package database

import (
	"context"
	"database/sql"
	"fmt"
)

// QuestionRepository handles question operations
type QuestionRepository struct {
	client *Client
}

// NewQuestionRepository creates a new question repository
func NewQuestionRepository(client *Client) *QuestionRepository {
	return &QuestionRepository{client: client}
}

// Create creates a new question
func (r *QuestionRepository) Create(ctx context.Context, question *Question) error {
	query := `
		INSERT INTO questions (id, theme, text, answer, hint, difficulty, is_active, created_at, updated_at)
		VALUES ($1, $2, $3, $4, $5, $6, $7, $8, $9)
	`
	
	_, err := r.client.db.ExecContext(ctx, query,
		question.ID,
		question.Theme,
		question.Text,
		question.Answer,
		question.Hint,
		question.Difficulty,
		question.IsActive,
		question.CreatedAt,
		question.UpdatedAt,
	)
	
	return err
}

// GetByID retrieves a question by ID
func (r *QuestionRepository) GetByID(ctx context.Context, id string) (*Question, error) {
	query := `
		SELECT id, theme, text, answer, hint, difficulty, is_active, created_at, updated_at
		FROM questions
		WHERE id = $1
	`
	
	var question Question
	err := r.client.db.QueryRowContext(ctx, query, id).Scan(
		&question.ID,
		&question.Theme,
		&question.Text,
		&question.Answer,
		&question.Hint,
		&question.Difficulty,
		&question.IsActive,
		&question.CreatedAt,
		&question.UpdatedAt,
	)
	
	if err != nil {
		if err == sql.ErrNoRows {
			return nil, fmt.Errorf("question not found: %s", id)
		}
		return nil, err
	}
	
	return &question, nil
}

// GetByTheme retrieves questions by theme
func (r *QuestionRepository) GetByTheme(ctx context.Context, theme string) ([]*Question, error) {
	query := `
		SELECT id, theme, text, answer, hint, difficulty, is_active, created_at, updated_at
		FROM questions
		WHERE theme = $1 AND is_active = true
		ORDER BY created_at DESC
	`
	
	rows, err := r.client.db.QueryContext(ctx, query, theme)
	if err != nil {
		return nil, err
	}
	defer rows.Close()
	
	var questions []*Question
	for rows.Next() {
		var question Question
		err := rows.Scan(
			&question.ID,
			&question.Theme,
			&question.Text,
			&question.Answer,
			&question.Hint,
			&question.Difficulty,
			&question.IsActive,
			&question.CreatedAt,
			&question.UpdatedAt,
		)
		if err != nil {
			return nil, err
		}
		questions = append(questions, &question)
	}
	
	return questions, rows.Err()
}

// GetRandom retrieves a random question
func (r *QuestionRepository) GetRandom(ctx context.Context, theme string, difficulty string) (*Question, error) {
	query := `
		SELECT id, theme, text, answer, hint, difficulty, is_active, created_at, updated_at
		FROM questions
		WHERE is_active = true
	`
	
	args := []interface{}{}
	argIndex := 1
	
	if theme != "" {
		query += fmt.Sprintf(" AND theme = $%d", argIndex)
		args = append(args, theme)
		argIndex++
	}
	
	if difficulty != "" {
		query += fmt.Sprintf(" AND difficulty = $%d", argIndex)
		args = append(args, difficulty)
		argIndex++
	}
	
	query += " ORDER BY RANDOM() LIMIT 1"
	
	var question Question
	err := r.client.db.QueryRowContext(ctx, query, args...).Scan(
		&question.ID,
		&question.Theme,
		&question.Text,
		&question.Answer,
		&question.Hint,
		&question.Difficulty,
		&question.IsActive,
		&question.CreatedAt,
		&question.UpdatedAt,
	)
	
	if err != nil {
		if err == sql.ErrNoRows {
			return nil, fmt.Errorf("no questions found for theme: %s, difficulty: %s", theme, difficulty)
		}
		return nil, err
	}
	
	return &question, nil
}