<?php
namespace PayPal\Core;

use PayPal\Exception\PPConfigurationException;
use PayPal\Exception\PPConnectionException;

/**
 * A wrapper class based on the curl extension.
 * Requires the PHP curl module to be enabled.
 * See for full requirements the PHP manual: http://php.net/curl
 */
class PPHttpConnection
{

    private $httpConfig;

    /**
     * HTTP status codes for which a retry must be attempted
     * retry is currently attempted for Request timeout, Bad Gateway,
     * Service Unavailable and Gateway timeout errors.
     */
    private static $retryCodes = array('408', '502', '503', '504',);

    private $logger;

    public function __construct($httpConfig, $config)
    {
        if (!function_exists("curl_init")) {
            throw new PPConfigurationException("Curl module is not available on this system");
        }
        $this->httpConfig = $httpConfig;
        $this->logger     = new PPLoggingManager(__CLASS__, $config);
    }

    private function getHttpHeaders()
    {

        $ret = array();
        foreach ($this->httpConfig->getHeaders() as $k => $v) {
            $ret[] = "$k: $v";
        }
        return $ret;
    }

    /**
     * Executes an HTTP request
     *
     * @param string $data query string OR POST content as a string
     *
     * @throws PPConnectionException
     */
    public function execute($data)
    {
        $this->logger->fine("Connecting to " . $this->httpConfig->getUrl());
        $this->logger->fine("Payload " . $data);

        $ch = curl_init($this->httpConfig->getUrl());
        curl_setopt_array($ch, $this->httpConfig->getCurlOptions());
        curl_setopt($ch, CURLOPT_URL, $this->httpConfig->getUrl());
        curl_setopt($ch, CURLOPT_HEADER, false);
        curl_setopt($ch, CURLOPT_HTTPHEADER, $this->getHttpHeaders());

        switch ($this->httpConfig->getMethod()) {
            case 'POST':
                curl_setopt($ch, CURLOPT_POST, true);
            case 'PUT':
            case 'PATCH':
                curl_setopt($ch, CURLOPT_POSTFIELDS, $data);
                break;
        }
        if ($this->httpConfig->getMethod() != null) {
            curl_setopt($ch, CURLOPT_CUSTOMREQUEST, $this->httpConfig->getMethod());
        }
        foreach ($this->getHttpHeaders() as $header) {
            //TODO: Strip out credentials and other secure info when logging.
            $this->logger->info("Adding header $header");
        }
        $result = curl_exec($ch);
        if (curl_errno($ch) == 60) {
            $this->logger->info("Invalid or no certificate authority found - Retrying using bundled CA certs file");
            curl_setopt($ch, CURLOPT_CAINFO,
              dirname(__FILE__) . '/cacert.pem');
            $result = curl_exec($ch);
        }
        $httpStatus = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        $retries    = 0;
        if (in_array($httpStatus, self::$retryCodes) && $this->httpConfig->getHttpRetryCount() != null) {
            $this->logger->info("Got $httpStatus response from server. Retrying");

            do {
                $result     = curl_exec($ch);
                $httpStatus = curl_getinfo($ch, CURLINFO_HTTP_CODE);
            } while (in_array($httpStatus, self::$retryCodes) && (++$retries < $this->httpConfig->getHttpRetryCount()));
        }
        if (curl_errno($ch)) {
            $ex = new PPConnectionException($this->httpConfig->getUrl(), curl_error($ch), curl_errno($ch));
            curl_close($ch);
            throw $ex;
        }

        curl_close($ch);

        if (in_array($httpStatus, self::$retryCodes)) {
            $ex = new PPConnectionException($this->httpConfig->getUrl(),
              "Got Http response code $httpStatus when accessing {$this->httpConfig->getUrl()}. Retried $retries times.");
            $ex->setData($result);
            throw $ex;
        } else if ($httpStatus < 200 || $httpStatus >= 300) {
            $ex = new PPConnectionException($this->httpConfig->getUrl(),
              "Got Http response code $httpStatus when accessing {$this->httpConfig->getUrl()}.");
            $ex->setData($result);
            throw $ex;
        }
        return $result;
    }

}
