Replace HighScores array and slot indirection with a map

Key HighScores directly by StartingBridge, eliminating the slot
constants, lookup table, and HighScoreSlot() function. Rename
updateHighScore to registerScore to better describe the operation.

Author: morozov

pkg/domain/constants.go

@@ -40,32 +40,6 @@ const (
 	PlaneY       = 120
 )
 
-// High score slot indices (0-based) corresponding to each StartingBridge option.
-const (
-	HighScoreSlotBridge01 = 0
-	HighScoreSlotBridge05 = 1
-	HighScoreSlotBridge20 = 2
-	HighScoreSlotBridge30 = 3
-)
-
-// highScoreSlotTable maps StartingBridge to a 0-based HighScores slot index.
-var highScoreSlotTable = map[StartingBridge]int{ //nolint:gochecknoglobals // constant lookup table
-	StartingBridge01: HighScoreSlotBridge01,
-	StartingBridge05: HighScoreSlotBridge05,
-	StartingBridge20: HighScoreSlotBridge20,
-	StartingBridge30: HighScoreSlotBridge30,
-}
-
-// HighScoreSlot returns the 0-based HighScores slot index for a StartingBridge value.
-func HighScoreSlot(sb StartingBridge) int {
-	slot, ok := highScoreSlotTable[sb]
-	if !ok {
-		panic("domain: unknown StartingBridge value")
-	}
-
-	return slot
-}
-
 const (
 	// DyingFrameCount is the number of frames the dying animation runs (~1.33 s).
 	DyingFrameCount = Tps * 4 / 3

pkg/game/overview_test.go

@@ -175,13 +175,12 @@ func TestUpdateGameOver_PreservesHighScore(t *testing.T) {
 	g := NewGame()
 	g.state.Screen = domain.ScreenGameOver
 	g.state.Config.StartingBridge = domain.StartingBridge01
-	slot := domain.HighScoreSlot(domain.StartingBridge01)
-	g.state.HighScores[slot] = 12345
+	g.state.HighScores[domain.StartingBridge01] = 12345
 
 	g.updateGameOver()
 
-	if g.state.HighScores[slot] != 12345 {
-		t.Errorf("HighScores[%d] = %d, want 12345 (score lost during overview init)", slot, g.state.HighScores[slot])
+	if g.state.HighScores[domain.StartingBridge01] != 12345 {
+		t.Errorf("HighScores[Bridge01] = %d, want 12345 (score lost during overview init)", g.state.HighScores[domain.StartingBridge01])
 	}
 }
 

pkg/logic/death.go

@@ -71,15 +71,14 @@ func handlePostDeath(s *state.GameState, terrain TerrainRenderer) {
 // triggerGameOver updates the high score and transitions to the game over screen.
 // In two-player mode the higher of both players' scores is used.
 func triggerGameOver(s *state.GameState) {
-	slot := domain.HighScoreSlot(s.Config.StartingBridge)
 	score := s.Players[s.CurrentPlayer].Score
 	if s.Config.IsTwoPlayer {
 		other := s.CurrentPlayer.Other()
 		if s.Players[other].Score > score {
 			score = s.Players[other].Score
 		}
 	}
-	updateHighScore(&s.HighScores, slot, score)
+	registerScore(s.HighScores, s.Config.StartingBridge, score)
 	s.Screen = domain.ScreenGameOver
 }
 

pkg/logic/death_test.go

@@ -307,9 +307,8 @@ func TestTriggerGameOver_TwoPlayer_UsesHigherScore(t *testing.T) {
 
 	triggerGameOver(s)
 
-	slot := domain.HighScoreSlot(domain.StartingBridge01)
-	if s.HighScores[slot] != 8000 {
-		t.Errorf("HighScores[%d] = %d, want 8000 (P2's higher score)", slot, s.HighScores[slot])
+	if s.HighScores[domain.StartingBridge01] != 8000 {
+		t.Errorf("HighScores[Bridge01] = %d, want 8000 (P2's higher score)", s.HighScores[domain.StartingBridge01])
 	}
 }
 

pkg/logic/scoring.go

@@ -1,6 +1,7 @@
 package logic
 
 import (
+	"github.com/morozov/river-raid-ebiten/pkg/domain"
 	"github.com/morozov/river-raid-ebiten/pkg/state"
 )
 
@@ -21,10 +22,10 @@ func addScore(player *state.PlayerState, controls *state.ControlFlags, points in
 	}
 }
 
-// updateHighScore replaces the high score for the given starting bridge slot if
-// the provided score exceeds it.
-func updateHighScore(highScores *[4]int, slot, score int) {
-	if score > highScores[slot] {
-		highScores[slot] = score
+// registerScore records the game score as the high score for the given starting
+// bridge if it exceeds the current record.
+func registerScore(highScores map[domain.StartingBridge]int, bridge domain.StartingBridge, score int) {
+	if score > highScores[bridge] {
+		highScores[bridge] = score
 	}
 }

pkg/logic/scoring_test.go

@@ -3,6 +3,7 @@ package logic
 import (
 	"testing"
 
+	"github.com/morozov/river-raid-ebiten/pkg/domain"
 	"github.com/morozov/river-raid-ebiten/pkg/state"
 )
 
@@ -50,41 +51,39 @@ func TestAddScore_NoBonusLifeWithinSameThreshold(t *testing.T) {
 	}
 }
 
-func TestUpdateHighScore_ReplacesIfHigher(t *testing.T) {
+func TestRegisterScore_ReplacesIfHigher(t *testing.T) {
 	t.Parallel()
 
-	var hs [4]int
-	hs[0] = 1000
-	updateHighScore(&hs, 0, 2000)
+	hs := map[domain.StartingBridge]int{domain.StartingBridge01: 1000}
+	registerScore(hs, domain.StartingBridge01, 2000)
 
-	if hs[0] != 2000 {
-		t.Errorf("high score = %d, want 2000", hs[0]) //nolint:gosec // G602: fixed-size [4]int, index 0 is always valid
+	if hs[domain.StartingBridge01] != 2000 {
+		t.Errorf("high score = %d, want 2000", hs[domain.StartingBridge01])
 	}
 }
 
-func TestUpdateHighScore_NoChangeIfLower(t *testing.T) {
+func TestRegisterScore_NoChangeIfLower(t *testing.T) {
 	t.Parallel()
 
-	var hs [4]int
-	hs[0] = 5000
-	updateHighScore(&hs, 0, 3000)
+	hs := map[domain.StartingBridge]int{domain.StartingBridge01: 5000}
+	registerScore(hs, domain.StartingBridge01, 3000)
 
-	if hs[0] != 5000 {
-		t.Errorf("high score = %d, want 5000", hs[0]) //nolint:gosec // G602: fixed-size [4]int, index 0 is always valid
+	if hs[domain.StartingBridge01] != 5000 {
+		t.Errorf("high score = %d, want 5000", hs[domain.StartingBridge01])
 	}
 }
 
-func TestUpdateHighScore_UsesCorrectSlot(t *testing.T) {
+func TestRegisterScore_UsesCorrectKey(t *testing.T) {
 	t.Parallel()
 
-	var hs [4]int
-	updateHighScore(&hs, 2, 9999)
+	hs := make(map[domain.StartingBridge]int)
+	registerScore(hs, domain.StartingBridge20, 9999)
 
-	if hs[2] != 9999 {
-		t.Errorf("hs[2] = %d, want 9999", hs[2]) //nolint:gosec // G602: fixed-size [4]int, index 2 is always valid
+	if hs[domain.StartingBridge20] != 9999 {
+		t.Errorf("hs[Bridge20] = %d, want 9999", hs[domain.StartingBridge20])
 	}
 
-	if hs[0] != 0 || hs[1] != 0 || hs[3] != 0 { //nolint:gosec // G602: fixed-size [4]int, indices 0/1/3 are always valid
-		t.Error("other slots should be unchanged")
+	if hs[domain.StartingBridge01] != 0 || hs[domain.StartingBridge05] != 0 || hs[domain.StartingBridge30] != 0 {
+		t.Error("other keys should be unchanged")
 	}
 }

pkg/render/hud.go

@@ -74,7 +74,7 @@ func DrawHUD(screen draw.Image, s *state.GameState) {
 				{Row: hudRow22, Col: hudColHIScore, Ink: platform.ColorCyan, Text: p2Score},
 			})
 		} else {
-			hiScore := fmt.Sprintf("%0*d", hudHIScoreDigits, s.HighScores[domain.HighScoreSlot(s.Config.StartingBridge)])
+			hiScore := fmt.Sprintf("%0*d", hudHIScoreDigits, s.HighScores[s.Config.StartingBridge])
 			DrawText(screen, []assets.TextSpan{
 				{Row: hudRow22, Col: hudColHILabel, Ink: platform.ColorWhite, Text: "HI"},
 				{Row: hudRow22, Col: hudColHIScore, Ink: platform.ColorWhite, Text: hiScore},

pkg/state/state.go

@@ -44,10 +44,10 @@ type GameState struct {
 	Missile         *PlayerMissile
 	TankShell       *TankShell
 	HeliMissile     *HeliMissile
+	HighScores      map[domain.StartingBridge]int
 	InputInterface  input.Interface
 	Explosion       Explosion
 	Players         [2]PlayerState
-	HighScores      [4]int
 	Controls        ControlFlags
 	Config          domain.GameConfig
 	BridgeYPosition domain.SP
@@ -88,6 +88,7 @@ func NewGameState() *GameState {
 			{Lives: domain.LivesInitial},
 			{Lives: domain.LivesInitial},
 		},
+		HighScores:     make(map[domain.StartingBridge]int),
 		InputInterface: input.InterfaceFor(0),
 	}
 }