<?php
// $Id: distro_server.module,v 1.1.2.4 2009/11/19 03:03:31 inadarei Exp $
/**
 * @file
 * Distro Server
 *
 */

/**
* hook_menu implementation. Callback for REST JSON calls.
*/
function distro_server_menu() {
 $items = array();

  $items['distro/components'] = array(
    'title' => 'Distribution Check',
    'page callback' => 'distro_server_check',
    'access callback' => 'distro_server_access_check',    
    'type' => MENU_CALLBACK,
  );

  return $items;
}

/**
* Checks the latest status of components againt the tracker server
* 
* @arg $protocol_version
*   The version of the communication protocol. These may change so we need to allow for backwards compatibility
*   and simultanous support of several protocols, in order to not break existing clients. Defaults to 1.0 the only
*   version where we were not, yet, passing explicit version number.
* @return 
*   JSON-encoded response
*/
function distro_server_check() {
  
  $protocol_version = arg(2);
  
  $remote = $_POST['info'];
  $remote = json_decode($remote);
  $remote->projects = (array) $remote->projects;
  
  //-- domain can be empty if client runs cron via drush on default. 
  if (empty($remote->domain) || trim($remote->domain) == 'http://default') {
    $remote->domain = $_SERVER['REMOTE_ADDR'];
  }
    
  $ret = distro_server_get_state($remote, $protocol_version);  
  
  // We are returning JavaScript, let the the browser know about it.
  drupal_set_header('Content-Type: text/javascript; charset=utf-8');
  $encoded = json_encode($ret);
  echo $encoded;
  exit();
}

/**
* Checks access permission to the distro server. 
*/
function distro_server_access_check(){
  return TRUE;
}


/**
* Returns list of required and 
*/
function distro_server_get_state($remote, $protocol_version) {

  $protocol_version = trim($protocol_version);
  $fname = 'distro_server_generate_response_' . str_replace('.', '_', $protocol_version);
  
  if (function_exists($fname)) {
    $ret = $fname ($remote, $protocol_version);
    
    $mods = module_implements('distro_pre_response');
    if (is_array($mods)) {
      foreach ($mods as $m) {
        $function = $m .'_distro_pre_response';
        $function($ret, $remote, $protocol_version);
      }
    }

  }
  else {
    $ret = new stdClass();
    $ret->error = 'DISTRO##ERR##UNKNOWN';
  }

  return $ret;
  
}

/**
*
* Generate response data, given the client data. Protocol v 2.0
*
* @arg $remote
*   client data.
* @return 
*   response data.
*/
function distro_server_generate_response_2_0 ($remote, $protocol_version) {

  $distro_data = module_invoke_all('distros', $remote->profile, $protocol_version);

  $ret = new stdClass();
  $allowed_types = array('module', 'theme');
    
  if (is_array($remote->projects)) {
    
    //-- First determine missing Drupal projects (i.e. components like modules or themes).
    foreach ($remote->projects as $type => $items) {
      if (is_array($items) && in_array($type, $allowed_types)) {
        sort($distro_data['required'][$type]);
        sort($items);
        $ret->missing[$type] = array_diff($distro_data['required'][$type], $items);
      }
    }
    
    //-- Now let's determine the ones that need to be removed.
    $ret->extra = array();
    foreach ($remote->projects as $type => $items) {
      if (in_array($type, $allowed_types)) {
        $ret->extra[$type] = array();
        if (is_array($items)) {
          foreach ($items as $client_component) {
            if (in_array($client_component, $distro_data['remove'][$type])) {
              $ret->extra[$type][] = $client_component;
            }
          }
        }
      }
    }
    
  }
  else {
    $ret->error = t('Distribution tracker client sent a request that server could not understand.');
  }
  
  return $ret;

}

function distro_server_diff_2_0 ($remote) {
}

/**
*
* Generate response data, given the client data. Protocol v 1.0
*
* @arg $remote
*   client data.
* @return 
*   response data.
*/

function distro_server_generate_response_1_0 ($remote, $protocol_version) {

  $all_distros = module_invoke_all('distros', $remote->profile, $protocol_version);
  
  $distro_prjs = $all_distros[$remote->profile];
  $client_prjs = $remote->projects;
  
  $ret = new stdClass();
  
  if (is_array($distro_prjs) && is_array($client_prjs)) {
    $ret->missing = array_diff($distro_prjs, $client_prjs);
    $ret->extra = array_diff($client_prjs, $distro_prjs);    
  }
  
  return $ret;

}