Added a /conditions/current endpoint with computed best-guess values for current conditions

internal/application/units/converter.go

@@ -9,10 +9,15 @@ import (
 type Converter interface {
 	TemperatureCToOutput(celsius *float64) *float64
 	SpeedKmhToOutput(kmh *float64) *float64
+	System() string
 }
 
 type USConverter struct{}
 
+func (USConverter) System() string {
+	return "us"
+}
+
 func (USConverter) TemperatureCToOutput(celsius *float64) *float64 {
 	if celsius == nil {
 		return nil
@@ -29,6 +34,28 @@ func (USConverter) SpeedKmhToOutput(kmh *float64) *float64 {
 	return &mph
 }
 
+type MetricConverter struct{}
+
+func (MetricConverter) System() string {
+	return "metric"
+}
+
+func (MetricConverter) TemperatureCToOutput(celsius *float64) *float64 {
+	return clone(celsius)
+}
+
+func (MetricConverter) SpeedKmhToOutput(kmh *float64) *float64 {
+	return clone(kmh)
+}
+
+func clone(v *float64) *float64 {
+	if v == nil {
+		return nil
+	}
+	out := *v
+	return &out
+}
+
 func round(v float64, precision int) float64 {
 	pow := math.Pow(10, float64(precision))
 	return math.Round(v*pow) / pow