using GalaSoft.MvvmLight;
using GalaSoft.MvvmLight.CommandWpf;
using Microsoft.Win32;
using Microsoft.WindowsAPICodePack.Taskbar;
using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.ComponentModel;
using System.Data;
using System.Diagnostics;
using System.Linq;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Threading;
using System.Threading.Tasks;
using System.Windows;
using System.Windows.Input;
using System.Windows.Threading;
using Xunit.Runner.Wpf.Persistence;
using Xunit.Runners;

namespace Xunit.Runner.Wpf.ViewModel
{
  public class MainViewModel : ViewModelBase
  {

    //public IAssemblyInjector Injector { get; set; }
    public List<string> StartupAssemblies { get; set; }

    #region commands
    public ICommand ExitCommand { get; }
    public ICommand WindowLoadedCommand { get; }
    public RelayCommand<CancelEventArgs> WindowClosingCommand { get; }
    public RelayCommand RunAllCommand { get; }
    public RelayCommand RunSelectedCommand { get; }
    public RelayCommand CancelCommand { get; }
    public ICommand TraitCheckedChangedCommand { get; }
    public ICommand TraitSelectionChangedCommand { get; }
    public ICommand TraitsClearCommand { get; }
    public ICommand AssemblyReloadCommand { get; }
    public ICommand AssemblyReloadAllCommand { get; }
    public ICommand AssemblyRemoveCommand { get; }
    public ICommand AssemblyRemoveAllCommand { get; }
    public ICommand AutoReloadAssembliesCommand { get; }

    public CommandBindingCollection CommandBindings { get; }

    #endregion

    private readonly Settings settings;


    private readonly ITestAssemblyWatcher assemblyWatcher;
    private readonly HashSet<string> allTestCaseUniqueIDs = new HashSet<string>();
    private readonly ObservableCollection<TestCaseViewModel> allTestCases = new ObservableCollection<TestCaseViewModel>();
    private readonly TraitCollectionView traitCollectionView = new TraitCollectionView();
    private readonly HashSet<string> runningTestSet = new HashSet<string>();

    private CancellationTokenSource filterCancellationTokenSource = new CancellationTokenSource();

    private CancellationTokenSource cancellationTokenSource;
    private bool isBusy;
    private SearchQuery searchQuery = new SearchQuery();
    private bool autoReloadAssemblies;

    public ObservableCollection<TestAssemblyViewModel> Assemblies { get; } = new ObservableCollection<TestAssemblyViewModel>();
    public FilteredCollectionView<TestCaseViewModel, SearchQuery> FilteredTestCases { get; }
    public ObservableCollection<TraitViewModel> Traits => this.traitCollectionView.Collection;
    public bool AutoReloadAssemblies
    {
      get => autoReloadAssemblies;
      set
      {
        var oldVal = autoReloadAssemblies;
        autoReloadAssemblies = value;
        RaisePropertyChanged(nameof(AutoReloadAssemblies), oldVal, autoReloadAssemblies);
      }
    }

    public ObservableCollection<RecentAssemblyViewModel> RecentAssemblies { get; } = new ObservableCollection<RecentAssemblyViewModel>();

    SynchronizationContext uiContext;
    /// <summary>
    /// Initializes a new instance of the MainViewModel class.
    /// </summary>
    public MainViewModel()
    {
      this.settings = Settings.Load();

      if (IsInDesignMode)
      {
        this.Assemblies.Add(new TestAssemblyViewModel(new AssemblyAndConfigFile(@"C:\Code\xunit.runner.wpf\SampleTestAssembly\bin\Debug\SampleTestAssembly.dll", null)));
      }

      //Commands
      CommandBindings = CreateCommandBindings();
      this.ExitCommand = new RelayCommand(OnExecuteExit);
      this.WindowLoadedCommand = new RelayCommand(OnExecuteWindowLoaded);
      this.WindowClosingCommand = new RelayCommand<CancelEventArgs>(OnExecuteWindowClosing);
      this.RunAllCommand = new RelayCommand(OnExecuteRunAll, CanExecuteRunAll);
      this.RunSelectedCommand = new RelayCommand(OnExecuteRunSelected, CanExecuteRunSelected);
      this.CancelCommand = new RelayCommand(OnExecuteCancel, CanExecuteCancel);
      this.TraitCheckedChangedCommand = new RelayCommand<TraitViewModel>(OnExecuteTraitCheckedChanged);
      this.TraitsClearCommand = new RelayCommand(OnExecuteTraitsClear);
      this.AssemblyReloadCommand = new RelayCommand(OnExecuteAssemblyReload, CanExecuteAssemblyReload);
      this.AssemblyReloadAllCommand = new RelayCommand(OnExecuteAssemblyReloadAll);
      this.AssemblyRemoveCommand = new RelayCommand(OnExecuteAssemblyRemove, CanExecuteAssemblyRemove);
      this.AssemblyRemoveAllCommand = new RelayCommand(OnExecuteAssemblyRemoveAll);
      this.AutoReloadAssembliesCommand = new RelayCommand(OnToggleAutoReloadAssemblies);

      this.FilteredTestCases = new FilteredCollectionView<TestCaseViewModel, SearchQuery>(
                allTestCases, TestCaseMatches, searchQuery, TestComparer.Instance);

      this.FilteredTestCases.CollectionChanged += TestCases_CollectionChanged;

      this.assemblyWatcher = new Impl.TestAssemblyWatcher(Dispatcher.CurrentDispatcher);
      this.TestCasesCaption = "Test Cases (0)";


      RebuildRecentAssembliesMenu();
      AutoReloadAssemblies = this.settings.GetAutoReloadAssemblies();
      UpdateAutoReloadStatus();

      uiContext = SynchronizationContext.Current;
    }



    private Task Discover(string assemblyPath)
    {
      var tcs = new TaskCompletionSource<string>();
      try
      {
        using (var runner = AssemblyRunner2.WithoutAppDomain(assemblyPath, tcs, cancellationTokenSource.Token))
        {
          runner.OnDiscoveryComplete = OnTestsDiscovered;
          runner.Discover();
        }
      }
      catch (Exception e)
      {
      }
      return tcs.Task;
    }



    private List<Task> RunTests(IEnumerable<TestCaseViewModel> testsToRun)
    {
      Debug.Assert(this.isBusy);
      Debug.Assert(this.cancellationTokenSource != null);

      TestsCompleted = 0;
      TestsRunning = 0;
      TestsPassed = 0;
      TestsFailed = 0;
      TestsSkipped = 0;
      CurrentRunState = TestState.NotRun;

      foreach (var test in testsToRun)
      {
        test.State = TestState.NotRun;
        test.ExecutionTime = "";
      }
        


      var taskList = new List<Task>();
      var assemblies = testsToRun.GroupBy(x => x.AssemblyFileName).ToDictionary(x => x.Key, y => y.ToList());

      foreach (var key in assemblies.Keys)
      {
        var path = assemblies[key].FirstOrDefault().AssemblyPath;
        taskList.Add(Run(path, key, assemblies[key]));
      }
      return taskList;

    }

    private Task Run(string assemblyPath, string assemblyName, IEnumerable<TestCaseViewModel> testsToRun)
    {

      var tcs = new TaskCompletionSource<string>();

      try
      {
          ////inject stuff into assembly
          //if (Injector != null)
          //{
          //  Assembly ass = AppDomain.CurrentDomain.GetAssemblies().FirstOrDefault(x => x.FullName == assemblyName);
          //  if (ass != null)
          //    Injector.Inject(ass);
          //}

          using (var runner = AssemblyRunner2.WithoutAppDomain(assemblyPath, tcs, cancellationTokenSource.Token))
          {
            runner.OnExecutionComplete = OnExecutionComplete;
            runner.OnTestStarting = OnTestStarting;
            runner.OnTestFailed = OnTestFailed;
            runner.OnTestSkipped = OnTestSkipped;
            runner.OnTestPassed = OnTestPassed;
            runner.OnTestFinished = OnTestFinished;

            runner.Run(testsToRun.Select(x => x.TestCase).ToList(), maxParallelThreads:1);
          }
        
      }
      catch (Exception e)
      {
      }

      return tcs.Task;
    }

    #region commands
    private bool CanExecuteCancel()
    {
      return this.cancellationTokenSource != null && !this.cancellationTokenSource.IsCancellationRequested;
    }

    private void OnExecuteCancel()
    {
      Debug.Assert(CanExecuteCancel());
      this.cancellationTokenSource.Cancel();
    }


    private async void OnExecuteOpen(object sender, ExecutedRoutedEventArgs e)
    {
      var fileDialog = new OpenFileDialog
      {
        Filter = "Unit Test Assemblies|*.dll",
        Multiselect = true
      };

      if (fileDialog.ShowDialog() != true)
      {
        return;
      }

      var assemblies = fileDialog.FileNames.Select(x => new AssemblyAndConfigFile(x, configFileName: null));
      await AddAssemblies(assemblies);
    }

    private static void OnExecuteExit()
    {
      //Application.Current.Shutdown();
    }

    private async void OnExecuteWindowLoaded()
    {
      if (StartupAssemblies == null)
        return;
      var assemblies = StartupAssemblies.Select(x => new AssemblyAndConfigFile(x, configFileName: null));
      await AddAssemblies(assemblies);
      //await AddAssemblies(ParseCommandLine(Environment.GetCommandLineArgs().Skip(1)));
    }

    private void OnExecuteWindowClosing(CancelEventArgs e)
    {
      this.settings.Save();
    }

    private bool CanExecuteRunAll()
    => !IsBusy && FilteredTestCases.Any();

    private bool CanExecuteRunSelected()
        => !IsBusy && SelectedTestCase != null;
    private async void OnExecuteRunAll()
    {
      UpdateTestCaseInfo(useSelected: false);

      await ExecuteTestSessionOperation(RunFilteredTests);
    }
    private async void OnExecuteRunSelected()
    {
      Debug.Assert(this.SelectedTestCase != null);
      UpdateTestCaseInfo(useSelected: true);

      await ExecuteTestSessionOperation(RunSelectedTests);

    }
    private List<Task> RunFilteredTests()
    {
      return RunTests(FilteredTestCases.ToImmutableList());
    }
    private List<Task> RunSelectedTests()
    {
      return RunTests(ImmutableList.CreateRange(FilteredTestCases.Where(x => x.IsSelected).ToList()));
    }

    private void OnTestsDiscovered(TestDiscoveryInfo discoveryInfo)
    {
      uiContext.Send(x =>
      {
        var traitWorkerList = new List<TraitViewModel>();

        foreach (var testCase in discoveryInfo.Cases)
        {
          traitWorkerList.Clear();

          // Get or create traits.
          if (testCase.Traits.Count > 0)
          {
            foreach (var kvp in testCase.Traits)
            {
              var name = kvp.Key;
              var values = kvp.Value;

              var parentTraitViewModel = traitCollectionView.GetOrAdd(name);

              foreach (var value in values)
              {
                var traitViewModel = parentTraitViewModel.GetOrAdd(value);
                traitWorkerList.Add(traitViewModel);
              }
            }
          }

          var vm = new TestCaseViewModel(
            testCase.DisplayName,
            testCase.UniqueID,
            testCase.SkipReason,
            testCase.TestMethod.TestClass.TestCollection.TestAssembly.Assembly.Name,
            testCase.TestMethod.TestClass.TestCollection.TestAssembly.Assembly.AssemblyPath,
          testCase,
            traitWorkerList);
          allTestCases.Add(vm);
        }
      }, null);

    }

    private void OnExecutionComplete(ExecutionCompleteInfo info)
    {
      //Console.WriteLine($"Finished: {info.TotalTests} tests in {Math.Round(info.ExecutionTime, 3)}s ({info.TestsFailed} failed, {info.TestsSkipped} skipped)");
      //uiContext.Send(x =>
      //{
      //  IsBusy = false;
      //}, null);
    }
    private void OnTestFinished(TestFinishedInfo info)
    {
      TestsCompleted++;
      var test = FilteredTestCases.FirstOrDefault(x => x.DisplayName == info.TestDisplayName);
      if (test != null)
      {
        test.ExecutionTime = Math.Round(info.ExecutionTime, 2) + "s";
      }
    }
    private void OnTestPassed(TestPassedInfo info)
    {
      TestsPassed++;
      var test = FilteredTestCases.FirstOrDefault(x => x.DisplayName == info.TestDisplayName);
      if (test != null)
      {
        test.Output = info.Output;
        test.State = TestState.Passed;
        CurrentRunState = test.State;
      }
    }

    private void OnTestFailed(TestFailedInfo info)
    {
      TestsFailed++;
      var test = FilteredTestCases.FirstOrDefault(x => x.DisplayName == info.TestDisplayName);
      if (test != null)
      {
        test.State = TestState.Failed;
        CurrentRunState = test.State;
        test.Output = info.ExceptionMessage;
        if (info.ExceptionStackTrace != null)
        {
          test.Output += "\n\n";
          test.Output += info.ExceptionStackTrace;
        }
      }
    }

    private void OnTestSkipped(TestSkippedInfo info)
    {
      TestsSkipped++;
      var test = FilteredTestCases.FirstOrDefault(x => x.DisplayName == info.TestDisplayName);
      if (test != null)
      {
        test.State = TestState.Skipped;
        CurrentRunState = test.State;
        test.Output = info.SkipReason;
      }
    }

    private void OnTestStarting(TestStartingInfo info)
    {
      var test = FilteredTestCases.FirstOrDefault(x => x.DisplayName == info.TestDisplayName);
      if (test != null)
      {
        test.State = TestState.Running;
      }
    }

    private void OnExecuteTraitCheckedChanged(TraitViewModel trait)
    {
      this.searchQuery.TraitSet = this.traitCollectionView.GetCheckedTraits();
      FilterAfterDelay();
    }

    private void OnExecuteTraitsClear()
    {
      foreach (var cur in this.traitCollectionView.Collection)
      {
        cur.IsChecked = false;
      }
    }

    private async void OnExecuteRecentAssembly(RecentAssemblyViewModel recentAssembly)
    {
      var assemblyAndConfig = new AssemblyAndConfigFile(recentAssembly.FilePath, configFileName: null);

      await this.AddAssemblies(new[] { assemblyAndConfig });
    }

    private bool CanExecuteAssemblyReload()
    {
      return SelectedAssemblies.Count > 0;
    }

    private async void OnExecuteAssemblyReload()
    {
      await ReloadAssemblies(SelectedAssemblies);
    }

    private async void OnExecuteAssemblyReloadAll()
    {
      await ReloadAssemblies(Assemblies);
    }

    private bool CanExecuteAssemblyRemove()
    {
      return SelectedAssemblies.Count > 0;
    }

    private void OnExecuteAssemblyRemove()
    {
      RemoveAssemblies(SelectedAssemblies);
    }

    private void OnExecuteAssemblyRemoveAll()
    {
      RemoveAssemblies(Assemblies.ToArray());
    }
    private void OnToggleAutoReloadAssemblies()
    {
      ToggleReloadAssemblies();
    }



    #endregion

    public List<TestAssemblyViewModel> SelectedAssemblies
    {
      get { return Assemblies.Where(x => x.IsSelected).ToList(); }
    }

    private void ToggleReloadAssemblies()
    {
      this.settings.ToggleAutoReloadAssemblies();
      AutoReloadAssemblies = this.settings.GetAutoReloadAssemblies();
      UpdateAutoReloadStatus();
    }

    private void UpdateAutoReloadStatus()
    {
      if (AutoReloadAssemblies)
      {
        assemblyWatcher.EnableWatch(ReloadAssemblies);
      }
      else
      {
        assemblyWatcher.DisableWatch();
      }
    }

    private void RebuildRecentAssembliesMenu()
    {
      this.RecentAssemblies.Clear();

      foreach (var recentAssembly in this.settings.GetRecentAssemblies())
      {
        var viewModel = new RecentAssemblyViewModel(recentAssembly, new RelayCommand<RecentAssemblyViewModel>(this.OnExecuteRecentAssembly));
        this.RecentAssemblies.Add(viewModel);
      }
    }

    private void RemoveAssemblyTestCases(string assemblyPath)
    {
      var i = 0;
      while (i < this.allTestCases.Count)
      {
        if (string.Compare(this.allTestCases[i].AssemblyFileName, assemblyPath, StringComparison.OrdinalIgnoreCase) == 0)
        {
          this.allTestCaseUniqueIDs.Remove(this.allTestCases[i].UniqueID);
          this.allTestCases.RemoveAt(i);
        }
        else
        {
          i++;
        }
      }
    }

    private CommandBindingCollection CreateCommandBindings()
    {
      var openBinding = new CommandBinding(ApplicationCommands.Open, OnExecuteOpen);
      CommandManager.RegisterClassCommandBinding(typeof(MainViewModel), openBinding);

      return new CommandBindingCollection
            {
                openBinding,
            };
    }

    private IEnumerable<AssemblyAndConfigFile> ParseCommandLine(IEnumerable<string> enumerable)
    {
      while (enumerable.Any())
      {
        var assemblyFileName = enumerable.First();
        enumerable = enumerable.Skip(1);

        var configFileName = (string)null;
        if (IsConfigFile(enumerable.FirstOrDefault()))
        {
          configFileName = enumerable.First();
          enumerable = enumerable.Skip(1);
        }

        yield return new AssemblyAndConfigFile(assemblyFileName, configFileName);
      }
    }

    private bool IsConfigFile(string fileName)
    => (fileName?.EndsWith(".config", StringComparison.OrdinalIgnoreCase) ?? false) ||
       (fileName?.EndsWith(".json", StringComparison.OrdinalIgnoreCase) ?? false);



    public async Task AddAssemblies(IEnumerable<AssemblyAndConfigFile> assemblies)
    {
      if (!assemblies.Any())
      {
        return;
      }

      var newAssemblyViewModels = new List<TestAssemblyViewModel>();

      try
      {
        await this.ExecuteTestSessionOperation(() =>
        {
          var taskList = new List<Task>();


          foreach (var assembly in assemblies)
          {

            taskList.Add(Discover(assembly.AssemblyFileName));

            var assemblyViewModel = new TestAssemblyViewModel(assembly);

            newAssemblyViewModels.Add(assemblyViewModel);
            this.Assemblies.Add(assemblyViewModel);
            this.settings.AddRecentAssembly(assembly.AssemblyFileName);

            assemblyViewModel.State = AssemblyState.Loading;
          }

          return taskList;
        });
      }
      finally
      {
        foreach (var assemblyViewModel in newAssemblyViewModels)
        {
          assemblyViewModel.State = AssemblyState.Ready;
          assemblyWatcher.AddAssembly(assemblyViewModel.FileName);
        }

        RebuildRecentAssembliesMenu();
      }
    }

    private async Task ExecuteTestSessionOperation(Func<List<Task>> operation)
    {
      Debug.Assert(!this.IsBusy);
      Debug.Assert(this.cancellationTokenSource == null);

      try
      {
        this.IsBusy = true;
        this.cancellationTokenSource = new CancellationTokenSource();

        var taskList = operation();
        await Task.WhenAll(taskList);
      }
      catch (Exception ex)
      {
        this.cancellationTokenSource?.Cancel();
        //MessageBox.Show(ex.ToString());
      }
      finally
      {
        this.cancellationTokenSource = null;
        this.IsBusy = false;
      }
    }

    public bool ReloadAssemblies(IEnumerable<string> assemblies)
    {
      if (IsBusy)
      {
        return false;
      }

      var testAssemblies = Assemblies.Where(assembly => assemblies.Contains(assembly.FileName));
      uiContext.Send(x => { ReloadAssemblies(testAssemblies); }, null);

      return true;
    }

    private async Task ReloadAssemblies(IEnumerable<TestAssemblyViewModel> assemblies)
    {
      try
      {
        await ExecuteTestSessionOperation(() =>
        {
          var taskList = new List<Task>();
          foreach (var assemblyViewModel in assemblies)
          {
            assemblyViewModel.State = AssemblyState.Loading;

            var assemblyFileName = assemblyViewModel.FileName;
            RemoveAssemblyTestCases(assemblyFileName);

            taskList.Add(Discover(assemblyFileName));
          }

          return taskList;
        });

        RebuildTraits();
      }
      finally
      {
        foreach (var assemblyViewModel in assemblies)
        {
          assemblyViewModel.State = AssemblyState.Ready;
        }
      }
    }

    private void RemoveAssemblies(IEnumerable<TestAssemblyViewModel> assemblies)
    {
      foreach (var assembly in assemblies.ToList())
      {
        assemblyWatcher.RemoveAssembly(assembly.FileName);
        RemoveAssemblyTestCases(assembly.FileName);
        Assemblies.Remove(assembly);
      }

      RebuildTraits();
    }

    /// <summary>
    /// Reloading an assembly could have changed the traits.  There is no easy way
    /// to selectively edit this list (traits can cross assembly boundaries).  Just
    /// do a full reload instead.
    /// way to
    /// </summary>
    private void RebuildTraits()
    {
      this.traitCollectionView.Collection.Clear();
      foreach (var testCase in this.allTestCases)
      {
        this.traitCollectionView.AddRange(testCase.Traits);
      }
    }


    private void TestCases_CollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
    {
      UpdateTestCaseInfo(useSelected: false);
      ClearSelectionFlags();
    }

    private void ClearSelectionFlags()
    {
      foreach (var test in this.allTestCases)
      {
        test.IsSelected = false;
      }
    }

    void UpdateTestCaseInfo(bool useSelected)
    {
      var count = FilteredTestCases.Count;
      if (useSelected)
      {
        var selected = FilteredTestCases.Count(tc => tc.IsSelected);
        if (selected > 0)
        {
          count = selected;
        }
      }

      //TestCasesCaption = $"Test Cases ({count:#,0})";
      MaximumProgress = count;
    }

    private void UpdateProgress()
    {
      if (TaskbarManager.IsPlatformSupported)
      {
        var tb = TaskbarManager.Instance;
        tb.SetProgressState(GetTaskBarState());
        tb.SetProgressValue(this.TestsCompleted, this.MaximumProgress);
      }
    }

    private TaskbarProgressBarState GetTaskBarState()
    {
      switch (this.CurrentRunState)
      {
        case TestState.Failed:
          return TaskbarProgressBarState.Error;
        case TestState.Skipped:
          return TaskbarProgressBarState.Paused;
        default:
          return TaskbarProgressBarState.Normal;
      }
    }

    private void FilterAfterDelay()
    {
      filterCancellationTokenSource.Cancel();
      filterCancellationTokenSource = new CancellationTokenSource();
      var token = filterCancellationTokenSource.Token;

      Task
          .Delay(TimeSpan.FromMilliseconds(200), token)
          .ContinueWith(
              x =>
              {
                FilteredTestCases.FilterArgument = searchQuery;
              },
              token,
              TaskContinuationOptions.None,
              TaskScheduler.FromCurrentSynchronizationContext());
    }

    #region bindings

    public string FilterString
    {
      get { return searchQuery.SearchString; }
      set
      {
        if (Set(ref searchQuery.SearchString, value))
        {
          FilterAfterDelay();
        }
      }
    }

    private int testsCompleted = 0;
    public int TestsCompleted
    {
      get { return testsCompleted; }

      set
      {
        Set(ref testsCompleted, value);
        UpdateProgress();
      }
    }

    private TestCaseViewModel selectedTest;
    public TestCaseViewModel SelectedTestCase
    {
      get { return selectedTest; }

      set
      {
        Set(ref selectedTest, value);
      }
    }

    private string testCasesCaption;
    public string TestCasesCaption
    {
      get { return testCasesCaption; }
      private set { Set(ref testCasesCaption, value); }
    }

    private bool IsBusy
    {
      get { return isBusy; }
      set
      {
        isBusy = value;
        RunAllCommand.RaiseCanExecuteChanged();
        RunSelectedCommand.RaiseCanExecuteChanged();
        CancelCommand.RaiseCanExecuteChanged();
      }
    }


    private int testsRunning = 0;
    public int TestsRunning
    {
      get { return testsRunning; }
      set { Set(ref testsRunning, value); }
    }

    private int testsPassed = 0;
    public int TestsPassed
    {
      get { return testsPassed; }
      set { Set(ref testsPassed, value); }
    }

    private int testsFailed = 0;
    public int TestsFailed
    {
      get { return testsFailed; }
      set { Set(ref testsFailed, value); }
    }

    private int testsSkipped = 0;
    public int TestsSkipped
    {
      get { return testsSkipped; }
      set { Set(ref testsSkipped, value); }
    }

    private int maximumProgress = int.MaxValue;
    public int MaximumProgress
    {
      get { return maximumProgress; }

      set
      {
        Set(ref maximumProgress, value);
        UpdateProgress();
      }
    }

    private TestState currentRunState;
    public TestState CurrentRunState
    {
      get { return currentRunState; }

      set
      {
        Set(ref currentRunState, value);
        UpdateProgress();
      }
    }

    public bool FilterRunningTests
    {
      get { return searchQuery.FilterRunningTests; }
      set
      {
        if (Set(ref searchQuery.FilterRunningTests, value))
        {
          FilterAfterDelay();
        }
      }
    }

    public bool FilterPassedTests
    {
      get { return searchQuery.FilterPassedTests; }
      set
      {
        if (Set(ref searchQuery.FilterPassedTests, value))
        {
          FilterAfterDelay();
        }
      }
    }

    public bool FilterFailedTests
    {
      get { return searchQuery.FilterFailedTests; }
      set
      {
        if (Set(ref searchQuery.FilterFailedTests, value))
        {
          FilterAfterDelay();
        }
      }
    }

    public bool FilterSkippedTests
    {
      get { return searchQuery.FilterSkippedTests; }
      set
      {
        if (Set(ref searchQuery.FilterSkippedTests, value))
        {
          FilterAfterDelay();
        }
      }
    }

    #endregion


    private static bool TestCaseMatches(TestCaseViewModel testCase, SearchQuery searchQuery)
    {
      if (testCase.DisplayName.IndexOf(searchQuery.SearchString, StringComparison.CurrentCultureIgnoreCase) < 0)
      {
        return false;
      }

      if (searchQuery.TraitSet.Count > 0)
      {
        var anyMatch = false;
        foreach (var cur in testCase.Traits)
        {
          if (searchQuery.TraitSet.Contains(cur))
          {
            anyMatch = true;
            break;
          }
        }

        if (!anyMatch)
        {
          return false;
        }
      }

      var noFilter = !(searchQuery.FilterRunningTests | searchQuery.FilterFailedTests | searchQuery.FilterPassedTests | searchQuery.FilterSkippedTests);

      switch (testCase.State)
      {
        case TestState.Running:
          return noFilter || searchQuery.FilterRunningTests;

        case TestState.Passed:
          return noFilter || searchQuery.FilterPassedTests;

        case TestState.Skipped:
          return noFilter || searchQuery.FilterSkippedTests;

        case TestState.Failed:
          return noFilter || searchQuery.FilterFailedTests;

        case TestState.NotRun:
          return noFilter;

        default:
          Debug.Assert(false, "What state is this test case in?");
          return true;
      }
    }
  }

  public class TestComparer : IComparer<TestCaseViewModel>
  {
    public static TestComparer Instance { get; } = new TestComparer();

    public int Compare(TestCaseViewModel x, TestCaseViewModel y)
    {
      int result = StringComparer.OrdinalIgnoreCase.Compare(x.DisplayName, y.DisplayName);
      if (result != 0)
        return result;

      result = StringComparer.Ordinal.Compare(x.DisplayName, y.DisplayName);
      if (result != 0)
        return result;

      return StringComparer.Ordinal.Compare(x.UniqueID, y.UniqueID);
    }

    private TestComparer() { }
  }
}