From 25a657df602024f0d32b7ee4c58b0b6a8e3af48b Mon Sep 17 00:00:00 2001
From: Ant Zucaro <azucaro@gmail.com>
Date: Tue, 12 Dec 2017 20:38:14 -0500
Subject: [PATCH] Add a KReducer struct.

---
 xonstat/util/xs_glicko.go | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/xonstat/util/xs_glicko.go b/xonstat/util/xs_glicko.go
index c34c326..1a8d8a5 100644
--- a/xonstat/util/xs_glicko.go
+++ b/xonstat/util/xs_glicko.go
@@ -74,6 +74,35 @@ type PlayerGameStat struct {
 	Score            int    `db:"score"`
 }
 
+type KReducer struct {
+	// Time in seconds required for full points
+	FullTime int
+
+	// The minimum time a player must play in the game
+	MinTime int
+
+	// The minimum ratio of time played in the game
+	MinRatio float64
+}
+
+func (kr *KReducer) Evaluate(pgstat PlayerGameStat, game Game) float64 {
+	k := 1.0
+
+	if pgstat.AliveTime < kr.FullTime {
+		k = float64(pgstat.AliveTime) / float64(kr.FullTime)
+	}
+
+	if pgstat.AliveTime < kr.MinTime || game.Duration < kr.MinTime {
+		k = 0
+	}
+
+	if (float64(pgstat.AliveTime) / float64(game.Duration)) < kr.MinRatio {
+		k = 0
+	}
+
+	return k
+}
+
 type GameProcessor struct {
 	config *Config
 	db     *sqlx.DB
-- 
2.39.2