Add Shelly EM (2 channels) meter (#4273)

meter/shelly/connection.go

@@ -87,12 +87,15 @@ func (d *Connection) CurrentPower() (float64, error) {
 			return 0, err
 		}
 
-		if d.channel >= len(res.Meters) {
+		switch {
+		case d.channel < len(res.Meters):
+			power = res.Meters[d.channel].Power
+		case d.channel < len(res.EMeters):
+			power = res.EMeters[d.channel].Power
+		default:
 			return 0, errors.New("invalid channel, missing power meter")
 		}
 
-		power = res.Meters[d.channel].Power
-
 	default:
 		var res Gen2StatusResponse
 		if err := d.execGen2Cmd("Shelly.GetStatus", false, &res); err != nil {

meter/shelly/types.go

@@ -42,4 +42,8 @@ type Gen1StatusResponse struct {
 	Meters []struct {
 		Power float64
 	}
+	// Shelly EM meter JSON response
+	EMeters []struct {
+		Power float64
+	}
 }