public static TimeSpan DurationOfPauses(this BlockItem This)
{
var ret = This.PauseList.Aggregate(TimeSpan.Zero,
(acc, x) => acc + (x.EndedAt - x.StartedAt));
This.Log().InfoFormat("Pause duration: {0}", ret);
return(ret);
}
public BlockTimerWindow(BlockItem Model)
{
this.InitializeComponent();
ViewModel = new BlockTimerViewModel(Model);
// N.B: This is a bit of a hack - the completion of this observable
// happens regardless of the value; I tried to use OnError for this
// instead but it actually ended up throwing the exception.
ViewModel.TimerState
.Where(x => x == BlockTimerViewState.ShouldCancel)
.Subscribe(
_ => Dispatcher.BeginInvoke(new Action(() => Close())),
() => Dispatcher.BeginInvoke(new Action(() => Close())));
Observable.Merge(
Observable.FromEvent<SizeChangedEventArgs>(this, "SizeChanged").Select(_ => new Unit()),
ViewModel.WhenAny(x => x.ProgressPercentage, _ => new Unit()))
.Select(_ => progressParentBorder.ActualWidth * ViewModel.ProgressPercentage)
.Subscribe(x => progressBorder.Width = x);
}
public BlockTimerViewModel(BlockItem Model)
{
this.Model = Model;
// Complete the TimerState when the break finishes
// When the TimerState ends (i.e. the dialog is closed), set the
// EndedAt time.
//
// Note that it's really important that whenever you use any
// time-based Rx operator like Timer or Delay, that you use an
// RxApp-based scheduler. If you don't do this (and it's really easy
// to forget!), your unit tests won't work properly!
var timer = Observable.Timer(TimeSpan.Zero, TimeSpan.FromSeconds(1.0), RxApp.DeferredScheduler)
.TakeWhile(_ => !isFinishedWithBreak())
.Finally(() => {
this.Model.EndedAt = RxApp.DeferredScheduler.Now;
_TimerState.OnCompleted();
});
// COOLSTUFF: Defining a Command-based State Machine
//
// Here, we're creating our Commands - let's look a bit further into
// how this actually works. Looking back to our problem definition,
// we can see that many of these buttons' CanExecute() are tied to
// each other (i.e. Hitting Pause means I can't hit it again until I
// hit Start).
//
// Here, we're defining the conditions when each of these buttons
// are allowed to be clicked. In the next block, we convert each of
// the Execute() Observables (each command is an Observable who
// fires whenever it is Executed), into the state that we *should*
// move to once the button is hit. We then subscribe to it, and move
// to the new state.
// Define when we can click each of these commands
Start = new ReactiveCommand(
_TimerState.Select(x => x == BlockTimerViewState.Initialized || x == BlockTimerViewState.Paused));
Pause = new ReactiveCommand(
_TimerState.Select(x => x == BlockTimerViewState.Started || x == BlockTimerViewState.StartedInBreak));
Cancel = new ReactiveCommand(
_TimerState.Select(x => x != BlockTimerViewState.Initialized));
// Move to the next state appropriately when the Start, Pause, and Cancel buttons are clicked
Observable.Merge(
Start.Select(_ => isInBreak() ? BlockTimerViewState.StartedInBreak : BlockTimerViewState.Started),
Pause.Select(_ => BlockTimerViewState.Paused),
Cancel.Select(_ => BlockTimerViewState.ShouldCancel)
).Subscribe(_TimerState.OnNext);
// Set the StartedAt time on the Model when we click the Start
// button. It's also important here to use RxApp's Now instead of
// DateTime.Now, or else our tests will be very confused.
Start.Subscribe(_ => this.Model.StartedAt = this.Model.StartedAt ?? RxApp.DeferredScheduler.Now);
// Create an Observable who yields the current State whenever the
// timer fires - it has the Rate of the Timer but the Value of the
// TimerState.
var timerAsState = timer.CombineLatest(_TimerState, (_, ts) => ts);
// Take the timer and derive a version that only notifies us when
// the TimerState has changed
var distinctTimerAsState = timerAsState.DistinctUntilChanged();
// Invalidate the object when they hit Cancel
Cancel.Subscribe(x => {
Model.StartedAt = null; Model.EndedAt = null;
});
// When someone hits the Start button, then Pause, then the Start
// button, we create a record of how long they pause.
//
// This code is a bit tricky - the key is BufferWithCount; if we
// have a sequence [1,2,3,4,5], BufferWithCount(3,1) will return:
// [[1,2,3], [2,3,4], [3,4,5], ...]: advancing forward one at a
// time, returning the last three items. This is important, since
// we're looking for the pattern, "Start, Pause, Start"
//
// Also, we again see here, whenever we use a Time-based operator
// like Timestamp, that we use an RxApp scheduler. This is a very
// common yet annoying-to-debug mistake!
distinctTimerAsState
.Timestamp(RxApp.DeferredScheduler)
.Buffer(3 /*items in buffer*/, 1 /*at a time*/)
.Where(isStateSequenceAPause)
.Subscribe(x => this.Model.AddRecordOfPause(new PauseRecord() {
StartedAt = x[1].Timestamp,
EndedAt = x[2].Timestamp,
}));
// Move to the Break when the normal timer expires
timerAsState
.Where(ts => isInBreak() && ts == BlockTimerViewState.Started)
.Subscribe(_ => _TimerState.OnNext(BlockTimerViewState.StartedInBreak));
/* COOLSTUFF: Superpowered Value Converters
*
* Here we're binding the application state Observables we've
* created above into real WPF properties that we can bind to (since
* WPF can't bind directly to Observables). However, unlike
* IValueConverters which are very simple, we can do much more
* interesting things here like filtering.
*/
//
// Set up our output properties
//
// When the state is Started, move the timer display forward
_TimeRemaining = timerAsState
.Where(isTimerCurrentlyRunning)
.Select(_ => currentTimeRemaining()).StartWith(currentTimeRemaining())
.ToProperty(this, x => x.TimeRemaining);
// Take the TimeSpan and convert it to the Caption (basically an
// IValueConverter).
//
// The WhenAny() operator allows us to easily bind one or more
// properties to another property, while still pulling in the
// Initial value (whereas ObservableForProperty would only update
// the property once it had changed at least once)
_TimeRemainingCaption = this
.WhenAny(x => x.TimeRemaining, x => String.Format("{0:mm}:{0:ss}", x.Value))
.ToProperty(this, x => x.TimeRemainingCaption);
_ProgressPercentage = timerAsState
.Where(isTimerCurrentlyRunning)
.Select(_ => progressBarPercentage())
.ToProperty(this, x => x.ProgressPercentage);
// Map states to background colors
var colorLookupTable = new Dictionary<BlockTimerViewState, Brush> {
{BlockTimerViewState.Initialized, null},
{BlockTimerViewState.Paused, new SolidColorBrush(Color.FromRgb(0xff, 0xff, 0x66))},
{BlockTimerViewState.Started, new SolidColorBrush(Color.FromRgb(0x99, 0xff, 0x66))},
{BlockTimerViewState.StartedInBreak, new SolidColorBrush(Color.FromRgb(0x99, 0xff, 0xff))},
{BlockTimerViewState.ShouldCancel, null},
};
// Every time the state changes on a Timer beat, update the
// background color.
_ProgressBackgroundBrush = distinctTimerAsState.Select(x => colorLookupTable[x])
.ToProperty(this, x => x.ProgressBackgroundBrush);
//
// Everything's set up! Kick off everything by moving to the
// Initialized state
//
_TimerState.OnNext(BlockTimerViewState.Initialized);
}
public BlockItemTileViewModel(BlockItem model)
{
Model = model;
}