sub2api/backend/internal/service/openai_ws_v2_passthrough_adapter.go

package service

import (
	"context"
	"errors"
	"fmt"
	"net/http"
	"net/url"
	"strings"
	"sync/atomic"

	"github.com/Wei-Shaw/sub2api/internal/pkg/logger"
	"github.com/Wei-Shaw/sub2api/internal/pkg/openai"
	openaiwsv2 "github.com/Wei-Shaw/sub2api/internal/service/openai_ws_v2"
	coderws "github.com/coder/websocket"
	"github.com/gin-gonic/gin"
	"github.com/tidwall/gjson"
)

type openAIWSClientFrameConn struct {
	conn *coderws.Conn
}

// openAIWSPolicyEnforcingFrameConn wraps a client-side FrameConn and runs
// every client→upstream frame through the OpenAI Fast Policy. It is the
// passthrough-relay equivalent of the parseClientPayload integration in the
// ingress session path. filter returns:
//   - newPayload, nil, nil: forward the (possibly mutated) payload
//   - _, *OpenAIFastBlockedError, nil: block — the wrapper sends an error
//     event via onBlock and surfaces a transport-level error so the relay
//     stops reading from the client.
//   - _, _, err: a transport error other than block.
type openAIWSPolicyEnforcingFrameConn struct {
	inner   openaiwsv2.FrameConn
	filter  func(msgType coderws.MessageType, payload []byte) ([]byte, *OpenAIFastBlockedError, error)
	onBlock func(blocked *OpenAIFastBlockedError)
}

var _ openaiwsv2.FrameConn = (*openAIWSPolicyEnforcingFrameConn)(nil)

func (c *openAIWSPolicyEnforcingFrameConn) ReadFrame(ctx context.Context) (coderws.MessageType, []byte, error) {
	if c == nil || c.inner == nil {
		return coderws.MessageText, nil, errOpenAIWSConnClosed
	}
	msgType, payload, err := c.inner.ReadFrame(ctx)
	if err != nil {
		return msgType, payload, err
	}
	if c.filter == nil {
		return msgType, payload, nil
	}
	updated, blocked, filterErr := c.filter(msgType, payload)
	if filterErr != nil {
		return msgType, payload, filterErr
	}
	if blocked != nil {
		if c.onBlock != nil {
			c.onBlock(blocked)
		}
		return msgType, nil, NewOpenAIWSClientCloseError(coderws.StatusPolicyViolation, blocked.Message, blocked)
	}
	return msgType, updated, nil
}

func (c *openAIWSPolicyEnforcingFrameConn) WriteFrame(ctx context.Context, msgType coderws.MessageType, payload []byte) error {
	if c == nil || c.inner == nil {
		return errOpenAIWSConnClosed
	}
	return c.inner.WriteFrame(ctx, msgType, payload)
}

func (c *openAIWSPolicyEnforcingFrameConn) Close() error {
	if c == nil || c.inner == nil {
		return nil
	}
	return c.inner.Close()
}

// openAIWSPassthroughPolicyModelForFrame returns the upstream-perspective
// model name that should be passed to evaluateOpenAIFastPolicy for a single
// passthrough WS frame. Mirrors the HTTP-side normalization
// (account.GetMappedModel + normalizeOpenAIModelForUpstream) so the WS path
// matches model whitelists identically.
func openAIWSPassthroughPolicyModelForFrame(account *Account, payload []byte) string {
	if account == nil || len(payload) == 0 {
		return ""
	}
	original := strings.TrimSpace(gjson.GetBytes(payload, "model").String())
	if original == "" {
		return ""
	}
	return normalizeOpenAIModelForUpstream(account, account.GetMappedModel(original))
}

// openAIWSPassthroughPolicyModelFromSessionFrame returns the upstream model
// derived from a session.update frame's session.model field. Returns "" when
// the frame is not a session.update event or carries no session.model. Used
// by the per-frame policy filter (client→upstream direction) to keep
// capturedSessionModel in sync with the session-level model the client may
// rotate mid-session.
//
// Realtime / Responses WS lets the client change the session model after
// the WS handshake via:
//
//	{"type":"session.update","session":{"model":"gpt-5.5", ...}}
//
// If we only capture the model from the very first frame, a client can ship
// gpt-4o on the first response.create (whitelisted as pass), then
// session.update to gpt-5.5, then send response.create without "model" so
// the per-frame resolver returns "" and the stale capturedSessionModel falls
// back to gpt-4o — defeating the gpt-5.5 fast-policy filter.
func openAIWSPassthroughPolicyModelFromSessionFrame(account *Account, payload []byte) string {
	if account == nil || len(payload) == 0 {
		return ""
	}
	frameType := strings.TrimSpace(gjson.GetBytes(payload, "type").String())
	if frameType != "session.update" {
		return ""
	}
	original := strings.TrimSpace(gjson.GetBytes(payload, "session.model").String())
	if original == "" {
		return ""
	}
	return normalizeOpenAIModelForUpstream(account, account.GetMappedModel(original))
}

const openaiWSV2PassthroughModeFields = "ws_mode=passthrough ws_router=v2"

var _ openaiwsv2.FrameConn = (*openAIWSClientFrameConn)(nil)

func (c *openAIWSClientFrameConn) ReadFrame(ctx context.Context) (coderws.MessageType, []byte, error) {
	if c == nil || c.conn == nil {
		return coderws.MessageText, nil, errOpenAIWSConnClosed
	}
	if ctx == nil {
		ctx = context.Background()
	}
	return c.conn.Read(ctx)
}

func (c *openAIWSClientFrameConn) WriteFrame(ctx context.Context, msgType coderws.MessageType, payload []byte) error {
	if c == nil || c.conn == nil {
		return errOpenAIWSConnClosed
	}
	if ctx == nil {
		ctx = context.Background()
	}
	return c.conn.Write(ctx, msgType, payload)
}

func (c *openAIWSClientFrameConn) Close() error {
	if c == nil || c.conn == nil {
		return nil
	}
	_ = c.conn.Close(coderws.StatusNormalClosure, "")
	_ = c.conn.CloseNow()
	return nil
}

func (s *OpenAIGatewayService) proxyResponsesWebSocketV2Passthrough(
	ctx context.Context,
	c *gin.Context,
	clientConn *coderws.Conn,
	account *Account,
	token string,
	firstClientMessage []byte,
	hooks *OpenAIWSIngressHooks,
	wsDecision OpenAIWSProtocolDecision,
) error {
	if s == nil {
		return errors.New("service is nil")
	}
	if clientConn == nil {
		return errors.New("client websocket is nil")
	}
	if account == nil {
		return errors.New("account is nil")
	}
	if strings.TrimSpace(token) == "" {
		return errors.New("token is empty")
	}
	requestModel := strings.TrimSpace(gjson.GetBytes(firstClientMessage, "model").String())
	requestPreviousResponseID := strings.TrimSpace(gjson.GetBytes(firstClientMessage, "previous_response_id").String())
	logOpenAIWSV2Passthrough(
		"relay_start account_id=%d model=%s previous_response_id=%s first_message_type=%s first_message_bytes=%d",
		account.ID,
		truncateOpenAIWSLogValue(requestModel, openAIWSLogValueMaxLen),
		truncateOpenAIWSLogValue(requestPreviousResponseID, openAIWSIDValueMaxLen),
		openaiwsv2RelayMessageTypeName(coderws.MessageText),
		len(firstClientMessage),
	)

	// Apply OpenAI Fast Policy on the first response.create frame. Subsequent
	// frames are filtered via a wrapping FrameConn below so every client→
	// upstream frame goes through the same policy evaluator/normalize/scope as
	// HTTP entrypoints.
	//
	// We capture the session-level model from the first frame here so the
	// per-frame filter (below) can fall back to it when a follow-up frame
	// omits "model" — Realtime clients are allowed to send response.create
	// without re-stating the model, in which case the upstream uses the model
	// negotiated at session.update time. Without this fallback, an empty
	// model would miss the default ["gpt-5.5","gpt-5.5*"] whitelist and be
	// silently passed through, defeating the policy on every frame after
	// the first.
	capturedSessionModel := openAIWSPassthroughPolicyModelForFrame(account, firstClientMessage)
	updatedFirst, blocked, policyErr := s.applyOpenAIFastPolicyToWSResponseCreate(ctx, account, capturedSessionModel, firstClientMessage)
	if policyErr != nil {
		return fmt.Errorf("apply openai fast policy on first ws frame: %w", policyErr)
	}
	if blocked != nil {
		// coder/websocket@v1.8.14 Conn.Write is synchronous: it acquires
		// writeFrameMu, writes the entire frame, and Flushes the underlying
		// bufio writer before returning (write.go:42 → write.go:307-311).
		// The subsequent close handshake re-acquires the same writeFrameMu
		// to send the close frame, so the error event is guaranteed to
		// reach the kernel send buffer before any close frame is queued.
		// No explicit flush hop is required here.
		eventBytes := buildOpenAIFastPolicyBlockedWSEvent(blocked)
		if eventBytes != nil {
			writeCtx, cancelWrite := context.WithTimeout(ctx, s.openAIWSWriteTimeout())
			_ = clientConn.Write(writeCtx, coderws.MessageText, eventBytes)
			cancelWrite()
		}
		return NewOpenAIWSClientCloseError(coderws.StatusPolicyViolation, blocked.Message, blocked)
	}
	firstClientMessage = updatedFirst

	// 在 policy filter 之后再提取 service_tier 用于 billing 上报：filter
	// 命中时 service_tier 已经从 firstClientMessage 中删除，billing 应当
	// 反映上游实际处理的 tier（nil = default），而不是用户最初请求的
	// "priority"。HTTP 入口（line ~2728 extractOpenAIServiceTier(reqBody)）
	// 与 WS ingress（openai_ws_forwarder.go:2991 取自 payload）的语义一致。
	//
	// 多轮 passthrough：OpenAI Realtime / Responses WS 协议允许客户端在
	// 同一连接的不同 response.create 帧上发送不同 service_tier（参考
	// codex-rs/core/src/client.rs build_responses_request 每次重新填值）。
	// 因此使用 atomic.Pointer[string] 在 filter（runClientToUpstream
	// goroutine）和 OnTurnComplete / final result（runUpstreamToClient
	// goroutine）之间同步当前 turn 的 service_tier。
	// extractOpenAIServiceTierFromBody 返回 *string，本身是指针类型，
	// 可直接 Store/Load 而无需额外封装。
	var requestServiceTierPtr atomic.Pointer[string]
	requestServiceTierPtr.Store(extractOpenAIServiceTierFromBody(firstClientMessage))

	wsURL, err := s.buildOpenAIResponsesWSURL(account)
	if err != nil {
		return fmt.Errorf("build ws url: %w", err)
	}
	wsHost := "-"
	wsPath := "-"
	if parsedURL, parseErr := url.Parse(wsURL); parseErr == nil && parsedURL != nil {
		wsHost = normalizeOpenAIWSLogValue(parsedURL.Host)
		wsPath = normalizeOpenAIWSLogValue(parsedURL.Path)
	}
	logOpenAIWSV2Passthrough(
		"relay_dial_start account_id=%d ws_host=%s ws_path=%s proxy_enabled=%v",
		account.ID,
		wsHost,
		wsPath,
		account.ProxyID != nil && account.Proxy != nil,
	)

	isCodexCLI := false
	if c != nil {
		isCodexCLI = openai.IsCodexOfficialClientByHeaders(c.GetHeader("User-Agent"), c.GetHeader("originator"))
	}
	if s.cfg != nil && s.cfg.Gateway.ForceCodexCLI {
		isCodexCLI = true
	}
	headers, _ := s.buildOpenAIWSHeaders(c, account, token, wsDecision, isCodexCLI, "", "", "")
	proxyURL := ""
	if account.ProxyID != nil && account.Proxy != nil {
		proxyURL = account.Proxy.URL()
	}

	dialer := s.getOpenAIWSPassthroughDialer()
	if dialer == nil {
		return errors.New("openai ws passthrough dialer is nil")
	}

	dialCtx, cancelDial := context.WithTimeout(ctx, s.openAIWSDialTimeout())
	defer cancelDial()
	upstreamConn, statusCode, handshakeHeaders, err := dialer.Dial(dialCtx, wsURL, headers, proxyURL)
	if err != nil {
		logOpenAIWSV2Passthrough(
			"relay_dial_failed account_id=%d status_code=%d err=%s",
			account.ID,
			statusCode,
			truncateOpenAIWSLogValue(err.Error(), openAIWSLogValueMaxLen),
		)
		return s.mapOpenAIWSPassthroughDialError(err, statusCode, handshakeHeaders)
	}
	defer func() {
		_ = upstreamConn.Close()
	}()
	logOpenAIWSV2Passthrough(
		"relay_dial_ok account_id=%d status_code=%d upstream_request_id=%s",
		account.ID,
		statusCode,
		openAIWSHeaderValueForLog(handshakeHeaders, "x-request-id"),
	)

	upstreamFrameConn, ok := upstreamConn.(openaiwsv2.FrameConn)
	if !ok {
		return errors.New("openai ws passthrough upstream connection does not support frame relay")
	}

	completedTurns := atomic.Int32{}
	policyClientConn := &openAIWSPolicyEnforcingFrameConn{
		inner: &openAIWSClientFrameConn{conn: clientConn},
		// 注意线程安全：filter 仅在 runClientToUpstream 这一条
		// goroutine 中被调用（passthrough_relay.go: ReadFrame loop），
		// capturedSessionModel 的读写都发生在该 goroutine 内，因此无需
		// 加锁/原子化。
		filter: func(msgType coderws.MessageType, payload []byte) ([]byte, *OpenAIFastBlockedError, error) {
			if msgType != coderws.MessageText {
				return payload, nil, nil
			}
			// 在评估策略前先刷新 capturedSessionModel：客户端可能通过
			// session.update 修改 session-level model（Realtime /
			// Responses WS 协议允许），如果不刷新就会出现
			// "首帧 model=gpt-4o（pass）→ session.update 改成 gpt-5.5
			// → 不带 model 的 response.create fallback 到 gpt-4o" 的
			// 绕过路径。这里只看 session.update 事件中的 session.model
			// 字段，response.create 自己的 model 仍然由其本帧字段决定。
			if updated := openAIWSPassthroughPolicyModelFromSessionFrame(account, payload); updated != "" {
				capturedSessionModel = updated
			}
			// Per-frame model first; if the client omits "model" on a
			// follow-up frame (legal in Realtime), fall back to the
			// session-level model captured from the first frame so the
			// model whitelist still resolves. An empty model would miss
			// any whitelist and silently fall back to pass.
			model := openAIWSPassthroughPolicyModelForFrame(account, payload)
			if model == "" {
				model = capturedSessionModel
			}
			out, blocked, policyErr := s.applyOpenAIFastPolicyToWSResponseCreate(ctx, account, model, payload)
			// 多轮 passthrough billing：仅在成功（non-block / non-err）
			// 的 response.create 帧上更新 requestServiceTierPtr，使用
			// filter 处理后的 payload，与首帧 policy-after-extract 语义
			// 保持一致（参见上方 extractOpenAIServiceTierFromBody 注释）。
			//   - 非 response.create 帧（response.cancel /
			//     conversation.item.create / session.update 等）不携带
			//     per-response service_tier，不应覆盖前一轮值。
			//   - blocked != nil：该帧不会发送上游，billing tier 应保持
			//     上一轮值。
			//   - policyErr != nil：异常路径，保持上一轮值。
			//   - 不带 service_tier 的 response.create 会让
			//     extractOpenAIServiceTierFromBody 返回 nil；这里有意
			//     覆盖（Store(nil)），因为 OpenAI 上游对该帧实际不传
			//     service_tier 时按 default 处理，billing 应如实反映。
			if policyErr == nil && blocked == nil &&
				strings.TrimSpace(gjson.GetBytes(payload, "type").String()) == "response.create" {
				requestServiceTierPtr.Store(extractOpenAIServiceTierFromBody(out))
			}
			return out, blocked, policyErr
		},
		onBlock: func(blocked *OpenAIFastBlockedError) {
			// See note above on Conn.Write being synchronous w.r.t. flush;
			// no explicit flush is required to ensure the error event lands
			// before the close frame.
			eventBytes := buildOpenAIFastPolicyBlockedWSEvent(blocked)
			if eventBytes == nil {
				return
			}
			writeCtx, cancel := context.WithTimeout(ctx, s.openAIWSWriteTimeout())
			_ = clientConn.Write(writeCtx, coderws.MessageText, eventBytes)
			cancel()
		},
	}
	relayResult, relayExit := openaiwsv2.RunEntry(openaiwsv2.EntryInput{
		Ctx:                ctx,
		ClientConn:         policyClientConn,
		UpstreamConn:       upstreamFrameConn,
		FirstClientMessage: firstClientMessage,
		Options: openaiwsv2.RelayOptions{
			WriteTimeout:     s.openAIWSWriteTimeout(),
			IdleTimeout:      s.openAIWSPassthroughIdleTimeout(),
			FirstMessageType: coderws.MessageText,
			OnUsageParseFailure: func(eventType string, usageRaw string) {
				logOpenAIWSV2Passthrough(
					"usage_parse_failed event_type=%s usage_raw=%s",
					truncateOpenAIWSLogValue(eventType, openAIWSLogValueMaxLen),
					truncateOpenAIWSLogValue(usageRaw, openAIWSLogValueMaxLen),
				)
			},
			OnTurnComplete: func(turn openaiwsv2.RelayTurnResult) {
				turnNo := int(completedTurns.Add(1))
				turnResult := &OpenAIForwardResult{
					RequestID: turn.RequestID,
					Usage: OpenAIUsage{
						InputTokens:              turn.Usage.InputTokens,
						OutputTokens:             turn.Usage.OutputTokens,
						CacheCreationInputTokens: turn.Usage.CacheCreationInputTokens,
						CacheReadInputTokens:     turn.Usage.CacheReadInputTokens,
					},
					Model:           turn.RequestModel,
					ServiceTier:     requestServiceTierPtr.Load(),
					Stream:          true,
					OpenAIWSMode:    true,
					ResponseHeaders: cloneHeader(handshakeHeaders),
					Duration:        turn.Duration,
					FirstTokenMs:    turn.FirstTokenMs,
				}
				logOpenAIWSV2Passthrough(
					"relay_turn_completed account_id=%d turn=%d request_id=%s terminal_event=%s duration_ms=%d first_token_ms=%d input_tokens=%d output_tokens=%d cache_read_tokens=%d",
					account.ID,
					turnNo,
					truncateOpenAIWSLogValue(turnResult.RequestID, openAIWSIDValueMaxLen),
					truncateOpenAIWSLogValue(turn.TerminalEventType, openAIWSLogValueMaxLen),
					turnResult.Duration.Milliseconds(),
					openAIWSFirstTokenMsForLog(turnResult.FirstTokenMs),
					turnResult.Usage.InputTokens,
					turnResult.Usage.OutputTokens,
					turnResult.Usage.CacheReadInputTokens,
				)
				if hooks != nil && hooks.AfterTurn != nil {
					hooks.AfterTurn(turnNo, turnResult, nil)
				}
			},
			OnTrace: func(event openaiwsv2.RelayTraceEvent) {
				logOpenAIWSV2Passthrough(
					"relay_trace account_id=%d stage=%s direction=%s msg_type=%s bytes=%d graceful=%v wrote_downstream=%v err=%s",
					account.ID,
					truncateOpenAIWSLogValue(event.Stage, openAIWSLogValueMaxLen),
					truncateOpenAIWSLogValue(event.Direction, openAIWSLogValueMaxLen),
					truncateOpenAIWSLogValue(event.MessageType, openAIWSLogValueMaxLen),
					event.PayloadBytes,
					event.Graceful,
					event.WroteDownstream,
					truncateOpenAIWSLogValue(event.Error, openAIWSLogValueMaxLen),
				)
			},
		},
	})

	result := &OpenAIForwardResult{
		RequestID: relayResult.RequestID,
		Usage: OpenAIUsage{
			InputTokens:              relayResult.Usage.InputTokens,
			OutputTokens:             relayResult.Usage.OutputTokens,
			CacheCreationInputTokens: relayResult.Usage.CacheCreationInputTokens,
			CacheReadInputTokens:     relayResult.Usage.CacheReadInputTokens,
		},
		Model:           relayResult.RequestModel,
		ServiceTier:     requestServiceTierPtr.Load(),
		Stream:          true,
		OpenAIWSMode:    true,
		ResponseHeaders: cloneHeader(handshakeHeaders),
		Duration:        relayResult.Duration,
		FirstTokenMs:    relayResult.FirstTokenMs,
	}

	turnCount := int(completedTurns.Load())
	if relayExit == nil {
		logOpenAIWSV2Passthrough(
			"relay_completed account_id=%d request_id=%s terminal_event=%s duration_ms=%d c2u_frames=%d u2c_frames=%d dropped_frames=%d turns=%d",
			account.ID,
			truncateOpenAIWSLogValue(result.RequestID, openAIWSIDValueMaxLen),
			truncateOpenAIWSLogValue(relayResult.TerminalEventType, openAIWSLogValueMaxLen),
			result.Duration.Milliseconds(),
			relayResult.ClientToUpstreamFrames,
			relayResult.UpstreamToClientFrames,
			relayResult.DroppedDownstreamFrames,
			turnCount,
		)
		// 正常路径按 terminal 事件逐 turn 已回调；仅在零 turn 场景兜底回调一次。
		if turnCount == 0 && hooks != nil && hooks.AfterTurn != nil {
			hooks.AfterTurn(1, result, nil)
		}
		return nil
	}
	logOpenAIWSV2Passthrough(
		"relay_failed account_id=%d stage=%s wrote_downstream=%v err=%s duration_ms=%d c2u_frames=%d u2c_frames=%d dropped_frames=%d turns=%d",
		account.ID,
		truncateOpenAIWSLogValue(relayExit.Stage, openAIWSLogValueMaxLen),
		relayExit.WroteDownstream,
		truncateOpenAIWSLogValue(relayErrorText(relayExit.Err), openAIWSLogValueMaxLen),
		result.Duration.Milliseconds(),
		relayResult.ClientToUpstreamFrames,
		relayResult.UpstreamToClientFrames,
		relayResult.DroppedDownstreamFrames,
		turnCount,
	)

	relayErr := relayExit.Err
	if relayExit.Stage == "idle_timeout" {
		relayErr = NewOpenAIWSClientCloseError(
			coderws.StatusPolicyViolation,
			"client websocket idle timeout",
			relayErr,
		)
	}
	turnErr := wrapOpenAIWSIngressTurnError(
		relayExit.Stage,
		relayErr,
		relayExit.WroteDownstream,
	)
	if hooks != nil && hooks.AfterTurn != nil {
		hooks.AfterTurn(turnCount+1, nil, turnErr)
	}
	return turnErr
}

func (s *OpenAIGatewayService) mapOpenAIWSPassthroughDialError(
	err error,
	statusCode int,
	handshakeHeaders http.Header,
) error {
	if err == nil {
		return nil
	}
	wrappedErr := err
	var dialErr *openAIWSDialError
	if !errors.As(err, &dialErr) {
		wrappedErr = &openAIWSDialError{
			StatusCode:      statusCode,
			ResponseHeaders: cloneHeader(handshakeHeaders),
			Err:             err,
		}
	}

	if errors.Is(err, context.Canceled) {
		return err
	}
	if errors.Is(err, context.DeadlineExceeded) {
		return NewOpenAIWSClientCloseError(
			coderws.StatusTryAgainLater,
			"upstream websocket connect timeout",
			wrappedErr,
		)
	}
	if statusCode == http.StatusTooManyRequests {
		return NewOpenAIWSClientCloseError(
			coderws.StatusTryAgainLater,
			"upstream websocket is busy, please retry later",
			wrappedErr,
		)
	}
	if statusCode == http.StatusUnauthorized || statusCode == http.StatusForbidden {
		return NewOpenAIWSClientCloseError(
			coderws.StatusPolicyViolation,
			"upstream websocket authentication failed",
			wrappedErr,
		)
	}
	if statusCode >= http.StatusBadRequest && statusCode < http.StatusInternalServerError {
		return NewOpenAIWSClientCloseError(
			coderws.StatusPolicyViolation,
			"upstream websocket handshake rejected",
			wrappedErr,
		)
	}
	return fmt.Errorf("openai ws passthrough dial: %w", wrappedErr)
}

func openaiwsv2RelayMessageTypeName(msgType coderws.MessageType) string {
	switch msgType {
	case coderws.MessageText:
		return "text"
	case coderws.MessageBinary:
		return "binary"
	default:
		return fmt.Sprintf("unknown(%d)", msgType)
	}
}

func relayErrorText(err error) string {
	if err == nil {
		return ""
	}
	return err.Error()
}

func openAIWSFirstTokenMsForLog(firstTokenMs *int) int {
	if firstTokenMs == nil {
		return -1
	}
	return *firstTokenMs
}

func logOpenAIWSV2Passthrough(format string, args ...any) {
	logger.LegacyPrintf(
		"service.openai_ws_v2",
		"[OpenAI WS v2 passthrough] %s "+format,
		append([]any{openaiWSV2PassthroughModeFields}, args...)...,
	)
}