public static IObservable <CourseEditorState> Create(CourseEditorActions actions, CourseData courseData,
Ref <ImmutableTransform> cameraTransform)
{
var commands = actions.CreateProp.Select(StoreAction.Create <Unit>("createProp"))
.Merge(actions.CreatePropOnLocation.Select(StoreAction.Create <ImmutableTransform>("createPropOnLocation")))
.Merge(actions.DeleteProp.Select(StoreAction.Create <PropId>("deleteProp")))
.Merge(actions.DeleteSelectedProp.Select(StoreAction.Create <Unit>("deleteSelectedProp")))
.Merge(actions.UpdateProp.Select(StoreAction.Create <Tuple <PropId, ImmutableTransform> >("updateProp")))
.Merge(actions.HighlightProp.Select(StoreAction.Create <Maybe <PropId> >("highlightProp")))
.Merge(actions.SelectProp.Select(StoreAction.Create <Maybe <PropId> >("selectProp")))
.Merge(actions.SelectPropType.Select(StoreAction.Create <PropType>("selectPropType")))
.Merge(actions.ReorderProps.Select(StoreAction.Create <IImmutableList <PropId> >("reorderProps")))
.Merge(actions.Undo.Select(StoreAction.Create <Unit>("undo")))
.Merge(actions.Redo.Select(StoreAction.Create <Unit>("redo")));
var initialHistoricalState = courseData.ToCourseEditorState();
var updatesWithHistory = commands
.Scan(new AppState <HistoricalCourseEditorState>(initialHistoricalState), (currentAppState, command) => {
var currentState = currentAppState.CurrentState;
AppState <HistoricalCourseEditorState> newAppState = currentAppState;
if (command.Id.Equals("createProp"))
{
var propTransform = cameraTransform.Deref().TranslateLocally(new Vector3(0, 0, 30));
newAppState = History.AddNewState(currentAppState, currentState.AddProp(propTransform));
}
else if (command.Id.Equals("createPropOnLocation"))
{
newAppState = History.AddNewState(currentAppState, currentState.AddProp((ImmutableTransform)command.Arguments));
}
else if (command.Id.Equals("updateProp"))
{
var args = (Tuple <PropId, ImmutableTransform>)command.Arguments;
var prop = currentState.Props[args._1];
var isTransformChanged = !prop.Transform.Equals(args._2);
if (isTransformChanged)
{
var updatedProp = prop.UpdateTransform(args._2);
newAppState = History.AddNewState(currentAppState, currentState.UpdateProp(updatedProp));
}
else
{
newAppState = currentAppState;
}
}
else if (command.Id.Equals("deleteProp"))
{
var propId = (PropId)command.Arguments;
if (currentState.PropOrder.Contains(propId))
{
newAppState = History.AddNewState(currentAppState, currentState.DeleteProp(propId));
}
}
else if (command.Id.Equals("deleteSelectedProp"))
{
if (currentState.SelectedProp.IsJust)
{
newAppState = History.AddNewState(currentAppState, currentState.DeleteProp(currentState.SelectedProp.Value));
}
}
else if (command.Id.Equals("selectProp"))
{
var selectedPropId = (Maybe <PropId>)command.Arguments;
if (selectedPropId.IsNothing ||
(selectedPropId.IsJust && currentState.Props.ContainsKey(selectedPropId.Value)))
{
newAppState = History.AddNewState(currentAppState, currentState.SelectProp(selectedPropId));
}
}
else if (command.Id.Equals("selectPropType"))
{
newAppState = History.AddNewState(currentAppState, currentState.SelectPropType((PropType)command.Arguments));
}
else if (command.Id.Equals("reorderProps"))
{
newAppState = History.AddNewState(currentAppState, currentState.UpdatePropOrder((IImmutableList <PropId>)command.Arguments));
}
else if (command.Id.Equals("undo"))
{
newAppState = History.Undo(currentAppState);
}
else if (command.Id.Equals("redo"))
{
newAppState = History.Redo(currentAppState);
}
else
{
newAppState = currentAppState;
}
return(newAppState);
})
.Select(appState => {
return(appState.CurrentState.UpdateUndoRedoAvailability(
!appState.UndoStack.IsEmpty, !appState.RedoStack.IsEmpty));
})
.StartWith(initialHistoricalState)
.Publish();
var initialTransientState = new TransientCourseEditorState(courseData.Name, Maybe.Nothing <PropId>(), TransformTool.Move);
var transientUpdates = actions.HighlightProp.Select(StoreAction.Create <Maybe <PropId> >("highlightProp"))
.Merge(actions.SelectTransformTool.Select(StoreAction.Create <TransformTool>("selectTransformTool")))
.Merge(actions.UpdateName.Select(StoreAction.Create <string>("updateName")))
.Scan(initialTransientState, (state, command) => {
if (command.Id.Equals("highlightProp"))
{
return(state.HighlightProp((Maybe <PropId>)command.Arguments));
}
else if (command.Id.Equals("selectTransformTool"))
{
// TODO Prevent transform tool selection when no prop is selected
return(state.SelectTransformTool((TransformTool)command.Arguments));
}
else if (command.Id.Equals("updateName"))
{
return(state.UpdateName((string)command.Arguments));
}
return(state);
})
.DistinctUntilChanged()
.StartWith(initialTransientState)
.CombineLatest(updatesWithHistory, (transientState, histState) => {
// Check if the highlighted prop still exists
var highlightedProp = transientState.HighlightedProp;
var isHighlightedItemDeleted = highlightedProp.IsJust &&
!histState.Props.ContainsKey(highlightedProp.Value);
if (isHighlightedItemDeleted)
{
return(transientState.HighlightProp(Maybe.Nothing <PropId>()));
}
return(transientState);
});
var updates = updatesWithHistory.CombineLatest(
transientUpdates, (histState, transientState) => new CourseEditorState(histState, transientState))
.DistinctUntilChanged()
.Replay(1);
updates.Connect();
updatesWithHistory.Connect();
return(updates);
}