refactor: advanced custom channel route editor (#6865)

* refactor: advanced custom channel route editor

* fix(channels): show raw balance response from balance cell

relay/channel/advancedcustom/adaptor.go

@@ -194,6 +194,14 @@ func (a *Adaptor) GetRequestURL(info *relaycommon.RelayInfo) (string, error) {
 }
 
 func (a *Adaptor) BuildModelListRequest(info *relaycommon.RelayInfo) (string, http.Header, error) {
+	return a.buildManagementRequest(info, dto.AdvancedCustomModelListPath)
+}
+
+func (a *Adaptor) BuildBalanceRequest(info *relaycommon.RelayInfo) (string, http.Header, error) {
+	return a.buildManagementRequest(info, dto.AdvancedCustomBalancePath)
+}
+
+func (a *Adaptor) buildManagementRequest(info *relaycommon.RelayInfo, managementPath string) (string, http.Header, error) {
 	if info == nil {
 		return "", nil, errors.New("missing relay info")
 	}
@@ -204,16 +212,25 @@ func (a *Adaptor) BuildModelListRequest(info *relaycommon.RelayInfo) (string, ht
 	if err := config.Validate(); err != nil {
 		return "", nil, err
 	}
-	route, ok := config.ModelListRoute()
+	var route dto.AdvancedCustomRoute
+	var ok bool
+	switch managementPath {
+	case dto.AdvancedCustomModelListPath:
+		route, ok = config.ModelListRoute()
+	case dto.AdvancedCustomBalancePath:
+		route, ok = config.BalanceRoute()
+	default:
+		return "", nil, fmt.Errorf("unsupported advanced custom management path: %s", managementPath)
+	}
 	if !ok {
-		return "", nil, errors.New("advanced custom channel does not configure a /v1/models route")
+		return "", nil, fmt.Errorf("advanced custom channel does not configure a %s route", managementPath)
 	}
 	converter := strings.TrimSpace(route.Converter)
 	if converter == "" {
 		converter = relayconvert.ConverterNone
 	}
 	if converter != relayconvert.ConverterNone {
-		return "", nil, fmt.Errorf("converter %q does not support model list requests", converter)
+		return "", nil, fmt.Errorf("converter %q does not support %s requests", converter, managementPath)
 	}
 
 	requestURL, err := buildRouteURL(route, converter, info)

relay/channel/advancedcustom/adaptor_test.go

@@ -422,6 +422,49 @@ func TestAdaptorBuildModelListRequestRequiresConfiguredRoute(t *testing.T) {
 	assert.Contains(t, err.Error(), "does not configure a /v1/models route")
 }
 
+func TestAdaptorBuildBalanceRequestUsesConfiguredRoute(t *testing.T) {
+	info := advancedCustomRelayInfo(&dto.AdvancedCustomConfig{
+		Routes: []dto.AdvancedCustomRoute{
+			{
+				IncomingPath: dto.AdvancedCustomModelListPath,
+				UpstreamPath: "/provider/models",
+			},
+			{
+				IncomingPath: dto.AdvancedCustomBalancePath,
+				UpstreamPath: "/provider/balance?existing=1",
+				Auth: &dto.AdvancedCustomRouteAuth{
+					Type:  dto.AdvancedCustomAuthTypeQuery,
+					Name:  "token",
+					Value: "prefix-{api_key}",
+				},
+			},
+		},
+	})
+
+	requestURL, header, err := (&Adaptor{}).BuildBalanceRequest(info)
+	require.NoError(t, err)
+
+	parsedURL, err := url.Parse(requestURL)
+	require.NoError(t, err)
+	assert.Equal(t, "/provider/balance", parsedURL.Path)
+	assert.Equal(t, "1", parsedURL.Query().Get("existing"))
+	assert.Equal(t, "prefix-sk-test", parsedURL.Query().Get("token"))
+	assert.Empty(t, header.Get("Authorization"))
+}
+
+func TestAdaptorBuildBalanceRequestRequiresConfiguredRoute(t *testing.T) {
+	info := advancedCustomRelayInfo(&dto.AdvancedCustomConfig{
+		Routes: []dto.AdvancedCustomRoute{{
+			IncomingPath: dto.AdvancedCustomModelListPath,
+			UpstreamPath: "/provider/models",
+		}},
+	})
+
+	_, _, err := (&Adaptor{}).BuildBalanceRequest(info)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "does not configure a /v1/dashboard/billing/credit_grants route")
+}
+
 func TestAdaptorConvertsResponsesRequestToOpenAIChatUpstream(t *testing.T) {
 	adaptor := &Adaptor{}
 	info := advancedCustomRelayInfo(&dto.AdvancedCustomConfig{