feat: add runner failover rules and cache affinity

apps/api/internal/clients/helpers.go

@@ -259,6 +259,9 @@ func NormalizeChatCompletionResult(result map[string]any) map[string]any {
 	if result == nil {
 		return nil
 	}
+	if usage, ok := result["usage"].(map[string]any); ok && len(usage) > 0 {
+		result["usage"] = NormalizeChatCompletionUsage(usage)
+	}
 	choices, _ := result["choices"].([]any)
 	for _, rawChoice := range choices {
 		choice, _ := rawChoice.(map[string]any)
@@ -280,6 +283,9 @@ func NormalizeChatCompletionStreamEvent(event map[string]any) map[string]any {
 	if event == nil {
 		return nil
 	}
+	if usage, ok := event["usage"].(map[string]any); ok && len(usage) > 0 {
+		event["usage"] = NormalizeChatCompletionUsage(usage)
+	}
 	choices, _ := event["choices"].([]any)
 	for _, rawChoice := range choices {
 		choice, _ := rawChoice.(map[string]any)
@@ -295,6 +301,33 @@ func NormalizeChatCompletionStreamEvent(event map[string]any) map[string]any {
 	return event
 }
 
+func NormalizeChatCompletionUsage(usage map[string]any) map[string]any {
+	if len(usage) == 0 {
+		return usage
+	}
+	normalized := usageFromOpenAIUsage(usage)
+	out := cloneMapAny(usage)
+	if normalized.InputTokens > 0 && intFromAny(out["prompt_tokens"]) == 0 {
+		out["prompt_tokens"] = normalized.InputTokens
+	}
+	if normalized.OutputTokens > 0 && intFromAny(out["completion_tokens"]) == 0 {
+		out["completion_tokens"] = normalized.OutputTokens
+	}
+	if normalized.TotalTokens > 0 && intFromAny(out["total_tokens"]) == 0 {
+		out["total_tokens"] = normalized.TotalTokens
+	}
+	if normalized.CachedInputTokens > 0 {
+		promptDetails, _ := firstPresent(out["prompt_tokens_details"], out["promptTokensDetails"]).(map[string]any)
+		normalizedPromptDetails := cloneMapAny(promptDetails)
+		if normalizedPromptDetails == nil {
+			normalizedPromptDetails = map[string]any{}
+		}
+		normalizedPromptDetails["cached_tokens"] = normalized.CachedInputTokens
+		out["prompt_tokens_details"] = normalizedPromptDetails
+	}
+	return out
+}
+
 func normalizeToolCallsContainer(container map[string]any, stream bool) {
 	if container == nil {
 		return
@@ -877,27 +910,36 @@ func sortedStreamToolCalls(toolCalls map[int]map[string]any) []any {
 
 func usageFromOpenAI(result map[string]any) Usage {
 	usage, _ := result["usage"].(map[string]any)
+	return usageFromOpenAIUsage(usage)
+}
+
+func usageFromOpenAIUsage(usage map[string]any) Usage {
 	input := intFromAny(firstPresent(usage["prompt_tokens"], usage["input_tokens"]))
 	output := intFromAny(firstPresent(usage["completion_tokens"], usage["output_tokens"]))
 	total := intFromAny(usage["total_tokens"])
 	if total == 0 {
 		total = input + output
 	}
-	cachedInput := cachedInputTokensFromOpenAIUsage(usage)
+	cachedInput, cachedInputKnown := cachedInputTokensValueFromOpenAIUsage(usage)
 	if cachedInput > input && input > 0 {
 		cachedInput = input
 	}
-	return Usage{InputTokens: input, OutputTokens: output, CachedInputTokens: cachedInput, TotalTokens: total}
+	return Usage{InputTokens: input, OutputTokens: output, CachedInputTokens: cachedInput, CachedInputTokensKnown: cachedInputKnown, TotalTokens: total}
 }
 
 func cachedInputTokensFromOpenAIUsage(usage map[string]any) int {
+	cachedInput, _ := cachedInputTokensValueFromOpenAIUsage(usage)
+	return cachedInput
+}
+
+func cachedInputTokensValueFromOpenAIUsage(usage map[string]any) (int, bool) {
 	if len(usage) == 0 {
-		return 0
+		return 0, false
 	}
 	promptDetails, _ := firstPresent(usage["prompt_tokens_details"], usage["promptTokensDetails"]).(map[string]any)
 	inputDetails, _ := firstPresent(usage["input_tokens_details"], usage["inputTokensDetails"]).(map[string]any)
 	usageMetadata, _ := usage["usageMetadata"].(map[string]any)
-	return intFromAny(firstPresent(
+	value, ok := firstPresentValue(
 		promptDetails["cached_tokens"],
 		promptDetails["cachedTokens"],
 		promptDetails["cache_read_input_tokens"],
@@ -918,7 +960,11 @@ func cachedInputTokensFromOpenAIUsage(usage map[string]any) int {
 		usage["cachedContentTokenCount"],
 		usageMetadata["cached_content_token_count"],
 		usageMetadata["cachedContentTokenCount"],
-	))
+	)
+	if !ok {
+		return 0, false
+	}
+	return intFromAny(value), true
 }
 
 func requestIDFromHTTPResponse(resp *http.Response) string {
@@ -979,12 +1025,17 @@ func firstNonEmptyString(values ...any) string {
 }
 
 func firstPresent(values ...any) any {
+	value, _ := firstPresentValue(values...)
+	return value
+}
+
+func firstPresentValue(values ...any) (any, bool) {
 	for _, value := range values {
 		if value != nil {
-			return value
+			return value, true
 		}
 	}
-	return nil
+	return nil, false
 }
 
 func errorMessage(raw []byte, fallback string) string {