using TINK.View;
using System.Windows.Input;
using Xamarin.Forms;
using System;
using System.ComponentModel;

namespace TINK.ViewModel.WhatsNew
{
    public class WhatsNewViewModel : INotifyPropertyChanged
    {
        /// <summary> Constructs view model. </summary>
        /// <param name="currentVersion"></param>
        /// <param name="whatsNewText"></param>
        /// <param name="isShowAgbRequired"></param>
        /// <param name="showMasterDetail">Delegate to invoke master detail.</param>
        /// <param name="p_oViewService">View service to show agb- page.</param>
        public WhatsNewViewModel(
            Version currentVersion,
            string whatsNewText,            
            bool isShowAgbRequired,
            Action showMasterDetail,
            IViewService p_oViewService)
        {
            ViewService = p_oViewService
               ?? throw new ArgumentException($"Can not instantiate {typeof(WhatsNewViewModel)}-object. No view available.");

            ShowMasterDetail = showMasterDetail
                ?? throw new ArgumentException($"Can not instantiate {typeof(WhatsNewViewModel)}-object. No delegate to activated maste detail page avilable.");

            CurrentVersion = currentVersion;
            WhatsNewText = new FormattedString();
            WhatsNewText.Spans.Add(new Span { Text = whatsNewText });
            IsAgbChangedVisible = isShowAgbRequired;
        }

        public Version CurrentVersion { get; }

        public FormattedString WhatsNewText {get;}

        /// <summary>
        /// Title of the WhatsNewPage.
        /// </summary>
        public string WhatsNewTitle
        {
            get
            {
                // Get version info.
                return $"Neu in Version {CurrentVersion}";
            }
        }

        /// <summary> Text saying that AGBs were modified.</summary>
        public FormattedString AgbChangedText
        {
            get
            {
                var l_oHint = new FormattedString();
                l_oHint.Spans.Add(new Span { Text = "AGBs ", ForegroundColor = ViewModelHelper.LINK_COLOR });
                l_oHint.Spans.Add(new Span { Text = "überarbeitet.\r\n" });
                
                return l_oHint;
            }
        }

        public bool IsAgbChangedVisible { get; }

        /// <summary> Command object to bind agb link to view model.</summary>
        public ICommand OnShowAgbTapped
        {
            get
            {
                return new Command(async () => await ViewService.PushModalAsync(ViewTypes.AgbPage));
            }
        }

        /// <summary> Called when dialog is disappearing.</summary>
        /// <param name="setWhatsNewWasShown"></param>
        public void OnDisappearing(Action setWhatsNewWasShown)
        {
            setWhatsNewWasShown();
        }

#if !SHOWFEEDBACK
        public bool IsFeedbackVisible => false;
#else
        public bool IsFeedbackVisible => true;
#endif
        /// <summary> User clicks rate button.</summary>
        public ICommand OnOk
        {
            get
            {
                return new Command(() => ShowMasterDetail());
            }
        }

        /// <summary>Reference to view service object.</summary>
        private IViewService ViewService;

        /// <summary>Reference to view service object.</summary>
        private Action ShowMasterDetail { get; }

        /// <summary> Fired whenever a property changes.</summary>
        public event PropertyChangedEventHandler PropertyChanged;
    }
}