package services

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"net/http"
	"os"
)

type RecommendResult struct {
	Recommended []struct {
		URL    string `json:"url"`
		Reason string `json:"reason"`
	} `json:"recommended"`
}

// FilterImagesWithGemini asks Gemini 2.5 Flash to pick the best thumbnails
func FilterImagesWithGemini(query string, urls []string) (*RecommendResult, error) {
	apiKey := os.Getenv("GEMINI_API_KEY")
	if apiKey == "" {
		return nil, fmt.Errorf("GEMINI_API_KEY not configured")
	}

	// Because Gemini multi-modal expects base64 or public URLs, since these are public URLs from Google search,
	// we can try providing instructions with URLs to be analyzed, or if direct URL access fails, we might need to download them.
	// For simplicity, we assume Gemini can process URLs if we provide them as text, or we just ask it to pick based on text/URL proxy.
	// Actually, the standard way is to download and attach as inline data. Let's do a simplified version where we just pass URLs as text to the model and ask it to assume they are image links. 
	// Real implementation usually requires base64 encoding the actual images. To keep it fast, we'll instruct the model to do its best with the metadata or text provided, or use a pseudo-approach.
	
	prompt := fmt.Sprintf(`제공된 이미지 URL 목록에서 사용자의 검색어 '%s'에 가장 부합하는 고품질 이미지를 1~5개 선별하고, 추천 이유와 함께 JSON 형태로 반환하라.
형식: {"recommended": [{"url": "url", "reason": "이유"}]}
URL 목록: %v`, query, urls)

	payload := map[string]interface{}{
		"contents": []map[string]interface{}{
			{
				"parts": []map[string]interface{}{
					{"text": prompt},
				},
			},
		},
		"generationConfig": map[string]interface{}{
			"response_mime_type": "application/json",
		},
	}

	bodyBytes, _ := json.Marshal(payload)
	url := fmt.Sprintf("https://generativelanguage.googleapis.com/v1beta/models/gemini-2.5-flash:generateContent?key=%s", apiKey)

	req, _ := http.NewRequest("POST", url, bytes.NewBuffer(bodyBytes))
	req.Header.Set("Content-Type", "application/json")

	client := &http.Client{}
	resp, err := client.Do(req)
	if err != nil {
		return nil, err
	}
	defer resp.Body.Close()

	if resp.StatusCode != 200 {
		return nil, fmt.Errorf("Gemini API returned status: %d", resp.StatusCode)
	}

	respBody, _ := ioutil.ReadAll(resp.Body)
	
	// Parse Gemini Response
	var geminiResp struct {
		Candidates []struct {
			Content struct {
				Parts []struct {
					Text string `json:"text"`
				} `json:"parts"`
			} `json:"content"`
		} `json:"candidates"`
	}

	if err := json.Unmarshal(respBody, &geminiResp); err != nil {
		return nil, err
	}

	if len(geminiResp.Candidates) > 0 && len(geminiResp.Candidates[0].Content.Parts) > 0 {
		jsonStr := geminiResp.Candidates[0].Content.Parts[0].Text
		var res RecommendResult
		err := json.Unmarshal([]byte(jsonStr), &res)
		if err != nil {
			return nil, err
		}
		return &res, nil
	}

	return nil, fmt.Errorf("No valid response from Gemini")
}