<?php
/**
 * Anonymous browser ballot.
 *
 * The cookie holds a random token. The database stores only a salted
 * hash of that token, so a ballot can be updated without storing an
 * account, address, or anything that identifies a person.
 *
 * @package Poller
 */

namespace BmltEnabled\Poller;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

class Voter {

	public const COOKIE = 'poller_ballot';

	public static function has_token(): bool {
		return (bool) preg_match( '/^[a-f0-9]{64}$/', self::cookie() );
	}

	public static function token(): string {
		$cookie = self::cookie();
		return preg_match( '/^[a-f0-9]{64}$/', $cookie ) ? $cookie : '';
	}

	private static function cookie(): string {
		if ( ! isset( $_COOKIE[ self::COOKIE ] ) ) {
			return '';
		}

		return sanitize_text_field( wp_unslash( $_COOKIE[ self::COOKIE ] ) );
	}

	public static function ensure(): string {
		if ( self::has_token() ) {
			return self::token();
		}

		$raw = bin2hex( random_bytes( 32 ) );
		setcookie(
			self::COOKIE,
			$raw,
			[
				'expires' => time() + 30 * DAY_IN_SECONDS,
				'path' => '/',
				'secure' => is_ssl(),
				'httponly' => true,
				'samesite' => 'Lax',
			]
		);
		$_COOKIE[ self::COOKIE ] = $raw;
		return $raw;
	}

	public static function hash( string $raw ): string {
		return hash( 'sha256', $raw . '|' . wp_salt( 'auth' ) );
	}
}