<?php
require_once 'config.php';

class AdminAuth {
    private $pdo;
    
    public function __construct() {
        try {
            $db = new Database();
            $this->pdo = $db->getConnection();
        } catch (Exception $e) {
            logError('Admin auth database connection failed: ' . $e->getMessage());
            throw new Exception('Database connection failed');
        }
    }
    
    public function login($username, $password, $rememberMe = false) {
        try {
            // Find admin user
            $stmt = $this->pdo->prepare("
                SELECT id, username, email, password, full_name, role, status 
                FROM admin_users 
                WHERE (username = ? OR email = ?) AND status = 'active'
            ");
            $stmt->execute([$username, $username]);
            $admin = $stmt->fetch();
            
            if (!$admin || !verifyPassword($password, $admin['password'])) {
                logError('Admin login failed', ['username' => $username]);
                return false;
            }
            
            // Create session
            session_start();
            session_regenerate_id(true);
            
            $_SESSION['admin_logged_in'] = true;
            $_SESSION['admin_id'] = $admin['id'];
            $_SESSION['admin_username'] = $admin['username'];
            $_SESSION['admin_full_name'] = $admin['full_name'];
            $_SESSION['admin_role'] = $admin['role'];
            $_SESSION['admin_login_time'] = time();
            
            // Update last login
            $stmt = $this->pdo->prepare("UPDATE admin_users SET last_login = NOW() WHERE id = ?");
            $stmt->execute([$admin['id']]);
            
            // Handle remember me
            if ($rememberMe) {
                $token = generateSecureToken();
                $expires = date('Y-m-d H:i:s', strtotime('+30 days'));
                
                $stmt = $this->pdo->prepare("
                    INSERT INTO admin_sessions (admin_id, session_token, expires_at) 
                    VALUES (?, ?, ?)
                    ON DUPLICATE KEY UPDATE session_token = ?, expires_at = ?
                ");
                $stmt->execute([$admin['id'], $token, $expires, $token, $expires]);
                
                setcookie('admin_remember_token', $token, strtotime('+30 days'), '/', '', true, true);
            }
            
            logError('Admin login successful', [
                'admin_id' => $admin['id'],
                'username' => $admin['username'],
                'role' => $admin['role']
            ]);
            
            return true;
            
        } catch (Exception $e) {
            logError('Admin login error', ['username' => $username, 'error' => $e->getMessage()]);
            return false;
        }
    }
    
    public function logout() {
        session_start();
        
        if (isset($_SESSION['admin_id'])) {
            logError('Admin logout', ['admin_id' => $_SESSION['admin_id']]);
        }
        
        // Clear remember token
        if (isset($_COOKIE['admin_remember_token'])) {
            try {
                $stmt = $this->pdo->prepare("DELETE FROM admin_sessions WHERE session_token = ?");
                $stmt->execute([$_COOKIE['admin_remember_token']]);
            } catch (Exception $e) {
                logError('Error clearing admin remember token', ['error' => $e->getMessage()]);
            }
            
            setcookie('admin_remember_token', '', time() - 3600, '/', '', true, true);
        }
        
        // Clear session
        session_unset();
        session_destroy();
        
        header('Location: support.php');
        exit;
    }
    
    public function isLoggedIn() {
        session_start();
        
        if (isset($_SESSION['admin_logged_in']) && $_SESSION['admin_logged_in'] === true) {
            // Check session timeout (4 hours)
            if (isset($_SESSION['admin_login_time']) && (time() - $_SESSION['admin_login_time']) > 14400) {
                $this->logout();
                return false;
            }
            return true;
        }
        
        // Check remember token
        if (isset($_COOKIE['admin_remember_token'])) {
            return $this->checkRememberToken($_COOKIE['admin_remember_token']);
        }
        
        return false;
    }
    
    private function checkRememberToken($token) {
        try {
            $stmt = $this->pdo->prepare("
                SELECT aus.admin_id, au.username, au.email, au.full_name, au.role
                FROM admin_sessions aus
                JOIN admin_users au ON aus.admin_id = au.id
                WHERE aus.session_token = ? AND aus.expires_at > NOW() AND au.status = 'active'
            ");
            $stmt->execute([$token]);
            $session = $stmt->fetch();
            
            if ($session) {
                // Auto-login with remember token
                session_start();
                session_regenerate_id(true);
                
                $_SESSION['admin_logged_in'] = true;
                $_SESSION['admin_id'] = $session['admin_id'];
                $_SESSION['admin_username'] = $session['username'];
                $_SESSION['admin_full_name'] = $session['full_name'];
                $_SESSION['admin_role'] = $session['role'];
                $_SESSION['admin_login_time'] = time();
                
                // Update last login
                $stmt = $this->pdo->prepare("UPDATE admin_users SET last_login = NOW() WHERE id = ?");
                $stmt->execute([$session['admin_id']]);
                
                return true;
            } else {
                // Invalid or expired token - clean up
                setcookie('admin_remember_token', '', time() - 3600, '/', '', true, true);
            }
        } catch (Exception $e) {
            logError('Error checking admin remember token', ['error' => $e->getMessage()]);
        }
        
        return false;
    }
    
    public function requireAdmin() {
        if (!$this->isLoggedIn()) {
            header('Location: support.php');
            exit;
        }
    }
    
    public function getCurrentAdmin() {
        if (!$this->isLoggedIn()) {
            return null;
        }
        
        session_start();
        return [
            'id' => $_SESSION['admin_id'],
            'username' => $_SESSION['admin_username'],
            'full_name' => $_SESSION['admin_full_name'],
            'role' => $_SESSION['admin_role']
        ];
    }
    
    public function createAdmin($username, $email, $password, $fullName, $role = 'admin') {
        try {
            // Check if username or email already exists
            $stmt = $this->pdo->prepare("SELECT id FROM admin_users WHERE username = ? OR email = ?");
            $stmt->execute([$username, $email]);
            if ($stmt->fetch()) {
                return false;
            }
            
            // Create admin user
            $hashedPassword = hashPassword($password);
            $stmt = $this->pdo->prepare("
                INSERT INTO admin_users (username, email, password, full_name, role, status) 
                VALUES (?, ?, ?, ?, ?, 'active')
            ");
            $result = $stmt->execute([$username, $email, $hashedPassword, $fullName, $role]);
            
            if ($result) {
                logError('Admin user created', [
                    'username' => $username,
                    'email' => $email,
                    'role' => $role
                ]);
            }
            
            return $result;
            
        } catch (Exception $e) {
            logError('Error creating admin user', ['username' => $username, 'error' => $e->getMessage()]);
            return false;
        }
    }
    
    public function getAllTickets($status = null, $priority = null, $limit = 50, $offset = 0) {
        try {
            $where = "1=1";
            $params = [];
            
            if ($status) {
                $where .= " AND st.status = ?";
                $params[] = $status;
            }
            
            if ($priority) {
                $where .= " AND st.priority = ?";
                $params[] = $priority;
            }
            
            $stmt = $this->pdo->prepare("
                SELECT st.*, u.email as user_email, au.full_name as assigned_to_name,
                       (SELECT COUNT(*) FROM support_messages sm WHERE sm.ticket_id = st.id AND sm.sender_type = 'user') as user_replies,
                       (SELECT COUNT(*) FROM support_messages sm WHERE sm.ticket_id = st.id AND sm.sender_type = 'admin') as admin_replies,
                       (SELECT sm.created_at FROM support_messages sm WHERE sm.ticket_id = st.id ORDER BY sm.created_at DESC LIMIT 1) as last_activity
                FROM support_tickets st
                JOIN users u ON st.user_id = u.id
                LEFT JOIN admin_users au ON st.assigned_to = au.id
                WHERE {$where}
                ORDER BY st.updated_at DESC, st.created_at DESC
                LIMIT ? OFFSET ?
            ");
            
            $params[] = $limit;
            $params[] = $offset;
            
            $stmt->execute($params);
            return $stmt->fetchAll();
            
        } catch (Exception $e) {
            logError('Error fetching admin tickets', ['error' => $e->getMessage()]);
            return [];
        }
    }
    
    public function getTicketById($ticketId) {
        try {
            $stmt = $this->pdo->prepare("
                SELECT st.*, u.email as user_email, au.full_name as assigned_to_name
                FROM support_tickets st
                JOIN users u ON st.user_id = u.id
                LEFT JOIN admin_users au ON st.assigned_to = au.id
                WHERE st.id = ?
            ");
            $stmt->execute([$ticketId]);
            return $stmt->fetch();
            
        } catch (Exception $e) {
            logError('Error fetching ticket by ID', ['ticket_id' => $ticketId, 'error' => $e->getMessage()]);
            return null;
        }
    }
    
    public function getTicketMessages($ticketId, $includeInternal = true) {
        try {
            $where = $includeInternal ? "1=1" : "sm.is_internal = 0";
            
            $stmt = $this->pdo->prepare("
                SELECT sm.*, 
                       CASE 
                           WHEN sm.sender_type = 'user' THEN u.email 
                           WHEN sm.sender_type = 'admin' THEN au.full_name 
                       END as sender_name
                FROM support_messages sm
                LEFT JOIN users u ON sm.sender_type = 'user' AND sm.sender_id = u.id
                LEFT JOIN admin_users au ON sm.sender_type = 'admin' AND sm.sender_id = au.id
                WHERE sm.ticket_id = ? AND {$where}
                ORDER BY sm.created_at ASC
            ");
            $stmt->execute([$ticketId]);
            return $stmt->fetchAll();
            
        } catch (Exception $e) {
            logError('Error fetching ticket messages', ['ticket_id' => $ticketId, 'error' => $e->getMessage()]);
            return [];
        }
    }
    
    public function updateTicketStatus($ticketId, $status, $adminId) {
    try {
        $stmt = $this->pdo->prepare("
            UPDATE support_tickets 
            SET status = ?, resolved_at = CASE WHEN ? = 'resolved' COLLATE utf8mb4_unicode_ci THEN NOW() ELSE resolved_at END
            WHERE id = ?
        ");
        $result = $stmt->execute([$status, $status, $ticketId]);
        
        if ($result) {
            logError('Ticket status updated', [
                'ticket_id' => $ticketId,
                'status' => $status,
                'admin_id' => $adminId
            ]);
        }
        
        return $result;
        
    } catch (Exception $e) {
        logError('Error updating ticket status', ['ticket_id' => $ticketId, 'error' => $e->getMessage()]);
        return false;
    }
}
    
    public function assignTicket($ticketId, $adminId, $assignedBy) {
        try {
            $stmt = $this->pdo->prepare("UPDATE support_tickets SET assigned_to = ? WHERE id = ?");
            $result = $stmt->execute([$adminId, $ticketId]);
            
            if ($result) {
                logError('Ticket assigned', [
                    'ticket_id' => $ticketId,
                    'assigned_to' => $adminId,
                    'assigned_by' => $assignedBy
                ]);
            }
            
            return $result;
            
        } catch (Exception $e) {
            logError('Error assigning ticket', ['ticket_id' => $ticketId, 'error' => $e->getMessage()]);
            return false;
        }
    }
    
    public function addReply($ticketId, $adminId, $message, $isInternal = false) {
        try {
            $this->pdo->beginTransaction();
            
            // Insert message
            $stmt = $this->pdo->prepare("
                INSERT INTO support_messages (ticket_id, sender_type, sender_id, message, is_internal) 
                VALUES (?, 'admin', ?, ?, ?)
            ");
            $stmt->execute([$ticketId, $adminId, $message, $isInternal ? 1 : 0]);
            
            // Update ticket status to pending if not internal
            if (!$isInternal) {
                $stmt = $this->pdo->prepare("UPDATE support_tickets SET status = 'pending' WHERE id = ?");
                $stmt->execute([$ticketId]);
            }
            
            $this->pdo->commit();
            
            logError('Admin reply added', [
                'ticket_id' => $ticketId,
                'admin_id' => $adminId,
                'is_internal' => $isInternal
            ]);
            
            return true;
            
        } catch (Exception $e) {
            $this->pdo->rollBack();
            logError('Error adding admin reply', ['ticket_id' => $ticketId, 'error' => $e->getMessage()]);
            return false;
        }
    }
    
    public function getAdminUsers() {
        try {
            $stmt = $this->pdo->prepare("SELECT id, username, full_name, role, status FROM admin_users WHERE status = 'active' ORDER BY full_name");
            $stmt->execute();
            return $stmt->fetchAll();
        } catch (Exception $e) {
            logError('Error fetching admin users', ['error' => $e->getMessage()]);
            return [];
        }
    }
    
    public function getTicketStats() {
        try {
            $stmt = $this->pdo->prepare("
                SELECT 
                    COUNT(*) as total,
                    SUM(CASE WHEN status = 'open' THEN 1 ELSE 0 END) as open,
                    SUM(CASE WHEN status = 'pending' THEN 1 ELSE 0 END) as pending,
                    SUM(CASE WHEN status = 'resolved' THEN 1 ELSE 0 END) as resolved,
                    SUM(CASE WHEN status = 'closed' THEN 1 ELSE 0 END) as closed,
                    SUM(CASE WHEN priority = 'urgent' THEN 1 ELSE 0 END) as urgent,
                    SUM(CASE WHEN created_at >= DATE_SUB(NOW(), INTERVAL 24 HOUR) THEN 1 ELSE 0 END) as today
                FROM support_tickets
            ");
            $stmt->execute();
            return $stmt->fetch();
        } catch (Exception $e) {
            logError('Error fetching ticket stats', ['error' => $e->getMessage()]);
            return [];
        }
    }
}

// Helper function for JSON responses
function adminJsonResponse($success, $message, $data = null) {
    header('Content-Type: application/json');
    echo json_encode([
        'success' => $success,
        'message' => $message,
        'data' => $data
    ]);
    exit;
}
?>