<?php
/**
 * UserModel - Handles user authentication and management
 */
class UserModel {
    private $conn;
    private static $userCache = [];

    public function __construct($conn) {
        $this->conn = $conn;
    }

    /**
     * Sync user from Authelia headers (create or update)
     *
     * @param string $username Username from Remote-User header
     * @param string $displayName Display name from Remote-Name header
     * @param string $email Email from Remote-Email header
     * @param string $groups Comma-separated groups from Remote-Groups header
     * @return array User data array
     */
    public function syncUserFromAuthelia($username, $displayName = '', $email = '', $groups = '') {
        // Check cache first
        $cacheKey = "user_$username";
        if (isset(self::$userCache[$cacheKey])) {
            return self::$userCache[$cacheKey];
        }

        // Determine if user is admin based on groups
        $isAdmin = $this->checkAdminStatus($groups);

        // Try to find existing user
        $stmt = $this->conn->prepare("SELECT * FROM users WHERE username = ?");
        $stmt->bind_param("s", $username);
        $stmt->execute();
        $result = $stmt->get_result();

        if ($result->num_rows > 0) {
            // Update existing user
            $user = $result->fetch_assoc();

            $updateStmt = $this->conn->prepare(
                "UPDATE users SET display_name = ?, email = ?, groups = ?, is_admin = ?, last_login = NOW() WHERE username = ?"
            );
            $updateStmt->bind_param("sssis", $displayName, $email, $groups, $isAdmin, $username);
            $updateStmt->execute();
            $updateStmt->close();

            // Refresh user data
            $user['display_name'] = $displayName;
            $user['email'] = $email;
            $user['groups'] = $groups;
            $user['is_admin'] = $isAdmin;
        } else {
            // Create new user
            $insertStmt = $this->conn->prepare(
                "INSERT INTO users (username, display_name, email, groups, is_admin, last_login) VALUES (?, ?, ?, ?, ?, NOW())"
            );
            $insertStmt->bind_param("ssssi", $username, $displayName, $email, $groups, $isAdmin);
            $insertStmt->execute();

            $userId = $this->conn->insert_id;
            $insertStmt->close();

            // Get the newly created user
            $stmt = $this->conn->prepare("SELECT * FROM users WHERE user_id = ?");
            $stmt->bind_param("i", $userId);
            $stmt->execute();
            $result = $stmt->get_result();
            $user = $result->fetch_assoc();
        }

        $stmt->close();

        // Cache user
        self::$userCache[$cacheKey] = $user;

        return $user;
    }

    /**
     * Get system user (for hwmonDaemon)
     *
     * @return array|null System user data or null if not found
     */
    public function getSystemUser() {
        // Check cache first
        if (isset(self::$userCache['system'])) {
            return self::$userCache['system'];
        }

        $stmt = $this->conn->prepare("SELECT * FROM users WHERE username = 'system'");
        $stmt->execute();
        $result = $stmt->get_result();

        if ($result->num_rows > 0) {
            $user = $result->fetch_assoc();
            self::$userCache['system'] = $user;
            $stmt->close();
            return $user;
        }

        $stmt->close();
        return null;
    }

    /**
     * Get user by ID
     *
     * @param int $userId User ID
     * @return array|null User data or null if not found
     */
    public function getUserById($userId) {
        // Check cache first
        $cacheKey = "user_id_$userId";
        if (isset(self::$userCache[$cacheKey])) {
            return self::$userCache[$cacheKey];
        }

        $stmt = $this->conn->prepare("SELECT * FROM users WHERE user_id = ?");
        $stmt->bind_param("i", $userId);
        $stmt->execute();
        $result = $stmt->get_result();

        if ($result->num_rows > 0) {
            $user = $result->fetch_assoc();
            self::$userCache[$cacheKey] = $user;
            $stmt->close();
            return $user;
        }

        $stmt->close();
        return null;
    }

    /**
     * Get user by username
     *
     * @param string $username Username
     * @return array|null User data or null if not found
     */
    public function getUserByUsername($username) {
        // Check cache first
        $cacheKey = "user_$username";
        if (isset(self::$userCache[$cacheKey])) {
            return self::$userCache[$cacheKey];
        }

        $stmt = $this->conn->prepare("SELECT * FROM users WHERE username = ?");
        $stmt->bind_param("s", $username);
        $stmt->execute();
        $result = $stmt->get_result();

        if ($result->num_rows > 0) {
            $user = $result->fetch_assoc();
            self::$userCache[$cacheKey] = $user;
            $stmt->close();
            return $user;
        }

        $stmt->close();
        return null;
    }

    /**
     * Check if user has admin privileges based on groups
     *
     * @param string $groups Comma-separated group names
     * @return bool True if user is in admin group
     */
    private function checkAdminStatus($groups) {
        if (empty($groups)) {
            return false;
        }

        // Split groups by comma and check for 'admin' group
        $groupArray = array_map('trim', explode(',', strtolower($groups)));
        return in_array('admin', $groupArray);
    }

    /**
     * Check if user is admin
     *
     * @param array $user User data array
     * @return bool True if user is admin
     */
    public function isAdmin($user) {
        return isset($user['is_admin']) && $user['is_admin'] == 1;
    }

    /**
     * Check if user has required group membership
     *
     * @param array $user User data array
     * @param array $requiredGroups Array of required group names
     * @return bool True if user is in at least one required group
     */
    public function hasGroupAccess($user, $requiredGroups = ['admin', 'employee']) {
        if (empty($user['groups'])) {
            return false;
        }

        $userGroups = array_map('trim', explode(',', strtolower($user['groups'])));
        $requiredGroups = array_map('strtolower', $requiredGroups);

        return !empty(array_intersect($userGroups, $requiredGroups));
    }

    /**
     * Get all users (for admin panel)
     *
     * @return array Array of user records
     */
    public function getAllUsers() {
        $stmt = $this->conn->prepare("SELECT * FROM users ORDER BY created_at DESC");
        $stmt->execute();
        $result = $stmt->get_result();

        $users = [];
        while ($row = $result->fetch_assoc()) {
            $users[] = $row;
        }

        $stmt->close();
        return $users;
    }
}