From 34c4433836ff89ef717331ae994682d77c9a7e1c Mon Sep 17 00:00:00 2001
From: Cyrille Nofficial <cynoffic@cyrilix.fr>
Date: Mon, 5 Sep 2022 16:44:02 +0200
Subject: [PATCH] refactor: extract code used to compute throttle

---
 pkg/throttle/controller.go     | 18 +++----
 pkg/throttle/processor.go      | 13 +++++
 pkg/throttle/processor_test.go | 86 ++++++++++++++++++++++++++++++++++
 3 files changed, 105 insertions(+), 12 deletions(-)
 create mode 100644 pkg/throttle/processor.go
 create mode 100644 pkg/throttle/processor_test.go

diff --git a/pkg/throttle/controller.go b/pkg/throttle/controller.go
index 4c0e4e7..4bfc334 100644
--- a/pkg/throttle/controller.go
+++ b/pkg/throttle/controller.go
@@ -6,7 +6,6 @@ import (
 	mqtt "github.com/eclipse/paho.mqtt.golang"
 	"go.uber.org/zap"
 	"google.golang.org/protobuf/proto"
-	"math"
 	"sync"
 	"time"
 )
@@ -18,18 +17,19 @@ func New(client mqtt.Client, throttleTopic, driveModeTopic, rcThrottleTopic, ste
 		driveModeTopic:        driveModeTopic,
 		rcThrottleTopic:       rcThrottleTopic,
 		steeringTopic:         steeringTopic,
-		minThrottle:           minValue,
 		maxThrottle:           maxValue,
 		driveMode:             events.DriveMode_USER,
 		publishPilotFrequency: publishPilotFrequency,
+		steeringProcessor:     &SteeringProcessor{minThrottle: minValue, maxThrottle: maxValue},
 	}
 
 }
 
 type Controller struct {
-	client                   mqtt.Client
-	throttleTopic            string
-	minThrottle, maxThrottle float32
+	client            mqtt.Client
+	throttleTopic     string
+	maxThrottle       float32
+	steeringProcessor *SteeringProcessor
 
 	muDriveMode sync.RWMutex
 	driveMode   events.DriveMode
@@ -69,7 +69,7 @@ func (c *Controller) onPublishPilotValue() {
 	}
 
 	throttleMsg := events.ThrottleMessage{
-		Throttle:   c.computeThrottle(),
+		Throttle:   c.steeringProcessor.Process(c.readSteering()),
 		Confidence: 1.0,
 	}
 	payload, err := proto.Marshal(&throttleMsg)
@@ -82,12 +82,6 @@ func (c *Controller) onPublishPilotValue() {
 
 }
 
-func (c *Controller) computeThrottle() float32 {
-	s := c.readSteering()
-	absSteering := math.Abs(float64(s))
-	return c.minThrottle + float32(float64(c.maxThrottle-c.minThrottle)*(1-absSteering))
-}
-
 func (c *Controller) readSteering() float32 {
 	c.muSteering.RLock()
 	defer c.muSteering.RUnlock()
diff --git a/pkg/throttle/processor.go b/pkg/throttle/processor.go
new file mode 100644
index 0000000..f90e805
--- /dev/null
+++ b/pkg/throttle/processor.go
@@ -0,0 +1,13 @@
+package throttle
+
+import "math"
+
+type SteeringProcessor struct {
+	minThrottle, maxThrottle float32
+}
+
+// Process compute throttle from steering value
+func (sp *SteeringProcessor) Process(steering float32) float32 {
+	absSteering := math.Abs(float64(steering))
+	return sp.minThrottle + float32(float64(sp.maxThrottle-sp.minThrottle)*(1-absSteering))
+}
diff --git a/pkg/throttle/processor_test.go b/pkg/throttle/processor_test.go
new file mode 100644
index 0000000..6fb80bc
--- /dev/null
+++ b/pkg/throttle/processor_test.go
@@ -0,0 +1,86 @@
+package throttle
+
+import "testing"
+
+func TestSteeringProcessor_Process(t *testing.T) {
+	type fields struct {
+		minThrottle float32
+		maxThrottle float32
+	}
+	type args struct {
+		steering float32
+	}
+	tests := []struct {
+		name   string
+		fields fields
+		args   args
+		want   float32
+	}{
+		{
+			name: "steering straight",
+			fields: fields{
+				minThrottle: 0.2,
+				maxThrottle: 0.5,
+			},
+			args: args{
+				steering: 0.,
+			},
+			want: 0.5,
+		},
+		{
+			name: "steering full left should return min throttle",
+			fields: fields{
+				minThrottle: 0.2,
+				maxThrottle: 0.5,
+			},
+			args: args{
+				steering: -1.,
+			},
+			want: 0.2,
+		},
+		{
+			name: "steering full right should return min throttle",
+			fields: fields{
+				minThrottle: 0.2,
+				maxThrottle: 0.5,
+			},
+			args: args{
+				steering: 1.,
+			},
+			want: 0.2,
+		},
+		{
+			name: "steering mid-left should return intermediate throttle",
+			fields: fields{
+				minThrottle: 0.3,
+				maxThrottle: 0.5,
+			},
+			args: args{
+				steering: -0.5,
+			},
+			want: 0.4,
+		},
+		{
+			name: "steering mid-right should return intermediate throttle",
+			fields: fields{
+				minThrottle: 0.3,
+				maxThrottle: 0.5,
+			},
+			args: args{
+				steering: 0.5,
+			},
+			want: 0.4,
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			sp := &SteeringProcessor{
+				minThrottle: tt.fields.minThrottle,
+				maxThrottle: tt.fields.maxThrottle,
+			}
+			if got := sp.Process(tt.args.steering); got != tt.want {
+				t.Errorf("Process() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}