Support decoding openWB status

provider/config.go

@@ -114,6 +114,8 @@ func NewStringGetterFromConfig(log *api.Logger, config Config) (res StringGetter
 		if pc.Cache > 0 {
 			res = NewCached(res, pc.Cache).StringGetter()
 		}
+	case "openwb":
+		res = openWBStatusFromConfig(log, config.Other)
 	default:
 		log.FATAL.Fatalf("invalid provider type %s", config.Type)
 	}

provider/openwb.go

@@ -0,0 +1,53 @@
+package provider
+
+import (
+	"time"
+
+	"github.com/andig/evcc/api"
+)
+
+// openWBConfig is the specific mqtt getter/setter configuration
+type openWBConfig struct {
+	PlugStat, ChargeStat string
+	Timeout              time.Duration
+}
+
+type openWBStatusProvider struct {
+	plugStat, chargeStat BoolGetter
+}
+
+func openWBStatusFromConfig(log *api.Logger, other map[string]interface{}) (res StringGetter) {
+	if MQTT == nil {
+		log.FATAL.Fatal("mqtt not configured")
+	}
+
+	var pc openWBConfig
+	api.DecodeOther(log, other, &pc)
+
+	o := &openWBStatusProvider{
+		plugStat:   MQTT.BoolGetter(pc.PlugStat, pc.Timeout),
+		chargeStat: MQTT.BoolGetter(pc.ChargeStat, pc.Timeout),
+	}
+
+	return o.stringGetter
+}
+
+func (o *openWBStatusProvider) stringGetter() (string, error) {
+	charging, err := o.chargeStat()
+	if err != nil {
+		return "", err
+	}
+	if charging {
+		return string(api.StatusC), nil
+	}
+
+	plugged, err := o.plugStat()
+	if err != nil {
+		return "", err
+	}
+	if plugged {
+		return string(api.StatusB), nil
+	}
+
+	return string(api.StatusA), nil
+}