using System.ComponentModel;
using System.Runtime.CompilerServices;
using Windows.ApplicationModel.Store;
 
namespace LicenseHelper
{
    public class LicenseChecker : INotifyPropertyChanged
    {
        static LicenseInformation licenseInformation;
        static bool IsTrialTested = false;
 
 
        private bool isTrial = false;
        public bool IsTrial
        {
            get
            {
                if (!IsTrialTested)
                {
                    InitializeLicense();
                }
                return isTrial;
            }
            set
            {
                if (isTrial != value)
                {
                    isTrial = value;
                }
                NotifyPropertyChanged("IsTrial");
 
            }
        }
 
        public void InitializeLicense()
        {
            // Initialize the license info for use in the app that is uploaded to the Store.
            // uncomment for release
            licenseInformation = CurrentApp.LicenseInformation;
 
            // Initialize the license info for testing.
            // comment the next line for release
            //licenseInformation = CurrentAppSimulator.LicenseInformation;
            // Register for the license state change event.
            licenseInformation.LicenseChanged += new LicenseChangedEventHandler(LicenseChangedEventHandler);
 
            IsTrial = licenseInformation.IsTrial;
        }
 
        public static void TestTrialPurchase()
        {
            CurrentAppSimulator.RequestAppPurchaseAsync(false);
        }
 
 
        public void LicenseChangedEventHandler()
        {
            ReloadLicense(); // code is in next steps
        }
 
        public void ReloadLicense()
        {
            if (licenseInformation.IsActive)
            {
                IsTrial = licenseInformation.IsTrial;
            }
            else
            {
                IsTrial = true;// A license is inactive only when there's an error.
            }
        }
 
        public event PropertyChangedEventHandler PropertyChanged;
 
        // This method is called by the Set accessor of each property. 
        // The CallerMemberName attribute that is applied to the optional propertyName 
        // parameter causes the property name of the caller to be substituted as an argument. 
        private void NotifyPropertyChanged([CallerMemberName] string propertyName = "")
        {
            if (PropertyChanged != null)
            {
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
            }
        }
    }
}