<?php

/**
* OAuth consumer using PHP cURL
* @author Ben Tadiar <ben@handcraftedbyben.co.uk>
* @link https://github.com/benthedesigner/dropbox
* @package Dropbox\OAuth
* @subpackage Consumer
*/

class Dropbox_Curl extends Dropbox_ConsumerAbstract
{
	/**
	 * Dropbox consumer key
	 * @var String
	 */
	protected $consumerKey;

	/**
	 * Dropbox oauth2_id
	 * @var String
	 */
	protected $oauth2_id;

	/**
	 * Dropbox consumer secret
	 * @var String
	 */
	protected $consumerSecret;

	/**
	 * Dropbox storage object
	 * @var \Dropbox\OAuth\Consumer\StorageInterface|Dropbox_StorageInterface
	 */
	protected $storage;

	/**
	 * Not used anywhere but it is set
	 * @var Callable|Null
	 */
	protected $callback;

	/**
	 * Callback URL
	 * @var String|null
	 */
	protected $callbackhome;

	/**
	 * Dropbox storage instance id
	 * @var String
	 */
	protected $instance_id;

    /**
     * Default cURL options
     * @var array
     */
    protected $defaultOptions = array(
        CURLOPT_VERBOSE        => true,
        CURLOPT_HEADER         => true,
        CURLINFO_HEADER_OUT    => false,
        CURLOPT_RETURNTRANSFER => true,
        CURLOPT_FOLLOWLOCATION => false,
    );
    
     /**
     * Store the last response form the API
     * @var mixed
     */
    protected $lastResponse = null;
    
    /**
     * Set properties and begin authentication
     * @param string $key
     * @param string $secret
     * @param \Dropbox\OAuth\Consumer\StorageInterface $storage
     * @param string $callback
     */
    public function __construct($key, $oauth2_id, $secret, Dropbox_StorageInterface $storage, $callback = null, $callbackhome = null, $deauthenticate = false, $instance_id = '')
    {
        // Check the cURL extension is loaded
        if (!extension_loaded('curl')) {
            throw new Dropbox_Exception('The cURL OAuth consumer requires the cURL extension. Please speak to your web hosting provider so that this missing PHP component can be installed.');
        }
        
        $this->consumerKey = $key;
        $this->oauth2_id = $oauth2_id;
        $this->consumerSecret = $secret;
        $this->storage = $storage;
        $this->callback = $callback;
        $this->callbackhome = $callbackhome;
        $this->instance_id = $instance_id;
        
        if ($deauthenticate) {
			$this->deauthenticate();
        } else {
			$this->authenticate();
        }
    }
    
    /**
     * Execute an API call
     * @todo Improve error handling
     * @param string $method The HTTP method
     * @param string $url The API endpoint
     * @param string $call The API method to call
     * @param array $additional Additional parameters
     * @return string|object stdClass
     */
    public function fetch($method, $url, $call, array $additional = array(), $retry_with_header = false)
    {
        // Get the signed request URL
        $request = $this->getSignedRequest($method, $url, $call, $additional);
        
        // Initialise and execute a cURL request
        $handle = curl_init($request['url']);
        
        // Get the default options array
        $options = $this->defaultOptions;
        if (!UpdraftPlus_Options::get_updraft_option('updraft_ssl_useservercerts')) {
            $options[CURLOPT_CAINFO] = UPDRAFTPLUS_DIR.'/includes/cacert.pem';
        }
        if (UpdraftPlus_Options::get_updraft_option('updraft_ssl_disableverify')) {
            $options[CURLOPT_SSL_VERIFYPEER] = false;
        } else {
            $options[CURLOPT_SSL_VERIFYPEER] = true;
        }

        if (!class_exists('WP_HTTP_Proxy')) require_once(ABSPATH.WPINC.'/class-http.php');
        $proxy = new WP_HTTP_Proxy();

        if ($proxy->is_enabled()) {
            # WP_HTTP_Proxy returns empty strings if nothing is set
            $user = $proxy->username();
            $pass = $proxy->password();
            $host = $proxy->host();
            $port = (int)$proxy->port();
            if (empty($port)) $port = 8080;
            if (!empty($host) && $proxy->send_through_proxy($request['url'])) {
                  $options[CURLOPT_PROXY] = $host;
                  $options[CURLOPT_PROXYTYPE] = CURLPROXY_HTTP;
                  $options[CURLOPT_PROXYPORT] = $port;
                  if (!empty($user) && !empty($pass)) {
                        $options[CURLOPT_PROXYAUTH] = CURLAUTH_ANY;
                        $options[CURLOPT_PROXYUSERPWD] = sprintf('%s:%s', $user, $pass);
                  }
            }
        }

        /*
            Add check to see if it's an API v2 call if so then json encode the contents. This is so that it is backwards compatible with API v1 endpoints.
         */
        if (isset($additional['api_v2']) && !empty($request['postfields'])) {
            $request['postfields'] = json_encode($request['postfields']);
        }

        if (isset($request['headers']) && !empty($request['headers'])) $options[CURLOPT_HTTPHEADER] = $request['headers'];

        if ($method == 'GET' && $this->outFile) { // GET
            $options[CURLOPT_RETURNTRANSFER] = false;
            $options[CURLOPT_HEADER] = false;
            $options[CURLOPT_FILE] = $this->outFile;
            $options[CURLOPT_BINARYTRANSFER] = true;
            $options[CURLOPT_FAILONERROR] = true;
            $this->outFile = null;
        }  elseif ($method == 'POST' && $this->outFile) { // POST
            $options[CURLOPT_POST] = true;
            $options[CURLOPT_RETURNTRANSFER] = false;
            $options[CURLOPT_HEADER] = false;
            $options[CURLOPT_FILE] = $this->outFile;
            $options[CURLOPT_BINARYTRANSFER] = true;
            $options[CURLOPT_FAILONERROR] = true;
            $this->outFile = null;
        } elseif ($method == 'POST' && $this->inFile) { // POST
            $options[CURLOPT_POST] = true;
            $options[CURLOPT_POSTFIELDS] = $this->inFile;
        } elseif ($method == 'POST') { // POST
            $options[CURLOPT_POST] = true;
            if (!empty($request['postfields'])) {
				$options[CURLOPT_POSTFIELDS] = $request['postfields'];
			} elseif (empty($additional['content_upload'])) {
				// JSON representation of nullity
				$options[CURLOPT_POSTFIELDS] = 'null';
			} elseif ($retry_with_header) {
				// It's a content upload, and there's no data. Versions of php-curl differ as to whether they add a Content-Length header automatically or not. Dropbox complains if it's not there. Here we have had a Dropbox 400 bad request returned so we try again with the header
				$options[CURLOPT_HTTPHEADER] = array_merge($options[CURLOPT_HTTPHEADER], array('Content-Length: 0'));
			}
        } elseif ($method == 'PUT' && $this->inFile) { // PUT
            $options[CURLOPT_PUT] = true;
            $options[CURLOPT_INFILE] = $this->inFile;
            // @todo Update so the data is not loaded into memory to get its size
            $options[CURLOPT_INFILESIZE] = strlen(stream_get_contents($this->inFile));
            fseek($this->inFile, 0);
            $this->inFile = null;
        }

        if (isset($additional['timeout'])) {
            $options[CURLOPT_TIMEOUT] = $additional['timeout'];
        }
        
        if (function_exists('apply_filters')) $options = apply_filters('updraftplus_dropbox_fetch_curl_options', $options, $method, $url, $call, $additional);

        // Set the cURL options at once
        curl_setopt_array($handle, $options);
        // Execute, get any error and close
        $response = curl_exec($handle);
        $error = curl_error($handle);
        $getinfo = curl_getinfo($handle);

        curl_close($handle);

        //Check if a cURL error has occured
        if ($response === false) {
            throw new Dropbox_CurlException($error);
        } else {
            // Parse the response if it is a string
            if (is_string($response)) {
                $response = $this->parse($response);
            }
            
            // Set the last response
            $this->lastResponse = $response;

            $code = (!empty($response['code'])) ? $response['code'] : $getinfo['http_code'];
            
            // The API doesn't return an error message for the 304 status code...
            // 304's are only returned when the path supplied during metadata calls has not been modified
            if ($code == 304) {
                $response['body'] = new stdClass;
                $response['body']->error = 'The folder contents have not changed';
            }
            
            // Check if an error occurred and throw an Exception
            if (!empty($response['body']->error) || $code >= 400) {
                // Dropbox returns error messages inconsistently...
                if (!empty($response['body']->error_summary)) {
                    $message = $response['body']->error_summary;
                } elseif (!empty($response['body']->error) && $response['body']->error instanceof stdClass) {
                    $array = array_values((array) $response['body']->error);
                    // Dropbox API v2 only throws 409 errors if this error is a incorrect_offset then we need the entire error array not just the message. PHP Exception messages have to be a string so JSON encode the array.
                    $extract_message = (is_object($array[0]) && isset($array[0]->{'.tag'})) ? $array[0]->{'.tag'} : $array[0];
                    if (strpos($extract_message, 'incorrect_offset') !== false) {
                        $message = json_encode($array);
                    } elseif (strpos($extract_message, 'lookup_failed') !== false ) {
                        // re-structure the array so it is correctly formatted for API
                        // Note: Dropbox v2 returns different errors at different stages hence this fix
                        $correctOffset = array(
                            '0' => $array[1]->{'.tag'},
                        );
                        // the lookup_failed response doesn't always return a correct_offset this happens when the lookup fails because the session has been closed e.g the file has already been uploaded but the response didn't make it back to the client so we try again
                        if (isset($array[1]->correct_offset)) $correctOffset['1'] = $array[1]->correct_offset;

                        $message = json_encode($correctOffset);
                    } else {
                        $message = '';
                        $property = 'error';
                        $resp = $response['body'];
                        while (isset($resp->$property)) {
                            if (is_string($resp->$property)) $message .= $resp->$property.'/';
                            if (!is_object($resp->$property) || empty($resp->$property->{'.tag'})) break;
                            $property = $resp->$property->{'.tag'};
                            $message .= $property.'/';
                            $resp = $response['body']->error;
                        }
                    }
                } elseif (!empty($response['body']->error)) {
                    $message = $response['body']->error;
                } elseif (is_string($response['body'])) {
					// 31 Mar 2017 - This case has been found to exist; though the docs imply that there's always an 'error' property and that what is returned in JSON, we found a case of this being returned just as a simple string, but detectable via an HTTP 400: Error in call to API function "files/upload_session/append_v2": HTTP header "Dropbox-API-Arg": cursor.offset: expected integer, got string
					$message = $response['body'];
                } else {
					$message = "HTTP bad response code: $code";
                }
                     
                // Throw an Exception with the appropriate with the appropriate message and code
                switch ($code) {
                    case 304:
                        throw new Dropbox_NotModifiedException($message, 304);
                    case 400:
                        if (!$retry_with_header) return $this->fetch($method, $url, $call, $additional, true);
                        throw new Dropbox_BadRequestException($message, 400);
                    case 404:
                        throw new Dropbox_NotFoundException($message, 404);
                    case 406:
                        throw new Dropbox_NotAcceptableException($message, 406);
                    case 415:
                        throw new Dropbox_UnsupportedMediaTypeException($message, 415);
                    case 401:
                    	//401 means oauth token is expired continue to manually handle the exception depending on the situation
                    	break;
                    case 409:
                        //409 in API V2 every error will return with a 409 to find out what the error is the error description should be checked.                      
                        throw new Dropbox_Exception($message, $code);
                    default:
                        throw new Dropbox_Exception($message, $code);
                }
            }
            
            return $response;
        }
    }
    
    /**
     * Parse a cURL response
     * @param string $response 
     * @return array
     */
    private function parse($response)
    {
        // Explode the response into headers and body parts (separated by double EOL)
        list($headers, $response) = explode("\r\n\r\n", $response, 2);
        
        // Explode response headers
        $lines = explode("\r\n", $headers);
        
        // If the status code is 100, the API server must send a final response
        // We need to explode the response again to get the actual response
        if (preg_match('#^HTTP/[\.\d]+ 100#i', $lines[0])) {
            list($headers, $response) = explode("\r\n\r\n", $response, 2);
            $lines = explode("\r\n", $headers);
        }
        
        // Get the HTTP response code from the first line
        $first = array_shift($lines);
        $pattern = '#^HTTP/[\.\d]+ ([0-9]{3})#i';
        preg_match($pattern, $first, $matches);
        $code = $matches[1];
        
        // Parse the remaining headers into an associative array
        $headers = array();
        foreach ($lines as $line) {
            list($k, $v) = explode(': ', $line, 2);
            $headers[strtolower($k)] = $v;
        }
        
        // If the response body is not a JSON encoded string
        // we'll return the entire response body
        if (!$body = json_decode($response)) {
            $body = $response;
        }

         if (is_string($body)) {
             $body_lines = explode("\r\n", $body);
             if (preg_match('#^HTTP/[\.\d]+ 100#i', $body_lines[0]) && preg_match('#^HTTP/\d#i', $body_lines[2])) {
             return $this->parse($body);
             }
         }
        
        return array('code' => $code, 'body' => $body, 'headers' => $headers);
    }

    /**
     * Return the response for the last API request
     * @return mixed
     */
    public function getlastResponse()
    {
       return $this->lastResponse;
     }
}
