static void data_SectionStoriesDownloadCompleted(object sender,
DownloadStringCompletedEventArgs downloadCompletedEvent,
ObservableCollection<Story> storyCollection,
Section section,
InsertStoriesAt insertStoriesAt)
{
if (downloadCompletedEvent.Error != null)
{
DownloadFailed(sender, downloadCompletedEvent);
return;
}
SunApiAdapter.handleJsonWithSanitization(
(json) =>
{
var stories = SunApiAdapter.StoriesOfApiResponse(json);
var existingNids = storyCollection.Select(s => s.Nid);
int countStoriesAdded = insertStoriesAt == InsertStoriesAt.Beginning ? 0 : storyCollection.Count;
foreach (Story story in stories.Where(article => !existingNids.Contains(article.Nid)))
{
story.Vid = section.Vid;
// cached stories will already be present
// so we want to add the new stuff to the beginning
// Do we need to sort anyway, or will this always work?
storyCollection.Insert(countStoriesAdded++, story);
}
},
() =>
{
Debug.Assert(false, "Why couldn't the JSON be parsed?");
DownloadFailed(sender, downloadCompletedEvent);
},
downloadCompletedEvent.Result
);
}
internal static bool ShouldAcceptSection(Section section)
{
// Just ignore subsections. Maybe later this app will handle them in some
// interesting way, but for now let's simplify.
return !section.HasParent &&
// In practice, this may be redundant with the previous check.
SunApiAdapter.SECTIONS_WHITELIST.Contains(section.Vid);
}
internal static ObservableCollection<Story> GetStories(Section section, InsertStoriesAt insertStoriesAt)
{
if (!_downloadedSectionStories.Contains(section) && !_currentlyDownloadingSectionStories.Contains(section))
{
_currentlyDownloadingSectionStories.Add(section);
downloadData(SunApiAdapter.StoriesUrlOfSection(section), (sender, e) =>
{
_downloadedSectionStories.Add(section);
_currentlyDownloadingSectionStories.Remove(section);
data_SectionStoriesDownloadCompleted(sender, e, getSectionStories()[section], section, insertStoriesAt);
section.LoadedPage++;
});
}
return getSectionStories()[section];
}
internal static ObservableCollection<Story> GetStories(Section section)
{
return GetStories(section, InsertStoriesAt.Beginning);
}
// Find the first page of story data that contains stories we don't already have,
// then load that page. This basically sucks, because we will request the last page twice
// (once to determine that we haven't loaded it yet, and once again to actually fetch the stories
// and update the models). It's shitty but I don't think it's worth fixing now.
//
// This could possibly be done much more simply on the server side
// Just have a service that returns the page number we need
// However, I'd rather minimize the serverside dependency, since it can break without notice.
internal static void GetMoreStories(Section section)
{
if (sectionsCurrentlyLoadingMoreStories.Contains(section))
{
return;
}
sectionsCurrentlyLoadingMoreStories.Add(section);
// TODO: this seems to fire off two queries for the first page it checks
// TODO: could the stories/nid view be used to save time when loading the 0th page?
// Perhaps it's not necessary to make that big call at all, if we're already fully cached.
string queryUrl = SunApiAdapter.StoriesUrlOfSection(section);
downloadData(queryUrl, (sender, e) =>
{
sectionsCurrentlyLoadingMoreStories.Remove(section);
if (e.Error != null)
{
Debug.WriteLine("Error getting story nids page: " + queryUrl);
return;
}
var stories = SunApiAdapter.StoriesOfApiResponse(e.Result);
var nids = stories.Select(story => story.Nid);
// if all the nids on this page are already in memory
IEnumerable<int> existingNids = _sectionStories[section].Select(story => story.Nid);
if (nids.Intersect(existingNids).Count() == nids.Count())
{
// try the next page
// Note: if we aren't constructing the url such that each successive attempt actually
// is giving us subsequent pages, this recursion will go on indefinitely.
section.LoadedPage++;
GetMoreStories(section);
return;
}
// We want more data for `section`,
// so remove it from the collection of sections
// we've already fully loaded.
_downloadedSectionStories.Remove(section);
GetStories(section, InsertStoriesAt.End);
});
}
public SectionViewModel(Section section)
{
Section = section;
SunData.GetFavorites().CollectionChanged += new NotifyCollectionChangedEventHandler(SectionViewModel_CollectionChanged);
}