Sub2API v1.0 - AI API 网关（二开初始版本，基于上游 Wei-Shaw/sub2api）

2026-08-21 18:30:13 +08:00
commit 6d655c9903
3584 changed files with 1270640 additions and 0 deletions
@@ -0,0 +1,552 @@
+package apicompat
+
+import (
+	"crypto/rand"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"strings"
+	"time"
+)
+
+// ---------------------------------------------------------------------------
+// Non-streaming: ResponsesResponse → ChatCompletionsResponse
+// ---------------------------------------------------------------------------
+
+// ResponsesToChatCompletions converts a Responses API response into a Chat
+// Completions response. Text output items are concatenated into
+// choices[0].message.content; function_call items become tool_calls.
+func ResponsesToChatCompletions(resp *ResponsesResponse, model string) *ChatCompletionsResponse {
+	id := resp.ID
+	if id == "" {
+		id = generateChatCmplID()
+	}
+
+	out := &ChatCompletionsResponse{
+		ID:      id,
+		Object:  "chat.completion",
+		Created: time.Now().Unix(),
+		Model:   model,
+	}
+
+	var contentText string
+	var reasoningText string
+	var toolCalls []ChatToolCall
+
+	for _, item := range resp.Output {
+		switch item.Type {
+		case "message":
+			for _, part := range item.Content {
+				if part.Type == "output_text" && part.Text != "" {
+					contentText += part.Text
+				}
+			}
+		case "function_call":
+			toolCalls = append(toolCalls, ChatToolCall{
+				ID:   item.CallID,
+				Type: "function",
+				Function: ChatFunctionCall{
+					Name:      item.Name,
+					Arguments: item.Arguments,
+				},
+			})
+		case "reasoning":
+			for _, s := range item.Summary {
+				if s.Type == "summary_text" && s.Text != "" {
+					reasoningText += s.Text
+				}
+			}
+		case "web_search_call":
+			// silently consumed — results already incorporated into text output
+		}
+	}
+
+	msg := ChatMessage{Role: "assistant"}
+	if len(toolCalls) > 0 {
+		msg.ToolCalls = toolCalls
+	}
+	if contentText != "" {
+		raw, _ := json.Marshal(contentText)
+		msg.Content = raw
+	}
+	if reasoningText != "" {
+		msg.ReasoningContent = reasoningText
+	}
+
+	finishReason := responsesStatusToChatFinishReason(resp.Status, resp.IncompleteDetails, toolCalls)
+
+	out.Choices = []ChatChoice{{
+		Index:        0,
+		Message:      msg,
+		FinishReason: finishReason,
+	}}
+
+	out.Usage = chatUsageFromResponsesUsage(resp.Usage)
+
+	return out
+}
+
+func responsesStatusToChatFinishReason(status string, details *ResponsesIncompleteDetails, toolCalls []ChatToolCall) string {
+	switch status {
+	case "incomplete":
+		if details != nil {
+			switch details.Reason {
+			case "max_output_tokens":
+				return "length"
+			case "content_filter":
+				return "content_filter"
+			}
+		}
+		return "stop"
+	case "completed":
+		if len(toolCalls) > 0 {
+			return "tool_calls"
+		}
+		return "stop"
+	default:
+		return "stop"
+	}
+}
+
+// ---------------------------------------------------------------------------
+// Streaming: ResponsesStreamEvent → []ChatCompletionsChunk (stateful converter)
+// ---------------------------------------------------------------------------
+
+// ResponsesEventToChatState tracks state for converting a sequence of Responses
+// SSE events into Chat Completions SSE chunks.
+type ResponsesEventToChatState struct {
+	ID                     string
+	Model                  string
+	Created                int64
+	SentRole               bool
+	SawToolCall            bool
+	SawText                bool
+	Finalized              bool        // true after finish chunk has been emitted
+	NextToolCallIndex      int         // next sequential tool_call index to assign
+	OutputIndexToToolIndex map[int]int // Responses output_index → Chat tool_calls index
+	IncludeUsage           bool
+	Usage                  *ChatUsage
+}
+
+// NewResponsesEventToChatState returns an initialised stream state.
+func NewResponsesEventToChatState() *ResponsesEventToChatState {
+	return &ResponsesEventToChatState{
+		ID:                     generateChatCmplID(),
+		Created:                time.Now().Unix(),
+		OutputIndexToToolIndex: make(map[int]int),
+	}
+}
+
+// ResponsesEventToChatChunks converts a single Responses SSE event into zero
+// or more Chat Completions chunks, updating state as it goes.
+func ResponsesEventToChatChunks(evt *ResponsesStreamEvent, state *ResponsesEventToChatState) []ChatCompletionsChunk {
+	switch evt.Type {
+	case "response.created":
+		return resToChatHandleCreated(evt, state)
+	case "response.output_text.delta":
+		return resToChatHandleTextDelta(evt, state)
+	case "response.output_item.added":
+		return resToChatHandleOutputItemAdded(evt, state)
+	case "response.function_call_arguments.delta",
+		// custom/freeform 工具（如新版 apply_patch）的输入增量与 function_call 参数增量同形，
+		// 均按 OutputIndex 累加到对应工具调用。
+		"response.custom_tool_call_input.delta":
+		return resToChatHandleFuncArgsDelta(evt, state)
+	case "response.reasoning_summary_text.delta",
+		// 原始推理文本增量（真实 Codex 客户端消费的 reasoning_text.delta），
+		// 与 reasoning summary 一样映射为 reasoning_content。
+		"response.reasoning_text.delta":
+		return resToChatHandleReasoningDelta(evt, state)
+	case "response.reasoning_summary_text.done":
+		return nil
+	// response.done 是 Realtime/WS 与项目透传路径使用的终止别名；
+	// 普通 Responses HTTP SSE 的公开终止事件仍以 response.completed 为主。
+	case "response.completed", "response.done", "response.incomplete", "response.failed":
+		return resToChatHandleCompleted(evt, state)
+	default:
+		return nil
+	}
+}
+
+// FinalizeResponsesChatStream emits a final chunk with finish_reason if the
+// stream ended without a proper completion event (e.g. upstream disconnect).
+// It is idempotent: if a completion event already emitted the finish chunk,
+// this returns nil.
+func FinalizeResponsesChatStream(state *ResponsesEventToChatState) []ChatCompletionsChunk {
+	if state.Finalized {
+		return nil
+	}
+	state.Finalized = true
+
+	finishReason := "stop"
+	if state.SawToolCall {
+		finishReason = "tool_calls"
+	}
+
+	chunks := []ChatCompletionsChunk{makeChatFinishChunk(state, finishReason)}
+
+	if state.IncludeUsage && state.Usage != nil {
+		chunks = append(chunks, ChatCompletionsChunk{
+			ID:      state.ID,
+			Object:  "chat.completion.chunk",
+			Created: state.Created,
+			Model:   state.Model,
+			Choices: []ChatChunkChoice{},
+			Usage:   state.Usage,
+		})
+	}
+
+	return chunks
+}
+
+// ChatChunkToSSE formats a ChatCompletionsChunk as an SSE data line.
+func ChatChunkToSSE(chunk ChatCompletionsChunk) (string, error) {
+	data, err := json.Marshal(chunk)
+	if err != nil {
+		return "", err
+	}
+	return fmt.Sprintf("data: %s\n\n", data), nil
+}
+
+// --- internal handlers ---
+
+func resToChatHandleCreated(evt *ResponsesStreamEvent, state *ResponsesEventToChatState) []ChatCompletionsChunk {
+	if evt.Response != nil {
+		if evt.Response.ID != "" {
+			state.ID = evt.Response.ID
+		}
+		if state.Model == "" && evt.Response.Model != "" {
+			state.Model = evt.Response.Model
+		}
+	}
+	// Emit the role chunk.
+	if state.SentRole {
+		return nil
+	}
+	state.SentRole = true
+
+	role := "assistant"
+	return []ChatCompletionsChunk{makeChatDeltaChunk(state, ChatDelta{Role: role})}
+}
+
+func resToChatHandleTextDelta(evt *ResponsesStreamEvent, state *ResponsesEventToChatState) []ChatCompletionsChunk {
+	if evt.Delta == "" {
+		return nil
+	}
+	state.SawText = true
+	content := evt.Delta
+	return []ChatCompletionsChunk{makeChatDeltaChunk(state, ChatDelta{Content: &content})}
+}
+
+func resToChatHandleOutputItemAdded(evt *ResponsesStreamEvent, state *ResponsesEventToChatState) []ChatCompletionsChunk {
+	// function_call 与 custom_tool_call（custom/freeform 工具）均按工具调用注册，
+	// 以便后续 *_input.delta / *_arguments.delta 能映射到正确的工具索引。
+	if evt.Item == nil || (evt.Item.Type != "function_call" && evt.Item.Type != "custom_tool_call") {
+		return nil
+	}
+
+	state.SawToolCall = true
+	idx := state.NextToolCallIndex
+	state.OutputIndexToToolIndex[evt.OutputIndex] = idx
+	state.NextToolCallIndex++
+
+	return []ChatCompletionsChunk{makeChatDeltaChunk(state, ChatDelta{
+		ToolCalls: []ChatToolCall{{
+			Index: &idx,
+			ID:    evt.Item.CallID,
+			Type:  "function",
+			Function: ChatFunctionCall{
+				Name: evt.Item.Name,
+			},
+		}},
+	})}
+}
+
+func resToChatHandleFuncArgsDelta(evt *ResponsesStreamEvent, state *ResponsesEventToChatState) []ChatCompletionsChunk {
+	if evt.Delta == "" {
+		return nil
+	}
+
+	idx, ok := state.OutputIndexToToolIndex[evt.OutputIndex]
+	if !ok {
+		return nil
+	}
+
+	return []ChatCompletionsChunk{makeChatDeltaChunk(state, ChatDelta{
+		ToolCalls: []ChatToolCall{{
+			Index: &idx,
+			Function: ChatFunctionCall{
+				Arguments: evt.Delta,
+			},
+		}},
+	})}
+}
+
+func resToChatHandleReasoningDelta(evt *ResponsesStreamEvent, state *ResponsesEventToChatState) []ChatCompletionsChunk {
+	if evt.Delta == "" {
+		return nil
+	}
+	reasoning := evt.Delta
+	return []ChatCompletionsChunk{makeChatDeltaChunk(state, ChatDelta{ReasoningContent: &reasoning})}
+}
+
+func resToChatHandleCompleted(evt *ResponsesStreamEvent, state *ResponsesEventToChatState) []ChatCompletionsChunk {
+	state.Finalized = true
+	finishReason := "stop"
+
+	if evt.Usage != nil {
+		state.Usage = chatUsageFromResponsesUsage(evt.Usage)
+	}
+	if evt.Response != nil {
+		if evt.Response.Usage != nil {
+			state.Usage = chatUsageFromResponsesUsage(evt.Response.Usage)
+		}
+
+		switch evt.Response.Status {
+		case "incomplete":
+			if evt.Response.IncompleteDetails != nil {
+				switch evt.Response.IncompleteDetails.Reason {
+				case "max_output_tokens":
+					finishReason = "length"
+				case "content_filter":
+					finishReason = "content_filter"
+				}
+			}
+		case "completed":
+			if state.SawToolCall {
+				finishReason = "tool_calls"
+			}
+		}
+	} else if state.SawToolCall {
+		finishReason = "tool_calls"
+	}
+
+	var chunks []ChatCompletionsChunk
+	chunks = append(chunks, makeChatFinishChunk(state, finishReason))
+
+	if state.IncludeUsage && state.Usage != nil {
+		chunks = append(chunks, ChatCompletionsChunk{
+			ID:      state.ID,
+			Object:  "chat.completion.chunk",
+			Created: state.Created,
+			Model:   state.Model,
+			Choices: []ChatChunkChoice{},
+			Usage:   state.Usage,
+		})
+	}
+
+	return chunks
+}
+
+func chatUsageFromResponsesUsage(u *ResponsesUsage) *ChatUsage {
+	if u == nil {
+		return nil
+	}
+	usage := &ChatUsage{
+		PromptTokens:     u.InputTokens,
+		CompletionTokens: u.OutputTokens,
+		TotalTokens:      u.InputTokens + u.OutputTokens,
+	}
+	usage.PromptTokensDetails = promptDetailsFromResponses(u.InputTokensDetails)
+	if u.CacheCreationInputTokens > 0 {
+		if usage.PromptTokensDetails == nil {
+			usage.PromptTokensDetails = &ChatTokenDetails{}
+		}
+		if usage.PromptTokensDetails.CacheWriteTokens == 0 && usage.PromptTokensDetails.CacheCreationTokens == 0 {
+			usage.PromptTokensDetails.CacheCreationTokens = u.CacheCreationInputTokens
+		}
+	}
+	usage.CompletionTokensDetails = completionDetailsFromResponses(u.OutputTokensDetails)
+	return usage
+}
+
+// promptDetailsFromResponses maps Responses-API input_tokens_details into a
+// Chat-Completions prompt_tokens_details. Returns nil when nothing would be
+// emitted, so upstreams that do not break down prompt usage stay clean.
+func promptDetailsFromResponses(src *ResponsesInputTokensDetails) *ChatTokenDetails {
+	if src == nil {
+		return nil
+	}
+	if src.CachedTokens == 0 && src.AudioTokens == 0 && src.CacheCreationTokens == 0 && src.CacheWriteTokens == 0 {
+		return nil
+	}
+	return &ChatTokenDetails{
+		CachedTokens:        src.CachedTokens,
+		AudioTokens:         src.AudioTokens,
+		CacheCreationTokens: src.CacheCreationTokens,
+		CacheWriteTokens:    src.CacheWriteTokens,
+	}
+}
+
+// completionDetailsFromResponses maps Responses-API output_tokens_details
+// into a Chat-Completions completion_tokens_details. Mirrors the OpenAI
+// official CompletionUsage schema: reasoning_tokens, audio_tokens, and
+// the predicted-outputs accepted/rejected counts. Returns nil when nothing
+// would be emitted so non-reasoning, non-audio responses stay clean.
+func completionDetailsFromResponses(src *ResponsesOutputTokensDetails) *ChatTokenDetails {
+	if src == nil {
+		return nil
+	}
+	if src.ReasoningTokens == 0 && src.AudioTokens == 0 &&
+		src.AcceptedPredictionTokens == 0 && src.RejectedPredictionTokens == 0 {
+		return nil
+	}
+	return &ChatTokenDetails{
+		ReasoningTokens:          src.ReasoningTokens,
+		AudioTokens:              src.AudioTokens,
+		AcceptedPredictionTokens: src.AcceptedPredictionTokens,
+		RejectedPredictionTokens: src.RejectedPredictionTokens,
+	}
+}
+
+func makeChatDeltaChunk(state *ResponsesEventToChatState, delta ChatDelta) ChatCompletionsChunk {
+	return ChatCompletionsChunk{
+		ID:      state.ID,
+		Object:  "chat.completion.chunk",
+		Created: state.Created,
+		Model:   state.Model,
+		Choices: []ChatChunkChoice{{
+			Index:        0,
+			Delta:        delta,
+			FinishReason: nil,
+		}},
+	}
+}
+
+func makeChatFinishChunk(state *ResponsesEventToChatState, finishReason string) ChatCompletionsChunk {
+	empty := ""
+	return ChatCompletionsChunk{
+		ID:      state.ID,
+		Object:  "chat.completion.chunk",
+		Created: state.Created,
+		Model:   state.Model,
+		Choices: []ChatChunkChoice{{
+			Index:        0,
+			Delta:        ChatDelta{Content: &empty},
+			FinishReason: &finishReason,
+		}},
+	}
+}
+
+// generateChatCmplID returns a "chatcmpl-" prefixed random hex ID.
+func generateChatCmplID() string {
+	b := make([]byte, 12)
+	_, _ = rand.Read(b)
+	return "chatcmpl-" + hex.EncodeToString(b)
+}
+
+// ---------------------------------------------------------------------------
+// BufferedResponseAccumulator: accumulates SSE delta events for non-streaming
+// paths where the terminal event may have empty output.
+// ---------------------------------------------------------------------------
+
+type bufferedFuncCall struct {
+	CallID string
+	Name   string
+	Args   strings.Builder
+}
+
+// BufferedResponseAccumulator collects content from Responses SSE delta events
+// so that non-streaming handlers can reconstruct output when the terminal event
+// (response.completed / response.done) carries an empty output array.
+type BufferedResponseAccumulator struct {
+	text                 strings.Builder
+	reasoning            strings.Builder
+	funcCalls            []bufferedFuncCall
+	outputIndexToFuncIdx map[int]int
+}
+
+// NewBufferedResponseAccumulator returns an initialised accumulator.
+func NewBufferedResponseAccumulator() *BufferedResponseAccumulator {
+	return &BufferedResponseAccumulator{
+		outputIndexToFuncIdx: make(map[int]int),
+	}
+}
+
+// ProcessEvent inspects a single Responses SSE event and accumulates any
+// content it carries. Only delta events that contribute to the final output
+// are handled; all other event types are silently ignored.
+func (a *BufferedResponseAccumulator) ProcessEvent(event *ResponsesStreamEvent) {
+	switch event.Type {
+	case "response.output_text.delta":
+		if event.Delta != "" {
+			_, _ = a.text.WriteString(event.Delta)
+		}
+	case "response.output_item.added":
+		if event.Item != nil && (event.Item.Type == "function_call" || event.Item.Type == "custom_tool_call") {
+			idx := len(a.funcCalls)
+			a.outputIndexToFuncIdx[event.OutputIndex] = idx
+			a.funcCalls = append(a.funcCalls, bufferedFuncCall{
+				CallID: event.Item.CallID,
+				Name:   event.Item.Name,
+			})
+		}
+	case "response.function_call_arguments.delta", "response.custom_tool_call_input.delta":
+		if event.Delta != "" {
+			if idx, ok := a.outputIndexToFuncIdx[event.OutputIndex]; ok {
+				_, _ = a.funcCalls[idx].Args.WriteString(event.Delta)
+			}
+		}
+	case "response.reasoning_summary_text.delta", "response.reasoning_text.delta":
+		if event.Delta != "" {
+			_, _ = a.reasoning.WriteString(event.Delta)
+		}
+	}
+}
+
+// HasContent reports whether any content has been accumulated.
+func (a *BufferedResponseAccumulator) HasContent() bool {
+	return a.text.Len() > 0 || len(a.funcCalls) > 0 || a.reasoning.Len() > 0
+}
+
+// BuildOutput constructs a []ResponsesOutput from the accumulated delta
+// content. The order matches what ResponsesToChatCompletions expects:
+// reasoning → message → function_calls.
+func (a *BufferedResponseAccumulator) BuildOutput() []ResponsesOutput {
+	var out []ResponsesOutput
+
+	if a.reasoning.Len() > 0 {
+		out = append(out, ResponsesOutput{
+			Type: "reasoning",
+			Summary: []ResponsesSummary{{
+				Type: "summary_text",
+				Text: a.reasoning.String(),
+			}},
+		})
+	}
+
+	if a.text.Len() > 0 {
+		out = append(out, ResponsesOutput{
+			Type: "message",
+			Role: "assistant",
+			Content: []ResponsesContentPart{{
+				Type: "output_text",
+				Text: a.text.String(),
+			}},
+		})
+	}
+
+	for i := range a.funcCalls {
+		out = append(out, ResponsesOutput{
+			Type:      "function_call",
+			CallID:    a.funcCalls[i].CallID,
+			Name:      a.funcCalls[i].Name,
+			Arguments: a.funcCalls[i].Args.String(),
+		})
+	}
+
+	return out
+}
+
+// SupplementResponseOutput fills resp.Output from accumulated delta content
+// when the terminal event delivered an empty output array. If resp.Output is
+// already populated, this is a no-op (preserves backward compatibility).
+func (a *BufferedResponseAccumulator) SupplementResponseOutput(resp *ResponsesResponse) {
+	if resp == nil || len(resp.Output) > 0 {
+		return
+	}
+	if !a.HasContent() {
+		return
+	}
+	resp.Output = a.BuildOutput()
+}