From 4bfeeecb05a193719cec5d676e268f23a4ede1d0 Mon Sep 17 00:00:00 2001
From: liuxiongfeng <liuxiongfeng@open-care.com>
Date: Mon, 2 Feb 2026 12:50:18 +0800
Subject: [PATCH] =?UTF-8?q?fix(billing):=20=E4=BF=AE=E5=A4=8D=20Gemini=20?=
 =?UTF-8?q?=E6=8E=A5=E5=8F=A3=E7=BC=93=E5=AD=98=20token=20=E7=BB=9F?=
 =?UTF-8?q?=E8=AE=A1?=
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extractGeminiUsage 函数未提取 cachedContentTokenCount，
导致计费时缓存读取 token 始终为 0。

修复：
- 提取 usageMetadata.cachedContentTokenCount
- 设置 CacheReadInputTokens 字段
- InputTokens 减去缓存 token（与 response_transformer 逻辑一致）
---
 .../internal/service/gemini_messages_compat_service.go    | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/backend/internal/service/gemini_messages_compat_service.go b/backend/internal/service/gemini_messages_compat_service.go
index aea880c2..659cdf03 100644
--- a/backend/internal/service/gemini_messages_compat_service.go
+++ b/backend/internal/service/gemini_messages_compat_service.go
@@ -2522,9 +2522,13 @@ func extractGeminiUsage(geminiResp map[string]any) *ClaudeUsage {
 	}
 	prompt, _ := asInt(usageMeta["promptTokenCount"])
 	cand, _ := asInt(usageMeta["candidatesTokenCount"])
+	cached, _ := asInt(usageMeta["cachedContentTokenCount"])
+	// 注意：Gemini 的 promptTokenCount 包含 cachedContentTokenCount，
+	// 但 Claude 的 input_tokens 不包含 cache_read_input_tokens，需要减去
 	return &ClaudeUsage{
-		InputTokens:  prompt,
-		OutputTokens: cand,
+		InputTokens:         prompt - cached,
+		OutputTokens:        cand,
+		CacheReadInputTokens: cached,
 	}
 }