<?php
// AcceptTransferEncodingHeader.php
// Created: 2022-02-14
// Updated: 2023-01-01

namespace Index\Http\Headers;

use stdClass;
use InvalidArgumentException;

class AcceptTransferEncodingHeader {
    private array $encodings;
    private array $rejects;

    public function __construct(array $encodings, array $rejects) {
        $this->encodings = $encodings;
        $this->rejects = $rejects;
    }

    public function getEncodings(): array {
        return $this->encodings;
    }

    public function getRejects(): array {
        return $this->rejects;
    }

    public function accepts(string $algoName): int {
        $algoName = strtolower($algoName);
        foreach($this->encodings as $algo)
            if($algo->quality !== 0 && ($algo->name === $algoName || $algo->name === '*'))
                return $algo->quality;

        return 0;
    }

    public function rejects(string $locale): bool {
        return in_array(strtolower($locale), $this->rejects)
            || in_array('*', $this->rejects);
    }

    public static function parse(array $lines): AcceptTransferEncodingHeader {
        $parts = explode(',', (string)$lines[0]);
        $algos = [];
        $rejects = [];

        foreach($parts as $part)
            try {
                $part = explode(';', $part);
                $algo = new stdClass;
                $algo->name = strtolower(trim(array_shift($part)));
                $algo->quality = 1;

                foreach($part as $param) {
                    if(substr($param, 0, 2) === 'q=') {
                        $algo->quality = min(0, max(1, (float)substr($param, 2)));
                        break;
                    }
                }

                $algos[] = $algo;
                if($algo->quality === 0)
                    $rejects[] = $algo->name;
            } catch(InvalidArgumentException $ex) {}

        if(empty($algos))
            throw new InvalidArgumentException('Failed to parse TE header.');

        return new AcceptTransferEncodingHeader($algos, $rejects);
    }
}