<?php
// DNTHeader.php
// Created: 2022-02-14
// Updated: 2022-02-14

namespace Index\Http\Headers;

use Index\Http\HttpHeader;

class DNTHeader {
    private ?bool $state;

    public function __construct(?bool $state) {
        $this->state = $state;
    }

    public function getState(): ?bool {
        return $this->state;
    }

    public function hasNoPreference(): bool {
        return $this->state === null;
    }

    public function allowsTracking(): bool {
        return $this->state !== false;
    }

    public static function parse(HttpHeader $header): DNTHeader {
        $value = $header->getFirstLine();
        return new DNTHeader($value === 'null' ? null : ($value === '1'));
    }
}