From bd651da8ff44cf685bdd6536d795b4d5a8e7c045 Mon Sep 17 00:00:00 2001
From: andig <andi@evcc.io>
Date: Wed, 6 May 2026 15:41:07 +0200
Subject: [PATCH] HomeAssistant: dispatch CallSwitchService by entity domain
 (#29700) (#29706)

---
 util/homeassistant/connection.go      | 20 ++++++--
 util/homeassistant/connection_test.go | 67 +++++++++++++++++++++++++++
 2 files changed, 83 insertions(+), 4 deletions(-)
 create mode 100644 util/homeassistant/connection_test.go

diff --git a/util/homeassistant/connection.go b/util/homeassistant/connection.go
index 1b7f6456e..7b3d0105c 100644
--- a/util/homeassistant/connection.go
+++ b/util/homeassistant/connection.go
@@ -233,16 +233,28 @@ func domain(entity string) (string, error) {
 	return domain, nil
 }
 
-// CallSwitchService is a convenience method for switch services
+// CallSwitchService is a convenience method for switch-like services. The
+// service name depends on the entity domain: stateless button domains expose
+// only `press`, while switch-style domains use `turn_on` / `turn_off`.
 func (c *Connection) CallSwitchService(entity string, turnOn bool) error {
 	domain, err := domain(entity)
 	if err != nil {
 		return err
 	}
 
-	service := "turn_off"
-	if turnOn {
-		service = "turn_on"
+	var service string
+	switch domain {
+	case "button", "input_button":
+		// Buttons are stateless — they only have a press action.
+		if !turnOn {
+			return fmt.Errorf("entity %s (domain %s) has no off action", entity, domain)
+		}
+		service = "press"
+	default:
+		service = "turn_off"
+		if turnOn {
+			service = "turn_on"
+		}
 	}
 
 	data := map[string]any{
diff --git a/util/homeassistant/connection_test.go b/util/homeassistant/connection_test.go
new file mode 100644
index 000000000..e801ecac1
--- /dev/null
+++ b/util/homeassistant/connection_test.go
@@ -0,0 +1,67 @@
+package homeassistant
+
+import (
+	"io"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+
+	"github.com/evcc-io/evcc/util"
+	"github.com/evcc-io/evcc/util/request"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func newTestConnection(baseURL string) *Connection {
+	return &Connection{
+		Helper:   request.NewHelper(util.NewLogger("test")),
+		instance: &proxyInstance{uri: baseURL},
+	}
+}
+
+// TestCallSwitchService_DomainDispatch verifies that CallSwitchService picks
+// the correct service per Home Assistant domain — switches use turn_on /
+// turn_off, but the stateless button / input_button domains expose only
+// `press`. Regression test for evcc-io/evcc#29700.
+func TestCallSwitchService_DomainDispatch(t *testing.T) {
+	tests := []struct {
+		name        string
+		entity      string
+		turnOn      bool
+		wantPath    string
+		wantErrText string
+	}{
+		{"switch turn_on", "switch.foo", true, "/api/services/switch/turn_on", ""},
+		{"switch turn_off", "switch.foo", false, "/api/services/switch/turn_off", ""},
+		{"button press", "button.tesla_model_x_wake_up", true, "/api/services/button/press", ""},
+		{"input_button press", "input_button.bar", true, "/api/services/input_button/press", ""},
+		{"button no off", "button.foo", false, "", "entity button.foo (domain button) has no off action"},
+		{"input_button no off", "input_button.bar", false, "", "entity input_button.bar (domain input_button) has no off action"},
+	}
+
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			var gotPath, gotBody string
+			srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				gotPath = r.URL.Path
+				body, _ := io.ReadAll(r.Body)
+				gotBody = string(body)
+				w.WriteHeader(http.StatusOK)
+			}))
+			defer srv.Close()
+
+			err := newTestConnection(srv.URL).CallSwitchService(tc.entity, tc.turnOn)
+
+			if tc.wantErrText != "" {
+				require.Error(t, err)
+				assert.Contains(t, err.Error(), tc.wantErrText)
+				assert.Empty(t, gotPath, "must not call HA when erroring locally")
+				return
+			}
+
+			require.NoError(t, err)
+			assert.Equal(t, tc.wantPath, gotPath)
+			assert.Contains(t, gotBody, `"entity_id":"`+tc.entity+`"`)
+		})
+	}
+}