<?php
/**
 * Hashed identifier rate-limit check.
 *
 * @package ZeroSpamForms
 */

namespace TwoOTwoCode\ZeroSpamForms\Engine\Checks;

defined( 'ABSPATH' ) || exit;

use TwoOTwoCode\ZeroSpamForms\Engine\CheckResult;
use TwoOTwoCode\ZeroSpamForms\Engine\RateLimit\RateLimitStoreInterface;
use TwoOTwoCode\ZeroSpamForms\Engine\ReasonCodeRegistry;
use TwoOTwoCode\ZeroSpamForms\Engine\SettingsSnapshot;
use TwoOTwoCode\ZeroSpamForms\Engine\SpamCheckInterface;
use TwoOTwoCode\ZeroSpamForms\Engine\SubmissionContext;
use TwoOTwoCode\ZeroSpamForms\Privacy\IdentifierHasher;

/**
 * Limits repeated submissions by a hashed identifier.
 */
final class RateLimitCheck implements SpamCheckInterface {
	/**
	 * Rate-limit store.
	 *
	 * @var RateLimitStoreInterface
	 */
	private $store;

	/**
	 * Identifier hasher.
	 *
	 * @var IdentifierHasher
	 */
	private $hasher;

	/**
	 * Constructor.
	 *
	 * @param RateLimitStoreInterface $store  Rate-limit store.
	 * @param IdentifierHasher        $hasher Identifier hasher.
	 */
	public function __construct( RateLimitStoreInterface $store, IdentifierHasher $hasher ) {
		$this->store  = $store;
		$this->hasher = $hasher;
	}

	/**
	 * Get check name.
	 */
	public function get_name(): string {
		return 'rate_limit';
	}

	/**
	 * Whether the check is enabled.
	 *
	 * @param SettingsSnapshot $settings Immutable settings snapshot.
	 */
	public function is_enabled( SettingsSnapshot $settings ): bool {
		return $settings->is_check_enabled( 'rate_limit_check_enabled' );
	}

	/**
	 * Evaluate rate limit.
	 *
	 * @param SubmissionContext $context  Normalized submission context.
	 * @param SettingsSnapshot  $settings Immutable settings snapshot.
	 */
	public function evaluate( SubmissionContext $context, SettingsSnapshot $settings ): CheckResult {
		$identifier = $context->get_rate_limit_identifier();

		if ( '' === $identifier ) {
			return CheckResult::pass();
		}

		$key   = $this->hasher->hash_identifier( 'rate_limit', $identifier );
		$count = $this->store->increment( $key, $settings->get_rate_limit_window_seconds(), $context->get_timestamp() );

		if ( $count > $settings->get_rate_limit_threshold() ) {
			return CheckResult::block( ReasonCodeRegistry::RATE_LIMIT_EXCEEDED );
		}

		return CheckResult::pass();
	}
}