feat(ev): add Tesla Wall Connector Gen 3 local HTTP

.changeset/tesla-wall-connector.md

@@ -0,0 +1,5 @@
+---
+"ftw": minor
+---
+
+Tesla Wall Connector Gen 3 can be added as a local EV charger. The setup wizard and Settings → EV take the box's LAN address; FTW reads plug state, power and session energy over HTTP with no Tesla account. The wall connector cannot take a current setpoint — steer a Tesla through tesla_vehicle. Experimental until a live Gen 3 has been exercised.

go/internal/config/config.go

@@ -330,14 +330,14 @@ type V2XPolicy struct {
 // handler on POST /api/config. Providers that don't need auth (e.g. local
 // Modbus) leave Username + Password empty.
 type EVCharger struct {
-	Provider string `yaml:"provider" json:"provider"` // "easee" | "zaptec" | "ctek"
+	Provider string `yaml:"provider" json:"provider"` // "easee" | "zaptec" | "tesla-wc" | "ctek"
 
 	// Connection — populate the block matching the provider's transport.
 	HTTP   *EVChargerHTTP   `yaml:"http,omitempty" json:"http,omitempty"`
 	Modbus *EVChargerModbus `yaml:"modbus,omitempty" json:"modbus,omitempty"`
 
 	// Optional auth — required by cloud HTTP providers like Easee and
-	// Zaptec, unused by local Modbus providers like CTEK.
+	// Zaptec, unused by local providers (CTEK Modbus, Tesla Wall Connector).
 	Username string `yaml:"username,omitempty" json:"username,omitempty"`
 	Password string `yaml:"-" json:"password,omitempty"` // persisted in state.db, not YAML
 
@@ -539,6 +539,19 @@ func (e *EVCharger) Validate() error {
 		if e.Modbus != nil {
 			return fmt.Errorf("ev_charger.modbus: not valid for provider %s (HTTP transport)", e.Provider)
 		}
+	case "tesla-wc":
+		// Local HTTP: LAN origin in http.base_url, no cloud account.
+		// Empty base_url is allowed so the wizard can write provider
+		// intent before the host is filled in.
+		if e.Modbus != nil {
+			return errors.New("ev_charger.modbus: not valid for provider tesla-wc (HTTP transport)")
+		}
+		// Switching from Easee/Zaptec leaves username/password on the
+		// posted document, and POST /api/config restores ev_charger_password
+		// from state.db. Drop them so the provider switch can save.
+		e.Username = ""
+		e.Password = ""
+		e.EmailLegacy = ""
 	case "ctek":
 		if e.Modbus == nil || e.Modbus.Host == "" {
 			return errors.New("ev_charger.modbus.host: required for provider ctek")
@@ -556,7 +569,7 @@ func (e *EVCharger) Validate() error {
 			return errors.New("ev_charger: username/password not valid for provider ctek")
 		}
 	default:
-		return fmt.Errorf("ev_charger.provider %q: not supported (valid: easee, zaptec, ctek)", e.Provider)
+		return fmt.Errorf("ev_charger.provider %q: not supported (valid: easee, zaptec, tesla-wc, ctek)", e.Provider)
 	}
 	return nil
 }

go/internal/config/evcharger_test.go

@@ -114,6 +114,53 @@ func TestEVChargerValidateZaptec(t *testing.T) {
 	}
 }
 
+func TestEVChargerValidateTeslaWC(t *testing.T) {
+	cases := []struct {
+		name    string
+		e       EVCharger
+		wantErr string
+	}{
+		{"happy", EVCharger{Provider: "tesla-wc", HTTP: &EVChargerHTTP{BaseURL: "http://192.168.1.50"}}, ""},
+		{"empty host allowed (wizard placeholder)", EVCharger{Provider: "tesla-wc"}, ""},
+		{"modbus block rejected", EVCharger{Provider: "tesla-wc", Modbus: &EVChargerModbus{Host: "h"}}, "modbus"},
+		{"leftover username stripped", EVCharger{Provider: "tesla-wc", HTTP: &EVChargerHTTP{BaseURL: "http://10.0.0.8"}, Username: "u"}, ""},
+		{"leftover password stripped", EVCharger{Provider: "tesla-wc", HTTP: &EVChargerHTTP{BaseURL: "http://10.0.0.8"}, Password: "p"}, ""},
+	}
+	for _, tc := range cases {
+		t.Run(tc.name, func(t *testing.T) {
+			err := tc.e.Validate()
+			if tc.wantErr == "" {
+				if err != nil {
+					t.Errorf("unexpected error: %v", err)
+				}
+				return
+			}
+			if err == nil {
+				t.Fatalf("expected error containing %q, got nil", tc.wantErr)
+			}
+			if !strings.Contains(err.Error(), tc.wantErr) {
+				t.Errorf("error %q does not contain %q", err.Error(), tc.wantErr)
+			}
+		})
+	}
+}
+
+func TestEVChargerValidateTeslaWCStripsCloudCreds(t *testing.T) {
+	e := EVCharger{
+		Provider:    "tesla-wc",
+		Username:    "old@example.com",
+		Password:    "easee-secret",
+		EmailLegacy: "old@example.com",
+		HTTP:        &EVChargerHTTP{BaseURL: "http://192.168.1.50"},
+	}
+	if err := e.Validate(); err != nil {
+		t.Fatalf("Validate: %v", err)
+	}
+	if e.Username != "" || e.Password != "" || e.EmailLegacy != "" {
+		t.Fatalf("leftover cloud creds after tesla-wc validate: %+v", e)
+	}
+}
+
 func TestEVChargerValidateCTek(t *testing.T) {
 	cases := []struct {
 		name    string