/// <summary>
/// Acquire a list of page loading tasks for the pages that are intended
/// to be tallied.
/// </summary>
/// <param name="quest">The quest for which the tally is being run.</param>
/// <param name="adapter">The forum adapter that handles the quest's thread.</param>
/// <param name="threadRangeInfo">The range of posts that are wanted in the tally.</param>
/// <param name="token">A cancellation token.</param>
/// <returns>Returns a list of page loading tasks.</returns>
private async Task <List <Task <HtmlDocument?> > > LoadQuestPagesAsync(
IQuest quest, IForumAdapter2 adapter, ThreadRangeInfo threadRangeInfo, IPageProvider pageProvider, CancellationToken token)
{
int firstPageNumber = threadRangeInfo.GetStartPage(quest);
// Get the first page in order to find out how many pages are in the thread
// Keep it as a task.
Task <HtmlDocument?> firstPage = GetFirstPage(firstPageNumber, quest, adapter, pageProvider, token);
// Get the last page number.
int lastPageNumber = await GetLastPageNumber(quest, adapter, threadRangeInfo, firstPage).ConfigureAwait(false);
// Initiate tasks for any remaining pages
IEnumerable <Task <HtmlDocument?> > remainingPages =
GetRemainingPages(firstPageNumber, lastPageNumber, quest, adapter, pageProvider, token);
// Collect all the page load tasks (including the finished first page) to return to caller.
List <Task <HtmlDocument?> > pagesToLoad = new List <Task <HtmlDocument?> >()
{
firstPage
};
pagesToLoad.AddRange(remainingPages);
return(pagesToLoad);
}
/// <summary>
/// Determines the page number range that will be loaded for the quest.
/// Returns a tuple of first page number, last page number, and pages to scan.
/// </summary>
/// <param name="quest">The quest being tallied.</param>
/// <param name="adapter">The forum adapter for the quest.</param>
/// <param name="threadRangeInfo">The thread range info, as provided by the adapter.</param>
/// <param name="token">The cancellation token.</param>
/// <returns>Returns a tuple of the page number info that was determined.</returns>
private async Task <Tuple <int, int, int> > GetPagesToScanAsync(
IQuest quest, IForumAdapter adapter, ThreadRangeInfo threadRangeInfo, CancellationToken token)
{
IPageProvider pageProvider = ViewModels.ViewModelService.MainViewModel.PageProvider;
int firstPageNumber = threadRangeInfo.GetStartPage(quest);
int lastPageNumber = 0;
int pagesToScan = 0;
if (threadRangeInfo.Pages > 0)
{
// If the startInfo obtained the thread pages info, just use that.
lastPageNumber = threadRangeInfo.Pages;
}
else if (quest.ReadToEndOfThread || threadRangeInfo.IsThreadmarkSearchResult)
{
// If we're reading to the end of the thread (end post 0, or based on a threadmark),
// then we need to load the first page to find out how many pages there are in the thread.
// Make sure to bypass the cache, since it may have changed since the last load.
string firstPageUrl = adapter.GetUrlForPage(firstPageNumber, quest.PostsPerPage);
HtmlDocument page = await pageProvider.GetPage(firstPageUrl, $"Page {firstPageNumber}",
CachingMode.BypassCache, ShouldCache.Yes, SuppressNotifications.No, token)
.ConfigureAwait(false);
if (page == null)
{
throw new InvalidOperationException($"Unable to load web page: {firstPageUrl}");
}
lastPageNumber = adapter.GetThreadInfo(page).Pages;
}
else
{
// If we're not reading to the end of the thread, just calculate
// what the last page number will be. Pages to scan will be the
// difference in pages +1.
lastPageNumber = quest.GetPageNumberOf(quest.EndPost);
}
pagesToScan = lastPageNumber - firstPageNumber + 1;
Tuple <int, int, int> result = new Tuple <int, int, int>(firstPageNumber, lastPageNumber, pagesToScan);
return(result);
}
/// <summary>
/// Gets all posts from the provided pages list.
/// </summary>
/// <param name="loadingPages">The pages that are being loaded for the tally.</param>
/// <param name="quest">The quest being tallied.</param>
/// <param name="adapter">The forum adapter that handles the quest's thread.</param>
/// <returns>Returns all posts extracted from all pages provided,
/// and the thread title.</returns>
private async Task <(ThreadInfo threadInfo, List <Post> posts)> GetPostsFromPagesAsync(
List <Task <HtmlDocument?> > loadingPages,
IQuest quest, IForumAdapter2 adapter,
ThreadRangeInfo threadRangeInfo)
{
ThreadInfo? threadInfo = null;
List <Post> postsList = new List <Post>();
int pageNumber = threadRangeInfo.GetStartPage(quest) - 1;
bool incomplete = false;
foreach (var loadingPage in loadingPages)
{
var page = await loadingPage.ConfigureAwait(false);
pageNumber++;
if (page == null)
{
incomplete = true;
continue;
}
if (threadInfo == null)
{
threadInfo = adapter.GetThreadInfo(page);
}
postsList.AddRange(adapter.GetPosts(page, quest, pageNumber));
}
if (incomplete)
{
InvalidOperationException e = new InvalidOperationException("Unable to load all pages.");
e.Data["Application"] = true;
throw e;
}
if (threadInfo == null)
{
threadInfo = new ThreadInfo("Unknown", "Unknown", 0);
}
return(threadInfo, postsList);
}