diff --git a/day22/day.go b/day22/day.go
index 58c248d..e06a042 100644
--- a/day22/day.go
+++ b/day22/day.go
@@ -67,6 +67,31 @@ func applyEffects(player, boss Entity) {
 	}
 }
 
+func fightRound(player, boss Entity, spell Spell) (outcome int) {
+	// outcome will be -1 on boss win, 0 on both living and 1 on player win
+
+	applyEffects(player, boss)
+	if player.mana < spell.cost {
+		return -1
+	}
+	// cast spell
+
+	if boss.hitpoints <= 0 {
+		return 1
+	}
+
+	applyEffects(player, boss)
+	if boss.hitpoints <= 0 {
+		return 1
+	}
+	player.hitpoints -= tools.Max(1, boss.damage-player.armor)
+	if player.hitpoints <= 0 {
+		return -1
+	}
+
+	return 0
+}
+
 func Part1(puzzle tools.AoCPuzzle) interface{} {
 	player := Entity{50, 500, 0, 0, make(map[string]Effect)}
 	boss := Entity{0, 0, 0, 0, make(map[string]Effect)}