using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Runtime.CompilerServices;
using Xamarin.Forms.CustomAttributes;
using Xamarin.Forms.Internals;

#if UITEST
using Xamarin.UITest;
using NUnit.Framework;
#endif

namespace Xamarin.Forms.Controls
{
	[Preserve(AllMembers = true)]
	[Issue(IssueTracker.Bugzilla, 37841, "TableView EntryCells and TextCells cease to update after focus change", PlatformAffected.Android)]
	public class Bugzilla37841 : TestContentPage
	{
		_37841ViewModel _viewModel;

		protected override void Init ()
		{
			_viewModel = new _37841ViewModel ();

			var instructions = new Label { FontSize = 16, Text = @"Click on the Generate button. 
The EntryCell should display '12345' and the TextCell should display '6789'. 
Click on the Generate button a second time. 
The EntryCell should display '112358' and the TextCell should display '48151623'." };

			var button = new Button { Text = "Generate" };
			button.SetBinding (Button.CommandProperty, nameof (_37841ViewModel.GetNextNumbersCommand));

			var random1 = new EntryCell { IsEnabled = false, Label = "Entry Cell" };
			random1.SetBinding (EntryCell.TextProperty, nameof (_37841ViewModel.Value1));

			var textCell = new TextCell { IsEnabled = false, Detail = "TextCell" };
			textCell.SetBinding (TextCell.TextProperty, nameof (_37841ViewModel.Value2));

			var buttonViewCell = new ViewCell { View = button };

			var section = new TableSection ("") {
				random1,
				textCell,
				buttonViewCell
			};

			var root = new TableRoot { section };
			var tv = new TableView { Root = root };

			Content = new StackLayout {
				Children = { instructions, tv }
			};

			BindingContext = _viewModel;
		}

		[Preserve (AllMembers = true)]
		public class _37841ViewModel : INotifyPropertyChanged
		{
			public int Value1
			{
				get { return _value1; }
				set
				{
					if (value != _value1) {
						_value1 = value;
						RaisePropertyChanged ();
					}
				}
			}

			public int Value2
			{
				get { return _value2; }
				set
				{
					if (value != _value2) {
						_value2 = value;
						RaisePropertyChanged ();
					}
				}
			}

			public Command GetNextNumbersCommand
				=> _getNextNumbersCommand ?? (_getNextNumbersCommand = new Command (ExecuteGenerateRandomCommand));

			class SomeNumbers : IEnumerable<int>
			{
				public IEnumerator<int> GetEnumerator ()
				{
					while (true) {
						yield return 12345;
						yield return 6789;
						yield return 112358;
						yield return 48151623;
					}
				}

				IEnumerator IEnumerable.GetEnumerator ()
				{
					return GetEnumerator ();
				}
			}

			readonly IEnumerator<int> _numberList = new SomeNumbers ().GetEnumerator ();

			void ExecuteGenerateRandomCommand ()
			{
				_numberList.MoveNext ();
				Value1 = _numberList.Current;
				_numberList.MoveNext ();
				Value2 = _numberList.Current;
			}

			void RaisePropertyChanged ([CallerMemberName] string propertyName = null)
			{
				PropertyChangedEventHandler handler = PropertyChanged;

				handler?.Invoke (this, new PropertyChangedEventArgs (propertyName));
			}

			#region INotifyPropertyChanged implementation

			public event PropertyChangedEventHandler PropertyChanged;

			#endregion

			Command _getNextNumbersCommand;
			int _value1;
			int _value2;
		}

#if UITEST
		[Test]
		public void TextAndEntryCellsDataBindInTableView()
		{
			RunningApp.WaitForElement ("Generate");
			RunningApp.Tap("Generate");

			RunningApp.Screenshot ("First Generate Tap");

			RunningApp.WaitForElement("12345");
			RunningApp.WaitForElement("6789");

			RunningApp.Tap("Generate");

			RunningApp.Screenshot("Second Generate Tap");

			RunningApp.WaitForElement("112358");
			RunningApp.WaitForElement("48151623");
		}
#endif
	}
}