<?php
/**
 * Comment Management Class
 * Handles all comment-related operations including creation, moderation, and replies
 */

class Comment {
    private $db;
    
    public function __construct() {
        $this->db = Database::getInstance();
    }
    
    /**
     * Create a new comment
     */
    public function create($data) {
        $sql = "INSERT INTO comments (publication_id, parent_id, name, email, content, ip_address, user_agent) 
                VALUES (?, ?, ?, ?, ?, ?, ?)";
        
        return $this->db->execute($sql, [
            $data['publication_id'],
            $data['parent_id'] ?? null,
            $data['name'],
            $data['email'] ?? null,
            $data['content'],
            $_SERVER['REMOTE_ADDR'] ?? null,
            $_SERVER['HTTP_USER_AGENT'] ?? null
        ]);
    }
    
    /**
     * Create an admin reply (bypasses captcha, auto-approved)
     */
    public function createAdminReply($data) {
        $sql = "INSERT INTO comments (publication_id, parent_id, name, content, status, admin_reply, replied_by) 
                VALUES (?, ?, ?, ?, 'approved', TRUE, ?)";
        
        return $this->db->execute($sql, [
            $data['publication_id'],
            $data['parent_id'],
            $data['name'] ?? 'Admin',
            $data['content'],
            $data['replied_by']
        ]);
    }
    
    /**
     * Get approved comments for a publication
     */
    public function getApprovedByPublication($publicationId) {
        $sql = "SELECT c.*, u.username as replied_by_username 
                FROM comments c 
                LEFT JOIN users u ON c.replied_by = u.id 
                WHERE c.publication_id = ? AND c.status = 'approved' 
                ORDER BY c.created_at ASC";
        
        return $this->db->fetchAll($sql, [$publicationId]);
    }
    
    /**
     * Get all comments for admin (including pending)
     */
    public function getAll($status = null, $limit = 50, $offset = 0) {
        $sql = "SELECT c.*, p.title as publication_title, u.username as replied_by_username 
                FROM comments c 
                LEFT JOIN publications p ON c.publication_id = p.id 
                LEFT JOIN users u ON c.replied_by = u.id";
        
        $params = [];
        if ($status) {
            $sql .= " WHERE c.status = ?";
            $params[] = $status;
        }
        
        $sql .= " ORDER BY c.created_at DESC LIMIT ? OFFSET ?";
        $params[] = $limit;
        $params[] = $offset;
        
        return $this->db->fetchAll($sql, $params);
    }
    
    /**
     * Get comment by ID
     */
    public function getById($id) {
        $sql = "SELECT c.*, p.title as publication_title, u.username as replied_by_username 
                FROM comments c 
                LEFT JOIN publications p ON c.publication_id = p.id 
                LEFT JOIN users u ON c.replied_by = u.id 
                WHERE c.id = ?";
        
        return $this->db->fetch($sql, [$id]);
    }
    
    /**
     * Update comment status (approve/reject)
     */
    public function updateStatus($id, $status) {
        $sql = "UPDATE comments SET status = ?, updated_at = CURRENT_TIMESTAMP WHERE id = ?";
        return $this->db->execute($sql, [$status, $id]);
    }
    
    /**
     * Delete a comment
     */
    public function delete($id) {
        $sql = "DELETE FROM comments WHERE id = ?";
        return $this->db->execute($sql, [$id]);
    }
    
    /**
     * Get comment count by status
     */
    public function getCountByStatus($status = null) {
        if ($status) {
            $sql = "SELECT COUNT(*) as count FROM comments WHERE status = ?";
            $result = $this->db->fetch($sql, [$status]);
        } else {
            $sql = "SELECT COUNT(*) as count FROM comments";
            $result = $this->db->fetch($sql);
        }
        return $result['count'];
    }
    
    /**
     * Get comment count for a publication
     */
    public function getCountByPublication($publicationId) {
        $sql = "SELECT COUNT(*) as count FROM comments 
                WHERE publication_id = ? AND status = 'approved'";
        $result = $this->db->fetch($sql, [$publicationId]);
        return $result['count'];
    }
    
    /**
     * Validate comment data
     */
    public function validate($data, $isAdmin = false) {
        $errors = [];
        
        // Common validations
        if (empty($data['content'])) {
            $errors[] = 'Comment content is required';
        } elseif (strlen($data['content']) > 2000) {
            $errors[] = 'Comment content is too long (max 2000 characters)';
        }
        
        if (empty($data['publication_id'])) {
            $errors[] = 'Publication ID is required';
        }
        
        // Public user validations (not for admin)
        if (!$isAdmin) {
            if (empty($data['name'])) {
                $errors[] = 'Name is required';
            } elseif (strlen($data['name']) > 100) {
                $errors[] = 'Name is too long (max 100 characters)';
            }
            
            if (!empty($data['email']) && !filter_var($data['email'], FILTER_VALIDATE_EMAIL)) {
                $errors[] = 'Invalid email address';
            }
        }
        
        return $errors;
    }
    
    /**
     * Check if user can reply to comment
     */
    public function canReply($commentId, $userId) {
        // Admins can reply to any comment
        if ($userId) {
            $userSql = "SELECT role FROM users WHERE id = ?";
            $user = $this->db->fetch($userSql, [$userId]);
            if ($user && $user['role'] === 'admin') {
                return true;
            }
        }
        
        // Check if this is a reply to own comment (for future enhancement)
        $commentSql = "SELECT user_id FROM comments WHERE id = ?";
        $comment = $this->db->fetch($commentSql, [$commentId]);
        
        return false; // Only admins can reply for now
    }
    
    /**
     * Get recent comments for admin dashboard
     */
    public function getRecent($limit = 10) {
        $sql = "SELECT c.*, p.title as publication_title 
                FROM comments c 
                LEFT JOIN publications p ON c.publication_id = p.id 
                ORDER BY c.created_at DESC 
                LIMIT ?";
        
        return $this->db->fetchAll($sql, [$limit]);
    }
    
    /**
     * Get pending comments count
     */
    public function getPendingCount() {
        return $this->getCountByStatus('pending');
    }
}