private IList <MediaItem> Shuffle(IEnumerable <GroupedMediaItem> list, CloneableRandom random)
{
GroupedMediaItem[] copy = list.ToArray();
int n = copy.Length;
while (n > 1)
{
n--;
int k = random.Next(n + 1);
(copy[k], copy[n]) = (copy[n], copy[k]);
}
return(GroupedMediaItem.FlattenGroups(copy, _mediaItemCount));
}
public static List <GroupedMediaItem> GroupMediaItems(IList <MediaItem> mediaItems, bool treatCollectionsAsShows)
{
var episodes = mediaItems.OfType <Episode>().ToList();
// var showIds = episodes.Map(e => e.Season.ShowId).Distinct().ToList();
var groups = new List <GroupedMediaItem>();
GroupedMediaItem group = null;
var showIds = new List <Option <int> >();
if (treatCollectionsAsShows)
{
showIds.Add(Option <int> .None);
}
else
{
showIds.AddRange(episodes.Map(e => Some(e.Season.ShowId)).Distinct());
}
foreach (Option <int> showId in showIds)
{
var lastNumber = 0;
void AddUngrouped(MediaItem item)
{
if (group != null && lastNumber != 0)
{
groups.Add(group);
group = null;
lastNumber = 0;
}
groups.Add(new GroupedMediaItem(item, null));
}
IEnumerable <Episode> sortedEpisodes = showId.Match(
id => episodes.Filter(e => e.Season.ShowId == id),
() => episodes).OrderBy(identity, new ChronologicalMediaComparer());
foreach (Episode episode in sortedEpisodes)
{
Option <int> maybeNumber = FindPartNumber(episode);
if (maybeNumber.IsSome)
{
int number = maybeNumber.ValueUnsafe();
if (number <= lastNumber && group != null)
{
groups.Add(group);
group = null;
lastNumber = 0;
}
if (number > lastNumber)
{
if (lastNumber == 0)
{
// start a new group
group = new GroupedMediaItem(episode, null);
lastNumber = number;
}
else if (number == lastNumber + 1)
{
if (group != null)
{
// add to current group
List <MediaItem> additional = group.Additional ?? new List <MediaItem>();
additional.Add(episode);
group = new GroupedMediaItem(group.First, additional);
}
else
{
// this should never happen
throw new InvalidOperationException(
$"Bad shuffle state; unexpected number {number} after {lastNumber} with no existing group");
}
lastNumber = number;
}
else
{
AddUngrouped(episode);
}
}
else
{
AddUngrouped(episode);
}
}
else
{
AddUngrouped(episode);
}
}
if (group != null && lastNumber != 0)
{
groups.Add(group);
group = null;
}
}
foreach (MediaItem notEpisode in mediaItems.Filter(i => i is not Episode))
{
groups.Add(new GroupedMediaItem(notEpisode, null));
}
return(groups);
}
