add processor to scale int values

internal/processor/int-scale.go

@@ -0,0 +1,70 @@
+package processor
+
+import (
+	"context"
+	"errors"
+	"fmt"
+
+	"github.com/jwetzell/showbridge-go/internal/config"
+)
+
+type IntScale struct {
+	OutMin int
+	OutMax int
+	InMin  int
+	InMax  int
+	config config.ProcessorConfig
+}
+
+func (ir *IntScale) Process(ctx context.Context, payload any) (any, error) {
+	payloadInt, ok := GetAnyAs[int](payload)
+	if !ok {
+		return nil, errors.New("int.scale can only process an int")
+	}
+
+	payloadInt = (payloadInt-ir.InMin)*(ir.OutMax-ir.OutMin)/(ir.InMax-ir.InMin) + ir.OutMin
+	return payloadInt, nil
+}
+
+func (ir *IntScale) Type() string {
+	return ir.config.Type
+}
+
+func init() {
+	RegisterProcessor(ProcessorRegistration{
+		Type: "int.scale",
+		New: func(config config.ProcessorConfig) (Processor, error) {
+			params := config.Params
+
+			inMinInt, err := params.GetInt("inMin")
+			if err != nil {
+				return nil, fmt.Errorf("int.scale inMin error: %w", err)
+			}
+
+			inMaxInt, err := params.GetInt("inMax")
+			if err != nil {
+				return nil, fmt.Errorf("int.scale inMax error: %w", err)
+			}
+
+			if inMaxInt < inMinInt {
+				return nil, errors.New("int.scale inMax must be greater than inMin")
+			}
+
+			outMinInt, err := params.GetInt("outMin")
+			if err != nil {
+				return nil, fmt.Errorf("int.scale outMin error: %w", err)
+			}
+
+			outMaxInt, err := params.GetInt("outMax")
+			if err != nil {
+				return nil, fmt.Errorf("int.scale outMax error: %w", err)
+			}
+
+			if outMaxInt < outMinInt {
+				return nil, errors.New("int.scale outMax must be greater than outMin")
+			}
+
+			return &IntScale{config: config, InMin: inMinInt, InMax: inMaxInt, OutMin: outMinInt, OutMax: outMaxInt}, nil
+		},
+	})
+}