<?php
/**
 * ---------------------------------------------------------------------
 * GLPI - Gestionnaire Libre de Parc Informatique
 * Copyright (C) 2015-2018 Teclib' and contributors.
 *
 * http://glpi-project.org
 *
 * based on GLPI - Gestionnaire Libre de Parc Informatique
 * Copyright (C) 2003-2014 by the INDEPNET Development Team.
 *
 * ---------------------------------------------------------------------
 *
 * LICENSE
 *
 * This file is part of GLPI.
 *
 * GLPI is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * GLPI is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with GLPI. If not, see <http://www.gnu.org/licenses/>.
 * ---------------------------------------------------------------------
 */

/**
 * @since 9.1
 */

class APIRest extends API {

   protected $request_uri;
   protected $url_elements;
   protected $verb;
   protected $parameters;
   protected $debug           = 0;
   protected $format          = "json";

   /**
    *
    * @param integer $nb Unused value
    *
    * @return string
    *
    * @see CommonGLPI::GetTypeName()
    */
   public static function getTypeName($nb = 0) {
      return __('Rest API');
   }

   /**
    * Upload and validate files from request and append to $this->parameters['input']
    *
    * @return void
    */
   public function manageUploadedFiles() {
      foreach (array_keys($_FILES) as $filename) {
         $upload_result
            = GLPIUploadHandler::uploadFiles(['name'           => $filename,
                                              'print_response' => false]);
         foreach ($upload_result as $uresult) {
            $this->parameters['input']->_filename[] = $uresult[0]->name;
            $this->parameters['input']->_prefix_filename[] = $uresult[0]->prefix;
         }
         $this->parameters['upload_result'][] = $upload_result;
      }
   }

   /**
    * Parse url and http body to retrieve :
    *  - HTTP VERB (GET/POST/DELETE/PUT)
    *  - Resource : Rest endpoint
    *  - Identifier
    *  - and parameters
    *
    *  And send to method corresponding identified resource
    *
    * @return mixed json with response or error
    */
   public function call() {

      //parse http request and find parts
      $this->request_uri  = $_SERVER['REQUEST_URI'];
      $this->verb         = $_SERVER['REQUEST_METHOD'];
      $path_info          = (isset($_SERVER['PATH_INFO'])) ? str_replace("api/", "", trim($_SERVER['PATH_INFO'], '/')) : '';
      $this->url_elements = explode('/', $path_info);

      // retrieve requested resource
      $resource      = trim(strval($this->url_elements[0]));
      $is_inline_doc = (strlen($resource) == 0) || ($resource == "api");

      // Add headers for CORS
      $this->cors($this->verb);

      // retrieve paramaters (in body, query_string, headers)
      $this->parseIncomingParams($is_inline_doc);

      // show debug if required
      if (isset($this->parameters['debug'])) {
         $this->debug = $this->parameters['debug'];
         if (empty($this->debug)) {
            $this->debug = 1;
         }

         if ($this->debug >= 2) {
            $this->showDebug();
         }
      }

      // retrieve session (if exist)
      $this->retrieveSession();
      $this->initApi();
      $this->manageUploadedFiles();

      // retrieve param who permit session writing
      if (isset($this->parameters['session_write'])) {
         $this->session_write = (bool)$this->parameters['session_write'];
      }

      // inline documentation (api/)
      if ($is_inline_doc) {
         return $this->inlineDocumentation("apirest.md");

      } else if ($resource === "initSession") {
         // ## DECLARE ALL ENDPOINTS ##
         // login into glpi
         $this->session_write = true;
         return $this->returnResponse($this->initSession($this->parameters));

      } else if ($resource === "killSession") {
         // logout from glpi
         $this->session_write = true;
         return $this->returnResponse($this->killSession());

      } else if ($resource === "changeActiveEntities") {
         // change active entities
         $this->session_write = true;
         return $this->returnResponse($this->changeActiveEntities($this->parameters));

      } else if ($resource === "getMyEntities") {
         // get all entities of logged user
         return $this->returnResponse($this->getMyEntities($this->parameters));

      } else if ($resource === "getActiveEntities") {
         // get curent active entity
         return $this->returnResponse($this->getActiveEntities($this->parameters));

      } else if ($resource === "changeActiveProfile") {
         // change active profile
         $this->session_write = true;
         return $this->returnResponse($this->changeActiveProfile($this->parameters));

      } else if ($resource === "getMyProfiles") {
         // get all profiles of current logged user
         return $this->returnResponse($this->getMyProfiles($this->parameters));

      } else if ($resource === "getActiveProfile") {
         // get current active profile
         return $this->returnResponse($this->getActiveProfile($this->parameters));

      } else if ($resource === "getFullSession") {
         // get complete php session
         return $this->returnResponse($this->getFullSession($this->parameters));

      } else if ($resource === "getGlpiConfig") {
         // get complete php var $CFG_GLPI
         return $this->returnResponse($this->getGlpiConfig($this->parameters));

      } else if ($resource === "listSearchOptions") {
         // list searchOptions of an itemtype
         $itemtype = $this->getItemtype(1);
         return $this->returnResponse($this->listSearchOptions($itemtype, $this->parameters));

      } else if ($resource === "getMultipleItems") {
         // get multiple items (with various itemtype)
         return $this->returnResponse($this->getMultipleItems($this->parameters));

      } else if ($resource === "search") {
         // Search on itemtype
         self::checkSessionToken();

         $itemtype = $this->getItemtype(1, true, true);
         //clean stdObjects in parameter
         $params   = json_decode(json_encode($this->parameters), true);
         //search
         $response =  $this->searchItems($itemtype, $params);

         //add pagination headers
         $additionalheaders                  = [];
         $additionalheaders["Accept-Range"]  = $itemtype." ".Toolbox::get_max_input_vars();
         if ($response['totalcount'] > 0) {
            $additionalheaders["Content-Range"] = $response['content-range'];
         }

         // diffent http return codes for complete or partial response
         if ($response['count'] >= $response['totalcount']) {
            $code = 200; // full content
         } else {
            $code = 206; // partial content
         }

         return $this->returnResponse($response, $code, $additionalheaders);

      } else if ($resource === "lostPassword") {
         if ($this->verb != 'PUT' && $this->verb != 'PATCH') {
            // forbid password reset when HTTP verb is not PUT or PATCH
            return $this->returnError(__("Only HTTP verb PUT is allowed"));
         }
         return $this->returnResponse($this->lostPassword($this->parameters));

      } else {
         // commonDBTM manipulation
         $itemtype          = $this->getItemtype(0);
         $id                = $this->getId();
         $additionalheaders = [];
         $code              = 200;
         switch ($this->verb) {
            default:
            case "GET" : // retrieve item(s)
               if ($id > 0
                   || ($id !== false && $id == 0 && $itemtype == "Entity")) {
                  $response = $this->getItem($itemtype, $id, $this->parameters);
                  if (isset($response['date_mod'])) {
                     $datemod = strtotime($response['date_mod']);
                     $additionalheaders['Last-Modified'] = gmdate("D, d M Y H:i:s", $datemod)." GMT";
                  }
               } else {
                  // return collection of items
                  $totalcount = 0;
                  $response = $this->getItems($itemtype, $this->parameters, $totalcount);

                  //add pagination headers
                  $range = [0, $_SESSION['glpilist_limit']];
                  if (isset($this->parameters['range'])) {
                     $range = explode("-", $this->parameters['range']);
                  }

                  // fix end range
                  if ($range[1] > $totalcount - 1) {
                     $range[1] = $totalcount - 1;
                  }

                  // trigger partial content return code
                  if ($range[1] - $range[0] + 1 < $totalcount) {
                        $code = 206; // partial content
                  }

                  $additionalheaders["Accept-Range"]  = $itemtype." ".Toolbox::get_max_input_vars();
                  if ($totalcount > 0) {
                     $additionalheaders["Content-Range"] = implode('-', $range)."/".$totalcount;
                  }
               }
               break;

            case "POST" : // create item(s)
               $response = $this->createItems($itemtype, $this->parameters);
               $code     = 201;
               if (isset($response['id'])) {
                  // add a location targetting created element
                  $additionalheaders['location'] = self::$api_url."/$itemtype/".$response['id'];
               } else {
                  // add a link header targetting created elements
                  $additionalheaders['link'] = "";
                  foreach ($response as $created_item) {
                     if ($created_item['id']) {
                        $additionalheaders['link'] .= self::$api_url."/$itemtype/".
                                                     $created_item['id'].",";
                     }
                  }
                  // remove last comma
                  $additionalheaders['link'] = trim($additionalheaders['link'], ",");
               }
               break;

            case "PUT" : // update item(s)
            case "PATCH" : // update item(s)
               if (!isset($this->parameters['input'])) {
                  $this->messageBadArrayError();
               }
               // if id is passed by query string, add it into input parameter
               $input = (array) ($this->parameters['input']);
               if (($id > 0 || $id == 0 && $itemtype == "Entity")
                     && !isset($input['id'])) {
                  $this->parameters['input']->id = $id;
               }
               $response = $this->updateItems($itemtype, $this->parameters);
               break;

            case "DELETE" : //delete item(s)
               // if id is passed by query string, construct an object with it
               if ($id !== false) {
                  //override input
                  $this->parameters['input']     = new stdClass();
                  $this->parameters['input']->id = $id;
               }
               $response = $this->deleteItems($itemtype, $this->parameters);
               break;
         }
         return $this->returnResponse($response, $code, $additionalheaders);
      }

      $this->messageLostError();
   }


   /**
    * Retrieve and check itemtype from $this->url_elements
    *
    * @param integer $index      we'll find itemtype in this index of $this->url_elements
    *                            (default o)
    * @param boolean $recursive  can we go depper or we trigger an http error if we fail to find itemtype?
    *                            (default true)
    * @param boolean $all_assets if we can have allasset virtual type (default false)
    *
    * @return boolean
    */
   private function getItemtype($index = 0, $recursive = true, $all_assets = false) {

      if (isset($this->url_elements[$index])) {
         if ((class_exists($this->url_elements[$index])
              && is_subclass_of($this->url_elements[$index], 'CommonDBTM'))
             || ($all_assets
                 && $this->url_elements[$index] == "AllAssets")) {
            $itemtype = $this->url_elements[$index];

            if ($recursive
                && ($additional_itemtype = $this->getItemtype(2, false))) {
               $this->parameters['parent_itemtype'] = $itemtype;
               $itemtype                            = $additional_itemtype;
            }
            $itemtype = ucfirst($itemtype);
            return $itemtype;
         }
         $this->returnError(__("resource not found or not an instance of CommonDBTM"),
                            400,
                            "ERROR_RESOURCE_NOT_FOUND_NOR_COMMONDBTM");

      } else if ($recursive) {
         $this->returnError(__("missing resource"), 400, "ERROR_RESOURCE_MISSING");
      }

      return false;
   }


   /**
    * Retrieve in url_element the current id. If we have a multiple id (ex /Ticket/1/TicketFollwup/2),
    * it always find the second
    *
    * @return integer|boolean id of current itemtype (or false if not found)
    */
   private function getId() {

      $id            = isset($this->url_elements[1]) && is_numeric($this->url_elements[1])
                       ?intval($this->url_elements[1])
                       :false;
      $additional_id = isset($this->url_elements[3]) && is_numeric($this->url_elements[3])
                       ?intval($this->url_elements[3])
                       :false;

      if ($additional_id || isset($this->parameters['parent_itemtype'])) {
         $this->parameters['parent_id'] = $id;
         $id = $additional_id;
      }

      return $id;
   }


   /**
    * Construct this->parameters from query string and http body
    *
    * @param boolean $is_inline_doc Is the current request asks to display inline documentation
    *  This will remove the default behavior who set content-type to application/json
    *
    * @return void
    */
   public function parseIncomingParams($is_inline_doc = false) {

      $parameters = [];

      // first of all, pull the GET vars
      if (isset($_SERVER['QUERY_STRING'])) {
         parse_str($_SERVER['QUERY_STRING'], $parameters);
      }

      // now how about PUT/POST bodies? These override what we got from GET
      $body = trim($this->getHttpBody());
      if (strlen($body) > 0 && $this->verb == "GET") {
         // GET method requires an empty body
         $this->returnError("GET Request should not have json payload (http body)", 400,
                            "ERROR_JSON_PAYLOAD_FORBIDDEN");
      }

      $content_type = "";
      if (isset($_SERVER['CONTENT_TYPE'])) {
         $content_type = $_SERVER['CONTENT_TYPE'];
      } else if (isset($_SERVER['HTTP_CONTENT_TYPE'])) {
         $content_type = $_SERVER['HTTP_CONTENT_TYPE'];
      } else {
         if (!$is_inline_doc) {
            $content_type = "application/json";
         }
      }

      if (strpos($content_type, "application/json") !== false) {
         if ($body_params = json_decode($body)) {
            foreach ($body_params as $param_name => $param_value) {
               $parameters[$param_name] = $param_value;
            }
         } else if (strlen($body) > 0) {
            $this->returnError("JSON payload seems not valid", 400, "ERROR_JSON_PAYLOAD_INVALID",
                               false);
         }
         $this->format = "json";

      } else if (strpos($content_type, "multipart/form-data") !== false) {
         if (count($_FILES) <= 0) {
            // likely uploaded files is too big so $_REQUEST will be empty also.
            // see http://us.php.net/manual/en/ini.core.php#ini.post-max-size
            $this->returnError("The file seems too big", 400,
                               "ERROR_UPLOAD_FILE_TOO_BIG_POST_MAX_SIZE", false);
         }

         // with this content_type, php://input is empty... (see http://php.net/manual/en/wrappers.php.php)
         if (!$uploadManifest = json_decode(stripcslashes($_REQUEST['uploadManifest']))) {
            $this->returnError("JSON payload seems not valid", 400, "ERROR_JSON_PAYLOAD_INVALID",
                               false);
         }
         foreach ($uploadManifest as $field => $value) {
            $parameters[$field] = $value;
         }
         $this->format = "json";

         // move files into _tmp folder
         $parameters['upload_result'] = [];
         $parameters['input']->_filename = [];
         $parameters['input']->_prefix_filename = [];

      } else if (strpos($content_type, "application/x-www-form-urlencoded") !== false) {
         /** @var array $postvars */
         parse_str($body, $postvars);
         foreach ($postvars as $field => $value) {
            $parameters[$field] = $value;
         }
         $this->format = "html";

      } else {
         $this->format = "html";
      }

      // retrieve HTTP headers
      $headers = [];
      if (function_exists('getallheaders')) {
         //apache specific
         $headers = getallheaders();
         if (false !== $headers && count($headers) > 0) {
            $fixedHeaders = [];
            foreach ($headers as $key => $value) {
               $fixedHeaders[ucwords(strtolower($key), '-')] = $value;
            }
            $headers = $fixedHeaders;
         }
      } else {
         // other servers
         foreach ($_SERVER as $server_key => $server_value) {
            if (substr($server_key, 0, 5) == 'HTTP_') {
               $headers[str_replace(' ', '-',
                                    ucwords(strtolower(str_replace('_', ' ',
                                                                   substr($server_key, 5)))))] = $server_value;
            }
         }
      }

      // try to retrieve basic auth
      if (isset($_SERVER['PHP_AUTH_USER'])
          && isset($_SERVER['PHP_AUTH_PW'])) {
         $parameters['login']    = $_SERVER['PHP_AUTH_USER'];
         $parameters['password'] = $_SERVER['PHP_AUTH_PW'];
      }

      // try to retrieve user_token in header
      if (isset($headers['Authorization'])
          && (strpos($headers['Authorization'], 'user_token') !== false)) {
         $auth = explode(' ', $headers['Authorization']);
         if (isset($auth[1])) {
            $parameters['user_token'] = $auth[1];
         }
      }

      // try to retrieve session_token in header
      if (isset($headers['Session-Token'])) {
         $parameters['session_token'] = $headers['Session-Token'];
      }

      // try to retrieve app_token in header
      if (isset($headers['App-Token'])) {
         $parameters['app_token'] = $headers['App-Token'];
      }

      // check boolean parameters
      foreach ($parameters as $key => &$parameter) {
         if ($parameter === "true") {
            $parameter = true;
         }
         if ($parameter === "false") {
            $parameter = false;
         }
      }

      $this->parameters = $parameters;

      return "";
   }


   /**
    * Generic function to send a message and an http code to client
    *
    * @param string  $response          message or array of data to send
    * @param integer $httpcode          http code (default 200)
    *                                   (see: https://en.wikipedia.org/wiki/List_of_HTTP_status_codes)
    * @param array   $additionalheaders headers to send with http response (must be an array(key => value))
    *
    * @return void
    */
   public function returnResponse($response, $httpcode = 200, $additionalheaders = []) {

      if (empty($httpcode)) {
         $httpcode = 200;
      }

      foreach ($additionalheaders as $key => $value) {
         header("$key: $value");
      }

      http_response_code($httpcode);
      self::header($this->debug);

      if ($response !== null) {
         $json = json_encode($response, JSON_UNESCAPED_UNICODE
                                      | JSON_UNESCAPED_SLASHES
                                      | JSON_NUMERIC_CHECK
                                      | ($this->debug
                                          ? JSON_PRETTY_PRINT
                                          : 0));
      } else {
         $json = '';
      }

      if ($this->debug) {
         echo "<pre>";
         var_dump($response);
         echo "</pre>";
      } else {
         echo $json;
      }
      exit;
   }


   /**
    * Display the APIRest Documentation in Html (parsed from markdown)
    *
    * @param string $file relative path of documentation file (default 'apirest.md')
    *
    * @return void
    */
   public function inlineDocumentation($file = "apirest.md") {

      if ($this->format == "html") {
         parent::inlineDocumentation($file);
      } else if ($this->format == "json") {
         echo file_get_contents(GLPI_ROOT.'/'.$file);
      }
   }
}
