<?php

namespace Negotiation;

/**
 * @author William Durand <william.durand1@gmail.com>
 */
class LanguageNegotiator extends Negotiator
{
    /**
     * {@inheritDoc}
     */
    protected function parseHeader($header)
    {
        $acceptHeaders = array();

        $header      = preg_replace('/\s+/', '', $header);
        $acceptParts = array();

        preg_match_all(
            '/(?<=[, ]|^)([a-zA-Z-]+|\*)(?:;q=([0-9.]+))?(?:$|\s*,\s*)/i',
            $header,
            $acceptParts,
            PREG_SET_ORDER
        );

        $index    = 0;
        $catchAll = null;
        foreach ($acceptParts as $acceptPart) {
            $value   = $acceptPart[1];
            $quality = isset($acceptPart[2]) ? (float) $acceptPart[2] : 1.0;

            if ('*' === $value) {
                $catchAll = new AcceptHeader($value, $quality);
            } else {
                $acceptHeaders[] = array(
                    'item'  => new AcceptHeader($value, $quality),
                    'index' => $index
                );
            }

            $index++;
        }

        return $this->sortAcceptHeaders($acceptHeaders, $catchAll);
    }

    /**
     * {@inheritDoc}
     */
    protected function match(array $acceptHeaders, array $priorities = array())
    {
        $wildcardAccept  = null;
        $genericAccept   = null;

        $prioritiesSet   = array();
        $prioritiesSet[] = $priorities;
        $prioritiesSet[] = array_map(function ($priority) {
            return strtok($priority, '-');
        }, $priorities);

        foreach ($acceptHeaders as $accept) {
            foreach ($prioritiesSet as $availablePriorities) {
                $sanitizedPriorities = $this->sanitize($availablePriorities);

                if (false !== $found = array_search(strtolower($accept->getValue()), $sanitizedPriorities)) {
                    return $priorities[$found];
                }

                if (null === $genericAccept && false !== strpos($accept->getValue(), '-')) {
                    $genericValue = explode('-', $accept->getValue());
                    if ($genericValue && (false !== $found = array_search(strtolower($genericValue[0]), $sanitizedPriorities))) {
                        $genericAccept = $priorities[$found];
                    }
                }

                if ('*' === $accept->getValue()) {
                    $wildcardAccept = $accept;
                }
            }
        }

        if ($genericAccept) {
            return $genericAccept;
        }

        if (null !== $wildcardAccept) {
            return reset($priorities);
        }
    }
}