<?php
/**
 * Security class.
 *
 * @package SpeedNest
 */

if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

/**
 * Class WPSCO_Security
 *
 * Enforces capabilities, verifies nonces, validates file paths,
 * prevents path traversal, and manages security headers.
 */
class WPSCO_Security {

    /**
     * Constructor.
     */
    public function __construct() {
        add_action( 'send_headers', array( $this, 'send_security_headers' ) );
    }

    /**
     * Send security headers if enabled.
     */
    public function send_security_headers() {
        if ( headers_sent() || is_admin() ) {
            return;
        }

        if ( wpsco_get_setting( 'security_headers_enabled', false ) ) {
            header( 'X-Content-Type-Options: nosniff' );
            header( 'X-Frame-Options: SAMEORIGIN' );
            header( 'Referrer-Policy: strict-origin-when-cross-origin' );
        }
    }

    /**
     * Verify current user has plugin administration capability.
     *
     * @return bool
     */
    public static function check_capability() {
        return current_user_can( WPSCO_CAPABILITY ) || current_user_can( 'manage_options' );
    }

    /**
     * Enforce capability or die.
     */
    public static function enforce_capability() {
        if ( ! self::check_capability() ) {
            wp_die(
                esc_html__( 'You do not have sufficient permissions to access this page or perform this action.', 'speednest' ),
                esc_html__( 'Permission Denied', 'speednest' ),
                array( 'response' => 403 )
            );
        }
    }

    /**
     * Verify nonce or die.
     *
     * @param string $action Nonce action.
     * @param string $query_arg Query arg or post field name.
     * @return bool
     */
    public static function verify_nonce( $action, $query_arg = '_wpnonce' ) {
        $nonce = '';
        if ( isset( $_REQUEST[ $query_arg ] ) ) {
            $nonce = sanitize_text_field( wp_unslash( $_REQUEST[ $query_arg ] ) );
        } elseif ( isset( $_REQUEST['nonce'] ) ) {
            $nonce = sanitize_text_field( wp_unslash( $_REQUEST['nonce'] ) );
        } elseif ( isset( $_REQUEST['_wpnonce'] ) ) {
            $nonce = sanitize_text_field( wp_unslash( $_REQUEST['_wpnonce'] ) );
        } elseif ( isset( $_REQUEST['security'] ) ) {
            $nonce = sanitize_text_field( wp_unslash( $_REQUEST['security'] ) );
        }
        if ( ! wp_verify_nonce( $nonce, $action ) ) {
            if ( wp_doing_ajax() ) {
                wp_send_json_error( array(
                    'message' => __( 'Security verification failed (invalid nonce). Please refresh the page and try again.', 'speednest' ),
                ), 403 );
            } else {
                wp_die(
                    esc_html__( 'Security check failed. Please reload the page and try again.', 'speednest' ),
                    esc_html__( 'Security Check Failed', 'speednest' ),
                    array( 'response' => 403 )
                );
            }
        }
        return true;
    }

    /**
     * Validate a file or directory path to prevent path traversal.
     * Only allows paths strictly inside the WP Content directory or plugin cache directory.
     *
     * @param string $path Target path.
     * @param string $allowed_base Base path that $path must reside within.
     * @return string|false Realpath if safe, false if invalid/traversal attempt.
     */
    public static function validate_path( $path, $allowed_base = '' ) {
        if ( empty( $path ) || ! is_string( $path ) ) {
            return false;
        }

        // Detect null bytes and directory traversal strings.
        if ( strpos( $path, "\0" ) !== false || strpos( $path, '..' ) !== false ) {
            wpsco_log( 'Potential path traversal detected and blocked: ' . sanitize_text_field( $path ), 'error' );
            return false;
        }

        if ( empty( $allowed_base ) ) {
            $allowed_base = function_exists( 'wpsco_get_cache_dir' ) ? wpsco_get_cache_dir() : ( defined( 'WPSCO_CACHE_DIR' ) ? WPSCO_CACHE_DIR : '' );
        }

        $real_base = realpath( $allowed_base );
        $real_path = realpath( $path );

        // If file doesn't exist yet, check directory of parent.
        if ( false === $real_path ) {
            $dir = dirname( $path );
            $real_dir = realpath( $dir );
            if ( false === $real_dir || false === $real_base || strpos( $real_dir, $real_base ) !== 0 ) {
                return false;
            }
            return $path;
        }

        if ( false === $real_base || strpos( $real_path, $real_base ) !== 0 ) {
            wpsco_log( 'Unauthorized path access attempt blocked: ' . sanitize_text_field( $path ), 'error' );
            return false;
        }

        return $real_path;
    }

    /**
     * Securely sanitize an array of settings.
     *
     * @param array $settings Raw settings.
     * @return array Sanitized settings.
     */
    public static function sanitize_settings( $settings ) {
        if ( ! is_array( $settings ) ) {
            return array();
        }

        $clean = array();
        foreach ( $settings as $key => $value ) {
            $key = sanitize_key( $key );

            if ( is_bool( $value ) ) {
                $clean[ $key ] = (bool) $value;
            } elseif ( is_numeric( $value ) ) {
                $clean[ $key ] = is_float( $value ) ? (float) $value : (int) $value;
            } elseif ( is_array( $value ) ) {
                $clean[ $key ] = array_map( function( $item ) {
                    return is_string( $item ) ? sanitize_text_field( $item ) : $item;
                }, $value );
            } elseif ( is_string( $value ) ) {
                // URLs.
                if ( strpos( $key, 'url' ) !== false ) {
                    $clean[ $key ] = esc_url_raw( trim( $value ) );
                } else {
                    $clean[ $key ] = sanitize_text_field( trim( $value ) );
                }
            } else {
                $clean[ $key ] = $value;
            }
        }

        return $clean;
    }
}