public async Task <PaginationQueryResult <Beatmap> > GetBeatmapsFromCollection(Collection collection,
int page = 0,
int countPerPage = 50,
BeatmapOrderOptions options = BeatmapOrderOptions.CreateTime)
{
if (collection.Id == Guid.Empty)
{
Console.WriteLine("No collection found.");
return(new PaginationQueryResult <Beatmap>(new List <Beatmap>(), 0));
}
collection = await Collections.FindAsync(collection.Id);
if (collection == null)
{
Console.WriteLine("No collection found.");
return(new PaginationQueryResult <Beatmap>(new List <Beatmap>(), 0));
}
var relations = Relations
.AsNoTracking()
.Where(k => k.CollectionId == collection.Id);
var beatmaps = relations.Join(Beatmaps, k => k.BeatmapId, k => k.Id, (k, x) => x);
var count = await beatmaps.CountAsync();
var enumerable = options switch
{
BeatmapOrderOptions.UpdateTime => beatmaps.OrderByDescending(k => k.UpdateTime),
BeatmapOrderOptions.CreateTime => beatmaps.OrderByDescending(k => k.CreateTime),
_ => throw new ArgumentOutOfRangeException(nameof(options), options, null)
};
var result = await enumerable
.Skip(page *countPerPage)
.Take(countPerPage)
.ToListAsync();
return(new PaginationQueryResult <Beatmap>(result, count));
}