TestCases.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Reflection;
using Xamarin.Forms.CustomAttributes;
using System.Threading.Tasks;

namespace Xamarin.Forms.Controls
{
	public static class TestCases
	{
		public class TestCaseScreen : TableView
		{
			public static Dictionary<string, Action> PageToAction = new Dictionary<string, Action> ();

			bool _filterBugzilla;
			bool _filterNone;
			bool _filterGitHub;
			string _filter;

			static TextCell MakeIssueCell (string text, string detail, Action tapped)
			{
				PageToAction[text] = tapped;
				if (detail != null)
					PageToAction[detail] = tapped;

				var cell = new TextCell { Text = text, Detail = detail };
				cell.Tapped += (s, e) => tapped();
				return cell;
			}

			Action ActivatePageAndNavigate (IssueAttribute issueAttribute, Type type)
			{
				Action navigationAction = null;

				if (issueAttribute.NavigationBehavior == NavigationBehavior.PushAsync) {
					return async () => {
						var page = ActivatePage (type);
						TrackOnInsights (page);
						await Navigation.PushAsync (page);
					};
				}

				if (issueAttribute.NavigationBehavior == NavigationBehavior.PushModalAsync) {
					return async () => {
						var page = ActivatePage (type);
						TrackOnInsights (page);
						await Navigation.PushModalAsync (page);
					};
				}

				if (issueAttribute.NavigationBehavior == NavigationBehavior.Default) {
					return async () => {
						var page = ActivatePage (type);
						TrackOnInsights (page);
						if (page is ContentPage || page is CarouselPage) {
							
							await Navigation.PushAsync (page);

						}
						else if (page is Shell)
						{
							Application.Current.MainPage = page;
						}
						else {
							await Navigation.PushModalAsync (page);
						}
					}; 
				}

				if (issueAttribute.NavigationBehavior == NavigationBehavior.SetApplicationRoot) {
					return () => {
						var page = ActivatePage (type);
						TrackOnInsights (page);
						Application.Current.MainPage = page;
					};
				}

				return navigationAction;
			}

			static void TrackOnInsights (Page page)
			{
				
			}

			Page ActivatePage (Type type)
			{
				var page = Activator.CreateInstance (type) as Page;
				if (page == null) {
					throw new InvalidCastException ("Issue must be of type Page");
				}
				return page;
			}

			class IssueModel
			{
				public IssueTracker IssueTracker { get; set; }
				public int IssueNumber { get; set; }
				public int IssueTestNumber { get; set; }
				public string Name { get; set; }
				public string Description {get; set; }
				public Action Action { get; set; }

				public bool Matches(string filter)
				{
					if (string.IsNullOrEmpty(filter))
					{
						return true;
					}

					// If the user has typed something which looks like part of a short issue name 
					// (e.g. 'B605' or 'G13'), make sure we match that
					if (string.Compare(Name, 0, filter, 0, filter.Length, StringComparison.OrdinalIgnoreCase) == 0)
					{
						return true;
					}

					if (Description.ToUpper().Contains(filter.ToUpper()))
					{
						return true;
					}

					if (IssueNumber.ToString().Contains(filter))
					{
						return true;
					}

					return false;
				}
			}

			readonly List<IssueModel> _issues;
			TableSection _section;

			void VerifyNoDuplicates()
			{
				var duplicates = new HashSet<string> ();
				_issues.ForEach (im =>
				{
					if (duplicates.Contains (im.Name) && !IsExempt (im.Name)) {
						throw new NotSupportedException ("Please provide unique tracker + issue number combo: " 
							+ im.IssueTracker.ToString () + im.IssueNumber.ToString () + im.IssueTestNumber.ToString());
					}

					duplicates.Add (im.Name);
				});
			}

			public TestCaseScreen()
			{
				AutomationId = "TestCasesIssueList";

				Intent = TableIntent.Settings;

				var assembly = typeof(TestCases).GetTypeInfo().Assembly;

				_issues = 
					(from typeInfo in assembly.DefinedTypes.Select (o => o.AsType ().GetTypeInfo ())
					where typeInfo.GetCustomAttribute<IssueAttribute> () != null
					let attribute = typeInfo.GetCustomAttribute<IssueAttribute> ()
					select new IssueModel {
						IssueTracker = attribute.IssueTracker,
						IssueNumber = attribute.IssueNumber,
						IssueTestNumber = attribute.IssueTestNumber,
						Name = attribute.DisplayName,
						Description = attribute.Description,
						Action = ActivatePageAndNavigate (attribute, typeInfo.AsType ())
					}).ToList();

				VerifyNoDuplicates();

				FilterIssues();
			}

			public void FilterTracker(IssueTracker tracker)
			{
				switch (tracker)
				{
					case IssueTracker.Github:
						_filterGitHub = !_filterGitHub;
						break;
					case IssueTracker.Bugzilla:
						_filterBugzilla = !_filterBugzilla;
						break;
					case IssueTracker.None:
						_filterNone = !_filterNone;
						break;
					default:
						throw new ArgumentOutOfRangeException(nameof(tracker), tracker, null);
				}

				FilterIssues(_filter);
			}

			public async void FilterIssues(string filter = null)
			{
				filter = filter?.Trim();
				_filter = filter;
				
				// Deeeee bounce
				await Task.Delay(10);
				if (_filter != filter)
					return;

				PageToAction.Clear();
				if(String.IsNullOrWhiteSpace(filter) && !Controls.App.PreloadTestCasesIssuesList)
				{
					if (_section != null)
					{
						Root.Remove(_section);
					}
					return;
				}

				var issueCells = Enumerable.Empty<TextCell>();

				if (!_filterBugzilla)
				{
					var bugzillaIssueCells =
						from issueModel in _issues
						where issueModel.IssueTracker == IssueTracker.Bugzilla && issueModel.Matches(filter)
						orderby issueModel.IssueNumber descending
						select MakeIssueCell(issueModel.Name, issueModel.Description, issueModel.Action);

					issueCells = issueCells.Concat(bugzillaIssueCells);
				}

				if (!_filterGitHub)
				{
					var githubIssueCells =
						from issueModel in _issues
						where issueModel.IssueTracker == IssueTracker.Github && issueModel.Matches(filter)
						orderby issueModel.IssueNumber descending
						select MakeIssueCell(issueModel.Name, issueModel.Description, issueModel.Action);

					issueCells = issueCells.Concat(githubIssueCells);
				}

				if (!_filterNone)
				{
					var untrackedIssueCells =
						from issueModel in _issues
						where issueModel.IssueTracker == IssueTracker.None && issueModel.Matches(filter)
						orderby issueModel.IssueNumber descending, issueModel.Description
						select MakeIssueCell(issueModel.Name, issueModel.Description, issueModel.Action);

					issueCells = issueCells.Concat(untrackedIssueCells);
				}
				
				if (_section != null)
				{
					Root.Remove(_section);
				}

				_section = new TableSection("Bug Repro");

				foreach (var issueCell in issueCells) {
					_section.Add (issueCell);
				} 

				Root.Add(_section);
			}

			HashSet<string> _exemptNames = new HashSet<string> { "N0", "G342", "G1305", "G1461", "G1653", "G1700" };

			// Legacy reasons, do not add to this list
			// Going forward, make sure only one Issue attribute exist for a Tracker + Issue number pair
			bool IsExempt(string name) => _exemptNames.Contains(name);
		}

		public static NavigationPage GetTestCases ()
		{
			var rootLayout = new StackLayout ();
			
			var testCasesRoot = new ContentPage {
				Title = "Bug Repro's",
				Content = rootLayout
			};

			var searchBar = new SearchBar() {
				MinimumHeightRequest = 42, // Need this for Android N, see https://bugzilla.xamarin.com/show_bug.cgi?id=43975
				AutomationId = "SearchBarGo"
			};

			var searchButton = new Button () {
				Text = "Search And Go To Issue",
				AutomationId = "SearchButton",
				Command = new Command (() => {
					try {
						TestCaseScreen.PageToAction[searchBar.Text?.Trim()] ();
					} catch (Exception e) {
						System.Diagnostics.Debug.WriteLine (e.Message);
					}
					 
				})
			};

			var leaveTestCasesButton = new Button {
				AutomationId = "GoBackToGalleriesButton",
				Text = "Go Back to Galleries",
				Command = new Command (() => testCasesRoot.Navigation.PopModalAsync ())
			};

			rootLayout.Children.Add (leaveTestCasesButton);
			rootLayout.Children.Add (searchBar);
			rootLayout.Children.Add (searchButton);

			var testCaseScreen = new TestCaseScreen();

			rootLayout.Children.Add(CreateTrackerFilter(testCaseScreen));

			rootLayout.Children.Add(testCaseScreen);

			searchBar.TextChanged += (sender, args) => SearchBarOnTextChanged(sender, args, testCaseScreen);

			var page = new NavigationPage(testCasesRoot);
			switch (Device.RuntimePlatform) {
			case Device.iOS:
			case Device.Android:
			default:
				page.Title = "Test Cases";
				break;
			case Device.UWP:
				page.Title = "Tests";
				break;
			}
			return page;
		}

		static Layout CreateTrackerFilter(TestCaseScreen testCaseScreen)
		{
			var trackerFilterLayout = new StackLayout
			{
				Orientation = StackOrientation.Horizontal,
				HorizontalOptions = LayoutOptions.Fill
			};

			var bzSwitch = new Switch { IsToggled = true };
			trackerFilterLayout.Children.Add(new Label { Text = "Bugzilla" });
			trackerFilterLayout.Children.Add(bzSwitch);
			bzSwitch.Toggled += (sender, args) => testCaseScreen.FilterTracker(IssueTracker.Bugzilla);

			var ghSwitch = new Switch { IsToggled = true };
			trackerFilterLayout.Children.Add(new Label { Text = "GitHub" });
			trackerFilterLayout.Children.Add(ghSwitch);
			ghSwitch.Toggled += (sender, args) => testCaseScreen.FilterTracker(IssueTracker.Github);

			var noneSwitch = new Switch { IsToggled = true };
			trackerFilterLayout.Children.Add(new Label { Text = "None" });
			trackerFilterLayout.Children.Add(noneSwitch);
			noneSwitch.Toggled += (sender, args) => testCaseScreen.FilterTracker(IssueTracker.None);

			return trackerFilterLayout;
		}

		static void SearchBarOnTextChanged(object sender, TextChangedEventArgs textChangedEventArgs, TestCaseScreen cases)
		{
			var filter = textChangedEventArgs.NewTextValue;

			if (String.IsNullOrEmpty(filter))
			{
				return;
			}

			cases.FilterIssues(filter);
		}
	}

}