feat(gemini): show grouding google search (#753)

* feat(gemini): show grouding google search

* fix(gemini): extra new line for grounding metadata of OpenAI stream choice

Author: GrayXu

providers/gemini/type.go

@@ -150,6 +150,14 @@ func (candidate *GeminiChatCandidate) ToOpenAIStreamChoice(request *types.ChatCo
 		choice.Delta.Image = images
 	}
 
+	// Add grounding metadata as markdown citations
+	if candidate.GroundingMetadata != nil && showGoogleSearchMeta(request) {
+		groundingMarkdown := formatGroundingMetadataAsMarkdown(candidate.GroundingMetadata)
+		if groundingMarkdown != "" {
+			content = append(content, "\n\n" + groundingMarkdown)
+		}
+	}
+
 	choice.Delta.Content = strings.Join(content, "\n")
 
 	if len(reasoningContent) > 0 {
@@ -230,6 +238,18 @@ func (candidate *GeminiChatCandidate) ToOpenAIChoice(request *types.ChatCompleti
 
 	choice.Message.Content = strings.Join(content, "\n")
 
+	// Add grounding metadata as markdown citations
+	if candidate.GroundingMetadata != nil && showGoogleSearchMeta(request) {
+		groundingMarkdown := formatGroundingMetadataAsMarkdown(candidate.GroundingMetadata)
+		if groundingMarkdown != "" {
+			if contentStr, ok := choice.Message.Content.(string); ok && contentStr != "" {
+				choice.Message.Content = contentStr + "\n\n" + groundingMarkdown
+			} else {
+				choice.Message.Content = groundingMarkdown
+			}
+		}
+	}
+
 	if len(reasoningContent) > 0 {
 		choice.Message.ReasoningContent = strings.Join(reasoningContent, "\n")
 	}
@@ -365,6 +385,7 @@ type GeminiChatCandidate struct {
 	CitationMetadata      any                      `json:"citationMetadata,omitempty"`
 	TokenCount            int                      `json:"tokenCount,omitempty"`
 	GroundingAttributions []any                    `json:"groundingAttributions,omitempty"`
+	GroundingMetadata     *GeminiGroundingMetadata `json:"groundingMetadata,omitempty"`
 	AvgLogprobs           any                      `json:"avgLogprobs,omitempty"`
 }
 
@@ -621,3 +642,67 @@ func isEmptyOrOnlyNewlines(s string) bool {
 	trimmed := strings.TrimSpace(s)
 	return trimmed == ""
 }
+
+type GeminiGroundingMetadata struct {
+	GroundingChunks  []GeminiGroundingChunk `json:"groundingChunks,omitempty"`
+	WebSearchQueries []string               `json:"webSearchQueries,omitempty"`
+}
+
+type GeminiGroundingChunk struct {
+	Web *GeminiGroundingChunkWeb `json:"web,omitempty"`
+}
+
+type GeminiGroundingChunkWeb struct {
+	Uri   string `json:"uri,omitempty"`
+	Title string `json:"title,omitempty"`
+}
+
+// checks if googleSearch tool has "show" parameter
+func showGoogleSearchMeta(request *types.ChatCompletionRequest) bool {
+	functions := request.GetFunctions()
+	if functions == nil {
+		return false
+	}
+
+	for _, function := range functions {
+		if function.Name == "googleSearch" && function.Parameters != nil {
+			if paramStr, ok := function.Parameters.(string); ok && paramStr == "show" {
+				return true
+			}
+		}
+	}
+
+	return false
+}
+
+// formats grounding metadata as markdown citation
+func formatGroundingMetadataAsMarkdown(metadata *GeminiGroundingMetadata) string {
+	if metadata == nil || len(metadata.GroundingChunks) == 0 {
+		return ""
+	}
+	var result strings.Builder
+	// Add search queries
+	if len(metadata.WebSearchQueries) > 0 {
+		result.WriteString("> Searched ")
+		for i, query := range metadata.WebSearchQueries {
+			if i > 0 {
+				result.WriteString(" and ")
+			}
+			result.WriteString(fmt.Sprintf(`"%s"`, query))
+		}
+		result.WriteString("\n")
+	}
+	// Add grounding chunks as numbered list
+	linkCount := 0
+	for _, chunk := range metadata.GroundingChunks {
+		if chunk.Web != nil && chunk.Web.Uri != "" {
+			linkCount++
+			title := chunk.Web.Title
+			if title == "" {
+				title = chunk.Web.Uri
+			}
+			result.WriteString(fmt.Sprintf("> %d. [%s](%s)\n", linkCount, title, chunk.Web.Uri))
+		}
+	}
+	return result.String()
+}