<?php
defined( 'ABSPATH' ) || exit;

/**
 * Background chores: heartbeat (plan, quota, rules), critical CSS refresh,
 * cache garbage collection. Everything is tolerant of the SaaS being down.
 */
class ZeroConfig_Cron {

	const HEARTBEAT = 'zeroconfig_heartbeat';
	const CRITICAL  = 'zeroconfig_critical';
	const GC        = 'zeroconfig_gc';
	const CLAIM     = 'zeroconfig_claim';

	public static function init() {
		add_action( self::HEARTBEAT, array( __CLASS__, 'heartbeat' ) );
		add_action( self::CLAIM, array( __CLASS__, 'claim' ) );
		add_action( self::CRITICAL, array( __CLASS__, 'critical' ) );
		add_action( self::GC, array( __CLASS__, 'gc' ) );
		add_action( 'switch_theme', array( __CLASS__, 'request_critical' ) );
		add_action( 'customize_save_after', array( __CLASS__, 'request_critical' ) );
		// Background calls exist only while the engine is on. Clean up events left by older versions.
		if ( ZeroConfig_Options::get( 'engine' ) ) {
			self::ensure();
		} elseif ( wp_next_scheduled( self::HEARTBEAT ) ) {
			self::clear();
		}
	}

	/** Core's own hourly and weekly schedules. Events on another schedule (older versions) are moved. */
	public static function ensure() {
		foreach ( array( self::HEARTBEAT => array( 'hourly', 300 ), self::CRITICAL => array( 'weekly', 600 ), self::GC => array( 'hourly', 900 ) ) as $hook => $when ) {
			if ( wp_next_scheduled( $hook ) && wp_get_schedule( $hook ) !== $when[0] ) {
				wp_unschedule_hook( $hook );
			}
			if ( ! wp_next_scheduled( $hook ) ) {
				wp_schedule_event( time() + $when[1], $when[0], $hook );
			}
		}
	}

	public static function clear() {
		foreach ( array( self::HEARTBEAT, self::CRITICAL, self::GC, self::CLAIM, ZeroConfig_Safe_Mode::EVENT_RUN, ZeroConfig_Safe_Mode::EVENT_POLL, ZeroConfig_Page_Cache::DEFERRED, ZeroConfig_CDN_Purge::EVENT, ZeroConfig_Warm::EVENT, ZeroConfig_API::EDGE_CHECK ) as $h ) {
			wp_unschedule_hook( $h ); // every event of the hook, whatever its args
		}
	}

	/** Finish a pending registration; retry a few times while the edge is still checking. */
	public static function claim( $attempt = 1 ) {
		if ( ! ZeroConfig_Options::get( 'engine' ) || ZeroConfig_Options::is_connected() ) {
			return;
		}
		$r = ZeroConfig_API::claim_pending();
		if ( 'pending' === $r && $attempt < 6 ) {
			wp_schedule_single_event( time() + 20, self::CLAIM, array( $attempt + 1 ) );
		}
	}

	public static function heartbeat() {
		// Local chores first, so they run even when the service is unreachable.
		ZeroConfig_Page_Cache::write_config(); // picks up a changed nonce_life (no write when unchanged)
		ZeroConfig_Page_Cache::refresh_dropin(); // a plugin update (auto-updates too) brings a new drop-in
		ZeroConfig_Htaccess::refresh(); // a failed write must not leave old .htaccess rules for good
		ZeroConfig_Page_Cache::gc();
		$before = ZeroConfig_Options::get( 'cdn_paused' );
		$rules  = (array) ZeroConfig_Options::get( 'rules' );
		$res    = ZeroConfig_API::heartbeat();
		if ( is_wp_error( $res ) ) {
			return;
		}
		// Quota state or rules changed: cached HTML embeds CDN URLs, so purge.
		if ( ZeroConfig_Options::get( 'cdn_paused' ) !== $before || ZeroConfig_Options::get( 'rules' ) !== $rules ) {
			ZeroConfig_Page_Cache::purge_all( 'settings' );
		}
		if ( ZeroConfig_Options::feature_on( 'critical' ) && ! ZeroConfig_Options::get( 'critical_css' ) ) {
			self::request_critical();
		}
		// Once a day the "Is it working?" card is refreshed even when nobody purges anything.
		if ( time() - (int) ( ZeroConfig_Probe::health()['doctor']['at'] ?? 0 ) > DAY_IN_SECONDS ) {
			ZeroConfig_Doctor::run();
		}
	}

	/** Ask the SaaS to (re)generate critical CSS for each template type. */
	public static function request_critical() {
		if ( ! ZeroConfig_Options::feature_on( 'critical' ) || ! ZeroConfig_Options::is_connected() ) {
			return;
		}
		$urls = array( 'front' => home_url( '/' ) );
		$post = get_posts( array( 'numberposts' => 1, 'post_status' => 'publish', 'fields' => 'ids' ) );
		if ( $post ) {
			$urls['single'] = get_permalink( $post[0] );
		}
		$page = get_posts( array( 'numberposts' => 1, 'post_type' => 'page', 'post_status' => 'publish', 'fields' => 'ids', 'exclude' => array( (int) get_option( 'page_on_front' ) ) ) ); // phpcs:ignore WordPressVIPMinimum.Performance.WPQueryParams.PostNotIn_exclude -- one id, one result
		if ( $page ) {
			$urls['page'] = get_permalink( $page[0] );
		}
		if ( get_option( 'page_for_posts' ) ) {
			$urls['home'] = get_permalink( (int) get_option( 'page_for_posts' ) );
		}
		$cat = get_categories( array( 'number' => 1, 'hide_empty' => true ) );
		if ( $cat ) {
			$urls['archive'] = get_category_link( $cat[0] );
		}
		if ( function_exists( 'wc_get_page_id' ) && wc_get_page_id( 'shop' ) > 0 ) {
			$urls['shop'] = get_permalink( wc_get_page_id( 'shop' ) );
			$prod         = ZeroConfig_Safe_Mode::sample_product(); // one with a gallery when there is one
			if ( $prod ) {
				$urls['product'] = get_permalink( $prod );
			}
		}
		ZeroConfig_API::request_critical( $urls );
		wp_schedule_single_event( time() + 180, self::CRITICAL );
	}

	/** Pull generated critical CSS down. */
	public static function critical() {
		if ( ! ZeroConfig_Options::feature_on( 'critical' ) ) {
			return;
		}
		$res = ZeroConfig_API::get_critical();
		if ( is_wp_error( $res ) || empty( $res['critical_css'] ) || ! is_array( $res['critical_css'] ) ) {
			return;
		}
		$clean = ZeroConfig_API::clean_critical( $res['critical_css'] );
		if ( $clean !== ZeroConfig_Options::get( 'critical_css' ) ) {
			ZeroConfig_Options::set( 'critical_css', $clean );
			ZeroConfig_Page_Cache::purge_all( 'settings' );
			ZeroConfig_Safe_Mode::schedule( 60 );
		}
	}

	/** Remove expired cache files so the directory never grows unbounded. */
	public static function gc() {
		ZeroConfig_Page_Cache::gc();
	}
}