Expose version/build metadata and improve provider error messaging

cmd/goaichat/main.go

@@ -10,6 +10,11 @@ import (
 	"github.com/stig/goaichat/internal/config"
 )
 
+var (
+	version    = "dev"
+	buildStamp = ""
+)
+
 func main() {
 	var configPath string
 	flag.StringVar(&configPath, "config", "", "Path to configuration file")
@@ -26,7 +31,12 @@ func main() {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	application := app.New(logger, cfg)
+	application := app.New(
+		logger,
+		cfg,
+		app.WithVersion(version),
+		app.WithBuild(buildStamp),
+	)
 	if err := application.Run(ctx); err != nil {
 		logger.Error("application terminated with error", "error", err)
 		os.Exit(1)

internal/app/app.go

@@ -27,16 +27,19 @@ type App struct {
 	input        io.Reader
 	output       io.Writer
 	status       string
+	version      string
+	build        string
 	streamBuffer strings.Builder
 }
 
 // New constructs a new App instance.
 func New(logger *slog.Logger, cfg *config.Config, opts ...Option) *App {
 	app := &App{
-		logger: logger,
-		config: cfg,
-		input:  os.Stdin,
-		output: os.Stdout,
+		logger:  logger,
+		config:  cfg,
+		input:   os.Stdin,
+		output:  os.Stdout,
+		version: "dev",
 	}
 
 	for _, opt := range opts {
@@ -64,6 +67,20 @@ func WithIO(in io.Reader, out io.Writer) Option {
 	}
 }
 
+// WithVersion sets the application version string presented in the UI header.
+func WithVersion(version string) Option {
+	return func(a *App) {
+		a.version = strings.TrimSpace(version)
+	}
+}
+
+// WithBuild sets the application build identifier presented in the UI header.
+func WithBuild(build string) Option {
+	return func(a *App) {
+		a.build = strings.TrimSpace(build)
+	}
+}
+
 // Run starts the application lifecycle.
 func (a *App) Run(ctx context.Context) error {
 	if a == nil {
@@ -201,7 +218,15 @@ func (a *App) runCLILoop(ctx context.Context) error {
 		}
 		a.clearStreamingContent()
 
-		a.setStatus("")
+		notice := ""
+		if a.chat != nil {
+			notice = a.chat.ConsumeStreamingNotice()
+		}
+		if strings.TrimSpace(notice) != "" {
+			a.setStatus("%s", notice)
+		} else {
+			a.setStatus("")
+		}
 
 		if err := a.maybeSuggestSessionName(ctx); err != nil {
 			a.logger.WarnContext(ctx, "session name suggestion failed", "error", err)
@@ -386,7 +411,15 @@ func (a *App) renderUI() error {
 		sessionName = a.chat.SessionName()
 	}
 
-	title := fmt.Sprintf("goaichat - %s", sessionName)
+	name := "goaichat"
+	if v := strings.TrimSpace(a.version); v != "" {
+		name = fmt.Sprintf("%s v%s", name, v)
+	}
+	if b := strings.TrimSpace(a.build); b != "" {
+		name = fmt.Sprintf("%s (build %s)", name, b)
+	}
+
+	title := fmt.Sprintf("%s - %s", name, sessionName)
 	underline := strings.Repeat("=", len(title))
 	if _, err := fmt.Fprintf(a.output, "%s\n%s\n\n", title, underline); err != nil {
 		return err

internal/chat/service.go

@@ -37,6 +37,7 @@ type Service struct {
 	model         string
 	temperature   float64
 	stream        bool
+	streamNotice  string
 	history       []openai.ChatMessage
 	sessionID     int64
 	summarySet    bool
@@ -92,6 +93,8 @@ func (s *Service) Send(ctx context.Context, input string, streamHandler openai.C
 	messages := append([]openai.ChatMessage(nil), s.history...)
 	temperature := s.temperature
 
+	s.streamNotice = ""
+
 	req := openai.ChatCompletionRequest{
 		Model:       s.model,
 		Messages:    messages,
@@ -105,11 +108,17 @@ func (s *Service) Send(ctx context.Context, input string, streamHandler openai.C
 	var err error
 	if s.stream {
 		resp, err = s.client.StreamChatCompletion(ctx, req, streamHandler)
+		if err != nil {
+			resp, err = s.handleStreamingFailure(ctx, req, err)
+			if err != nil {
+				return "", s.translateProviderError(err)
+			}
+		}
 	} else {
 		resp, err = s.client.CreateChatCompletion(ctx, req)
-	}
-	if err != nil {
-		return "", err
+		if err != nil {
+			return "", s.translateProviderError(err)
+		}
 	}
 	if len(resp.Choices) == 0 {
 		return "", errors.New("no choices returned from completion")
@@ -135,6 +144,16 @@ func (s *Service) History() []openai.ChatMessage {
 	return historyCopy
 }
 
+// ConsumeStreamingNotice returns any pending streaming notice and clears it.
+func (s *Service) ConsumeStreamingNotice() string {
+	if s == nil {
+		return ""
+	}
+	notice := s.streamNotice
+	s.streamNotice = ""
+	return notice
+}
+
 // StreamingEnabled reports whether streaming completions are configured for this service.
 func (s *Service) StreamingEnabled() bool {
 	if s == nil {
@@ -143,6 +162,74 @@ func (s *Service) StreamingEnabled() bool {
 	return s.stream
 }
 
+func (s *Service) translateProviderError(err error) error {
+	var reqErr *openai.RequestError
+	if !errors.As(err, &reqErr) {
+		return err
+	}
+
+	if guidance, ok := providerStatusGuidance(reqErr.StatusCode()); ok {
+		return errors.New(guidance)
+	}
+
+	return err
+}
+
+func (s *Service) handleStreamingFailure(ctx context.Context, req openai.ChatCompletionRequest, streamErr error) (*openai.ChatCompletionResponse, error) {
+	if s == nil {
+		return nil, streamErr
+	}
+
+	var reqErr *openai.RequestError
+	if !errors.As(streamErr, &reqErr) {
+		return nil, streamErr
+	}
+
+	status := reqErr.StatusCode()
+	if status < 400 || status >= 500 {
+		return nil, streamErr
+	}
+
+	guidance, hasGuidance := providerStatusGuidance(status)
+	message := guidance
+	if !hasGuidance {
+		message = strings.TrimSpace(reqErr.Message())
+		if message == "" {
+			message = strings.TrimSpace(streamErr.Error())
+		}
+		if message == "" {
+			message = "Streaming is unavailable"
+		}
+	}
+	message = fmt.Sprintf("%s\nStreaming has been disabled; responses will be fully buffered.", message)
+
+	s.logger.WarnContext(ctx, "streaming disabled", "status", status, "error", strings.TrimSpace(reqErr.Message()))
+	s.stream = false
+	s.streamNotice = message
+	req.Stream = false
+
+	resp, err := s.client.CreateChatCompletion(ctx, req)
+	if err != nil {
+		return nil, s.translateProviderError(err)
+	}
+	return resp, nil
+}
+
+func providerStatusGuidance(status int) (string, bool) {
+	switch status {
+	case 401:
+		return "Incorrect API key provided.\nVerify API key, clear browser cache, or generate a new key.", true
+	case 429:
+		return "Rate limit reached.\nPace requests and implement exponential backoff.", true
+	case 500:
+		return "Server error.\nRetry after a brief wait; contact support if persistent.", true
+	case 503:
+		return "Engine overloaded.\nRetry request after a brief wait; contact support if persistent.", true
+	default:
+		return "", false
+	}
+}
+
 // Reset clears the in-memory conversation history.
 func (s *Service) Reset() {
 	if s == nil {

internal/openai/client.go

@@ -22,6 +22,55 @@ type Client struct {
 	httpClient *http.Client
 }
 
+type contentPart struct {
+	Type string `json:"type"`
+	Text string `json:"text"`
+}
+
+func extractRoleAndContent(raw json.RawMessage) (string, string) {
+	if len(raw) == 0 || string(raw) == "null" {
+		return "", ""
+	}
+
+	var envelope map[string]json.RawMessage
+	if err := json.Unmarshal(raw, &envelope); err != nil {
+		return "", ""
+	}
+
+	var role string
+	if value, ok := envelope["role"]; ok {
+		_ = json.Unmarshal(value, &role)
+	}
+
+	value, ok := envelope["content"]
+	if !ok {
+		return role, ""
+	}
+
+	var text string
+	if err := json.Unmarshal(value, &text); err == nil {
+		return role, text
+	}
+
+	var parts []contentPart
+	if err := json.Unmarshal(value, &parts); err == nil {
+		var builder strings.Builder
+		for _, part := range parts {
+			if part.Text != "" {
+				builder.WriteString(part.Text)
+			}
+		}
+		return role, builder.String()
+	}
+
+	var single contentPart
+	if err := json.Unmarshal(value, &single); err == nil {
+		return role, single.Text
+	}
+
+	return role, ""
+}
+
 // ClientOption customizes client construction.
 type ClientOption func(*Client)
 
@@ -131,10 +180,10 @@ func (c *Client) StreamChatCompletion(ctx context.Context, req ChatCompletionReq
 		ID      string `json:"id"`
 		Object  string `json:"object"`
 		Choices []struct {
-			Index        int         `json:"index"`
-			Message      ChatMessage `json:"message"`
-			Delta        ChatMessage `json:"delta"`
-			FinishReason string      `json:"finish_reason"`
+			Index        int             `json:"index"`
+			Message      json.RawMessage `json:"message"`
+			Delta        json.RawMessage `json:"delta"`
+			FinishReason string          `json:"finish_reason"`
 		} `json:"choices"`
 		Usage Usage `json:"usage"`
 	}
@@ -145,6 +194,7 @@ func (c *Client) StreamChatCompletion(ctx context.Context, req ChatCompletionReq
 	finish := ""
 	var usage Usage
 	usageReceived := false
+	var lastMessageText string
 
 	for scanner.Scan() {
 		line := scanner.Text()
@@ -190,19 +240,22 @@ func (c *Client) StreamChatCompletion(ctx context.Context, req ChatCompletionReq
 		finishReason := ""
 		if len(chunk.Choices) > 0 {
 			choice := chunk.Choices[0]
-			if choice.Message.Role != "" {
-				role = choice.Message.Role
+			choiceRole, choiceContent := extractRoleAndContent(choice.Message)
+			if choiceRole != "" {
+				role = choiceRole
 			}
-			if choice.Delta.Role != "" {
-				role = choice.Delta.Role
+			deltaRole, deltaContent := extractRoleAndContent(choice.Delta)
+			if deltaRole != "" {
+				role = deltaRole
 			}
-			if choice.Delta.Content != "" {
-				chunkText = choice.Delta.Content
-			} else if choice.Message.Content != "" && builder.Len() == 0 {
-				chunkText = choice.Message.Content
+			if deltaContent != "" {
+				chunkText = deltaContent
 			}
-			if choice.Message.Content != "" && builder.Len() == 0 && chunkText == "" {
-				chunkText = choice.Message.Content
+			if chunkText == "" && builder.Len() == 0 && choiceContent != "" {
+				chunkText = choiceContent
+			}
+			if choiceContent != "" {
+				lastMessageText = choiceContent
 			}
 			if choice.FinishReason != "" {
 				finishReason = choice.FinishReason
@@ -237,7 +290,23 @@ func (c *Client) StreamChatCompletion(ctx context.Context, req ChatCompletionReq
 
 	content := strings.TrimSpace(builder.String())
 	if content == "" {
-		return nil, errors.New("stream response contained no content")
+		if trimmed := strings.TrimSpace(lastMessageText); trimmed != "" {
+			content = trimmed
+		}
+	}
+	if content == "" {
+		aggregated.Choices = []ChatCompletionChoice{{
+			Index: 0,
+			Message: ChatMessage{
+				Role:    role,
+				Content: "",
+			},
+			FinishReason: finish,
+		}}
+		if usageReceived {
+			aggregated.Usage = usage
+		}
+		return &aggregated, nil
 	}
 
 	aggregated.Choices = []ChatCompletionChoice{{
@@ -280,8 +349,13 @@ func decodeSuccess(r io.Reader) (*ChatCompletionResponse, error) {
 func decodeError(r io.Reader, status int) error {
 	var apiErr ErrorResponse
 	if err := json.NewDecoder(r).Decode(&apiErr); err != nil {
-		return fmt.Errorf("api error (status %d): failed to decode body: %w", status, err)
+		return &RequestError{
+			Status: status,
+			Response: ErrorResponse{
+				Error: APIError{Message: fmt.Sprintf("failed to decode error body: %v", err)},
+			},
+		}
 	}
 
-	return fmt.Errorf("api error (status %d): %s", status, apiErr.Error.Message)
+	return &RequestError{Status: status, Response: apiErr}
 }

internal/openai/types.go

@@ -1,5 +1,10 @@
 package openai
 
+import (
+	"fmt"
+	"strings"
+)
+
 // ChatMessage represents a single message within a chat completion request or response.
 type ChatMessage struct {
 	Role    string `json:"role"`
@@ -50,6 +55,48 @@ type ChatCompletionStreamEvent struct {
 // ChatCompletionStreamHandler consumes streaming completion events.
 type ChatCompletionStreamHandler func(ChatCompletionStreamEvent) error
 
+// RequestError captures an error response returned by the API together with the HTTP status code.
+type RequestError struct {
+	Status   int
+	Response ErrorResponse
+}
+
+// Error implements the error interface.
+func (e *RequestError) Error() string {
+	if e == nil {
+		return ""
+	}
+	msg := strings.TrimSpace(e.Response.Error.Message)
+	if msg == "" {
+		return fmt.Sprintf("api error (status %d)", e.Status)
+	}
+	return fmt.Sprintf("api error (status %d): %s", e.Status, msg)
+}
+
+// StatusCode returns the originating HTTP status code.
+func (e *RequestError) StatusCode() int {
+	if e == nil {
+		return 0
+	}
+	return e.Status
+}
+
+// Message returns the raw message provided by the API, if any.
+func (e *RequestError) Message() string {
+	if e == nil {
+		return ""
+	}
+	return e.Response.Error.Message
+}
+
+// Type returns the OpenAI error type string, when present.
+func (e *RequestError) Type() string {
+	if e == nil {
+		return ""
+	}
+	return e.Response.Error.Type
+}
+
 // APIError captures structured error responses returned by the API.
 type APIError struct {
 	Message string `json:"message"`