feat: add score type

game/score.go

@@ -0,0 +1,33 @@
+package game
+
+// SCORE_MAX is the highest allowed score (7 digits, 9,999,999).
+// Any additions beyond this value are clamped.
+const SCORE_MAX Score = 9999999
+
+// Score is a running total of points earned.
+// It’s a distinct type (over uint32) to prevent mixing raw integers with scores.
+type Score uint32
+
+// Lines adds points for clearing a number of lines at once.
+//
+// The formula used is: s = L^2 * 100  (where L is the number of lines cleared)
+// That yields the following values:
+//
+//	L=0 => 0
+//	L=1 => 100
+//	L=2 => 400
+//	L=3 => 900
+//	L=4 => 1600
+//
+// Note: `lines` is a byte (0..255). Even at 255 the delta (255^2*100=6,502,500)
+// fits comfortably in uint32 and is then clamped against SCORE_MAX on add.
+func (s *Score) Lines(lines byte) {
+	L := uint32(lines)
+	s.Add(L * L * 100)
+}
+
+// Add increases the score by num and clamps the result to SCORE_MAX.
+// No effect if the score is already at SCORE_MAX
+func (s *Score) Add(num uint32) {
+	*s = min(*s+Score(num), SCORE_MAX)
+}