<?php

namespace Happyr\LinkedIn\Http;

/**
 * @author Tobias Nyholm <tobias.nyholm@gmail.com>
 */
class UrlGenerator implements UrlGeneratorInterface
{
    /**
     * @var array knownLinkedInParams
     *
     * A list of params that might be in the query string
     */
    public static $knownLinkedInParams = ['state', 'code', 'access_token', 'user'];

    /**
     * @var array domainMap
     *
     * Maps aliases to LinkedIn domains.
     */
    public static $domainMap = [
        'api' => 'https://api.linkedin.com/',
        'www' => 'https://www.linkedin.com/',
    ];

    /**
     * @var bool
     *
     * Indicates if we trust HTTP_X_FORWARDED_* headers.
     */
    protected $trustForwarded = false;

    /**
     * {@inheritdoc}
     */
    public function getUrl($name, $path = '', $params = [])
    {
        $url = self::$domainMap[$name];
        if ($path) {
            if ($path[0] === '/') {
                $path = substr($path, 1);
            }
            $url .= $path;
        }

        if (!empty($params)) {
            // does it exist a query string?
            $queryString = parse_url($url, PHP_URL_QUERY);
            if (empty($queryString)) {
                $url .= '?';
            } else {
                $url .= '&';
            }

            // it needs to be PHP_QUERY_RFC3986. We want to have %20 between scopes
            $url .= http_build_query($params, null, '&', PHP_QUERY_RFC3986);
        }

        return $url;
    }

    /**
     * {@inheritdoc}
     */
    public function getCurrentUrl()
    {
        $protocol = $this->getHttpProtocol().'://';
        $host = $this->getHttpHost();
        $currentUrl = $protocol.$host.$_SERVER['REQUEST_URI'];
        $parts = parse_url($currentUrl);

        $query = '';
        if (!empty($parts['query'])) {
            // drop known linkedin params
            $query = $this->dropLinkedInParams($parts['query']);
        }

        // use port if non default
        $port =
            isset($parts['port']) &&
            (($protocol === 'http://' && $parts['port'] !== 80) ||
                ($protocol === 'https://' && $parts['port'] !== 443))
                ? ':'.$parts['port'] : '';

        // rebuild
        return $protocol.$parts['host'].$port.$parts['path'].$query;
    }

    /**
     * Drop known LinkedIn params. Ie those in self::$knownLinkeInParams.
     *
     * @param string $query
     *
     * @return string query without LinkedIn params. This string is prepended with a question mark '?'
     */
    protected function dropLinkedInParams($query)
    {
        if ($query == '') {
            return '';
        }

        $params = explode('&', $query);
        foreach ($params as $i => $param) {
            /*
             * A key or key/value pair might me 'foo=bar', 'foo=', or 'foo'.
             */
            //get the first value of the array you will get when you explode()
            list($key) = explode('=', $param, 2);
            if (in_array($key, self::$knownLinkedInParams)) {
                unset($params[$i]);
            }
        }

        //assert: params is an array. It might be empty
        if (!empty($params)) {
            return '?'.implode($params, '&');
        }

        return '';
    }

    /**
     * Get the host.
     *
     *
     * @return mixed
     */
    protected function getHttpHost()
    {
        if ($this->trustForwarded && isset($_SERVER['HTTP_X_FORWARDED_HOST'])) {
            return $_SERVER['HTTP_X_FORWARDED_HOST'];
        }

        return $_SERVER['HTTP_HOST'];
    }

    /**
     * Get the protocol.
     *
     *
     * @return string
     */
    protected function getHttpProtocol()
    {
        if ($this->trustForwarded && isset($_SERVER['HTTP_X_FORWARDED_PROTO'])) {
            if ($_SERVER['HTTP_X_FORWARDED_PROTO'] === 'https') {
                return 'https';
            }

            return 'http';
        }

        /*apache + variants specific way of checking for https*/
        if (isset($_SERVER['HTTPS']) &&
            ($_SERVER['HTTPS'] === 'on' || $_SERVER['HTTPS'] == 1)) {
            return 'https';
        }

        /*nginx way of checking for https*/
        if (isset($_SERVER['SERVER_PORT']) &&
            ($_SERVER['SERVER_PORT'] === '443')) {
            return 'https';
        }

        return 'http';
    }

    /**
     * {@inheritdoc}
     */
    public function setTrustForwarded($trustForwarded)
    {
        $this->trustForwarded = $trustForwarded;

        return $this;
    }
}