zkldi_Tachi/docs/docs/tachi-server/import/sessions.md

Sessions

This page documents how Sessions are constructed. For a humanised explaination of sessions, see this page.

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Creating New Sessions

Scores are sorted on the time they were achieved. Scores without timestamps are discarded from any session processing.

Scores are then grouped into buckets of two hours, in pseudocode:

let lastTimestamp = 0;

for (score of scores) {
	if (score.timestamp > lastTimestamp + TWO_HOURS) {
		CloseBucket();
		CreateNewBucketWithThisScore();
	}
	else {
		AppendToBucket();
	}

	lastTimestamp = score.timestamp;
}

This means that if there was more than two hours between any two successive scores, the session is marked as terminated and a new bucket of scores is created.

For every bucket of scores we have, we iterate over the scores inside the bucket, and compare them against the users' current PB. Since PBs are updated after sessions are processed, this means we are processing them against their past PBs.

!!! bug If a user ends up making sessions in the past, this step will compare against their current PBs - instead of the PBs they would've had at the time of that session.

Once we have compared all the scores against the PBs, we can create a session from it. We need to generate a random name (we have some stuff in src/datasets for this).

We also need to calculate statistics for this session, this is dependent on the game + playtype being used.

Appending To Sessions

If a score within 2 hours of an existing session, then that score is appended to the session.

!!! bug Sessions do not currently conjoin if a user was to get a score between two sessions such that there was now less than two hours between the first sessions last score and the second sessions first score.