Validate and compose provider endpoints

internal/llm/openai_compatible_client.go

@@ -51,9 +51,11 @@ type OpenAICompatibleClient struct {
 }
 
 func NewOpenAICompatibleClient(cfg OpenAICompatibleConfig) (*OpenAICompatibleClient, error) {
-	baseURL := strings.TrimSpace(cfg.BaseURL)
-	if baseURL != "" {
-		if _, err := url.ParseRequestURI(baseURL); err != nil {
+	baseURL := ""
+	if strings.TrimSpace(cfg.BaseURL) != "" {
+		var err error
+		baseURL, err = domain.NormalizeOpenAICompatibleBaseEndpoint(cfg.BaseURL)
+		if err != nil {
 			return nil, fmt.Errorf("%w: invalid base URL: %v", ErrInvalidConfig, err)
 		}
 	}
@@ -75,7 +77,7 @@ func NewOpenAICompatibleClient(cfg OpenAICompatibleConfig) (*OpenAICompatibleCli
 	}
 
 	return &OpenAICompatibleClient{
-		baseURL:      strings.TrimRight(baseURL, "/"),
+		baseURL:      baseURL,
 		defaultModel: cfg.Model,
 		httpClient:   client,
 	}, nil
@@ -86,14 +88,18 @@ func (c *OpenAICompatibleClient) Generate(ctx context.Context, req domain.Genera
 		return nil, fmt.Errorf("%w: %v", ErrInvalidRequest, err)
 	}
 
-	endpoint := strings.TrimSpace(req.Target.Endpoint)
-	if endpoint == "" {
-		endpoint = c.baseURL
+	selectedEndpoint := req.Target.Endpoint
+	if strings.TrimSpace(selectedEndpoint) == "" {
+		selectedEndpoint = c.baseURL
 	}
-	if endpoint == "" {
-		return nil, fmt.Errorf("%w: endpoint is required", ErrInvalidRequest)
+	endpoint, err := domain.NormalizeOpenAICompatibleBaseEndpoint(selectedEndpoint)
+	if err != nil {
+		return nil, fmt.Errorf("%w: invalid endpoint: %v", ErrInvalidRequest, err)
+	}
+	endpoint, err = url.JoinPath(endpoint, defaults.OpenAIChatCompletionsPath)
+	if err != nil {
+		return nil, fmt.Errorf("%w: invalid endpoint path: %v", ErrInvalidRequest, err)
 	}
-	endpoint = strings.TrimRight(endpoint, "/") + defaults.OpenAIChatCompletionsPath
 
 	wireReq, err := openAIChatRequestFromGenerateRequest(req, c.defaultModel)
 	if err != nil {