<?php

// Do not allow the file to be called directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * This class is used to schedule the tasks used by Patchstack.
 */
class P_Cron extends P_Core {

	/**
	 * Add the actions required for the task scheduler.
	 *
	 * @param Patchstack $core
	 * @return void
	 */
	public function __construct( $core ) {
		parent::__construct( $core );
		add_action( 'init', [ $this, 'schedule_events' ] );
		add_filter( 'cron_schedules', [ $this, 'cron_schedules' ] );
		add_action( 'patchstack_check_env', [ $this, 'check_env' ] );
	}

	/**
	 * Define our own custom cron schedules.
	 *
	 * @param array $schedules
	 * @return array
	 */
	public function cron_schedules( $schedules ) {
		// Define the scheduled tasks.
		$schedules['patchstack_15minute'] = [
			'interval' => ( 60 * 15 ),
			'display'  => esc_attr__( 'Every 15 Minutes' ),
		];

		$schedules['patchstack_hourly'] = [
			'interval' => ( 60 * 60 ),
			'display'  => esc_attr__( 'Every Hour' ),
		];

		$schedules['patchstack_trihourly'] = [
			'interval' => ( 60 * 60 * 3 ),
			'display'  => esc_attr__( 'Every 3 Hours' ),
		];

		$schedules['patchstack_twicedaily'] = [
			'interval' => ( 60 * 60 * 12 ),
			'display'  => esc_attr__( '2 Times Daily' ),
		];

		$schedules['patchstack_daily'] = [
			'interval' => ( 60 * 60 * 24 ),
			'display'  => esc_attr__( '1 Time Daily' ),
		];

		return $schedules;
	}

	/**
	 * Initialize our scheduled tasks.
	 *
	 * @return void
	 */
	public function schedule_events() {
		// Random time throughout the day to make sure not all sites synchronize at the same time.
		$crons = get_option( 'patchstack_cron_offset', false );
		if ( ! $crons || ! isset ( $crons['patchstack_daily'] ) ) {
			$crons = [
				'patchstack_daily'      => strtotime( 'today' ) + mt_rand( 0, 86399 ),
				'patchstack_hourly'     => strtotime( 'today' ) + mt_rand( 0, 3600 ),
				'patchstack_trihourly'  => strtotime( 'today' ) + mt_rand( 0, 9599 ),
				'patchstack_twicedaily' => strtotime( 'today' ) + mt_rand( 0, 43199 ),
				'patchstack_15minute'   => strtotime( 'today' ) + mt_rand( 0, 899 ),
			];
			update_option( 'patchstack_cron_offset', $crons );

			// Clear existing scheduled events so we can use the new timestamps.
			foreach ( [ 'patchstack_send_software_data', 'patchstack_send_hacker_logs', 'patchstack_post_firewall_rules', 'patchstack_post_firewall_htaccess_rules', 'patchstack_post_dynamic_firewall_rules', 'patchstack_update_license_status', 'patchstack_send_event_logs', 'patchstack_update_plugins', 'patchstack_send_ping' ] as $event ) {
				wp_clear_scheduled_hook( $event );
			}
		}

		// List of the different events.
		$free = [
			'patchstack_send_software_data'    => 'patchstack_twicedaily',
			'patchstack_update_license_status' => 'patchstack_twicedaily',
			'patchstack_send_ping'             => 'patchstack_trihourly',
			'patchstack_update_plugins'        => 'patchstack_15minute'
		];

		$premium = [
			'patchstack_send_hacker_logs'             => 'patchstack_15minute',
			'patchstack_post_firewall_rules'          => 'patchstack_daily',
			'patchstack_post_firewall_htaccess_rules' => 'patchstack_daily',
			'patchstack_post_dynamic_firewall_rules'  => 'patchstack_hourly',
			'patchstack_send_event_logs'              => 'patchstack_15minute',
			'patchstack_check_env'             		  => 'patchstack_trihourly'
		];

		// Schedule the events if they are not scheduled yet.
		if ( $this->get_option( 'patchstack_clientid', false ) ) {
			// These events should always be scheduled for activated sites.
			foreach ( $free as $event => $interval ) {
				if ( ! wp_next_scheduled( $event ) ) {
					wp_schedule_event( $crons[ $interval ], $interval, $event );
				}
			}

			// Only schedule these events for protected sites.
			if ( $this->get_option( 'patchstack_license_free', 0 ) != 1 && $this->license_is_active() ) {
				foreach ( $premium as $event => $interval ) {
					if ( ! wp_next_scheduled( $event ) ) {
						wp_schedule_event( $crons[ $interval ], $interval, $event );
					}
				}
			}
		}
	}

	/**
	 * Determine if the environment has been changed, we must do this to determine if the 
	 * real IP address header has changed to a different HTTP field.
	 * 
	 * @return void
	 */
	public function check_env() {
		$hash = $this->get_option( 'patchstack_environment_hash', '' );
		$computed = $this->get_option( 'patchstack_ip_header_computed', 0 );
		$env_hash = $this->get_env_hash();

		// If hash has not been computed yet, but IP header has been computed, we ignore for the first time.
		if ( $hash == '' && $computed ) {
			update_option( 'patchstack_environment_hash', $env_hash );
			return;
		}

		// If computed hash and previous hash are the same, we ignore.
		if ( $hash == $env_hash ) {
			return;
		}

		// At this point we can assume the previous environment hash and the current environment hash are different.
		// In this scenario, we want to determine which IP address header contains the appropriate IP address.
		update_option( 'patchstack_ip_header_force_compute', 1 );
		update_option( 'patchstack_environment_hash', $env_hash );
		do_action( 'patchstack_send_header_request' );
	}

	/**
	 * Compute a hash of several server specific values.
	 * 
	 * @return string
	 */
	private function get_env_hash() {
		// Parameters of which we want the full string.
		$params_full = [ 'SERVER_ADDR', 'SERVER_NAME', 'SERVER_SOFTWARE' ];

		// Parameters of which we want to get boolean value.
		$params_boolean = [ 'REMOTE_ADDR', 'HTTP_CF_CONNECTING_IP', 'HTTP_X_FORWARDED_FOR' ];

		// String to compute hash value of.
		$string = '';

		// Append full parameter to string.
		foreach ( $params_full as $param ) {
			$string .= isset( $_SERVER[$param] ) ? $_SERVER[$param] : '';
		}

		// Append existence to string, only if not running under cli.
		$sapi = function_exists( 'php_sapi_name' ) ? php_sapi_name() : false;
		if ( $sapi && substr( $sapi, 0, 3 ) != 'cli' ) {
			foreach ( $params_boolean as $param ) {
				$string .= isset( $_SERVER[$param] ) ? '1' : '0';
			}
		}

		return sha1( $string );
	}
}