feat: implement managed-account rotation on 429 empty-output completion retries

internal/completionruntime/stream_retry.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"strings"
 
+	"ds2api/internal/assistantturn"
 	"ds2api/internal/auth"
 	"ds2api/internal/config"
 	"ds2api/internal/httpapi/openai/shared"
@@ -27,6 +28,7 @@ type StreamRetryHooks struct {
 	OnRetry         func(attempts int)
 	OnRetryPrompt   func(prompt string)
 	OnRetryFailure  func(status int, message, code string)
+	OnAccountSwitch func(sessionID string)
 	OnTerminal      func(attempts int)
 }
 
@@ -48,16 +50,48 @@ func ExecuteStreamWithRetry(ctx context.Context, ds DeepSeekCaller, a *auth.Requ
 	}
 
 	attempts := 0
+	accountSwitchAttempted := false
 	currentResp := initialResp
+	currentPayload := clonePayload(payload)
 	for {
-		terminalWritten, retryable := hooks.ConsumeAttempt(currentResp, opts.RetryEnabled && attempts < retryMax)
+		allowAccountSwitch := opts.RetryEnabled && attempts >= retryMax && !accountSwitchAttempted && a != nil && a.UseConfigToken
+		terminalWritten, retryable := hooks.ConsumeAttempt(currentResp, opts.RetryEnabled && (attempts < retryMax || allowAccountSwitch))
 		if terminalWritten {
 			if hooks.OnTerminal != nil {
 				hooks.OnTerminal(attempts)
 			}
 			return
 		}
-		if !retryable || !opts.RetryEnabled || attempts >= retryMax {
+		if !retryable || !opts.RetryEnabled {
+			if hooks.Finalize != nil {
+				hooks.Finalize(attempts)
+			}
+			return
+		}
+
+		if attempts >= retryMax {
+			if canRetryOnAlternateAccount(ctx, a, &assistantturn.OutputError{Status: http.StatusTooManyRequests}, opts.RetryEnabled, &accountSwitchAttempted) {
+				switched, switchErr := startPayloadCompletionOnAlternateAccount(ctx, ds, a, payload, maxAttempts)
+				if switchErr != nil {
+					if hooks.OnRetryFailure != nil {
+						hooks.OnRetryFailure(switchErr.Status, switchErr.Message, switchErr.Code)
+					}
+					return
+				}
+				if switched.Response != nil {
+					config.Logger.Info("[completion_runtime_account_switch_retry] retrying after 429", "surface", surface, "stream", opts.Stream, "account", a.AccountID)
+					currentResp = switched.Response
+					currentPayload = switched.Payload
+					pow = switched.Pow
+					if hooks.OnAccountSwitch != nil {
+						hooks.OnAccountSwitch(switched.SessionID)
+					}
+					if hooks.OnRetryPrompt != nil {
+						hooks.OnRetryPrompt(opts.UsagePrompt)
+					}
+					continue
+				}
+			}
 			if hooks.Finalize != nil {
 				hooks.Finalize(attempts)
 			}
@@ -75,7 +109,7 @@ func ExecuteStreamWithRetry(ctx context.Context, ds DeepSeekCaller, a *auth.Requ
 			config.Logger.Warn("[completion_runtime_empty_retry] retry PoW fetch failed, falling back to original PoW", "surface", surface, "stream", opts.Stream, "retry_attempt", attempts, "error", powErr)
 			retryPow = pow
 		}
-		nextResp, err := ds.CallCompletion(ctx, a, shared.ClonePayloadForEmptyOutputRetry(payload, parentMessageID), retryPow, maxAttempts)
+		nextResp, err := ds.CallCompletion(ctx, a, shared.ClonePayloadForEmptyOutputRetry(currentPayload, parentMessageID), retryPow, maxAttempts)
 		if err != nil {
 			if hooks.OnRetryFailure != nil {
 				hooks.OnRetryFailure(http.StatusInternalServerError, "Failed to get completion.", "error")
@@ -108,6 +142,33 @@ func ExecuteStreamWithRetry(ctx context.Context, ds DeepSeekCaller, a *auth.Requ
 	}
 }
 
+func startPayloadCompletionOnAlternateAccount(ctx context.Context, ds DeepSeekCaller, a *auth.RequestAuth, payload map[string]any, maxAttempts int) (StartResult, *assistantturn.OutputError) {
+	sessionID, err := ds.CreateSession(ctx, a, maxAttempts)
+	if err != nil {
+		return StartResult{}, authOutputError(a)
+	}
+	pow, err := ds.GetPow(ctx, a, maxAttempts)
+	if err != nil {
+		return StartResult{SessionID: sessionID}, &assistantturn.OutputError{Status: http.StatusUnauthorized, Message: "Failed to get PoW (invalid token or unknown error).", Code: "error"}
+	}
+	nextPayload := clonePayload(payload)
+	nextPayload["chat_session_id"] = sessionID
+	delete(nextPayload, "parent_message_id")
+	resp, err := ds.CallCompletion(ctx, a, nextPayload, pow, maxAttempts)
+	if err != nil {
+		return StartResult{SessionID: sessionID, Payload: nextPayload, Pow: pow}, &assistantturn.OutputError{Status: http.StatusInternalServerError, Message: "Failed to get completion.", Code: "error"}
+	}
+	return StartResult{SessionID: sessionID, Payload: nextPayload, Pow: pow, Response: resp}, nil
+}
+
+func clonePayload(payload map[string]any) map[string]any {
+	clone := make(map[string]any, len(payload))
+	for k, v := range payload {
+		clone[k] = v
+	}
+	return clone
+}
+
 func closeRetryBody(surface string, body io.Closer) {
 	if body == nil {
 		return