public ProjectsPageViewModel(
INavigationService navigationService,
IProjectDataStore projectDataStore,
IAnalyticService analyticService) : base(navigationService)
{
Title = "Projects";
this.WhenActivated((CompositeDisposable _) =>
{
// track every time this screen is activated
analyticService.TrackScreen("my-projects");
});
ViewProjectDetails = ReactiveCommand.CreateFromTask <Project, Unit>(async project =>
{
analyticService.TrackTapEvent("view-project");
await NavigationService.NavigateAsync(
nameof(ProjectDetailsPage),
new NavigationParameters
{
{ "project", project }
}).ConfigureAwait(false);
return(Unit.Default);
});
AddProject = ReactiveCommand.CreateFromTask(async() =>
{
analyticService.TrackTapEvent("new-project");
await NavigationService.NavigateAsync($"NavigationPage/{nameof(EditProjectPage)}", useModalNavigation: true).ConfigureAwait(false);
});
Filter = ReactiveCommand.CreateFromTask(async() =>
{
// TODO: Finish this
await NavigationService.NavigateAsync(
$"NavigationPage/{nameof(ProjectFilterPage)}",
new NavigationParameters
{
{ "filter", _filter }
},
useModalNavigation: true).ConfigureAwait(false);
});
// set up the command used to load projects
LoadProjects = ReactiveCommand.CreateFromTask(_ =>
{
this.Log().Debug($"Loading projects on thread: {Thread.CurrentThread.ManagedThreadId}, IsBackground = {Thread.CurrentThread.IsBackground}");
AssertRunningOnBackgroundThread();
return(projectDataStore.LoadOldProjects(_oldestProject, ItemsPerPage));
});
// set up the command used to refresh projects
RefreshProjects = ReactiveCommand.CreateFromTask(_ =>
{
// TODO: Should track this with analytics?
this.Log().Debug($"Refreshing projects on thread: {Thread.CurrentThread.ManagedThreadId}, IsBackground = {Thread.CurrentThread.IsBackground}");
AssertRunningOnBackgroundThread();
return(_newestProject != null ?
projectDataStore.LoadNewProjects(_newestProject, ItemsPerPage) :
projectDataStore.LoadNewProjects(ItemsPerPage));
});
LoadProjects
.Merge(RefreshProjects)
.SubscribeSafe(projects =>
{
if (projects.Any())
{
// NOTE: This probably isn't necessary...
projects = projects.ExceptBy(Projects, p => p.ProjectId);
// get the oldest and newest projects from the new data set. Age is simply
// determined by the date the project was created
var oldProject = projects.MinBy(p => p.CreateDate).First();
var newProject = projects.MaxBy(p => p.CreateDate).First();
if (_oldestProject == null && _newestProject == null)
{
_oldestProject = oldProject;
_newestProject = newProject;
// first projects being added. Add them to the list
Projects.AddRange(projects);
}
else if (_oldestProject?.CreateDate > oldProject.CreateDate)
{
_oldestProject = oldProject;
// if the projects are older, add them to the end of the list
Projects.AddRange(projects);
}
else if (_newestProject?.CreateDate < newProject.CreateDate)
{
_newestProject = newProject;
// if the projects are newer, insert them at the beginning of the list
Projects.InsertRange(0, projects);
}
}
});
// when either of the commands are executing, update the busy state
LoadProjects.IsExecuting
.CombineLatest(RefreshProjects.IsExecuting, (isLoadExecuting, isRefreshExecuting) => isLoadExecuting || isRefreshExecuting)
.DistinctUntilChanged()
.StartWith(false)
.ToProperty(this, x => x.IsBusy, out _isBusy, scheduler: RxApp.MainThreadScheduler);
// When an exception is thrown for either command, log the error and let the user handle
// the exception
LoadProjects.ThrownExceptions
.Merge(RefreshProjects.ThrownExceptions)
.SelectMany(exception =>
{
this.Log().ErrorException("Error loading or refreshing data", exception);
return(SharedInteractions.Error.Handle(exception));
})
.Subscribe();
}
