Modernize invertergui: MQTT write support, HA integration, UI updates

mk2driver/mk2interface.go

@@ -76,3 +76,29 @@ type Mk2 interface {
 	C() chan *Mk2Info
 	Close()
 }
+
+type PanelSwitchState byte
+
+const (
+	// PanelSwitchChargerOnly enables charging only.
+	PanelSwitchChargerOnly PanelSwitchState = 0x01
+	// PanelSwitchInverterOnly enables inverter output and disables charging.
+	PanelSwitchInverterOnly PanelSwitchState = 0x02
+	// PanelSwitchOn enables both inverter and charger.
+	PanelSwitchOn PanelSwitchState = 0x03
+	// PanelSwitchOff disables inverter and charger.
+	PanelSwitchOff PanelSwitchState = 0x04
+)
+
+type SettingsWriter interface {
+	// WriteRAMVar writes a signed 16-bit value to a RAM variable id.
+	WriteRAMVar(id uint16, value int16) error
+	// WriteSetting writes a signed 16-bit value to a setting id.
+	WriteSetting(id uint16, value int16) error
+	// SetPanelState sends the MK2 "S" command using a virtual panel switch state.
+	// If currentLimitA is nil, the command does not update the AC current limit.
+	SetPanelState(switchState PanelSwitchState, currentLimitA *float64) error
+	// SetStandby configures the remote panel standby line.
+	// When enabled, the inverter is prevented from sleeping while switched off.
+	SetStandby(enabled bool) error
+}