<?php

# -*- coding: utf-8; mode: php; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- vim:fenc=utf-8:filetype=php:et:sw=4:ts=4:sts=4
# Copyright (c) 2008, The MacPorts Project.

class AcceptAbstract {

    function __construct($accept_header) {
        $this->accept = array();

        if (empty($accept_header)) {
            return;
        }

        $fudge_factor = 0.00001;

        $components = preg_split('%\s*,\s*%', $accept_header);
        $temp = array();
        foreach ($components as $i => $component) {

            // Find the parts of the string.
            preg_match('%^
                ([^\s;]+)            # one or more chars -- the value -- match 1
                (?:                  # begin group (optional)
                    \s*;\s*              # semicolon optionally surrounded by whitespace
                    q=                   # literal text "q="
                    ([01](?:\.\d+)?)     # floating-point number, 0 >= n >= 1 -- the quality -- match 2
                )?                   # end group
                $%ix',
                $component, $matches
            );

            $value = $matches[1];

            // If no quality is given, quality 1 is assumed.
            $q = isset($matches[2]) ? (float)$matches[2] : (float)1;

            // Stuff it in the array, if the quality is non-zero.
            if ($q > 0) {
                $temp[$value] = array(
                    'value' => $value,
                    'q' => $q - ($i * $fudge_factor),
                    'i' => $i,
                );
            }

        }

        // Sort descending by quality.
        usort($temp, create_function('$a, $b', 'return ($a["q"] == $b["q"]) ? 0 : ($a["q"] > $b["q"]) ? -1 : 1;'));

        // Unfudge the quality parameter and simplify the array.
        foreach ($temp as $x) {
            $this->accept[$x['value']] = $x['q'] + $x['i'] * $fudge_factor;
        }
    }

    function getPreferred() {
        if (empty($this->accept)) {
            return false;
        } else {
            $keys = array_keys($this->accept);
            return $this->accept[$keys[0]];
        }
    }

    function acceptable($value) {
        return array_key_exists($value, $this->accept);
    }

}