {
            Address = new Address();
        }

        /// <summary>
        /// Gibt zurück ob der Iban gültig ist
        /// </summary>
        /// <returns>true wenn gültig, false sonst</returns>
        public bool IsIbanValid()
        {
            if (string.IsNullOrEmpty(Iban))
                return false;

            var iban = Iban.ToUpper().Replace(" ", "").Replace("-", "");
            if (!Regex.IsMatch(iban, @"^[A-Z]{2}[0-9]{2}[A-Z0-9]{4}[0-9]{7}([A-Z0-9]?){0,16}$"))
                return false;

            var ibanWithoutCountryAndChecksum = iban.Substring(4) + iban.Substring(0, 4);
            var ibanWithoutCountryAndChecksumAsNumber = string.Concat(ibanWithoutCountryAndChecksum.Select(c => char.IsLetter(c) ? c - 55 : c - '0'));

            var checksum = BigInteger.Parse(ibanWithoutCountryAndChecksumAsNumber) % 97;
            return checksum == 1;
        }

        /// <summary>
        /// Gibt zurück ob der Bic gültig ist.
        /// Der BIC ist optional und wird nur geprüft wenn er nicht leer ist
        /// </summary>
        /// <returns>true wenn gültig, false sonst</returns>
        public bool IsBicValid()
        {
            if (string.IsNullOrWhiteSpace(Bic))
                return true;

            var bic = Bic.ToUpper().Replace(" ", "").Replace("-", "");
            if (!Regex.IsMatch(bic, @"^[A-Z]{6}[A-Z2-9][A-NP-Z0-9]([A-Z0-9]{3})?$"))
                return false;

            return true;
        }
    }
}