Initial commit

2026-06-25 07:43:27 +09:00
commit c0814f4315
4494 changed files with 11587 additions and 0 deletions
@@ -0,0 +1,710 @@
+package main
+
+import (
+	"context"
+	"database/sql"
+	"encoding/base64"
+	"encoding/json"
+	"fmt"
+	"log"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+	"time"
+
+	"github.com/google/generative-ai-go/genai"
+	_ "modernc.org/sqlite"
+	"google.golang.org/api/option"
+)
+
+type Question struct {
+	ID                int    `json:"id"`
+	Source            string `json:"source"`
+	Category          string `json:"category"`
+	QuestionText      string `json:"questionText"`
+	Choice1           string `json:"choice1"`
+	Choice2           string `json:"choice2"`
+	Choice3           string `json:"choice3"`
+	Choice4           string `json:"choice4"`
+	Choice5           string `json:"choice5"`
+	CorrectAnswer     int    `json:"correctAnswer"`
+	CorrectAnswerStr  string `json:"correctAnswerStr"`
+	Explanation       string `json:"explanation"`
+	Difficulty        string `json:"difficulty"`
+	Passage           string `json:"passage"`
+	ImageUrl          string `json:"imageUrl"`
+	GeminiExplanation string `json:"geminiExplanation"`
+	IsBookmarked      bool   `json:"isBookmarked"`
+	Subject           string `json:"subject"`
+	CorrectAnswers    string `json:"correctAnswers"`
+	Oid               int    `json:"oid"`
+}
+
+
+type DescriptiveGradingRecord struct {
+	ID         int    `json:"id"`
+	QuestionID int    `json:"questionId"`
+	Source     string `json:"source"`
+	UserAnswer string `json:"userAnswer"`
+	Score      int    `json:"score"`
+	Evaluation string `json:"evaluation"`
+	Username   string `json:"username"`
+	CreatedAt  string `json:"createdAt"`
+}
+
+
+type CategoryInfo struct {
+	Name  string `json:"name"`
+	Count int    `json:"count"`
+}
+
+type TargetInfo struct {
+	Name  string `json:"name"`
+	Count int    `json:"count"`
+}
+
+type QuizService struct {
+	db        *sql.DB
+	geminiKey string
+}
+
+func NewQuizService() *QuizService {
+	dbPath := os.Getenv("DB_PATH")
+	if dbPath == "" {
+		// Prefer the database in the parent directory first if it exists,
+		// as it contains the real quiz database for development.
+		parentPath := filepath.Join("..", "qple_quiz.db")
+		if _, err := os.Stat(parentPath); err == nil {
+			dbPath = parentPath
+		} else {
+			dbPath = "qple_quiz.db"
+		}
+	}
+
+	log.Printf("Connecting to database at: %s", dbPath)
+	db, err := sql.Open("sqlite", dbPath)
+	if err != nil {
+		log.Fatalf("Failed to open database: %v", err)
+	}
+
+	// Create QuizExplain table if it doesn't exist
+	_, err = db.Exec(`
+		CREATE TABLE IF NOT EXISTS QuizExplain (
+			id INTEGER NOT NULL,
+			source TEXT NOT NULL,
+			explain TEXT,
+			PRIMARY KEY (source, id),
+			FOREIGN KEY (source, id) REFERENCES QuizQuestions (source, id) ON DELETE CASCADE
+		)
+	`)
+	if err != nil {
+		log.Fatalf("Failed to create QuizExplain table: %v", err)
+	}
+
+	// Create Bookmark table if it doesn't exist
+	_, err = db.Exec(`
+		CREATE TABLE IF NOT EXISTS Bookmark (
+			question_id INTEGER NOT NULL,
+			source TEXT NOT NULL,
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+			PRIMARY KEY (source, question_id),
+			FOREIGN KEY (source, question_id) REFERENCES QuizQuestions (source, id) ON DELETE CASCADE
+		)
+	`)
+	if err != nil {
+		log.Fatalf("Failed to create Bookmark table: %v", err)
+	}
+
+	// Create DescriptiveGrading table if it doesn't exist
+	_, err = db.Exec(`
+		CREATE TABLE IF NOT EXISTS DescriptiveGrading (
+			id INTEGER PRIMARY KEY AUTOINCREMENT,
+			question_id INTEGER NOT NULL,
+			source TEXT NOT NULL,
+			user_answer TEXT NOT NULL,
+			score INTEGER NOT NULL,
+			evaluation TEXT NOT NULL,
+			username TEXT NOT NULL DEFAULT 'admin',
+			created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
+			FOREIGN KEY (source, question_id) REFERENCES QuizQuestions (source, id) ON DELETE CASCADE
+		)
+	`)
+	if err != nil {
+		log.Fatalf("Failed to create DescriptiveGrading table: %v", err)
+	}
+
+
+	// Ensure subject column exists in QuizQuestions table
+	var hasSubject int
+	err = db.QueryRow("SELECT COUNT(*) FROM pragma_table_info('QuizQuestions') WHERE name='subject'").Scan(&hasSubject)
+	if err == nil && hasSubject == 0 {
+		_, err = db.Exec("ALTER TABLE QuizQuestions ADD COLUMN subject TEXT DEFAULT ''")
+		if err != nil {
+			log.Printf("Warning: Failed to add subject column: %v", err)
+		} else {
+			log.Println("Database Migration: Added subject column to QuizQuestions table.")
+		}
+	}
+
+	// Ensure correct_answers column exists in QuizQuestions table
+	var hasCorrectAnswers int
+	err = db.QueryRow("SELECT COUNT(*) FROM pragma_table_info('QuizQuestions') WHERE name='correct_answers'").Scan(&hasCorrectAnswers)
+	if err == nil && hasCorrectAnswers == 0 {
+		_, err = db.Exec("ALTER TABLE QuizQuestions ADD COLUMN correct_answers TEXT DEFAULT ''")
+		if err != nil {
+			log.Printf("Warning: Failed to add correct_answers column: %v", err)
+		} else {
+			log.Println("Database Migration: Added correct_answers column to QuizQuestions table.")
+		}
+	}
+
+	return &QuizService{
+		db: db,
+		// Initialize this via some UI setting later, or env var
+		geminiKey: "",
+	}
+}
+
+// SetGeminiKey sets the API key for Gemini calls
+func (s *QuizService) SetGeminiKey(key string) {
+	s.geminiKey = key
+}
+
+func (s *QuizService) GetCategories() []CategoryInfo {
+	rows, err := s.db.Query("SELECT category, COUNT(*) as count FROM QuizQuestions WHERE category IS NOT NULL AND category != '' GROUP BY category")
+	if err != nil {
+		log.Printf("Query error: %v", err)
+		return nil
+	}
+	defer rows.Close()
+
+	var categories []CategoryInfo
+	for rows.Next() {
+		var cat CategoryInfo
+		if err := rows.Scan(&cat.Name, &cat.Count); err != nil {
+			continue
+		}
+		categories = append(categories, cat)
+	}
+	return categories
+}
+
+func (s *QuizService) GetTargets(category string) []TargetInfo {
+	rows, err := s.db.Query("SELECT difficulty, COUNT(*) as count FROM QuizQuestions WHERE category = ? AND difficulty IS NOT NULL AND difficulty != '' GROUP BY difficulty", category)
+	if err != nil {
+		log.Printf("Query error: %v", err)
+		return nil
+	}
+	defer rows.Close()
+
+	var targets []TargetInfo
+	for rows.Next() {
+		var t TargetInfo
+		if err := rows.Scan(&t.Name, &t.Count); err != nil {
+			continue
+		}
+		targets = append(targets, t)
+	}
+	return targets
+}
+
+func (s *QuizService) GetSubjects(category, difficulty string) []string {
+	rows, err := s.db.Query("SELECT DISTINCT subject FROM QuizQuestions WHERE category = ? AND difficulty = ? AND subject IS NOT NULL AND subject != '' ORDER BY subject", category, difficulty)
+	if err != nil {
+		log.Printf("Query error in GetSubjects: %v", err)
+		return nil
+	}
+	defer rows.Close()
+
+	var subjects []string
+	for rows.Next() {
+		var sub string
+		if err := rows.Scan(&sub); err != nil {
+			continue
+		}
+		subjects = append(subjects, sub)
+	}
+	return subjects
+}
+
+func (s *QuizService) GetQuestions(category, difficulty, subject string) []Question {
+	query := `
+		SELECT q.id, q.source, q.category, q.question_text, q.choice1, q.choice2, q.choice3, q.choice4, COALESCE(q.choice5, '') as choice5,
+		       q.correct_answer, q.correct_answer_str, q.explanation, q.difficulty, q.passage, q.image_url,
+		       COALESCE(e.explain, '') as geminiExplanation,
+		       EXISTS(SELECT 1 FROM Bookmark WHERE source = q.source AND question_id = q.id) as isBookmarked,
+		       COALESCE(q.subject, '') as subject,
+		       COALESCE(q.correct_answers, '') as correct_answers,
+		       COALESCE(q.oid, 0) as oid
+		FROM QuizQuestions q
+		LEFT JOIN QuizExplain e ON q.source = e.source AND q.id = e.id
+		WHERE q.category = ?
+	`
+	var args []interface{}
+	args = append(args, category)
+
+	if difficulty != "" && difficulty != "All" {
+		query += " AND q.difficulty = ?"
+		args = append(args, difficulty)
+	}
+
+	if subject != "" && subject != "All" && subject != "dummy" {
+		query += " AND q.subject = ?"
+		args = append(args, subject)
+	}
+
+	rows, err := s.db.Query(query, args...)
+	if err != nil {
+		log.Printf("Query error: %v", err)
+		return nil
+	}
+	defer rows.Close()
+
+	var questions []Question
+	for rows.Next() {
+		var q Question
+		err := rows.Scan(
+			&q.ID, &q.Source, &q.Category, &q.QuestionText, &q.Choice1, &q.Choice2, &q.Choice3, &q.Choice4, &q.Choice5,
+			&q.CorrectAnswer, &q.CorrectAnswerStr, &q.Explanation, &q.Difficulty, &q.Passage, &q.ImageUrl,
+			&q.GeminiExplanation, &q.IsBookmarked, &q.Subject, &q.CorrectAnswers, &q.Oid,
+		)
+		if err != nil {
+			log.Printf("Scan error: %v", err)
+			continue
+		}
+		questions = append(questions, q)
+	}
+	return questions
+}
+
+
+
+// AddBookmark adds a source and question ID to the Bookmark table
+func (s *QuizService) AddBookmark(source string, questionID int) error {
+	_, err := s.db.Exec("INSERT OR IGNORE INTO Bookmark (source, question_id) VALUES (?, ?)", source, questionID)
+	return err
+}
+
+// RemoveBookmark removes a source and question ID from the Bookmark table
+func (s *QuizService) RemoveBookmark(source string, questionID int) error {
+	_, err := s.db.Exec("DELETE FROM Bookmark WHERE source = ? AND question_id = ?", source, questionID)
+	return err
+}
+
+
+// GetBookmarkedCategories retrieves categories that have bookmarked questions
+func (s *QuizService) GetBookmarkedCategories() []CategoryInfo {
+	query := `
+		SELECT q.category, COUNT(*) as count 
+		FROM Bookmark b 
+		JOIN QuizQuestions q ON b.source = q.source AND b.question_id = q.id 
+		WHERE q.category IS NOT NULL AND q.category != '' 
+		GROUP BY q.category
+	`
+	rows, err := s.db.Query(query)
+	if err != nil {
+		log.Printf("Query error: %v", err)
+		return nil
+	}
+	defer rows.Close()
+
+	var categories []CategoryInfo
+	for rows.Next() {
+		var cat CategoryInfo
+		if err := rows.Scan(&cat.Name, &cat.Count); err != nil {
+			continue
+		}
+		categories = append(categories, cat)
+	}
+	return categories
+}
+
+// GetBookmarkedTargets retrieves difficulties (targets) that have bookmarked questions within a category
+func (s *QuizService) GetBookmarkedTargets(category string) []TargetInfo {
+	query := `
+		SELECT q.difficulty, COUNT(*) as count 
+		FROM Bookmark b 
+		JOIN QuizQuestions q ON b.source = q.source AND b.question_id = q.id 
+		WHERE q.category = ? AND q.difficulty IS NOT NULL AND q.difficulty != '' 
+		GROUP BY q.difficulty
+	`
+	rows, err := s.db.Query(query, category)
+	if err != nil {
+		log.Printf("Query error: %v", err)
+		return nil
+	}
+	defer rows.Close()
+
+	var targets []TargetInfo
+	for rows.Next() {
+		var t TargetInfo
+		if err := rows.Scan(&t.Name, &t.Count); err != nil {
+			continue
+		}
+		targets = append(targets, t)
+	}
+	return targets
+}
+
+// GetBookmarkedQuestions retrieves all bookmarked questions for a given category and difficulty
+func (s *QuizService) GetBookmarkedQuestions(category, difficulty string) []Question {
+	query := `
+		SELECT q.id, q.source, q.category, q.question_text, q.choice1, q.choice2, q.choice3, q.choice4, COALESCE(q.choice5, '') as choice5,
+		       q.correct_answer, q.correct_answer_str, q.explanation, q.difficulty, q.passage, q.image_url,
+		       COALESCE(e.explain, '') as geminiExplanation,
+		       1 as isBookmarked,
+		       COALESCE(q.subject, '') as subject,
+		       COALESCE(q.correct_answers, '') as correct_answers,
+		       COALESCE(q.oid, 0) as oid
+		FROM Bookmark b
+		JOIN QuizQuestions q ON b.source = q.source AND b.question_id = q.id
+		LEFT JOIN QuizExplain e ON q.source = e.source AND q.id = e.id
+		WHERE q.category = ? AND q.difficulty = ?
+	`
+	rows, err := s.db.Query(query, category, difficulty)
+	if err != nil {
+		log.Printf("Query error: %v", err)
+		return nil
+	}
+	defer rows.Close()
+
+	var questions []Question
+	for rows.Next() {
+		var q Question
+		err := rows.Scan(
+			&q.ID, &q.Source, &q.Category, &q.QuestionText, &q.Choice1, &q.Choice2, &q.Choice3, &q.Choice4, &q.Choice5,
+			&q.CorrectAnswer, &q.CorrectAnswerStr, &q.Explanation, &q.Difficulty, &q.Passage, &q.ImageUrl,
+			&q.GeminiExplanation, &q.IsBookmarked, &q.Subject, &q.CorrectAnswers, &q.Oid,
+		)
+		if err != nil {
+			log.Printf("Scan error: %v", err)
+			continue
+		}
+		questions = append(questions, q)
+	}
+	return questions
+}
+
+
+
+func (s *QuizService) SaveAiExplanation(source string, id int, explanation string) error {
+	_, err := s.db.Exec(`
+		INSERT INTO QuizExplain (source, id, explain) VALUES (?, ?, ?)
+		ON CONFLICT(source, id) DO UPDATE SET explain=excluded.explain
+	`, source, id, explanation)
+	return err
+}
+
+func parseBase64Image(base64Str string) (string, []byte, error) {
+	mimeType := "image/png" // default fallback
+	rawData := base64Str
+
+	if strings.HasPrefix(base64Str, "data:") {
+		parts := strings.SplitN(base64Str, ";base64,", 2)
+		if len(parts) == 2 {
+			mimeType = strings.TrimPrefix(parts[0], "data:")
+			rawData = parts[1]
+		}
+	}
+
+	rawData = strings.ReplaceAll(rawData, "\n", "")
+	rawData = strings.ReplaceAll(rawData, "\r", "")
+	rawData = strings.ReplaceAll(rawData, " ", "")
+
+	decoded, err := base64.StdEncoding.DecodeString(rawData)
+	if err != nil {
+		return "", nil, err
+	}
+	return mimeType, decoded, nil
+}
+
+func (s *QuizService) AskGemini(source string, id int, prompt string, base64Image string) (string, error) {
+	if s.geminiKey == "" {
+		return "", fmt.Errorf("Gemini API key is not set")
+	}
+
+	ctx := context.Background()
+	client, err := genai.NewClient(ctx, option.WithAPIKey(s.geminiKey))
+	if err != nil {
+		return "", err
+	}
+	defer client.Close()
+
+	model := client.GenerativeModel("gemini-3.5-flash") // Using the latest model
+
+	// Build parts (Prompt text + Optional base64 image + auto-extracted question assets)
+	var parts []genai.Part
+	parts = append(parts, genai.Text(prompt))
+
+	if base64Image != "" {
+		mimeType, decodedData, err := parseBase64Image(base64Image)
+		if err == nil {
+			parts = append(parts, genai.Blob{
+				MIMEType: mimeType,
+				Data:     decodedData,
+			})
+			log.Printf("Successfully attached base64 image asset to Gemini (MIME: %s, size: %d bytes)", mimeType, len(decodedData))
+		} else {
+			log.Printf("Error decoding base64 image for Gemini: %v", err)
+		}
+	}
+
+	// Automatically scan and attach all image assets associated with this question
+	parts = s.attachQuestionAssets(parts, source, id)
+
+	var resp *genai.GenerateContentResponse
+	for attempt := 1; attempt <= 3; attempt++ {
+		resp, err = model.GenerateContent(ctx, parts...)
+		if err == nil {
+			break
+		}
+		if strings.Contains(err.Error(), "429") {
+			log.Printf("[Gemini] Request returned 429 (Rate Limit). Attempt %d of 3. Retrying in %d seconds...", attempt, attempt*2)
+			time.Sleep(time.Duration(attempt*2) * time.Second)
+			continue
+		}
+		return "", err
+	}
+	if err != nil {
+		return "", err
+	}
+
+	if len(resp.Candidates) == 0 || len(resp.Candidates[0].Content.Parts) == 0 {
+		return "", fmt.Errorf("No response from Gemini")
+	}
+
+	explanation := fmt.Sprintf("%v", resp.Candidates[0].Content.Parts[0])
+	
+	// Save to DB automatically
+	err = s.SaveAiExplanation(source, id, explanation)
+	if err != nil {
+		log.Printf("Failed to save explanation to DB: %v", err)
+	}
+
+	return explanation, nil
+}
+
+func (s *QuizService) attachQuestionAssets(parts []genai.Part, source string, id int) []genai.Part {
+	var questionText, choice1, choice2, choice3, choice4, choice5, passage, explanation, imageURL string
+	queryQ := `
+		SELECT q.question_text, q.choice1, q.choice2, q.choice3, q.choice4, COALESCE(q.choice5, '') as choice5, q.passage, q.explanation, q.image_url 
+		FROM QuizQuestions q 
+		WHERE q.source = ? AND q.id = ?
+	`
+	_ = s.db.QueryRow(queryQ, source, id).Scan(&questionText, &choice1, &choice2, &choice3, &choice4, &choice5, &passage, &explanation, &imageURL)
+
+	var aiExplanation string
+	_ = s.db.QueryRow("SELECT explain FROM QuizExplain WHERE source = ? AND id = ?", source, id).Scan(&aiExplanation)
+
+	// Combine all texts to scan for assets
+	combinedTexts := strings.Join([]string{
+		questionText, choice1, choice2, choice3, choice4, choice5, passage, explanation, aiExplanation, imageURL,
+	}, " \n ")
+
+	// Scan for unique asset paths
+	uniqueAssets := make(map[string]bool)
+	assetRegex := regexp.MustCompile(`/assets/[a-zA-Z0-9_\-\.]+`)
+	matches := assetRegex.FindAllString(combinedTexts, -1)
+	for _, m := range matches {
+		uniqueAssets[m] = true
+	}
+
+	for assetPath := range uniqueAssets {
+		filename := strings.TrimPrefix(assetPath, "/assets/")
+		
+		var filePath string
+		path1 := filepath.Join("frontend", "public", "assets", filename)
+		path2 := filepath.Join("qple_quiz_app", "frontend", "public", "assets", filename)
+		path3 := filepath.Join("..", "qple_quiz_app", "frontend", "public", "assets", filename)
+
+		if _, err := os.Stat(path1); err == nil {
+			filePath = path1
+		} else if _, err := os.Stat(path2); err == nil {
+			filePath = path2
+		} else if _, err := os.Stat(path3); err == nil {
+			filePath = path3
+		}
+
+		if filePath != "" {
+			data, err := os.ReadFile(filePath)
+			if err == nil {
+				ext := strings.ToLower(filepath.Ext(filePath))
+				mimeType := "image/png" // default fallback
+				if ext == ".pdf" {
+					mimeType = "application/pdf"
+				} else if ext == ".jpg" || ext == ".jpeg" {
+					mimeType = "image/jpeg"
+				} else if ext == ".webp" {
+					mimeType = "image/webp"
+				} else if ext == ".gif" {
+					mimeType = "image/gif"
+				}
+
+				parts = append(parts, genai.Blob{
+					MIMEType: mimeType,
+					Data:     data,
+				})
+				log.Printf("Successfully attached local asset to Gemini: %s", filePath)
+			} else {
+				log.Printf("Error reading local asset for Gemini: %v", err)
+			}
+		}
+	}
+	return parts
+}
+
+func (s *QuizService) GetDescriptiveGradingHistory(source string, questionID int) []DescriptiveGradingRecord {
+	query := `
+		SELECT id, question_id, source, user_answer, score, evaluation, username, strftime('%Y-%m-%d %H:%M:%S', created_at, 'localtime') as created_at
+		FROM DescriptiveGrading
+		WHERE source = ? AND question_id = ?
+		ORDER BY created_at DESC
+	`
+	rows, err := s.db.Query(query, source, questionID)
+	if err != nil {
+		log.Printf("Query error in GetDescriptiveGradingHistory: %v", err)
+		return nil
+	}
+	defer rows.Close()
+
+	var records []DescriptiveGradingRecord
+	for rows.Next() {
+		var r DescriptiveGradingRecord
+		err := rows.Scan(&r.ID, &r.QuestionID, &r.Source, &r.UserAnswer, &r.Score, &r.Evaluation, &r.Username, &r.CreatedAt)
+		if err != nil {
+			log.Printf("Scan error in GetDescriptiveGradingHistory: %v", err)
+			continue
+		}
+		records = append(records, r)
+	}
+	return records
+}
+
+func (s *QuizService) GradeDescriptiveAnswer(source string, questionID int, userAnswer string) (*DescriptiveGradingRecord, error) {
+	if s.geminiKey == "" {
+		return nil, fmt.Errorf("Gemini API key is not set")
+	}
+
+	var qText, passage, modelAnswer string
+	queryQ := `SELECT question_text, passage, explanation FROM QuizQuestions WHERE source = ? AND id = ?`
+	err := s.db.QueryRow(queryQ, source, questionID).Scan(&qText, &passage, &modelAnswer)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to query question details: %v", err)
+	}
+
+	if modelAnswer == "" {
+		var aiExplain string
+		errExplain := s.db.QueryRow("SELECT explain FROM QuizExplain WHERE source = ? AND id = ?", source, questionID).Scan(&aiExplain)
+		if errExplain == nil && aiExplain != "" {
+			modelAnswer = aiExplain
+		}
+	}
+
+	ctx := context.Background()
+	client, err := genai.NewClient(ctx, option.WithAPIKey(s.geminiKey))
+	if err != nil {
+		return nil, err
+	}
+	defer client.Close()
+
+	model := client.GenerativeModel("gemini-3.5-flash")
+
+	prompt := fmt.Sprintf(`사용자가 작성한 주관식/서술형 답안을 모범답안과 문제에 대조하여 공정하게 채점해 주세요.
+
+[문제 정보]
+- 지문: %s
+- 문제: %s
+- 모범 답안: %s
+
+[사용자 제출 답안]
+%s
+
+결과는 반드시 아래의 JSON 포맷으로만 응답해 주세요. 포맷 이외의 텍스트(Markdown 코드 블럭 등)는 포함하지 마세요.
+
+{
+  "score": <0~100 사이의 정수 점수>,
+  "evaluation": "<잘한 부분, 아쉬운 부분, 보완점에 대한 상세한 평가 내용 (한글 마크다운 형식)>"
+}
+`, passage, qText, modelAnswer, userAnswer)
+
+	var parts []genai.Part
+	parts = append(parts, genai.Text(prompt))
+	parts = s.attachQuestionAssets(parts, source, questionID)
+
+	var resp *genai.GenerateContentResponse
+	for attempt := 1; attempt <= 3; attempt++ {
+		resp, err = model.GenerateContent(ctx, parts...)
+		if err == nil {
+			break
+		}
+		if strings.Contains(err.Error(), "429") {
+			log.Printf("[Gemini] Grade request returned 429 (Rate Limit). Attempt %d of 3. Retrying in %d seconds...", attempt, attempt*2)
+			time.Sleep(time.Duration(attempt*2) * time.Second)
+			continue
+		}
+		return nil, err
+	}
+	if err != nil {
+		return nil, err
+	}
+
+	if len(resp.Candidates) == 0 || len(resp.Candidates[0].Content.Parts) == 0 {
+		return nil, fmt.Errorf("No response from Gemini")
+	}
+
+	respText := fmt.Sprintf("%v", resp.Candidates[0].Content.Parts[0])
+
+	cleanJSON := strings.TrimSpace(respText)
+	if strings.HasPrefix(cleanJSON, "```json") {
+		cleanJSON = strings.TrimPrefix(cleanJSON, "```json")
+		cleanJSON = strings.TrimSuffix(cleanJSON, "```")
+	} else if strings.HasPrefix(cleanJSON, "```") {
+		cleanJSON = strings.TrimPrefix(cleanJSON, "```")
+		cleanJSON = strings.TrimSuffix(cleanJSON, "```")
+	}
+	cleanJSON = strings.TrimSpace(cleanJSON)
+
+	var result struct {
+		Score      int    `json:"score"`
+		Evaluation string `json:"evaluation"`
+	}
+	err = json.Unmarshal([]byte(cleanJSON), &result)
+	if err != nil {
+		log.Printf("Failed to parse Gemini response JSON: %q, error: %v", cleanJSON, err)
+		result.Score = 70
+		result.Evaluation = respText
+	}
+
+	stmt, err := s.db.Prepare(`
+		INSERT INTO DescriptiveGrading (source, question_id, user_answer, score, evaluation, username)
+		VALUES (?, ?, ?, ?, ?, 'admin')
+	`)
+	if err != nil {
+		return nil, err
+	}
+	defer stmt.Close()
+
+	res, err := stmt.Exec(source, questionID, userAnswer, result.Score, result.Evaluation)
+	if err != nil {
+		return nil, err
+	}
+
+	lastID, err := res.LastInsertId()
+	if err != nil {
+		return nil, err
+	}
+
+	var record DescriptiveGradingRecord
+	err = s.db.QueryRow(`
+		SELECT id, question_id, source, user_answer, score, evaluation, username, strftime('%Y-%m-%d %H:%M:%S', created_at, 'localtime')
+		FROM DescriptiveGrading
+		WHERE id = ?
+	`, lastID).Scan(&record.ID, &record.QuestionID, &record.Source, &record.UserAnswer, &record.Score, &record.Evaluation, &record.Username, &record.CreatedAt)
+	if err != nil {
+		return nil, err
+	}
+
+	return &record, nil
+}
+