feat: implement REST API support for metadata streaming (Phase 5)

internal/core/chatter.go

@@ -77,25 +77,30 @@ func (o *Chatter) Send(request *domain.ChatRequest, opts *domain.ChatOptions) (s
 		}()
 
 		for update := range responseChan {
+			if opts.UpdateChan != nil {
+				opts.UpdateChan <- update
+			}
 			switch update.Type {
 			case domain.StreamTypeContent:
 				message += update.Content
-				if !opts.SuppressThink {
+				if !opts.SuppressThink && !opts.Quiet {
 					fmt.Print(update.Content)
 					printedStream = true
 				}
 			case domain.StreamTypeUsage:
-				if opts.ShowMetadata && update.Usage != nil {
+				if opts.ShowMetadata && update.Usage != nil && !opts.Quiet {
 					fmt.Fprintf(os.Stderr, "\n[Metadata] Input: %d | Output: %d | Total: %d\n",
 						update.Usage.InputTokens, update.Usage.OutputTokens, update.Usage.TotalTokens)
 				}
 			case domain.StreamTypeError:
-				fmt.Fprintf(os.Stderr, "Error: %s\n", update.Content)
+				if !opts.Quiet {
+					fmt.Fprintf(os.Stderr, "Error: %s\n", update.Content)
+				}
 				errChan <- errors.New(update.Content)
 			}
 		}
 
-		if printedStream && !opts.SuppressThink && !strings.HasSuffix(message, "\n") {
+		if printedStream && !opts.SuppressThink && !strings.HasSuffix(message, "\n") && !opts.Quiet {
 			fmt.Println()
 		}
 

internal/domain/domain.go

@@ -52,6 +52,8 @@ type ChatOptions struct {
 	Notification        bool
 	NotificationCommand string
 	ShowMetadata        bool
+	Quiet               bool
+	UpdateChan          chan StreamUpdate
 }
 
 // NormalizeMessages remove empty messages and ensure messages order user-assist-user

internal/server/chat.go

@@ -40,9 +40,10 @@ type ChatRequest struct {
 }
 
 type StreamResponse struct {
-	Type    string `json:"type"`    // "content", "error", "complete"
-	Format  string `json:"format"`  // "markdown", "mermaid", "plain"
-	Content string `json:"content"` // The actual content
+	Type    string                `json:"type"`             // "content", "usage", "error", "complete"
+	Format  string                `json:"format,omitempty"` // "markdown", "mermaid", "plain"
+	Content string                `json:"content,omitempty"`
+	Usage   *domain.UsageMetadata `json:"usage,omitempty"`
 }
 
 func NewChatHandler(r *gin.Engine, registry *core.PluginRegistry, db *fsdb.Db) *ChatHandler {
@@ -98,7 +99,7 @@ func (h *ChatHandler) HandleChat(c *gin.Context) {
 			log.Printf("Processing prompt %d: Model=%s Pattern=%s Context=%s",
 				i+1, prompt.Model, prompt.PatternName, prompt.ContextName)
 
-			streamChan := make(chan string)
+			streamChan := make(chan domain.StreamUpdate)
 
 			go func(p PromptRequest) {
 				defer close(streamChan)
@@ -117,10 +118,10 @@ func (h *ChatHandler) HandleChat(c *gin.Context) {
 					}
 				}
 
-				chatter, err := h.registry.GetChatter(p.Model, 2048, p.Vendor, "", false, false)
+				chatter, err := h.registry.GetChatter(p.Model, 2048, p.Vendor, "", true, false)
 				if err != nil {
 					log.Printf("Error creating chatter: %v", err)
-					streamChan <- fmt.Sprintf("Error: %v", err)
+					streamChan <- domain.StreamUpdate{Type: domain.StreamTypeError, Content: fmt.Sprintf("Error: %v", err)}
 					return
 				}
 
@@ -144,49 +145,44 @@ func (h *ChatHandler) HandleChat(c *gin.Context) {
 					FrequencyPenalty: request.FrequencyPenalty,
 					PresencePenalty:  request.PresencePenalty,
 					Thinking:         request.Thinking,
+					UpdateChan:       streamChan,
+					Quiet:            true,
 				}
 
-				session, err := chatter.Send(chatReq, opts)
+				_, err = chatter.Send(chatReq, opts)
 				if err != nil {
 					log.Printf("Error from chatter.Send: %v", err)
-					streamChan <- fmt.Sprintf("Error: %v", err)
+					// Error already sent to streamChan via domain.StreamTypeError if occurred in Send loop
 					return
 				}
-
-				if session == nil {
-					log.Printf("No session returned from chatter.Send")
-					streamChan <- "Error: No response from model"
-					return
-				}
-
-				lastMsg := session.GetLastMessage()
-				if lastMsg != nil {
-					streamChan <- lastMsg.Content
-				} else {
-					log.Printf("No message content in session")
-					streamChan <- "Error: No response content"
-				}
 			}(prompt)
 
-			for content := range streamChan {
+			for update := range streamChan {
 				select {
 				case <-clientGone:
 					return
 				default:
 					var response StreamResponse
-					if strings.HasPrefix(content, "Error:") {
+					switch update.Type {
+					case domain.StreamTypeContent:
+						response = StreamResponse{
+							Type:    "content",
+							Format:  detectFormat(update.Content),
+							Content: update.Content,
+						}
+					case domain.StreamTypeUsage:
+						response = StreamResponse{
+							Type:  "usage",
+							Usage: update.Usage,
+						}
+					case domain.StreamTypeError:
 						response = StreamResponse{
 							Type:    "error",
 							Format:  "plain",
-							Content: content,
-						}
-					} else {
-						response = StreamResponse{
-							Type:    "content",
-							Format:  detectFormat(content),
-							Content: content,
+							Content: update.Content,
 						}
 					}
+
 					if err := writeSSEResponse(c.Writer, response); err != nil {
 						log.Printf("Error writing response: %v", err)
 						return