Add debug stats

internal/service/service.go

@@ -457,6 +457,10 @@ type Response struct {
 	Provider string `json:"used_provider,omitempty"`
 	// Model is the LLM model used for the response.
 	Model string `json:"used_model,omitempty"`
+	// Usage is token usage from the API response.
+	Usage *llm.Usage `json:"usage,omitempty"`
+	// Timings is llama.cpp timing info from the API response.
+	Timings *llm.Timings `json:"timings,omitempty"`
 }
 
 // chat processes text chat requests.
@@ -536,7 +540,7 @@ func (svc *Service) chat(w http.ResponseWriter, r *http.Request) {
 		}
 	}
 
-	msgs, err := llmc.Completions(
+	res, err := llmc.Completions(
 		ctx, model, req.SystemMessage, 0, req.Messages,
 	)
 	if err != nil {
@@ -548,7 +552,7 @@ func (svc *Service) chat(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "LLM error", http.StatusInternalServerError)
 		return
 	}
-	if len(msgs) == 0 {
+	if len(res.Messages) == 0 {
 		http.Error(
 			w,
 			"no response from LLM",
@@ -556,7 +560,7 @@ func (svc *Service) chat(w http.ResponseWriter, r *http.Request) {
 		)
 		return
 	}
-	final := msgs[len(msgs)-1]
+	final := res.Messages[len(res.Messages)-1]
 	log.DebugContext(
 		ctx,
 		"LLM response",
@@ -567,9 +571,11 @@ func (svc *Service) chat(w http.ResponseWriter, r *http.Request) {
 
 	w.Header().Set("Content-Type", "application/json")
 	if err := json.NewEncoder(w).Encode(Response{
-		Messages: msgs,
+		Messages: res.Messages,
 		Provider: provider,
 		Model:    model,
+		Usage:    res.Usage,
+		Timings:  res.Timings,
 	}); err != nil {
 		log.ErrorContext(
 			ctx,
@@ -593,6 +599,10 @@ type StreamMessage struct {
 	Provider string `json:"provider,omitempty"`
 	// Model is the LLM model used for the response.
 	Model string `json:"model,omitempty"`
+	// Usage is token usage from the API response.
+	Usage *llm.Usage `json:"usage,omitempty"`
+	// Timings is llama.cpp timing info from the API response.
+	Timings *llm.Timings `json:"timings,omitempty"`
 }
 
 // chatStream processes chat requests with streaming SSE output.
@@ -719,6 +729,12 @@ func (svc *Service) chatStream(w http.ResponseWriter, r *http.Request) {
 		if evt.Message.Role != "" {
 			msg.Message = &evt.Message
 		}
+		if evt.Usage != nil {
+			msg.Usage = evt.Usage
+		}
+		if evt.Timings != nil {
+			msg.Timings = evt.Timings
+		}
 		send(evt.Type, msg)
 	}
 	if err := <-errs; err != nil {