/// <exception cref="DataSourceException">Exception while fetching data.</exception>
/// <exception cref="ConnectionException">No data available (disconnected from data source and not in cache).</exception>
public async Task <ICollection <Category> > GetAllCategoriesAsync()
{
var cachedCategories = await GetCachedCategoriesAsync().ConfigureAwait(false);
if (cachedCategories.Any())
{
UpdateCategoryListCacheAsync();
return(cachedCategories);
}
if (!Current.IsConnected)
{
throw new ConnectionException();
}
ICollection <Category> categories;
try
{
categories = await _userInitiatedClient.GetCategoriesAsync().ConfigureAwait(false);
categories.SetCountProperty(c => c.PresentationOrder);
}
catch (Exception exc)
{
throw new DataSourceException(exc);
}
UpdateCategoryListCacheAsync(categories);
return(categories);
}
private async Task UpdateCategoryListCacheAsync(ICollection <Category> categories = null)
{
if (!Current.IsConnected || _isBackgroundFetching)
{
return;
}
lock (LockObject)
{
_isBackgroundFetching = true;
}
if (categories == null)
{
categories = await _speculativeClient.GetCategoriesAsync().ConfigureAwait(false);
}
categories.SetCountProperty(c => c.PresentationOrder);
if (Current.IsFast())
{
// ReSharper disable once PossibleMultipleEnumeration
var detailed = new List <Category>();
foreach (var category in categories)
{
try
{
var cat = await _speculativeClient.GetCategoryDetailsAsync(category.Id).ConfigureAwait(false);
cat.Subcategories.SetCountProperty(sc => sc.PresentationOrder);
detailed.Add(cat);
}
catch (Exception e)
{
_loggingService.Report(e, this);
}
}
await
Cache.InsertAllIfMoreDetailsAsync(detailed.ToDictionary(GetCategoryCacheKey, c => c),
TimeSpan.FromDays(Constants.Internet.DefaultCacheDays)).ConfigureAwait(false);
}
else if (Current.IsSlow())
{
await
Cache.InsertAllIfMoreDetailsAsync(categories.ToDictionary(GetCategoryCacheKey, c => c),
TimeSpan.FromDays(Constants.Internet.DefaultCacheDays)).ConfigureAwait(false);
}
var catlist = string.Join(",", categories.Select(c => c.Id));
await Cache.InsertObject(CategoryListKey, catlist);
lock (LockObject)
{
_isBackgroundFetching = false;
}
}