using System;
using System.Collections.Generic;
using System.Linq;
using System.Windows.Input;
using TINK.View;
using Xamarin.Forms;

namespace TINK.ViewModel.WhatsNew
{
	public class WhatsNewViewModel
	{
		/// <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,
			IDictionary<Version, 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 = GetWhatNextHtmlText(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 readonly IViewService ViewService;

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

		public static string GetWhatNextHtmlText(IDictionary<Version, string> whatsNew)
			=> string.Join("", whatsNew.Select(element => $"<p><b>{element.Key}</b><br/>{element.Value}</p>").ToArray());
	}
}