/// <summary>
/// Parses a DataSnapshot of score records into UserScore objects, and filters out records
/// whose timestamp does not fall between startTS and endTS.
/// </summary>
/// <param name="snapshot">DataSnapshot record of user scores.</param>
/// <param name="startTS">Earliest valid timestamp of a user score to retrieve.</param>
/// <param name="endTS">Latest valid timestamp of a user score to retrieve.</param>
/// <returns>List of valid UserScore objects.</returns>
private List <UserScore> ParseValidUserScoreRecords(
DataSnapshot snapshot,
long startTS,
long endTS)
{
return(snapshot.Children
.Select(scoreRecord => UserScore.CreateScoreFromRecord(scoreRecord))
.Where(score => score != null && score.Timestamp > startTS && score.Timestamp <= endTS)
.Reverse()
.ToList());
}
/// <summary>
/// Callback when a score record is removed from the database.
/// </summary>
private void OnScoreRemoved(object sender, ChildChangedEventArgs args)
{
if (args.Snapshot == null || !args.Snapshot.Exists)
{
return;
}
var score = UserScore.CreateScoreFromRecord(args.Snapshot);
if (score == null)
{
return;
}
if (TopScores.Contains(score))
{
TopScores.Remove(score);
RefreshScores();
}
}
/// <summary>
/// Callback when a score record is added with a score high enough for a spot on the
/// leaderboard.
/// </summary>
private void OnScoreAdded(object sender, ChildChangedEventArgs args)
{
if (args.Snapshot == null || !args.Snapshot.Exists)
{
return;
}
var score = UserScore.CreateScoreFromRecord(args.Snapshot);
if (score == null)
{
return;
}
// Verify that score is within start/end times, and isn't already in TopScores.
if (TopScores.Contains(score))
{
return;
}
if (EndTime > 0 || Interval > 0)
{
var EndTimeInternal = EndTime > 0 ?
EndTime :
(DateTime.UtcNow.Ticks / TimeSpan.TicksPerSecond);
var startTime = Interval > 0 ? EndTimeInternal - Interval : 0;
if (score.Timestamp > EndTimeInternal || score.Timestamp < startTime)
{
return;
}
}
// Don't add if the same user already has a better score.
// If the same user has a worse score, remove it.
var existingScore = TopScores.Find(s => s.UserID == score.UserID);
if (existingScore != null)
{
var bestScore = GetBestScore(existingScore, score);
if (existingScore == bestScore)
{
return;
}
TopScores.Remove(existingScore);
}
if (TopScores.Any(s => s.UserID == score.UserID))
{
return;
}
TopScores.Add(score);
if (LowestFirst)
{
TopScores = TopScores.OrderBy(s => s.Score).Take(ScoresToRetrieve).ToList();
}
else
{
TopScores = TopScores.OrderByDescending(s => s.Score).Take(ScoresToRetrieve).ToList();
}
sendUpdateTopScoresEvent = true;
}
