<?php

class BGSUserAgentParse
{
	public static function parse($u_agent = null)
	{
		if (is_null($u_agent)) {
			if (isset($_SERVER['HTTP_USER_AGENT'])) {
				$u_agent = $_SERVER['HTTP_USER_AGENT'];
			}
			else {
				throw new Exception('parse_user_agent requires a user agent');
			}
		}

		$platform = null;
		$browser  = null;
		$version  = null;

		$empty = array('platform' => $platform, 'browser' => $browser, 'version' => $version);

		if (!$u_agent) {
			return $empty;
		}

		if (preg_match('/\((.*?)\)/im', $u_agent, $parent_matches)) {
			preg_match_all('/(?P<platform>BB\d+;|Android|CrOS|Tizen|iPhone|iPad|iPod|Linux|(Open|Net|Free)BSD|Macintosh|Windows(\ Phone)?|Silk|linux-gnu|BlackBerry|PlayBook|X11|(New\ )?Nintendo\ (WiiU?|3?DS|Switch)|Xbox(\ One)?)
					(?:\ [^;]*)?
					(?:;|$)/imx', $parent_matches[1], $result, PREG_PATTERN_ORDER);

			$priority = array('Xbox One', 'Xbox', 'Windows Phone', 'Tizen', 'Android', 'FreeBSD', 'NetBSD', 'OpenBSD', 'CrOS', 'X11');

			$result['platform'] = array_unique($result['platform']);
			if (count($result['platform']) > 1) {
				if ($keys = array_intersect($priority, $result['platform'])) {
					$platform = reset($keys);
				}
				else {
					$platform = $result['platform'][0];
				}
			}
			else if (isset($result['platform'][0])) {
				$platform = $result['platform'][0];
			}
		}

		if ($platform == 'linux-gnu' || $platform == 'X11') {
			$platform = 'Linux';
		}
		else if ($platform == 'CrOS') {
			$platform = 'Chrome OS';
		}

		preg_match_all('%(?P<browser>Camino|Kindle(\ Fire)?|Firefox|Iceweasel|IceCat|Safari|MSIE|Trident|AppleWebKit|
					TizenBrowser|Chrome|Vivaldi|IEMobile|Opera|OPR|Silk|Midori|Edge|CriOS|UCBrowser|Puffin|SamsungBrowser|
					Baiduspider|Googlebot|YandexBot|bingbot|Lynx|Version|Wget|curl|
					Valve\ Steam\ Tenfoot|
					NintendoBrowser|PLAYSTATION\ (\d|Vita)+)
					(?:\)?;?)
					(?:(?:[:/ ])(?P<version>[0-9A-Z.]+)|/(?:[A-Z]*))%ix',
			$u_agent, $result, PREG_PATTERN_ORDER);

		// If nothing matched, return null (to avoid undefined index errors)
		if (!isset($result['browser'][0]) || !isset($result['version'][0])) {
			if (preg_match('%^(?!Mozilla)(?P<browser>[A-Z0-9\-]+)(/(?P<version>[0-9A-Z.]+))?%ix', $u_agent, $result)) {
				return array('platform' => $platform ?: null, 'browser' => $result['browser'], 'version' => isset($result['version']) ? $result['version'] ?: null : null);
			}

			return $empty;
		}

		if (preg_match('/rv:(?P<version>[0-9A-Z.]+)/si', $u_agent, $rv_result)) {
			$rv_result = $rv_result['version'];
		}

		$browser = $result['browser'][0];
		$version = $result['version'][0];

		$lowerBrowser = array_map('strtolower', $result['browser']);

		$find = function ($search, &$key, &$value = null) use ($lowerBrowser) {
			$search = (array)$search;

			foreach ($search as $val) {
				$xkey = array_search(strtolower($val), $lowerBrowser);
				if ($xkey !== false) {
					$value = $val;
					$key   = $xkey;

					return true;
				}
			}

			return false;
		};

		$key = 0;
		$val = '';
		if ($browser == 'Iceweasel' || strtolower($browser) == 'icecat') {
			$browser = 'Firefox';
		}
		else if ($find('Playstation Vita', $key)) {
			$platform = 'PlayStation Vita';
			$browser  = 'Browser';
		}
		else if ($find(array('Kindle Fire', 'Silk'), $key, $val)) {
			$browser  = $val == 'Silk' ? 'Silk' : 'Kindle';
			$platform = 'Kindle Fire';
			if (!($version = $result['version'][$key]) || !is_numeric($version[0])) {
				$version = $result['version'][array_search('Version', $result['browser'])];
			}
		}
		else if ($find('NintendoBrowser', $key) || $platform == 'Nintendo 3DS') {
			$browser = 'NintendoBrowser';
			$version = $result['version'][$key];
		}
		else if ($find('Kindle', $key, $platform)) {
			$browser = $result['browser'][$key];
			$version = $result['version'][$key];
		}
		else if ($find('OPR', $key)) {
			$browser = 'Opera';
			$version = $result['version'][$key];
		}
		else if ($find('Opera', $key, $browser)) {
			$find('Version', $key);
			$version = $result['version'][$key];
		}
		else if ($find('Puffin', $key, $browser)) {
			$version = $result['version'][$key];
			if (strlen($version) > 3) {
				$part = substr($version, -2);
				if (ctype_upper($part)) {
					$version = substr($version, 0, -2);

					$flags = array('IP' => 'iPhone', 'IT' => 'iPad', 'AP' => 'Android', 'AT' => 'Android', 'WP' => 'Windows Phone', 'WT' => 'Windows');
					if (isset($flags[$part])) {
						$platform = $flags[$part];
					}
				}
			}
		}
		else if ($find(array('IEMobile', 'Edge', 'Midori', 'Vivaldi', 'SamsungBrowser', 'Valve Steam Tenfoot', 'Chrome'), $key, $browser)) {
			$version = $result['version'][$key];
		}
		else if ($rv_result && $find('Trident', $key)) {
			$browser = 'MSIE';
			$version = $rv_result;
		}
		else if ($find('UCBrowser', $key)) {
			$browser = 'UC Browser';
			$version = $result['version'][$key];
		}
		else if ($find('CriOS', $key)) {
			$browser = 'Chrome';
			$version = $result['version'][$key];
		}
		else if ($browser == 'AppleWebKit') {
			if ($platform == 'Android' && !($key = 0)) {
				$browser = 'Android Browser';
			}
			else if (strpos($platform, 'BB') === 0) {
				$browser  = 'BlackBerry Browser';
				$platform = 'BlackBerry';
			}
			else if ($platform == 'BlackBerry' || $platform == 'PlayBook') {
				$browser = 'BlackBerry Browser';
			}
			else {
				$find('Safari', $key, $browser) || $find('TizenBrowser', $key, $browser);
			}

			$find('Version', $key);
			$version = $result['version'][$key];
		}
		else if ($pKey = preg_grep('/playstation \d/i', array_map('strtolower', $result['browser']))) {
			$pKey = reset($pKey);

			$platform = 'PlayStation ' . preg_replace('/[^\d]/i', '', $pKey);
			$browser  = 'NetFront';
		}

		return array('platform' => $platform ?: null, 'browser' => $browser ?: null, 'version' => $version ?: null);
	}
}