<?php

namespace Podlove\Http;

use Podlove\Log;

/**
 * Wrapper for WordPress' WP_Http_Curl class.
 */
class Curl
{
    // WP_Http_Curl instance
    private $curl;

    // request call parameters
    private $request = [];

    private $response;

    public function __construct()
    {
        $this->curl = new \WP_Http_Curl();
    }

    public function request($url, $params = [])
    {
        $defaults = [
            'user-agent' => self::user_agent(),
            'stream' => false,
            'decompress' => false,
            'filename' => null,
            'sslcertificates' => ABSPATH.WPINC.'/certificates/ca-bundle.crt',  // i guess this is just a missing default in the current wp curl lib
        ];

        $params = wp_parse_args($params, $defaults);

        if (!isset($params['_redirection']) || $params['_redirection']) {
            if (!self::curl_can_follow_redirects()) {
                $url = self::resolve_redirects($url, 5);
            }
        }

        $this->response = $this->curl->request($url, $params);

        if (is_wp_error($this->response)) {
            Log::get()->addError('Curl error', [
                'url' => $url,
                'error' => $this->response->get_error_message(),
            ]);
        } elseif (substr($this->response['response']['code'], 0, 1) >= 4) {
            Log::get()->addError('Curl error', [
                'url' => $url,
                'response code' => $this->response['response']['code'],
                'debug' => $this->response,
            ]);
        }
    }

    public function isSuccessful()
    {
        return
            $this->response               // request has been made
            && !is_wp_error($this->response) // there was no error
            && substr($this->response['response']['code'], 0, 1) < 4; // 1xx 2xx or 3xx
    }

    public function get_response()
    {
        return $this->response;
    }

    /**
     * Podlove User Agent for cURL requests.
     *
     * @return string
     */
    public static function user_agent()
    {
        $curl_version = curl_version();

        return sprintf(
            'PHP/%s (; ) cURL/%s(OpenSSL/%s; zlib/%s) Wordpress/%s (; ) %s/%s (; )',
            phpversion(),
            $curl_version['version'],
            $curl_version['ssl_version'],
            $curl_version['libz_version'],
            get_bloginfo('version'),
            \Podlove\get_plugin_header('Name'),
            \Podlove\get_plugin_header('Version')
        );
    }

    /**
     * Manually resolve redirects.
     *
     * Some server configurations can't deal with cURL CURLOPT_FOLLOWLOCATION
     * setting. This method resolves a URL without using that setting.
     *
     * @param string $url               URL to resolve
     * @param int    $maximum_redirects Maximum redirects. Default: 5.
     *
     * @return string Final URL
     */
    public static function resolve_redirects($url, $maximum_redirects = 5)
    {
        $curl = new Curl();
        $curl->request($url, ['method' => 'HEAD', '_redirection' => 0]);
        $response = $curl->get_response();

        if (is_wp_error($response)) {
            $message = sprintf('Unable to resolve URL. Might be related to PHP setting open_basedir, which should be empty, but is: "%s"', ini_get('open_basedir'));
            Log::get()->addError($message, [
                'url' => $url,
                'error' => $response->get_error_message(),
            ]);

            return $url;
        }

        $http_code = $response['response']['code'];
        $location = isset($response['headers']['location']) ? $response['headers']['location'] : null;

        if ($http_code >= 300 && $http_code <= 400 && $location && $maximum_redirects > 0) {
            return self::resolve_redirects($location, $maximum_redirects - 1);
        }

        return $url;
    }

    /**
     * Check for CURLOPT_FOLLOWLOCATION bug.
     *
     * If open_basedir path is set,
     * CURLOPT_FOLLOWLOCATION does not work.
     *
     * safe_mode is not checked because it was removed in PHP 5.4 and we require at least 5.4
     *
     * @see  https://stackoverflow.com/questions/2511410/curl-follow-location-error
     * @see  https://stackoverflow.com/questions/19539922/php-can-curlopt-followlocation-and-open-basedir-be-used-together
     *
     * @return bool
     */
    public static function curl_can_follow_redirects()
    {
        return !ini_get('open_basedir');
    }
}