/// <summary>
/// Finds the gallery objects with the specified rating. Guaranteed to not return null. Albums cannot be
/// rated and are thus not returned. Only items the current user is authorized to view are returned.
/// </summary>
/// <returns><see cref="IEnumerable<IGalleryObject>" />.</returns>
private IEnumerable <IGalleryObject> FindMediaObjectsMatchingRating()
{
var galleryObjects = new GalleryObjectCollection();
if (SearchOptions.Filter != GalleryObjectType.Album)
{
galleryObjects.AddRange(GetRatedMediaObjects(SearchOptions.MaxNumberResults));
}
var filteredGalleryObjects = FilterGalleryObjects(galleryObjects);
if (filteredGalleryObjects.Count != galleryObjects.Count && filteredGalleryObjects.Count < SearchOptions.MaxNumberResults && galleryObjects.Count >= SearchOptions.MaxNumberResults)
{
// We lost some objects in the filter and now we have less than the desired MaxNumberResults. Get more.
// Note: Performance can be very poor for large galleries when using a filter. For example, a gallery where 20 videos
// were added and then 200,000 images were added, a search for the most recent 20 videos causes this algorithm
// to load all 200,000 images into memory before finding the videos. The good news is that by default the filter
// is for media objects, which will be very fast. If filters end up being commonly used, this algorithm should be improved.
var max = SearchOptions.MaxNumberResults * 2;
var skip = SearchOptions.MaxNumberResults;
const int maxTries = 5;
for (var i = 0; i < maxTries; i++)
{
// Add items up to maxTries times, each time doubling the number of items to retrieve.
filteredGalleryObjects.AddRange(GetRatedMediaObjects(max, skip));
filteredGalleryObjects = FilterGalleryObjects(filteredGalleryObjects);
if (filteredGalleryObjects.Count >= SearchOptions.MaxNumberResults)
{
break;
}
if (i < (maxTries - 1))
{
skip = skip + max;
max = max * 2;
}
}
if (filteredGalleryObjects.Count < SearchOptions.MaxNumberResults)
{
// We still don't have enough objects. Search entire set of albums and media objects.
filteredGalleryObjects.AddRange(GetRatedMediaObjects(int.MaxValue, skip));
filteredGalleryObjects = FilterGalleryObjects(filteredGalleryObjects);
}
}
if (SearchOptions.MaxNumberResults > 0 && filteredGalleryObjects.Count > SearchOptions.MaxNumberResults)
{
return(filteredGalleryObjects.OrderByDescending(g => g.DateAdded).Take(SearchOptions.MaxNumberResults));
}
return(filteredGalleryObjects);
}
/// <summary>
/// Finds the gallery objects matching tags. Guaranteed to not return null. Call this function only when the search type
/// is <see cref="GalleryObjectSearchType.SearchByTag" /> or <see cref="GalleryObjectSearchType.SearchByPeople" />.
/// Only items the user has permission to view are returned.
/// </summary>
/// <returns>An instance of <see cref="IGalleryObjectCollection" />.</returns>
private IEnumerable <IGalleryObject> FindItemsMatchingTags()
{
var galleryObjects = new GalleryObjectCollection();
if (SearchOptions.Filter == GalleryObjectType.All || SearchOptions.Filter == GalleryObjectType.Album)
{
galleryObjects.AddRange(GetAlbumsHavingTags());
}
if (SearchOptions.Filter != GalleryObjectType.Album)
{
galleryObjects.AddRange(GetMediaObjectsHavingTags());
}
var filteredGalleryObjects = FilterGalleryObjects(galleryObjects);
return(SearchOptions.MaxNumberResults > 0 ? filteredGalleryObjects.ToSortedList().Take(SearchOptions.MaxNumberResults) : filteredGalleryObjects);
}