<?php
class Review {
    private $db;
    private $notification;
    
    public function __construct($db, $notification) {
        $this->db = $db;
        $this->notification = $notification;
    }
    
    public function addReview($user_id, $product_id, $rating, $comment, $images = []) {
        // Start transaction
        $this->db->begin_transaction();
        
        try {
            // Add review
            $stmt = $this->db->prepare("INSERT INTO reviews (user_id, product_id, rating, comment, created_at) VALUES (?, ?, ?, ?, NOW())");
            $stmt->bind_param('iiis', $user_id, $product_id, $rating, $comment);
            $stmt->execute();
            $review_id = $stmt->insert_id;
            
            // Add review images if any
            if (!empty($images)) {
                $stmt = $this->db->prepare("INSERT INTO review_images (review_id, image_path) VALUES (?, ?)");
                foreach ($images as $image) {
                    $stmt->bind_param('is', $review_id, $image);
                    $stmt->execute();
                }
            }
            
            // Update product rating
            $this->updateProductRating($product_id);
            
            // Notify product owner
            $this->notifyProductOwner($product_id, $user_id, $rating);
            
            $this->db->commit();
            return $review_id;
            
        } catch (\Exception $e) {
            $this->db->rollback();
            throw $e;
        }
    }
    
    public function getProductReviews($product_id, $limit = 10, $offset = 0) {
        $stmt = $this->db->prepare("
            SELECT r.*, u.username, u.avatar,
                   GROUP_CONCAT(ri.image_path) as images
            FROM reviews r
            LEFT JOIN users u ON r.user_id = u.id
            LEFT JOIN review_images ri ON r.id = ri.review_id
            WHERE r.product_id = ?
            GROUP BY r.id
            ORDER BY r.created_at DESC
            LIMIT ? OFFSET ?
        ");
        $stmt->bind_param('iii', $product_id, $limit, $offset);
        $stmt->execute();
        return $stmt->get_result()->fetch_all(MYSQLI_ASSOC);
    }
    
    public function getUserReviews($user_id, $limit = 10, $offset = 0) {
        $stmt = $this->db->prepare("
            SELECT r.*, p.name as product_name, p.image as product_image,
                   GROUP_CONCAT(ri.image_path) as images
            FROM reviews r
            LEFT JOIN products p ON r.product_id = p.id
            LEFT JOIN review_images ri ON r.id = ri.review_id
            WHERE r.user_id = ?
            GROUP BY r.id
            ORDER BY r.created_at DESC
            LIMIT ? OFFSET ?
        ");
        $stmt->bind_param('iii', $user_id, $limit, $offset);
        $stmt->execute();
        return $stmt->get_result()->fetch_all(MYSQLI_ASSOC);
    }
    
    public function updateReview($review_id, $user_id, $rating, $comment, $images = []) {
        $this->db->begin_transaction();
        
        try {
            // Update review
            $stmt = $this->db->prepare("UPDATE reviews SET rating = ?, comment = ?, updated_at = NOW() WHERE id = ? AND user_id = ?");
            $stmt->bind_param('isii', $rating, $comment, $review_id, $user_id);
            $stmt->execute();
            
            // Update images
            if (!empty($images)) {
                // Delete old images
                $stmt = $this->db->prepare("DELETE FROM review_images WHERE review_id = ?");
                $stmt->bind_param('i', $review_id);
                $stmt->execute();
                
                // Add new images
                $stmt = $this->db->prepare("INSERT INTO review_images (review_id, image_path) VALUES (?, ?)");
                foreach ($images as $image) {
                    $stmt->bind_param('is', $review_id, $image);
                    $stmt->execute();
                }
            }
            
            // Update product rating
            $stmt = $this->db->prepare("SELECT product_id FROM reviews WHERE id = ?");
            $stmt->bind_param('i', $review_id);
            $stmt->execute();
            $result = $stmt->get_result()->fetch_assoc();
            $this->updateProductRating($result['product_id']);
            
            $this->db->commit();
            return true;
            
        } catch (\Exception $e) {
            $this->db->rollback();
            throw $e;
        }
    }
    
    public function deleteReview($review_id, $user_id) {
        $this->db->begin_transaction();
        
        try {
            // Get product_id before deletion
            $stmt = $this->db->prepare("SELECT product_id FROM reviews WHERE id = ? AND user_id = ?");
            $stmt->bind_param('ii', $review_id, $user_id);
            $stmt->execute();
            $result = $stmt->get_result()->fetch_assoc();
            
            if (!$result) {
                throw new \Exception('Review not found or unauthorized');
            }
            
            // Delete review images
            $stmt = $this->db->prepare("DELETE FROM review_images WHERE review_id = ?");
            $stmt->bind_param('i', $review_id);
            $stmt->execute();
            
            // Delete review
            $stmt = $this->db->prepare("DELETE FROM reviews WHERE id = ? AND user_id = ?");
            $stmt->bind_param('ii', $review_id, $user_id);
            $stmt->execute();
            
            // Update product rating
            $this->updateProductRating($result['product_id']);
            
            $this->db->commit();
            return true;
            
        } catch (\Exception $e) {
            $this->db->rollback();
            throw $e;
        }
    }
    
    private function updateProductRating($product_id) {
        $stmt = $this->db->prepare("
            UPDATE products p
            SET rating = (
                SELECT AVG(rating)
                FROM reviews
                WHERE product_id = ?
            )
            WHERE id = ?
        ");
        $stmt->bind_param('ii', $product_id, $product_id);
        $stmt->execute();
    }
    
    private function notifyProductOwner($product_id, $reviewer_id, $rating) {
        $stmt = $this->db->prepare("SELECT user_id FROM products WHERE id = ?");
        $stmt->bind_param('i', $product_id);
        $stmt->execute();
        $result = $stmt->get_result()->fetch_assoc();
        
        if ($result) {
            $message = $rating >= 4 
                ? "Someone left a positive review on your product!"
                : "You received a new review on your product.";
                
            $this->notification->createNotification(
                $result['user_id'],
                'product_review',
                $message,
                [
                    'product_id' => $product_id,
                    'reviewer_id' => $reviewer_id,
                    'rating' => $rating
                ]
            );
        }
    }
}