feat: 重构Gemini API调用实现

重构改进:
- 参考Python demo.py实现重写Gemini API调用
- 添加完整的配置参数支持 (model_name, max_retries, retry_delay等)
- 实现Cloudflare Gateway兼容的API端点格式
- 添加完整的重试机制和错误处理

 API端点修正:
- 修改为正确的generateContent端点格式
- 支持gemini-2.5-flash等模型配置
- 优化请求头和认证方式
- 改进超时和重试策略

 配置增强:
- 支持自定义temperature和max_tokens
- 可配置重试次数和延迟时间
- 更好的客户端配置管理
- 详细的日志和错误信息

 代码结构:
- 分离请求发送和响应解析逻辑
- 更清晰的错误处理流程
- 符合Rust最佳实践的异步处理

这个重构应该能解决API调用的兼容性问题。

apps/desktop/src-tauri/src/infrastructure/gemini_service.rs

@@ -12,6 +12,11 @@ pub struct GeminiConfig {
     pub base_url: String,
     pub bearer_token: String,
     pub timeout: u64,
+    pub model_name: String,
+    pub max_retries: u32,
+    pub retry_delay: u64,
+    pub temperature: f32,
+    pub max_tokens: u32,
 }
 
 impl Default for GeminiConfig {
@@ -20,6 +25,11 @@ impl Default for GeminiConfig {
             base_url: "https://bowongai-dev--bowong-ai-video-gemini-fastapi-webapp.modal.run".to_string(),
             bearer_token: "bowong7777".to_string(),
             timeout: 120,
+            model_name: "gemini-2.5-flash".to_string(),
+            max_retries: 3,
+            retry_delay: 2,
+            temperature: 0.1,
+            max_tokens: 2048,
         }
     }
 }
@@ -31,6 +41,13 @@ struct TokenResponse {
     expires_in: u64,
 }
 
+/// 客户端配置
+#[derive(Debug)]
+struct ClientConfig {
+    gateway_url: String,
+    headers: std::collections::HashMap<String, String>,
+}
+
 /// Gemini上传响应
 #[derive(Debug, Deserialize)]
 struct UploadResponse {
@@ -186,6 +203,18 @@ impl GeminiService {
         Ok(token_response.access_token)
     }
 
+    /// 创建Gemini客户端配置
+    fn create_gemini_client(&self, access_token: &str) -> ClientConfig {
+        let mut headers = std::collections::HashMap::new();
+        headers.insert("Authorization".to_string(), format!("Bearer {}", access_token));
+        headers.insert("Content-Type".to_string(), "application/json".to_string());
+
+        ClientConfig {
+            gateway_url: format!("{}/google/vertex-ai", self.config.base_url),
+            headers,
+        }
+    }
+
     /// 上传视频文件到Gemini
     pub async fn upload_video_file(&mut self, video_path: &str) -> Result<String> {
         println!("📤 开始上传视频文件: {}", video_path);
@@ -262,7 +291,7 @@ impl GeminiService {
         Ok(file_uri)
     }
 
-    /// 生成内容分析
+    /// 生成内容分析 (参考Python demo.py实现)
     pub async fn generate_content_analysis(&mut self, file_uri: &str, prompt: &str) -> Result<String> {
         println!("🧠 开始生成内容分析...");
         println!("📁 文件URI: {}", file_uri);
@@ -271,11 +300,14 @@ impl GeminiService {
         // 获取访问令牌
         let access_token = self.get_access_token().await?;
 
+        // 创建客户端配置
+        let client_config = self.create_gemini_client(&access_token);
+
         // 格式化GCS URI
         let formatted_uri = self.format_gcs_uri(file_uri);
         println!("🔗 格式化后的URI: {}", formatted_uri);
 
-        // 准备请求数据
+        // 准备请求数据，参考demo.py实现
         let request_data = GenerateContentRequest {
             contents: vec![ContentPart {
                 role: "user".to_string(),
@@ -290,28 +322,62 @@ impl GeminiService {
                 ],
             }],
             generation_config: GenerationConfig {
-                temperature: 0.1,
+                temperature: self.config.temperature,
                 top_k: 32,
                 top_p: 1.0,
-                max_output_tokens: 2048,
+                max_output_tokens: self.config.max_tokens,
             },
         };
 
         println!("📦 请求数据: {}", serde_json::to_string_pretty(&request_data).unwrap_or_default());
 
-        // 发送生成请求
-        let generate_url = format!("{}/google/vertex-ai/generate", self.config.base_url);
+        // 发送请求到Cloudflare Gateway，参考demo.py
+        let generate_url = format!("{}:generateContent", client_config.gateway_url);
         println!("📡 生成URL: {}", generate_url);
 
-        let response = self.client
-            .post(&generate_url)
-            .header("Authorization", format!("Bearer {}", access_token))
-            .header("x-google-api-key", &access_token)
-            .header("Content-Type", "application/json")
-            .json(&request_data)
-            .send()
-            .await?;
+        // 重试机制
+        let mut last_error = None;
+        for attempt in 0..self.config.max_retries {
+            println!("🔄 尝试 {}/{}", attempt + 1, self.config.max_retries);
 
+            match self.send_generate_request(&generate_url, &client_config, &request_data).await {
+                Ok(result) => {
+                    println!("✅ 成功获取Gemini分析结果");
+                    return self.parse_gemini_response_content(&result);
+                }
+                Err(e) => {
+                    last_error = Some(e);
+                    println!("⚠️ 尝试 {}/{} 失败: {}", attempt + 1, self.config.max_retries, last_error.as_ref().unwrap());
+
+                    if attempt < self.config.max_retries - 1 {
+                        println!("⏳ 等待 {} 秒后重试...", self.config.retry_delay);
+                        tokio::time::sleep(tokio::time::Duration::from_secs(self.config.retry_delay)).await;
+                    }
+                }
+            }
+        }
+
+        Err(anyhow!("内容生成失败，已重试{}次: {}", self.config.max_retries, last_error.unwrap()))
+    }
+
+    /// 发送生成请求
+    async fn send_generate_request(
+        &self,
+        url: &str,
+        client_config: &ClientConfig,
+        request_data: &GenerateContentRequest,
+    ) -> Result<GeminiResponse> {
+        let mut request_builder = self.client
+            .post(url)
+            .timeout(tokio::time::Duration::from_secs(self.config.timeout))
+            .json(request_data);
+
+        // 添加请求头
+        for (key, value) in &client_config.headers {
+            request_builder = request_builder.header(key, value);
+        }
+
+        let response = request_builder.send().await?;
         let status = response.status();
         let headers = response.headers().clone();
 
@@ -321,7 +387,7 @@ impl GeminiService {
         if !status.is_success() {
             let error_text = response.text().await.unwrap_or_default();
             println!("❌ 生成失败响应体: {}", error_text);
-            return Err(anyhow!("生成内容分析失败: {} - {}", status, error_text));
+            return Err(anyhow!("API请求失败: {} - {}", status, error_text));
         }
 
         let response_text = response.text().await?;
@@ -330,6 +396,15 @@ impl GeminiService {
         let gemini_response: GeminiResponse = serde_json::from_str(&response_text)
             .map_err(|e| anyhow!("解析生成响应失败: {} - 响应内容: {}", e, response_text))?;
 
+        if gemini_response.candidates.is_empty() {
+            return Err(anyhow!("API返回结果为空"));
+        }
+
+        Ok(gemini_response)
+    }
+
+    /// 解析Gemini响应内容
+    fn parse_gemini_response_content(&self, gemini_response: &GeminiResponse) -> Result<String> {
         if let Some(candidate) = gemini_response.candidates.first() {
             if let Some(part) = candidate.content.parts.first() {
                 println!("✅ 内容分析完成，响应长度: {} 字符", part.text.len());