BuyEDalerModel.cs

using LegalLab.Models;
using System.Threading.Tasks;
using System.Windows.Input;
 
namespace LegalLab.Dialogs.BuyEDaler
{
    public class BuyEDalerModel : Model
    {
        private readonly ServiceProviderModel[] providers;
        private readonly Property<ServiceProviderModel> selectedServiceProvider;
        private readonly Property<decimal> amount;
        private readonly Property<string> currency;
        private readonly BuyEDalerDialog dialog;
        private readonly Command buy;
        private readonly Command cancel;
 
        public BuyEDalerModel(BuyEDalerDialog Dialog, Waher.Networking.XMPP.Contracts.IServiceProvider[] Providers, string DefaultCurrency)
        {
            this.selectedServiceProvider = new Property<ServiceProviderModel>(nameof(this.SelectedServiceProvider), null, this);
            this.amount = new Property<decimal>(nameof(this.Amount), 0M, this);
            this.currency = new Property<string>(nameof(this.Currency), DefaultCurrency, this);
 
            int i, c = Providers.Length;
            this.providers = new ServiceProviderModel[c];
 
            for (i = 0; i < c; i++)
                this.providers[i] = new ServiceProviderModel(Providers[i]);
 
            this.dialog = Dialog;
            this.dialog.DataContext = this;
 
            this.buy = new Command(this.CanExecuteBuy, this.ExecuteBuy);
            this.cancel = new Command(this.ExecuteCancel);
        }
 
        public ServiceProviderModel SelectedServiceProvider
        {
            get => this.selectedServiceProvider.Value;
            set
            {
                this.selectedServiceProvider.Value = value;
                this.buy.RaiseCanExecuteChanged();
            }
        }
 
        public ServiceProviderModel[] ServiceProviders => this.providers;
 
        public decimal Amount
        {
            get => this.amount.Value;
            set
            {
                this.amount.Value = value;
                this.buy.RaiseCanExecuteChanged();
            }
        }
 
        public string Currency
        {
            get => this.currency.Value;
            set
            {
                this.currency.Value = value;
                this.buy.RaiseCanExecuteChanged();
            }
        }
 
        public ICommand Buy => this.buy;
 
        public ICommand Cancel => this.cancel;
 
        private bool CanExecuteBuy()
        {
            return
                !(this.SelectedServiceProvider is null) &&
                this.Amount > 0 &&
                this.Currency.Length == 3 &&
                this.Currency.ToUpper() == this.Currency;
        }
 
        private Task ExecuteBuy()
        {
            this.dialog.DialogResult = true;
            return Task.CompletedTask;
        }
 
        private Task ExecuteCancel()
        {
            this.dialog.DialogResult = false;
            return Task.CompletedTask;
        }
    }
}