<?php
/**
 * Result returned by a single anti-spam check.
 *
 * @package ZeroSpamForms
 */

namespace TwoOTwoCode\ZeroSpamForms\Engine;

defined( 'ABSPATH' ) || exit;

/**
 * Immutable single-check result.
 */
final class CheckResult {
	public const STATUS_PASS       = 'pass';
	public const STATUS_SUSPICIOUS = 'suspicious';
	public const STATUS_BLOCK      = 'block';

	/**
	 * Result status.
	 *
	 * @var string
	 */
	private $status;

	/**
	 * Safe internal reason codes.
	 *
	 * @var array<int, string>
	 */
	private $reason_codes;

	/**
	 * Constructor.
	 *
	 * @param string             $status       Result status.
	 * @param array<int, string> $reason_codes Safe internal reason codes.
	 */
	private function __construct( string $status, array $reason_codes = array() ) {
		$this->status       = $status;
		$this->reason_codes = $this->filter_reason_codes( $reason_codes );
	}

	/**
	 * Create a passing result.
	 */
	public static function pass(): self {
		return new self( self::STATUS_PASS );
	}

	/**
	 * Create a suspicious result.
	 *
	 * @param string $reason_code Safe internal reason code.
	 */
	public static function suspicious( string $reason_code ): self {
		return new self( self::STATUS_SUSPICIOUS, array( $reason_code ) );
	}

	/**
	 * Create a blocking result.
	 *
	 * @param string $reason_code Safe internal reason code.
	 */
	public static function block( string $reason_code ): self {
		return new self( self::STATUS_BLOCK, array( $reason_code ) );
	}

	/**
	 * Get status.
	 */
	public function get_status(): string {
		return $this->status;
	}

	/**
	 * Check if result blocks the submission.
	 */
	public function is_blocking(): bool {
		return self::STATUS_BLOCK === $this->status;
	}

	/**
	 * Check if result is suspicious.
	 */
	public function is_suspicious(): bool {
		return self::STATUS_SUSPICIOUS === $this->status;
	}

	/**
	 * Get safe internal reason codes.
	 *
	 * @return array<int, string>
	 */
	public function get_reason_codes(): array {
		return $this->reason_codes;
	}

	/**
	 * Keep only stable reason-code-like strings.
	 *
	 * @param array<int, string> $reason_codes Raw reason codes.
	 *
	 * @return array<int, string>
	 */
	private function filter_reason_codes( array $reason_codes ): array {
		$filtered = array();

		foreach ( $reason_codes as $reason_code ) {
			if ( preg_match( '/^[a-z0-9_]+$/', $reason_code ) ) {
				$filtered[] = $reason_code;
			}
		}

		return array_values( array_unique( $filtered ) );
	}
}