<?php

namespace RoosterLMS\Events;

use RoosterLMS\Core\Clock;
use RoosterLMS\Registration\Front\RateLimiter;

defined( 'ABSPATH' ) || exit;

final class FeedRate {

	public const OPTION = 'rooster_lms_events_rate';

	public const GROUP = 'rooster_lms_events_rate';

	public const LIMIT = 120;

	public const WINDOW = HOUR_IN_SECONDS;

	public const MAX_KEYS = 500;

	public static function hit(): bool {
		$limit = max( 1, (int) apply_filters( 'rooster_lms_events_feed_rate_limit', self::LIMIT ) );
		return self::count( 'feed', $limit );
	}

	public static function count( string $subject, int $limit, string $extra = '' ): bool {
		$key = substr( wp_hash( 'rl_events|' . $subject . '|' . ( '' !== $extra ? $extra : RateLimiter::client_ip() ) ), 0, 20 );
		$now = Clock::timestamp();
		if ( wp_using_ext_object_cache() ) {
			$slot = $key . ':' . (int) floor( $now / self::WINDOW );
			wp_cache_add( $slot, 0, self::GROUP, self::WINDOW );
			return (int) wp_cache_incr( $slot, 1, self::GROUP ) <= $limit;
		}
		$all    = wp_load_alloptions();
		$stored = isset( $all[ self::OPTION ] ) ? maybe_unserialize( $all[ self::OPTION ] ) : array();
		$stored = is_array( $stored ) ? $stored : array();
		foreach ( $stored as $k => $entry ) {
			if ( ! is_array( $entry ) || (int) ( $entry[1] ?? 0 ) <= $now ) {
				unset( $stored[ $k ] );
			}
		}
		$entry = $stored[ $key ] ?? array( 0, $now + self::WINDOW );
		unset( $stored[ $key ] );
		$entry[0]       = (int) $entry[0] + 1;
		$stored[ $key ] = $entry;
		if ( count( $stored ) > self::MAX_KEYS ) {
			$stored = array_slice( $stored, -self::MAX_KEYS, null, true );
		}
		update_option( self::OPTION, $stored, true );
		return $entry[0] <= $limit;
	}

	public static function reset(): void {
		delete_option( self::OPTION );
	}
}