using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Xamarin.Forms.CustomAttributes;
using Xamarin.Forms.Internals;

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

namespace Xamarin.Forms.Controls.Issues
{
	[Preserve(AllMembers = true)]
	[Issue(IssueTracker.Github, 2411, "ListView.ScrollTo not working in TabbedPage", PlatformAffected.Android)]
	public class Issue2411 : TestTabbedPage
	{
		protected override void Init()
		{
			Children.Add(new XamarinListViewScrollToBugPage1());
			Children.Add(new XamarinListViewScrollToBugPage2());
			Children.Add(new XamarinListViewScrollToBugPage3());
		}

#if UITEST
		[Test]
#if __ANDROID__
		[Ignore("Appearing event is tied to virtualization in TabbedPage for Material")]
#endif
#if __MACOS__
		[Ignore("ScrollTo not implemented on MacOS")]
#endif
		[Issue(IssueTracker.Github, 2411, "ScrollToPosition.MakeVisible not called every time TabbedPage", PlatformAffected.Android)]
		public void Issue2411ScrollToPositionMakeVisible()
		{
			RunningApp.WaitForElement(q => q.Marked("99 99 99 99 99 99"));
			RunningApp.Screenshot("ScrollTo working correctly");
			RunningApp.Tap(q => q.Marked("Crash in ScrollToPosition.End"));
			RunningApp.Screenshot("On Second Tab");
			RunningApp.WaitForElement(q => q.Marked("2 0 0 0 0 0 0"));
			RunningApp.Tap(q => q.Marked("Scroll To in OnAppearing"));
			RunningApp.Screenshot("On First Tab");
			RunningApp.WaitForElement(q => q.Marked("99 99 99 99 99 99"));

			var listViewBound = RunningApp.Query(q => q.Marked("listView"))[0].Rect;
			Xamarin.Forms.Core.UITests.Gestures.ScrollForElement(RunningApp, "* marked:'0 0 0 0 0 0'", new Xamarin.Forms.Core.UITests.Drag(listViewBound, Xamarin.Forms.Core.UITests.Drag.Direction.TopToBottom, Xamarin.Forms.Core.UITests.Drag.DragLength.Long));
			RunningApp.Screenshot("Scrolled to Top");

			RunningApp.Tap(q => q.Marked("Crash in ScrollToPosition.End"));
			RunningApp.Screenshot("On Second Tab");
			RunningApp.WaitForElement(q => q.Marked("2 0 0 0 0 0 0"));
			RunningApp.Tap(q => q.Marked("Scroll To in OnAppearing"));
			RunningApp.Screenshot("On First Tab");
			RunningApp.WaitForElement(q => q.Marked("99 99 99 99 99 99"));
		}

		[Test]
		[Issue(IssueTracker.Github, 2411, "ScrollToPosition.End crashing in TabbedPage", PlatformAffected.Android)]
#if __MACOS__
		[Ignore("ScrollTo not implemented on MacOS")]
#endif
		public void Issue2411ScrollToPositionEndCrash()
		{
			RunningApp.Tap(q => q.Marked("Crash in ScrollToPosition.End"));
			RunningApp.Screenshot("On Second Tab");
			RunningApp.Tap(q => q.Marked("Scroll To in OnAppearing"));
			RunningApp.Screenshot("On First Tab");
			RunningApp.Tap(q => q.Marked("Crash in ScrollToPosition.End"));
			RunningApp.Screenshot("On Second Tab Again");
			RunningApp.Tap(q => q.Marked("ScrollToPosition.End End - Not animated"));
			RunningApp.WaitForElement(q => q.Marked("2 99 99 99 99 99 99"));
		}

		[Test]
		[Issue(IssueTracker.Github, 2411, "ScrollToPositon.End crashing in TabbedPage", PlatformAffected.Android)]
		public void Issue2411ScrollToPositionWrongOnUneven()
		{
			RunningApp.Tap(q => q.Marked("Crash in ScrollToPosition.End"));
			RunningApp.Tap(q => q.Marked("Scroll To in OnAppearing Uneven"));

			var dontRun = RunningApp.Query(q => q.Marked(XamarinListViewScrollToBugPage3.DontRun));
			if (dontRun.Length > 0)
				Assert.Inconclusive("Ignored on iOS < 9 until Bugzilla 28277 is resolved.");

			RunningApp.Screenshot("On Third Tab");
			RunningApp.WaitForElement(q => q.Marked("99 99 99 99 99 99"));
		}
#endif
	}

	[Preserve(AllMembers = true)]
	internal class ListObj
	{
		public string Name { get; set; }
	}

	[Preserve(AllMembers = true)]
	public class CellTemplateScrollTo : ViewCell
	{
		public CellTemplateScrollTo()
		{
			Label cellLabel = new Label()
			{
				HorizontalOptions = LayoutOptions.FillAndExpand,
			};

			cellLabel.SetBinding(Label.TextProperty, new Binding("Name", BindingMode.OneWay));

			StackLayout root = new StackLayout()
			{
				Children = {
					cellLabel
				}
			};

			View = root;
		}
	}

	[Preserve(AllMembers = true)]
	public class CellTemplateScrollToUneven : CellTemplateScrollTo
	{
		public CellTemplateScrollToUneven()
		{

			Height = 60 + new Random().Next(10, 100);
		}
	}

	[Preserve(AllMembers = true)]
	public class XamarinListViewScrollToBugPage1 : ContentPage
	{
		ListView _listView;
		ObservableCollection<ListObj> _collection = new ObservableCollection<ListObj>();

		public XamarinListViewScrollToBugPage1()
		{
			Title = "Scroll To in OnAppearing";

			for (int i = 0; i < 100; i++)
			{
				var item = new ListObj { Name = string.Format("{0} {0} {0} {0} {0} {0}", i) };
				_collection.Add(item);
			}

			_listView = new ListView
			{
				ItemsSource = _collection,
				ItemTemplate = new DataTemplate(typeof(CellTemplateScrollTo))
			};

			_listView.AutomationId = "listView";

			Content = new StackLayout
			{
				Children = {
					_listView
				}
			};
		}

		protected override void OnAppearing()
		{
			base.OnAppearing();
			_listView.ScrollTo(_collection.Last(), ScrollToPosition.MakeVisible, false);
		}
	}

	[Preserve(AllMembers = true)]
	public class XamarinListViewScrollToBugPage2 : ContentPage
	{
		ListView _listView;
		ObservableCollection<ListObj> _collection = new ObservableCollection<ListObj>();

		public XamarinListViewScrollToBugPage2()
		{
			Title = "Crash in ScrollToPosition.End";

			for (int i = 0; i < 100; i++)
			{
				var item = new ListObj { Name = string.Format("2 {0} {0} {0} {0} {0} {0}", i) };
				_collection.Add(item);
			}

			_listView = new ListView
			{
				ItemsSource = _collection,
				ItemTemplate = new DataTemplate(typeof(CellTemplateScrollTo))
			};

			var endButton = new Button
			{
				Text = "ScrollToPosition.End End - Not animated",
				Command = new Command(() =>
				{
					_listView.ScrollTo(_collection.Last(), ScrollToPosition.End, false);
				})
			};

			var endButtonAnimated = new Button
			{
				Text = "ScrollToPosition.MakeVisible End - Animated",
				Command = new Command(() =>
				{
					_listView.ScrollTo(_collection.Last(), ScrollToPosition.MakeVisible, true);
				})
			};

			Content = new StackLayout
			{
				Children = {
					endButton,
					endButtonAnimated,
					_listView
				}
			};
		}
	}

	public class XamarinListViewScrollToBugPage3 : ContentPage
	{
		ListView _listView;
		ObservableCollection<ListObj> _collection = new ObservableCollection<ListObj>();
		int _i = 0;
		public const string DontRun = "Don't run";
		public XamarinListViewScrollToBugPage3()
		{
			Title = "Scroll To in OnAppearing Uneven";

			bool runTest = true;
			// This test will fail in iOS < 9 because using ScrollTo with UnevenRows with estimation is currently not working.
			// It did not previously fail because this test used `TakePerformanceHit` to turn off row estimation. However, as
			// that was never a public feature, it was never a valid fix for the test.
			// https://bugzilla.xamarin.com/show_bug.cgi?id=28277
#if !UITEST
				if (App.IOSVersion < 9)
					runTest = false;
#endif

			if (!runTest)
				_collection.Add(new ListObj { Name = DontRun });
			else
			{
				for (_i = 0; _i < 100; _i++)
				{
					var item = new ListObj { Name = string.Format("{0} {0} {0} {0} {0} {0}", _i) };
					_collection.Add(item);
				}
			}

			var btnAdd = new Button
			{
				Text = "Add item",
				WidthRequest = 100
			};
			btnAdd.Clicked += BtnAddOnClicked;

			var btnBottom = new Button
			{
				Text = "Scroll to end",
				WidthRequest = 100
			};
			btnBottom.Clicked += BtnBottomOnClicked;

			var btnPanel = new StackLayout
			{
				Orientation = StackOrientation.Horizontal,
				HorizontalOptions = LayoutOptions.Center,
				Children = {
					btnAdd,
					btnBottom
				}
			};

			_listView = new ListView
			{
				ItemsSource = _collection,
				BackgroundColor = Color.Transparent,
				VerticalOptions = LayoutOptions.FillAndExpand,
				HasUnevenRows = true,
				ItemTemplate = new DataTemplate(typeof(CellTemplateScrollToUneven))
			};
			_listView.ItemTapped += (sender, e) => ((ListView)sender).SelectedItem = null;

			_listView.AutomationId = "listView";

			Content = new StackLayout
			{
				Children = {
					btnPanel,
					_listView
				}
			};
		}

		protected override void OnAppearing()
		{
			base.OnAppearing();
			_listView.ScrollTo(_collection.Last(), ScrollToPosition.MakeVisible, false);
		}

		void BtnBottomOnClicked(object sender, EventArgs e)
		{
			var item = _collection.Last();
			_listView.ScrollTo(item, ScrollToPosition.End, true);
		}

		void BtnAddOnClicked(object sender, EventArgs eventArgs)
		{
			var str = string.Format("Item {0}", _i++);
			var item = new ListObj { Name = string.Format("{0} {0} {0} {0} {0} {0}", _i) };
			_collection.Add(item);

			_listView.ScrollTo(item, ScrollToPosition.End, true);
		}
	}
}