From 45120fe46e03112475c049aacec54bf2afbe5c53 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Dawid=20Wysoki=C5=84ski?= <contact@dwysokinski.me>
Date: Thu, 30 Nov 2023 08:24:23 +0100
Subject: [PATCH] refactor: refactor ball <-> paddle collision logic

---
 .golangci.yml                   |  6 ++++-
 internal/ball.go                | 43 +++++++++++++++++++++------------
 internal/{court.go => match.go} |  7 +-----
 internal/paddle.go              |  2 +-
 4 files changed, 35 insertions(+), 23 deletions(-)
 rename internal/{court.go => match.go} (84%)

diff --git a/.golangci.yml b/.golangci.yml
index 8c27c22..707c1eb 100644
--- a/.golangci.yml
+++ b/.golangci.yml
@@ -5,6 +5,7 @@ run:
 linters:
   disable-all: true
   enable:
+    - gocyclo
     - asasalint
     - asciicheck
     - bodyclose
@@ -54,6 +55,8 @@ linters:
     - revive
 
 linters-settings:
+  gocyclo:
+    min-complexity: 10
   tagliatelle:
     case:
       rules:
@@ -176,7 +179,7 @@ linters-settings:
       # https://github.com/mgechev/revive/blob/master/RULES_DESCRIPTIONS.md#cyclomatic
       - name: cyclomatic
         severity: warning
-        disabled: false
+        disabled: true
         arguments: [10]
       # https://github.com/mgechev/revive/blob/master/RULES_DESCRIPTIONS.md#datarace
       - name: datarace
@@ -465,6 +468,7 @@ issues:
     - path: _test\.go
       linters:
         - gosec
+        - gocyclo
     - path: _test\.go
       text: add-constant
     - linters:
diff --git a/internal/ball.go b/internal/ball.go
index e44b40a..f9b18c3 100644
--- a/internal/ball.go
+++ b/internal/ball.go
@@ -47,35 +47,52 @@ func (b *ball) draw(img *ebiten.Image) {
 	vector.DrawFilledCircle(img, b.x, b.y, b.r, ballColor, false)
 }
 
-func (b *ball) update(bounds image.Rectangle) error {
-	b.x, b.y, b.speedX, b.speedY = b.nextPosAndSpeed(bounds)
+func (b *ball) update(bounds image.Rectangle, obstacles ...image.Rectangle) error {
+	b.x, b.y, b.speedX, b.speedY = b.nextPosAndSpeed(bounds, obstacles...)
 	return nil
 }
 
 //nolint:nonamedreturns
-func (b *ball) nextPos(bounds image.Rectangle) (x, y float32) {
-	x, y, _, _ = b.nextPosAndSpeed(bounds)
+func (b *ball) nextPos(bounds image.Rectangle, obstacles ...image.Rectangle) (x, y float32) {
+	x, y, _, _ = b.nextPosAndSpeed(bounds, obstacles...)
 	return x, y
 }
 
 //nolint:nonamedreturns
-func (b *ball) nextPosAndSpeed(bounds image.Rectangle) (x, y, speedX, speedY float32) {
-	speedX, speedY = b.nextSpeed(bounds)
+func (b *ball) nextPosAndSpeed(bounds image.Rectangle, obstacles ...image.Rectangle) (x, y, speedX, speedY float32) {
+	speedX, speedY = b.nextSpeed(bounds, obstacles...)
 	return b.x + speedX, b.y + speedY, speedX, speedY
 }
 
-//nolint:nonamedreturns
-func (b *ball) nextSpeed(bounds image.Rectangle) (speedX, speedY float32) {
+//nolint:nonamedreturns,gocyclo
+func (b *ball) nextSpeed(bounds image.Rectangle, obstacles ...image.Rectangle) (speedX, speedY float32) {
+	ballBounds := b.bounds()
 	speedX = b.speedX
-	if b.x+b.r >= float32(bounds.Max.X) || b.x-b.r <= float32(bounds.Min.X) {
+	speedY = b.speedY
+
+	if ballBounds.Max.X >= bounds.Max.X || ballBounds.Min.X <= bounds.Min.X {
 		speedX *= -1
 	}
 
-	speedY = b.speedY
-	if b.y+b.r >= float32(bounds.Max.Y) || b.y-b.r <= float32(bounds.Min.Y) {
+	if ballBounds.Max.Y >= bounds.Max.Y || ballBounds.Min.Y <= bounds.Min.Y {
 		speedY *= -1
 	}
 
+	for _, ob := range obstacles {
+		inter := ob.Intersect(ballBounds)
+		if inter == (image.Rectangle{}) {
+			continue
+		}
+
+		if float32(ob.Min.X) >= b.x || float32(ob.Max.X) <= b.x {
+			speedX *= -1
+		}
+
+		if float32(ob.Min.Y) >= b.y || float32(ob.Max.Y) <= b.y {
+			speedY *= -1
+		}
+	}
+
 	return speedX, speedY
 }
 
@@ -94,10 +111,6 @@ func (b *ball) resize(x, y float32) {
 	b.r *= y
 }
 
-func (b *ball) reverseDirectionHorizontal() {
-	b.speedX *= -1
-}
-
 func (b *ball) bounds() image.Rectangle {
 	return image.Rect(int(b.x-b.r), int(b.y-b.r), int(b.x+b.r), int(b.y+b.r))
 }
diff --git a/internal/court.go b/internal/match.go
similarity index 84%
rename from internal/court.go
rename to internal/match.go
index 62c7f77..2989c24 100644
--- a/internal/court.go
+++ b/internal/match.go
@@ -39,7 +39,7 @@ func (m *match) draw(img *ebiten.Image) {
 }
 
 func (m *match) update(bounds image.Rectangle) error {
-	if err := m.ball.update(bounds); err != nil {
+	if err := m.ball.update(bounds, m.leftPaddle.bounds(), m.rightPaddle.bounds()); err != nil {
 		return fmt.Errorf("couldn't update ball: %w", err)
 	}
 
@@ -51,11 +51,6 @@ func (m *match) update(bounds image.Rectangle) error {
 		return fmt.Errorf("couldn't update right paddle: %w", err)
 	}
 
-	if m.ball.bounds().Intersect(m.leftPaddle.bounds()) != (image.Rectangle{}) ||
-		m.ball.bounds().Intersect(m.rightPaddle.bounds()) != (image.Rectangle{}) {
-		m.ball.reverseDirectionHorizontal()
-	}
-
 	if err := m.score.update(bounds, m.ball, m.leftPaddle, m.rightPaddle); err != nil {
 		return fmt.Errorf("couldn't update score: %w", err)
 	}
diff --git a/internal/paddle.go b/internal/paddle.go
index 3e6e37b..1baa2bd 100644
--- a/internal/paddle.go
+++ b/internal/paddle.go
@@ -71,7 +71,7 @@ func (p *paddle) draw(img *ebiten.Image) {
 	vector.DrawFilledRect(img, p.x, p.y, p.width, p.height, paddleColor, false)
 }
 
-// nolint:Revive,cyclomatic
+//nolint:gocyclo
 func (p *paddle) update(bounds image.Rectangle, b *ball) error {
 	newY := p.y
 
-- 
2.45.1