<?php
/**
* @package   Warp Theme Framework
* @author    YOOtheme http://www.yootheme.com
* @copyright Copyright (C) YOOtheme GmbH
* @license   http://www.gnu.org/licenses/gpl.html GNU/GPL
*/

namespace Warp\Helper;

/**
 * User agent helper class, detect browser, version and operating system.
 * 
 * Based on Simple PHP User agent (http://github.com/ornicar/php-user-agent, Thibault Duplessis <thibault.duplessis@gmail.com>, MIT License)
 */
class UseragentHelper extends AbstractHelper
{
    /**
     * @var array
     */
    protected $info;

    /**
     * Retrieve browser name.
     * 
     * @return string
     */
    public function browser()
    {
        if (empty($this->info)) {
            $this->info = $this->parse();
        }

        return $this->info['browser_name'];
    }

    /**
     * Retrieve browser version.
     * 
     * @return string
     */
    public function version()
    {
        if (empty($this->info)) {
            $this->info = $this->parse();
        }

        return $this->info['browser_version'];
    }

    /**
     * Retrieve operating system.
     * 
     * @return string
     */
    public function os()
    {
        if (empty($this->info)) {
            $this->info = $this->parse();
        }

        return $this->info['operating_system'];
    }

    /**
     * Parse a user agent string.
     *
     * @param string $userAgentString defaults to $_SERVER['HTTP_USER_AGENT'] if empty
     * 
     * @return  array ( (the user agent informations)
     *            'browser_name'      => 'firefox',
     *            'browser_version'   => '3.6',
     *            'operating_system'  => 'linux'
     *          )
     */
    public function parse($userAgentString = null)
    {
        // use current user agent string as default
        if (!$userAgentString) {
            $userAgentString = isset($_SERVER['HTTP_USER_AGENT']) ? $_SERVER['HTTP_USER_AGENT'] : null;
        }

        // parse quickly (with medium accuracy)
        $informations = $this->doParse($userAgentString);

        // run some filters to increase accuracy
        foreach ($this->getFilters() as $filter) {
            $this->$filter($informations);
        }

        return $informations;
    }

    /**
     * Detect quickly informations from the user agent string.
     *
     * @param string $userAgentString user agent string
     * 
     * @return array user agent informations array
     */
    public function doParse($userAgentString)
    {
        $userAgent = array(
            'string' => $this->cleanUserAgentString($userAgentString) ,
            'browser_name' => null,
            'browser_version' => null,
            'operating_system' => null
        );

        if (empty($userAgent['string'])) {
            return $userAgent;
        }

        // build regex that matches phrases for known browsers
        // (e.g. "Firefox/2.0" or "MSIE 6.0" (This only matches the major and minor
        // version numbers.  E.g. "2.0.0.6" is parsed as simply "2.0"
        $pattern = '#(' . join('|', $this->getKnownBrowsers()) . ')[/ ]+([0-9]+(?:\.[0-9]+)?)#';

        // Find all phrases (or return empty array if none found)
        if (preg_match_all($pattern, $userAgent['string'], $matches)) {

            // Since some UAs have more than one phrase (e.g Firefox has a Gecko phrase,
            // Opera 7,8 have a MSIE phrase), use the last one found (the right-most one
            // in the UA).  That's usually the most correct.
            $i = count($matches[1]) - 1;

            if (isset($matches[1][$i])) {
                $userAgent['browser_name'] = $matches[1][$i];
            }

            if (isset($matches[2][$i])) {
                $userAgent['browser_version'] = $matches[2][$i];
            }
        }

        // Find operating system
        $pattern = '#' . join('|', $this->getKnownOperatingSystems()) . '#';

        if (preg_match($pattern, $userAgent['string'], $match)) {
            if (isset($match[0])) {
                $userAgent['operating_system'] = $match[0];
            }
        }

        return $userAgent;
    }

    /**
     * Make user agent string lowercase, and replace browser aliases
     *
     * @param string $userAgentString the dirty user agent string
     * 
     * @return string the clean user agent string
     */
    public function cleanUserAgentString($userAgentString)
    {
        // clean up the string
        $userAgentString = trim(strtolower($userAgentString));

        // replace browser names with their aliases
        $userAgentString = strtr($userAgentString, $this->getKnownBrowserAliases());

        // replace operating system names with their aliases
        $userAgentString = strtr($userAgentString, $this->getKnownOperatingSystemAliases());

        return $userAgentString;
    }

    /**
     * Get the list of filters that get called when parsing a user agent
     *
     * @return array list of valid callables
     */
    public function getFilters()
    {
        return array(
            'filterGoogleAndroid',
            'filterGoogleChrome',
            'filterSafariVersion',
            'filterOperaVersion',
            'filterYahoo'
        );
    }

    /**
     * Add a filter to be called when parsing a user agent
     *
     * @param   string $filter name of the filter method
     */
    public function addFilter($filter)
    {
        $this->filters+= $filter;
    }

    /**
     * Get known browsers
     *
     * @return array the browsers
     */
    public function getKnownBrowsers()
    {
        return array(
            'msie',
            'firefox',
            'safari',
            'webkit',
            'opera',
            'netscape',
            'konqueror',
            'gecko',
            'chrome',
            'googlebot',
            'iphone',
            'msnbot',
            'applewebkit'
        );
    }

    /**
     * Get known browser aliases
     *
     * @return array the browser aliases
     */
    public function getKnownBrowserAliases()
    {
        return array(
            'shiretoko' => 'firefox',
            'namoroka' => 'firefox',
            'shredder' => 'firefox',
            'minefield' => 'firefox',
            'granparadiso' => 'firefox'
        );
    }

    /**
     * Get known operating system
     *
     * @return array the operating systems
     */
    public function getKnownOperatingSystems()
    {
        return array(
            'windows',
            'macintosh',
            'linux',
            'freebsd',
            'unix',
            'iphone',
            'ipod',
            'ipad',
            'android',
        );
    }

    /**
     * Get known operating system aliases
     *
     * @return array the operating system aliases
     */
    public function getKnownOperatingSystemAliases()
    {
        return array();
    }

    /**
     * Filters
     */

    /**
     * Google android os
     *
     * @param string $userAgentString the user agent string
     */
    public function filterGoogleAndroid(&$userAgent)
    {
        if ('safari' === $userAgent['browser_name'] && strpos($userAgent['string'], 'android')) {
            $userAgent['operating_system'] = strpos($userAgent['string'], 'mobile') ? 'android' : 'android.tablet';
        }
    }

    /**
     * Google chrome has a safari like signature
     * 
     * @param string $userAgentString the user agent string
     */
    public function filterGoogleChrome(&$userAgent)
    {
        if ('safari' === $userAgent['browser_name'] && strpos($userAgent['string'], 'chrome/')) {
            $userAgent['browser_name'] = 'chrome';
            $userAgent['browser_version'] = preg_replace('|.+chrome/([0-9]+(?:\.[0-9]+)?).+|', '$1', $userAgent['string']);
        }
    }

    /**
     * Safari version is not encoded "normally"
     * 
     * @param string $userAgentString the user agent string
     */
    public function filterSafariVersion(&$userAgent)
    {
        if ('safari' === $userAgent['browser_name'] && strpos($userAgent['string'], ' version/')) {
            $userAgent['browser_version'] = preg_replace('|.+\sversion/([0-9]+(?:\.[0-9]+)?).+|', '$1', $userAgent['string']);
        }
    }

    /**
     * Opera 10.00 (and higher) version number is located at the end
     * 
     * @param string $userAgentString the user agent string
     */
    public function filterOperaVersion(&$userAgent)
    {
        if ('opera' === $userAgent['browser_name'] && strpos($userAgent['string'], ' version/')) {
            $userAgent['browser_version'] = preg_replace('|.+\sversion/([0-9]+\.[0-9]+)\s*.*|', '$1', $userAgent['string']);
        }
    }

    /**
     * Yahoo bot has a special user agent string
     * 
     * @param string $userAgentString the user agent string
     */
    public function filterYahoo(&$userAgent)
    {
        if (null === $userAgent['browser_name'] && strpos($userAgent['string'], 'yahoo! slurp')) {
            $userAgent['browser_name'] = 'yahoobot';
        }
    }
}