refactor: centralize assistant turn semantics and stream accumulation into new assistantturn and completionruntime packages

internal/httpapi/gemini/convert_request.go

@@ -33,6 +33,9 @@ func normalizeGeminiRequest(store ConfigReader, routeModel string, req map[strin
 
 	toolsRaw := convertGeminiTools(req["tools"])
 	finalPrompt, toolNames := promptcompat.BuildOpenAIPromptForAdapter(messagesRaw, toolsRaw, "", thinkingEnabled)
+	if len(toolNames) == 0 && len(toolsRaw) > 0 {
+		toolNames = []string{"__any_tool__"}
+	}
 	passThrough := collectGeminiPassThrough(req)
 
 	return promptcompat.StandardRequest{
@@ -42,6 +45,7 @@ func normalizeGeminiRequest(store ConfigReader, routeModel string, req map[strin
 		ResponseModel:   requestedModel,
 		Messages:        messagesRaw,
 		PromptTokenText: finalPrompt,
+		ToolsRaw:        toolsRaw,
 		FinalPrompt:     finalPrompt,
 		ToolNames:       toolNames,
 		Stream:          stream,

internal/httpapi/gemini/handler_generate.go

@@ -11,7 +11,11 @@ import (
 
 	"github.com/go-chi/chi/v5"
 
+	"ds2api/internal/assistantturn"
+	"ds2api/internal/auth"
+	"ds2api/internal/completionruntime"
 	"ds2api/internal/httpapi/requestbody"
+	"ds2api/internal/promptcompat"
 	"ds2api/internal/sse"
 	"ds2api/internal/toolcall"
 	"ds2api/internal/translatorcliproxy"
@@ -21,14 +25,80 @@ import (
 )
 
 func (h *Handler) handleGenerateContent(w http.ResponseWriter, r *http.Request, stream bool) {
-	if h.OpenAI == nil {
-		writeGeminiError(w, http.StatusInternalServerError, "OpenAI proxy backend unavailable.")
+	if isGeminiVercelProxyRequest(r) && h.proxyViaOpenAI(w, r, stream) {
 		return
 	}
-	if h.proxyViaOpenAI(w, r, stream) {
+	if h.Auth == nil || h.DS == nil {
+		if h.OpenAI != nil && h.proxyViaOpenAI(w, r, stream) {
+			return
+		}
+		writeGeminiError(w, http.StatusInternalServerError, "Gemini runtime backend unavailable.")
 		return
 	}
-	writeGeminiError(w, http.StatusBadGateway, "Failed to proxy Gemini request.")
+	if h.handleGeminiDirect(w, r, stream) {
+		return
+	}
+	writeGeminiError(w, http.StatusBadGateway, "Failed to handle Gemini request.")
+}
+
+func isGeminiVercelProxyRequest(r *http.Request) bool {
+	if r == nil || r.URL == nil {
+		return false
+	}
+	return strings.TrimSpace(r.URL.Query().Get("__stream_prepare")) == "1" ||
+		strings.TrimSpace(r.URL.Query().Get("__stream_release")) == "1"
+}
+
+func (h *Handler) handleGeminiDirect(w http.ResponseWriter, r *http.Request, stream bool) bool {
+	raw, err := io.ReadAll(r.Body)
+	if err != nil {
+		if errors.Is(err, requestbody.ErrInvalidUTF8Body) {
+			writeGeminiError(w, http.StatusBadRequest, "invalid json")
+		} else {
+			writeGeminiError(w, http.StatusBadRequest, "invalid body")
+		}
+		return true
+	}
+	routeModel := strings.TrimSpace(chi.URLParam(r, "model"))
+	var req map[string]any
+	if err := json.Unmarshal(raw, &req); err != nil {
+		writeGeminiError(w, http.StatusBadRequest, "invalid json")
+		return true
+	}
+	stdReq, err := normalizeGeminiRequest(h.Store, routeModel, req, stream)
+	if err != nil {
+		writeGeminiError(w, http.StatusBadRequest, err.Error())
+		return true
+	}
+	a, err := h.Auth.Determine(r)
+	if err != nil {
+		writeGeminiError(w, http.StatusUnauthorized, err.Error())
+		return true
+	}
+	defer h.Auth.Release(a)
+	if stream {
+		h.handleGeminiDirectStream(w, r, a, stdReq)
+		return true
+	}
+	result, outErr := completionruntime.ExecuteNonStreamWithRetry(r.Context(), h.DS, a, stdReq, completionruntime.Options{
+		StripReferenceMarkers: h.compatStripReferenceMarkers(),
+		RetryEnabled:          true,
+	})
+	if outErr != nil {
+		writeGeminiError(w, outErr.Status, outErr.Message)
+		return true
+	}
+	writeJSON(w, http.StatusOK, buildGeminiGenerateContentResponseFromTurn(result.Turn))
+	return true
+}
+
+func (h *Handler) handleGeminiDirectStream(w http.ResponseWriter, r *http.Request, a *auth.RequestAuth, stdReq promptcompat.StandardRequest) {
+	start, outErr := completionruntime.StartCompletion(r.Context(), h.DS, a, stdReq, completionruntime.Options{})
+	if outErr != nil {
+		writeGeminiError(w, outErr.Status, outErr.Message)
+		return
+	}
+	h.handleStreamGenerateContent(w, r, start.Response, stdReq.ResponseModel, stdReq.PromptTokenText, stdReq.Thinking, stdReq.Search, stdReq.ToolNames, stdReq.ToolsRaw)
 }
 
 func (h *Handler) proxyViaOpenAI(w http.ResponseWriter, r *http.Request, stream bool) bool {
@@ -250,6 +320,48 @@ func buildGeminiGenerateContentResponse(model, finalPrompt, finalThinking, final
 	}
 }
 
+func buildGeminiGenerateContentResponseFromTurn(turn assistantturn.Turn) map[string]any {
+	parts := buildGeminiPartsFromTurn(turn)
+	return map[string]any{
+		"candidates": []map[string]any{
+			{
+				"index": 0,
+				"content": map[string]any{
+					"role":  "model",
+					"parts": parts,
+				},
+				"finishReason": "STOP",
+			},
+		},
+		"modelVersion": turn.Model,
+		"usageMetadata": map[string]any{
+			"promptTokenCount":     turn.Usage.InputTokens,
+			"candidatesTokenCount": turn.Usage.OutputTokens,
+			"totalTokenCount":      turn.Usage.TotalTokens,
+		},
+	}
+}
+
+func buildGeminiPartsFromTurn(turn assistantturn.Turn) []map[string]any {
+	if len(turn.ToolCalls) > 0 {
+		parts := make([]map[string]any, 0, len(turn.ToolCalls))
+		for _, tc := range turn.ToolCalls {
+			parts = append(parts, map[string]any{
+				"functionCall": map[string]any{
+					"name": tc.Name,
+					"args": tc.Input,
+				},
+			})
+		}
+		return parts
+	}
+	text := turn.Text
+	if text == "" {
+		text = turn.Thinking
+	}
+	return []map[string]any{{"text": text}}
+}
+
 //nolint:unused // retained for native Gemini non-stream handling path.
 func buildGeminiUsage(model, finalPrompt, finalThinking, finalText string) map[string]any {
 	promptTokens := util.CountPromptTokens(finalPrompt, model)

internal/httpapi/gemini/handler_stream_runtime.go

@@ -7,13 +7,14 @@ import (
 	"strings"
 	"time"
 
+	"ds2api/internal/assistantturn"
 	dsprotocol "ds2api/internal/deepseek/protocol"
 	"ds2api/internal/sse"
 	streamengine "ds2api/internal/stream"
 )
 
 //nolint:unused // retained for native Gemini stream handling path.
-func (h *Handler) handleStreamGenerateContent(w http.ResponseWriter, r *http.Request, resp *http.Response, model, finalPrompt string, thinkingEnabled, searchEnabled bool, toolNames []string) {
+func (h *Handler) handleStreamGenerateContent(w http.ResponseWriter, r *http.Request, resp *http.Response, model, finalPrompt string, thinkingEnabled, searchEnabled bool, toolNames []string, toolsRaw any) {
 	defer func() { _ = resp.Body.Close() }()
 	if resp.StatusCode != http.StatusOK {
 		body, _ := io.ReadAll(resp.Body)
@@ -28,7 +29,7 @@ func (h *Handler) handleStreamGenerateContent(w http.ResponseWriter, r *http.Req
 
 	rc := http.NewResponseController(w)
 	_, canFlush := w.(http.Flusher)
-	runtime := newGeminiStreamRuntime(w, rc, canFlush, model, finalPrompt, thinkingEnabled, searchEnabled, h.compatStripReferenceMarkers(), toolNames)
+	runtime := newGeminiStreamRuntime(w, rc, canFlush, model, finalPrompt, thinkingEnabled, searchEnabled, h.compatStripReferenceMarkers(), toolNames, toolsRaw)
 
 	initialType := "text"
 	if thinkingEnabled {
@@ -64,9 +65,11 @@ type geminiStreamRuntime struct {
 	bufferContent         bool
 	stripReferenceMarkers bool
 	toolNames             []string
+	toolsRaw              any
 
-	thinking strings.Builder
-	text     strings.Builder
+	accumulator       *assistantturn.Accumulator
+	contentFilter     bool
+	responseMessageID int
 }
 
 //nolint:unused // retained for native Gemini stream handling path.
@@ -80,6 +83,7 @@ func newGeminiStreamRuntime(
 	searchEnabled bool,
 	stripReferenceMarkers bool,
 	toolNames []string,
+	toolsRaw any,
 ) *geminiStreamRuntime {
 	return &geminiStreamRuntime{
 		w:                     w,
@@ -92,6 +96,12 @@ func newGeminiStreamRuntime(
 		bufferContent:         len(toolNames) > 0,
 		stripReferenceMarkers: stripReferenceMarkers,
 		toolNames:             toolNames,
+		toolsRaw:              toolsRaw,
+		accumulator: assistantturn.NewAccumulator(assistantturn.AccumulatorOptions{
+			ThinkingEnabled:       thinkingEnabled,
+			SearchEnabled:         searchEnabled,
+			StripReferenceMarkers: stripReferenceMarkers,
+		}),
 	}
 }
 
@@ -111,32 +121,24 @@ func (s *geminiStreamRuntime) onParsed(parsed sse.LineResult) streamengine.Parse
 	if !parsed.Parsed {
 		return streamengine.ParsedDecision{}
 	}
+	if parsed.ResponseMessageID > 0 {
+		s.responseMessageID = parsed.ResponseMessageID
+	}
 	if parsed.ContentFilter || parsed.ErrorMessage != "" || parsed.Stop {
+		if parsed.ContentFilter {
+			s.contentFilter = true
+		}
 		return streamengine.ParsedDecision{Stop: true}
 	}
 
-	contentSeen := false
-	for _, p := range parsed.Parts {
-		cleanedText := cleanVisibleOutput(p.Text, s.stripReferenceMarkers)
-		if cleanedText == "" {
-			continue
-		}
-		if p.Type != "thinking" && s.searchEnabled && sse.IsCitation(cleanedText) {
-			continue
-		}
-		contentSeen = true
+	accumulated := s.accumulator.Apply(parsed)
+	for _, p := range accumulated.Parts {
 		if p.Type == "thinking" {
-			if s.thinkingEnabled {
-				if cleanedText != "" {
-					s.thinking.WriteString(cleanedText)
-				}
-			}
 			continue
 		}
-		if cleanedText == "" {
+		if p.RawText == "" || p.CitationOnly || p.VisibleText == "" {
 			continue
 		}
-		s.text.WriteString(cleanedText)
 		if s.bufferContent {
 			continue
 		}
@@ -146,23 +148,38 @@ func (s *geminiStreamRuntime) onParsed(parsed sse.LineResult) streamengine.Parse
 					"index": 0,
 					"content": map[string]any{
 						"role":  "model",
-						"parts": []map[string]any{{"text": cleanedText}},
+						"parts": []map[string]any{{"text": p.VisibleText}},
 					},
 				},
 			},
 			"modelVersion": s.model,
 		})
 	}
-	return streamengine.ParsedDecision{ContentSeen: contentSeen}
+	return streamengine.ParsedDecision{ContentSeen: accumulated.ContentSeen}
 }
 
 //nolint:unused // retained for native Gemini stream handling path.
 func (s *geminiStreamRuntime) finalize() {
-	finalThinking := s.thinking.String()
-	finalText := cleanVisibleOutput(s.text.String(), s.stripReferenceMarkers)
+	rawText, text, rawThinking, thinking, detectionThinking := s.accumulator.Snapshot()
+	turn := assistantturn.BuildTurnFromStreamSnapshot(assistantturn.StreamSnapshot{
+		RawText:           rawText,
+		VisibleText:       text,
+		RawThinking:       rawThinking,
+		VisibleThinking:   thinking,
+		DetectionThinking: detectionThinking,
+		ContentFilter:     s.contentFilter,
+		ResponseMessageID: s.responseMessageID,
+	}, assistantturn.BuildOptions{
+		Model:                 s.model,
+		Prompt:                s.finalPrompt,
+		SearchEnabled:         s.searchEnabled,
+		StripReferenceMarkers: s.stripReferenceMarkers,
+		ToolNames:             s.toolNames,
+		ToolsRaw:              s.toolsRaw,
+	})
 
 	if s.bufferContent {
-		parts := buildGeminiPartsFromFinal(finalText, finalThinking, s.toolNames)
+		parts := buildGeminiPartsFromTurn(turn)
 		s.sendChunk(map[string]any{
 			"candidates": []map[string]any{
 				{
@@ -190,7 +207,11 @@ func (s *geminiStreamRuntime) finalize() {
 				"finishReason": "STOP",
 			},
 		},
-		"modelVersion":  s.model,
-		"usageMetadata": buildGeminiUsage(s.model, s.finalPrompt, finalThinking, finalText),
+		"modelVersion": s.model,
+		"usageMetadata": map[string]any{
+			"promptTokenCount":     turn.Usage.InputTokens,
+			"candidatesTokenCount": turn.Usage.OutputTokens,
+			"totalTokenCount":      turn.Usage.TotalTokens,
+		},
 	})
 }