<?php
/**
 * Generic local anti-spam engine.
 *
 * @package ZeroSpamForms
 */

namespace TwoOTwoCode\ZeroSpamForms\Engine;

defined( 'ABSPATH' ) || exit;

/**
 * Runs checks in deterministic order and combines their results.
 */
final class SpamEngine {
	/**
	 * Ordered checks.
	 *
	 * @var array<int, SpamCheckInterface>
	 */
	private $checks;

	/**
	 * Constructor.
	 *
	 * @param array<int, SpamCheckInterface> $checks Ordered checks.
	 */
	public function __construct( array $checks ) {
		$this->checks = array_values( $checks );
	}

	/**
	 * Evaluate a submission context.
	 *
	 * @param SubmissionContext $context  Normalized submission context.
	 * @param SettingsSnapshot  $settings Immutable settings snapshot.
	 */
	public function evaluate( SubmissionContext $context, SettingsSnapshot $settings ): SpamDecision {
		if ( SettingsSnapshot::MODE_DISABLED === $settings->get_protection_mode() ) {
			return SpamDecision::allow();
		}

		$reason_codes   = array();
		$has_block      = false;
		$has_suspicious = false;

		foreach ( $this->checks as $check ) {
			if ( ! $check->is_enabled( $settings ) ) {
				continue;
			}

			$result = $check->evaluate( $context, $settings );

			if ( $result->is_blocking() ) {
				$has_block = true;
			}

			if ( $result->is_suspicious() ) {
				$has_suspicious = true;
			}

			foreach ( $result->get_reason_codes() as $reason_code ) {
				$reason_codes[] = $reason_code;
			}
		}

		$reason_codes = array_values( array_unique( $reason_codes ) );

		if ( SettingsSnapshot::MODE_MONITOR === $settings->get_protection_mode() ) {
			return array() === $reason_codes ? SpamDecision::allow() : SpamDecision::suspicious( $reason_codes );
		}

		if ( $has_block ) {
			return SpamDecision::block( $reason_codes );
		}

		if ( $has_suspicious ) {
			return SpamDecision::suspicious( $reason_codes );
		}

		return SpamDecision::allow();
	}
}