modules/carbon/carbon.module

<?php
/**
 * $Id: carbon.module,v 1.33 2009/05/05 14:45:41 johnackers Exp $
 *
 * Drupal carbon module
 *
 * Created on 6-Sep-2006
 *
 * @file
 * This file implements the drupal module hooks including
 * _help, _menu, _user and _block.  It also implements
 * _access for all the carbon nodes.
 */


define("CARBON_PATH", drupal_get_path("module", "carbon"));
define("CARBON_PALETTE", "heating=AA0000, elec=0000AA, car=AA00AA, surface=00AA00, air=5555FF, mixed=808080");

// core routines that handle basic database ops

include(CARBON_PATH ."/carbon_account.inc");    // create/delete carbon account
include(CARBON_PATH ."/carbon_stamp.inc");      // create/edit/list meter readings etc
include(CARBON_PATH ."/carbon_source.inc");     // create/edit/list sources eg. gas, elec
include(CARBON_PATH ."/carbon_transfer.inc");   // create/edit/list carbon transfers

include(CARBON_PATH ."/carbon_view.inc");       // generates overview/meter/travel pane
include(CARBON_PATH ."/carbon_edit.inc");       // handles in situ editing

// included dynamically by drupal's menu mechanism or using require_once():

//include(CARBON_PATH ."/carbon_admin.inc");      // settings and database integrity check
//include(CARBON_PATH ."/carbon_report.inc");     // group and sector reports
//include(CARBON_PATH ."/carbon_crag.inc");       // crag reports


//include(CARBON_PATH ."/carbon_calculate.inc");  // co2 & kWh settings
//include(CARBON_PATH ."/carbon_chart.inc");      // generate bar and pie PNGs


/**
 * Display help and module information
 * @param section which section of the site we're displaying help
 * @return help text for section
 */
/*
 function carbon_help($section='', $arg) {

 $output = '';

 switch ($section) {
 case "admin/modules#description":
 $output = t("Allows users to create and maintain online carbon accounts. " .
 "By entering utility meter readings, gas/petrol consumption and trips " .
 "by air, users can build an accurate record of CO2 emissions about " .
 "which they have some influence. Users can also view records submitted " .
 "by others. Administrators can add, adjust and remove different sources " .
 "of carbon emissions.");
 break ;

 case "help#carbon_source":
 return t("Display a list of all carbon sources.");


 case "help#carbon_account":
 return t("Display all public accounts.");


 case "user/help#carbon":
 return t("<p>The carbon module allows you to create a personal <em>carbon account</em>.</p>" .
 "<p>You can</p>" .
 "<ul>" .
 "<li>Submit a carbon account at <a href='%node-add-carbon-account'>create content &gt;&gt; carbon account</a>. " .
 "You can create more than one account.</li>" .
 "<li>Look at your account at <a href='%node-my-carbon-account'>carbon &gt;&gt; account &gt;&gt; my</a>.</li>" .
 "<li>Each account contains carbon stamps which can be viewed at <a href='%node-my-carbon-stamp'>carbon &gt;&gt; stamp &gt;&gt; my  </a> </li>" .
 "<li>Display other carbon accounts that others want to share with you <a href='%node-list-carbon-account'>carbon &gt;&gt; account</a></li>" .
 "<li>Display a list of carbon sources at <a href='%node-list-carbon-source'>carbon &gt;&gt; stamp</a> </li>" .
 "<li>configure carbon accounts at <a href='%admin-node-configure-types'> administer &gt;&gt; content &gt;&gt; " .
 "configure types &gt;&gt; carbon accounts configure</a>.</li>" .
 "</ul>", array(
 "%node-add-carbon-account" => url("node/add/carbon-account"),
 "%node-my-carbon-account" => url("carbon/account/my"),
 "%node-my-carbon-stamp" => url("carbon/stamp/my"),
 "%node-list-carbon-account" => url("carbon/account"),
 "%node-list-carbon-source" => url("carbon/source"),
 "%admin-node-configure-types" => url("admin/node/configure/types")
 ));


 case "admin/help#carbon":
 return t("<p>The carbon module allows users to create a personal <em>carbon account</em>.</p>" .
 "<p>The optional menu entries for users are not all enabled by default. " .
 "You might want to add them but they are not necessary." .
 "<p/> " .
 "<p>You can add and remove individual carbon sources by editing it and checking " .
 "or unchecking the 'published' box in the 'Publishing Options' group ." .
 "<p/> " .
 "",
 array(
 "%node-add-carbon-account" => url("node/add/carbon-account"),
 "%node-list-carbon-stamp" => url("admin/carbon/stamp"),
 "%node-list-carbon-account" => url("admin/carbon/account"),
 "%node-list-carbon-source" => url("admin/carbon/source"),
 "%admin-node-configure-types" => url("admin/node/configure/types"),
 "%admin-carbon-settings" => url("admin/carbon/settings")
 ));

 }
 return $output;

 }
 */


function carbon_include_core_js()
{
  // load the basic javascript routines
  $path = drupal_get_path("module", 'carbon');
  drupal_add_js($path . "/carbon.js", 'module');

  // enhance fieldset operations
  drupal_add_js('misc/collapse.js', 'core', 'header', FALSE, TRUE);

  // all css in this file, leading slash needed
  drupal_add_css($path . "/misc/carbon.css");

  return $path ;
}


/**
 * Implementation of hook_node_info().
 * Define the node type  4.7?
 */

function carbon_node_info() {
  return array(
  "carbon_account" => array("name" => t("Carbon Account"),
  "module" => "carbon_account",
  "description"=> t("A record of personal carbon emissions covering multiple " .
          "years. The account can be appended and updated at at any time " .
          "future. Previous trips etc can be added to build a account for " .
          "previous years. A registered user can create and update accounts for " .
          "many others. Accounts can be made public so they can be shared with " .
          "other logged in users.  " .
          "")),

  "carbon_stamp"     => array("name" => t("Carbon Stamp"),
  "title_label"      => t("Description"),
  "has_body"         => false,
  "module" => "carbon_stamp",
  "description"=> t("A single record of carbon emissions such as ongoing household electricity ".
          "use or a daily commute or a single air trip." )),
  /*
   "carbon_meter"    => array("name" => t("Meter"),
   "module" => "carbon_meter",
   "description"=> t("A utility meter e.g. gas or electricity or car mileometer.")),

   "carbon_reading"    => array("name" => t("Meter reading"),
   "module" => "carbon_reading",
   "description"=> t("A reading taken from a utility meter or a car mileometer.")),
   */
  "carbon_transfer"     => array("name" => t("Carbon Transfer"),
  "title_label"      => t("Description"),
  "has_body"         => false,
  "module" => "carbon_transfer",
  "description"=> t("Transfer of carbon credit from one carbon account to another ".
          "account"),
  'has_title' => true,
  'has_body' => false),

  "carbon_source"    => array("name" => t("Carbon Source"),
  "module" => "carbon_source",
  "description"=> t("A source of emissions such as a new type of fuel or a type of " .
          "travel that is not already held in the database. All the usual sources of " .
          "emissions such as gas, electricity and car are normally configured by the " .
          "administrator or <em>carbon accountant</em> at installation time.")));
}

/**
 * only carbon_account has extra tabs
 *
 * @param $op
 * @param $node  may or may not be a carbon_account
 * @return boolean
 */

function carbon_tab_access($op, $node)
{
  $ab = $op ;
  return $node->type == "carbon_account";
}


/**
 * Valid permissions for this module. Note that these
 * permissions are accessed principally by the menu
 * system to determine which options should be presented
 * to the user.
 *
 * Access to specific carbon accounts is determined by the
 * user under preferences under the account node.
 *
 * @return An array of valid permissions this module
 */
function carbon_perm() {

  return array(
  //"access content"        // gives access to node/12xx34, implemented by drupal core
	"access accounts",			// give access to carbon/acccount and carbon/stamp pages
	"create/edit account",
	"administer accounts",	    // carbon accountant?
	"administer carbon nodes",	// can do anything
  );
}


/**
 * Implementation of hook_access().
 *
 * The carbon accounts are protected because we dont want personal data to be
 * displayed to other users without the permission of that user, same goes for
 * carbon_stamps. Carbon sources do not matter as the data is impersonal,
 * just need to be granted 'access content'.
 *
 * Note that $node->protection, $node->type and $node->uid are required
 *
 * @param create | view | update | delete
 * @param node->type OR the node itself (crazy API)
 */

function carbon_access($op, $node) {
  global $user;

  $node_type       = is_object($node) ? $node->type : $node ;

  switch ($op) {
    case 'meter' :
    case 'travel' :
      if ($node_type != "carbon_account") return false ;
  }

  // let annonymous users view carbon sources if node access permitted

  if ($op == "view" && $node_type == "carbon_source")
    return (user_access("access content")) ;

  $node_protection = is_object($node) ? $node->protection : 0 ;
  $uid             = is_object($node) ? $node->uid : 0 ;

  $carbon_data = $node_type == "carbon_account"
  || $node_type == "carbon_stamp"
  || $node_type == "carbon_source"
  || $node_type == "carbon_transfer"  ;

  if ($op == "view")
  {
    if ($carbon_data)
    {
      // public nodes viewable to all
      if ($node_protection >= 3)
      return TRUE;

      // public nodes viewable to logged in users
      if ($user->uid != 0)
      if ($node_protection >= 2)
      return TRUE;

      // my own node
      if (user_access("create/edit account") && ($user->uid == $uid))
      return TRUE;

      if ($node_protection >= 1)
      if (!empty($node->shared_uid))
      if ($node->shared_uid == $user->uid)
      return TRUE;

      if (user_access("administer accounts"))
      return TRUE;
    }
  }

  if ($op == "create" || $op == "update" || $op == "delete")
  {
    if ($carbon_data)
    {
      if (user_access("create/edit account") &&  ($op == "update") && ($user->uid == $uid))
      return TRUE;

      if (user_access("create/edit account") &&  ($op == "delete") && ($user->uid == $uid))
      return TRUE;

      if (user_access("create/edit account") &&  ($op == "create"))
      return TRUE;

      if (user_access("administer accounts"))
      return TRUE;
    }
  }

  if (user_access("administer carbon nodes"))
  if ($carbon_data)
  return TRUE;

  return FALSE ;
}


/**
 * menu hook
 * @return array of menu items
 */
function carbon_menu()
{
  global $user ;
  $items = array();
  /*
   $items['carbon/help'] = array(
   'title' => 'Carbon',  // does not work
   'description' => 'Carbon help',

   'access callback' => 'user_access',
   'access arguments' => array('access accounts'),

   'page callback' => 'carbon_help',
   'page arguments' => array("user/help#carbon",2)
   );
   */

  //--------------------------------------------------------------
  // set tabs around the account node
  // these provide the main access to
  // the carbon account
  //--------------------------------------------------------------


  $items["node/%node/meter"] = array(
    'title' => 'Meters',

    'access callback' => 'carbon_tab_access',
    'access arguments' => array(2,1),

    'file path' => CARBON_PATH,
    'file' => 'carbon_view.inc',

    'page callback' => 'carbon_view',
    'page arguments' => array(1,2),
    'weight' => -2,
    'type' => MENU_LOCAL_TASK
  );

  $items["node/%node/travel"] = array(
    'title' => 'Travel and other',

    'file path' => CARBON_PATH,
    'file' => 'carbon_view.inc',

    'access callback' => 'carbon_tab_access',
    'access arguments' => array(2,1),

    'page callback' => 'carbon_view',
    'page arguments' => array(1,2),
    'weight' => -1,
    'type' => MENU_LOCAL_TASK
  );

  //--------------------------------------------------------------
  // add another tab to the user's profile
  // users can have multiple accounts,
  // we list them here.
  //--------------------------------------------------------------

  $items["user/%user/carbon"] = array(
    'title' => 'Carbon acounts',
    'description' => 'Carbon accounts owned by user',
    'access callback' => 'user_access',
    'access arguments' => array('access accounts'),

    'file path' => CARBON_PATH,
    'file' => 'carbon_report.inc',

    'page callback' => 'carbon_report_create',
    'page arguments' => array(1, false),     // $user, no display query
    'weight' => 10,
    'type' => MENU_LOCAL_TASK
  );

  $items["user/%user/stamp"] = array(
    'title' => 'Carbon stamps',
    'description' => 'Carbon stamps owned by user',
    'access callback' => 'user_access',
    'access arguments' => array('access accounts'),

    'page callback' => 'carbon_stamp_page',
    'page arguments' => array(null,1,null),

    'weight' => 10,
    'type' => MENU_LOCAL_TASK
  );

  //--------------------------------------------------------------
  // accessing groups of accounts, sector reports
  // supports ajax calls
  //--------------------------------------------------------------

  $items["carbon/report"] = array(
    'title' => "Carbon account summary",
    'description' => 'summary of accounts, parameters specified in GET parameters',
    'access callback' => 'user_access',
    'access arguments' => array('access accounts'),

    'file path' => CARBON_PATH,
    'file' => 'carbon_report.inc',

    'page callback' => 'carbon_report_create',
    'page arguments' => array(null, true), // $target_user, displayForm
    'type' => MENU_CALLBACK
  );


  $items['carbon/%node/transfer'] = array(
    'title' => 'Carbon trades',
    'description' => 'movement between accounts',

    'access callback' => 'user_access',
    'access arguments' => array('access accounts'),

//    'file path' => CARBON_PATH,
//    'file' => 'carbon_transfer.inc',

    'page callback' => 'carbon_transfer_page',
    'page arguments' => array(1),

    'type' => MENU_CALLBACK
  );

  $items['carbon/transfer'] = array(
    'title' => 'Carbon trades',
    'description' => 'movement between accounts',

    'access callback' => 'user_access',
    'access arguments' => array('access accounts'),

//    'file path' => CARBON_PATH,
//    'file' => 'carbon_transfer.inc',

    'page callback' => 'carbon_transfer_page',
    'page arguments' => array(null),

    'type' => MENU_CALLBACK
  );


  $items['carbon/share'] = array(
    'title' => 'Carbon Account sharing',
    'description' => 'Adjust how i want to share?',

    'access callback' => 'user_access',
    'access arguments' => array('access accounts'),

    'page callback' => 'carbon_view_consolidated',
    'page arguments' => array($user->uid),

    'type' => MENU_CALLBACK
  );

  // admin type functions which are not put into the
  // drupal menu structure. Perhaps they should

  $items["carbon/source"] = array(
    'title' => "Carbon sources",
    'description' => "list/edit all sources of carbon emissions",
    'access callback' => 'carbon_access',
    'access arguments' => array('view', 'carbon_source'),

    'page callback' => 'carbon_source_page',
    'page arguments' => array(null),

    'type' => MENU_NORMAL_ITEM
  );


  $items["carbon/source/install"] = array(
    'title' => "Install default carbon sources",

    'access callback' => "user_access",
    'access arguments' => array("administer carbon nodes"),

    'page callback' => "carbon_source_install",
    'page arguments' => array(),

    'type' => MENU_CALLBACK
  );


  $items["admin/settings/carbon"] = array(
    'title' => "Carbon settings",
    'description' => "Settings, administrative functions and database checks.",

    'access callback' => "user_access",
    'access arguments' => array("administer carbon nodes"),

    'page callback' => "drupal_get_form",
    'page arguments' => array("carbon_admin_settings"),
    'type' => MENU_NORMAL_ITEM
  );


  $items["admin/settings/carbon/settings"] = array(
    'title' => "Settings",

    'access callback' => "user_access",
    'access arguments' => array("administer carbon nodes"),

    'page callback' => "drupal_get_form",
    'page arguments' => array("carbon_admin_settings"),
    'type' => MENU_DEFAULT_LOCAL_TASK
  );


  $items["admin/settings/carbon/database"] = array(
    "title" => "Database check and repair",

    'access callback' => "user_access",
    'access arguments' => array("administer carbon nodes"),

    'page callback' => "carbon_admin",
    'page arguments' => array(),

    'file path' => drupal_get_path("module", "carbon"),
    'file' => 'carbon_admin.inc',
    'weight' =>  +10,
    'type' => MENU_LOCAL_TASK
  );

  // load a form as a row at the bottom of an
  // existing page so that it can be edited insitu

  //  %node/table-name/add

  $items["carbon/%node/%/add"] = array(
    "title" => "Add carbon node",

    'access callback' => 'node_access',
    'access arguments' => array('view', 1),

    'file path' => drupal_get_path("module", "carbon"),
    'file' => 'carbon_edit.inc',

    'page callback' => "carbon_ajax_edit",
    'page arguments' => array(1,2,3,null),  // note arguments
  );

  // load a form onto a row on an existing page so
  // that it can be edited insitu

  //  %node/table-name/edit|clone/%node

  $items["carbon/%node/%/%/%node"] = array(
    "title" => "Edit carbon node",

    'access callback' => 'node_access',
    'access arguments' => array('view', 4),

    'file path' => drupal_get_path("module", "carbon"),
    'file' => 'carbon_edit.inc',

    'page callback' => "carbon_ajax_edit",
    'page arguments' => array(1,2,3,4),
  );
  return $items;
}


/**
 * Implementation of hook_block().
 * Declare the name of this block, later we will generate HTML for the carbon block
 * @param op the operation from the URL
 * @param delta offset
 * @returns block HTML
 */

function carbon_block($op='list', $delta=0, $edit = array()) {
  global $user ;

  // variable_set('menu_rebuild_needed', true);  // for debugging

  // listing of blocks, such as on the admin/block page
  if ($op == "list") {
    $block[0]["info"] = t(" Carbon accounts");
    return $block;

  }
  else if ($op == "view")
  {
    require_once(CARBON_PATH ."/carbon_report.inc");
    $block_size = variable_get("carbon_account_block_items",5);
    $accountMap = new CarbonAccountMap();
    $accountMap->init()->sortByRevisionDate();

    foreach ($accountMap->account_map as $account) {
      if ($block_size-- <= 0 )  break ;
      $block_content .= carbon_link_from_title($account, $account, "") . '<br />';
    }

    // check to see if there was any content before setting up the block
    if (empty($block_content)) {
      return;
    }
    // set up the block
    $block["subject"] = "Active carbon accounts";
    $block["content"] = $block_content;
    return $block;
  }
  else if ($op == "configure" && $delta == 0) {
    $form["items"] = array(
		"#type" => "select",
		"#title" => t("Number of items"),
		"#default_value" => variable_get("carbon_account_block_items", 10),
		"#options" => drupal_map_assoc(array(2, 3, 5, 8, 10, 12, 15, 20, 25, 30, 40, 50, 70, 100))
    );
    return $form ;
  }
  else if ($op == "save" && $delta == 0) {
    variable_set("carbon_account_block_items", $edit["items"]);
  }
}


/*
 * implementation of the (rather annoying) hook_theme
 * These declarations are required for drupal 6
 *
 * They are only read when the module is enabled (i think)
 */

function carbon_theme($existing, $type, $theme, $path)
{
  return array(
    'carbon_source_table_view' => array(
      'arguments' => array('node' => NULL)),
    'carbon_stamp_view' => array(
      'arguments' => array('node' => NULL)),
    'table_inside_form' => array(   // not sure this is useful
      'arguments' => array('header' => NULL, 'rows')),
    'carbon_editable_row_form' => array(
      'arguments' => array('form'=>NULL)),
    'carbon_static_box' => array(
      'arguments' => array('title' => NULL, 'body' => NULL)),
    'carbon_loadable_box' => array(
      'arguments' => array('title' => NULL, 'url' => NULL))
  );
}


/**
 * create a set of links that can be appended to a table of stamps,
 * accounts or sources.
 *
 * Note that $node->type, $node->organization, $node->uid, $node->name
 * and other properties must be set for links to be created correctly.
 */

function carbon_link($type, $node = 0, $main = 0)
{
  global $user ;

  $links = array();

  if ($type != "node")
    return $links ;

  if (empty($user->uid))
    return $links;

  if (($node->type == "carbon_stamp") || ($node->type == "carbon_account") || ($node->type == "carbon_stamp"))
  $links["my_account"] = array("title"=>"My carbon accounts", "href"=> "user/".$node->uid."/carbon",
    "attributes" => array("title" => t("Accounts owned by !name", array("!name"=>$node->name))));

  if (($node->type == "carbon_stamp") || ($node->type == "carbon_account"))
  {
    $links["my_stamps"] = array("title" => "My stamps", "href"=>"user/".$node->uid."/stamp",
    "attributes" => array("title" => t("All stamps owned by !name", array("!name"=>$node->name))));

    if (!empty($node->organization))
    {
      $links["group_accounts"] = array("title"=>"Group accounts", "href"=>"carbon/report/",
      "query"=> "org=".$node->organization,
      "attributes" => array("title" => t("Accounts of all users in !name", array("!name"=>$node->organization))));
    }
    else
    {
      $links["all_accounts"] = array("title"=>"All accounts", "href"=>"carbon/report",
      "attributes"=> array("title" => t("All accounts.")));
    }

    $links["carbon_sources"] = array("title" => t("All carbon sources"), "href"=>"carbon/source",
    "attributes" => array("title" => t("All sources of carbon emissions.")));
  }
  elseif ($node->type == "carbon_source")
  {
    $links["carbon_sources"] = array("title" => t("All Carbon sources"), "href"=>"carbon/source",
    "attributes" => array("title" => t("All sources of carbon emissions.")));

    $links["add_new_source"] = array("title"=>"Create new source", "href" => "node/add/carbon-source",
    "attributes" => array("title"=> t("Add new source of carbon emissions")));
    //  $links["xml"] = l(t("view as XML"),    "carbon/account/xml", array('title' => t("view/export as XML (todo)")));
  }
  return $links;
}


function carbon_share()
{
  return "Sharing not supported yet";
}


/**
 * revamped for drupal 5.0
 */

function carbon_admin_settings() {

  $form["carbon_models"] = array(
      "#type" => "textfield",
      "#title" => t("Carbon source model filter"),
      "#default_value" => variable_get("carbon_models", ""),
      "#description" => t("Specify each carbon source model you want users and admins to see. " .
      " Each model name should be separated with a comma." .
      " Existing source selections made by users are unaffected. " .
      " Leave blank to include all models."),
	    "#maxlength" => "80",
      "#size" => "80");

  $form["carbon_energy_units_0"] = array(
      "#type" => "textfield",
      "#title" => t("Units of energy field 0"),
      "#default_value" => variable_get("carbon_energy_units_0", ""),
      "#description" => t("Set description to match what is provided in carbon sources ".
      "e.g. non renewable kWh. This field is not shown to users until units are specified above."),
      "#maxlength" => "30",
      "#size" => "30");

  $form["carbon_energy_units_1"] = array(
      "#type" => "textfield",
      "#title" => t("Units of energy field 1"),
      "#default_value" => variable_get("carbon_energy_units_1", ""),
      "#description" => t("Set description to match what is provided in carbon sources ".
      "e.g. renewable kWh. This field is not shown to users until units are specified above."),
      "#maxlength" => "30",
      "#size" => "30");


  $form["carbon_units"] = array(
      "#type" => "textfield",
      "#title" => t("Units of carbon dioxide"),
      "#default_value" => variable_get("carbon_units", "Kg of C02"),
      "#description" => t("The default carbon sources calculate carbon emissions in Kg. " .
      "However in some countries, you might want to use pounds. ".
      "No conversions are done within the software."),
      "#maxlength" => "30",
      "#size" => "30");

  $form["carbon_sectors"] = array(
      "#type" => "textfield",
      "#title" => t("Sector color palette"),
      "#default_value" => variable_get("carbon_sectors", CARBON_PALETTE),
      "#description" => t("You can use any sector names in carbon sources. ".
      "However you can associate sectors with particular colors e.g. ".CARBON_PALETTE."."),
      "#maxlength" => "255",
      "#size" => "80");

/*
  $form["carbon_chart_provider"] = array(
    "#type" => "select",
    "#options" => _get_carbon_chart_providers(),
    "#title" => t("Chart provider"),
    "#default_value" => variable_get("carbon_chart_provider", 'internal'),

  //    "#description" => t("The drupal charts module (%is_enabled) is required for all options except internal.",
  //    array("%is_enabled"=>module_exists('charts') ? 'enabled' : 'disabled'))

*/
  $form["carbon_default_chart"] = array(
    "#type" => "textfield",
    "#title" => t("Default chart shown with a carbon account"),
    "#default_value" => variable_get("carbon_default_chart", ""),
    "#description" => t("Leave blank or specify 'bar' or 'pie'. Note that creating a bar or pie chart for each account by default " .
        "puts extra load on the server."),
    "#maxlength" => "10",
    "#size" => "10");

  $form["carbon_use_model_selection"] = array(
      "#type" => "checkbox",
      "#title" => t("Prompt user for preferred model"),
      "#default_value" => variable_get("use_model_selection", 1),
      "#description" => t("If users are not able to select a model make sure that " .
            "are not a lot of similar carbon sources with the same code e.g. elec-kwh as this will " .
            "confuse users. This could be done by just enabling a single model above."),
      "#maxlength" => "10",
      "#size" => "10");


  $form["carbon_use_postal_code"] = array(
      "#type" => "checkbox",
      "#title" => t("Prompt user for postal code or zipcode and display"),
      "#default_value" => variable_get("carbon_use_postal_code", 1),
      "#maxlength" => "10",
      "#size" => "10");

  $form["carbon_use_organization"] = array(
      "#type" => "checkbox",
      "#title" => t("Prompt user for organizaton and display"),
      "#default_value" => variable_get("carbon_use_organization", 1),
      "#maxlength" => "10",
      "#size" => "10");

  $form["carbon_enable_crag_functions"] = array(
      "#type" => "checkbox",
      "#title" => t("Enable CRAG functions"),
      "#default_value" => variable_get("carbon_enable_crag_functions", 0),
      "#description" => t("Adds additional reporting functions"),
      "#maxlength" => "10",
      "#size" => "10");


  $form["carbon_money_units"] = array(
      "#type" => "textfield",
      "#title" => t("Units of money"),
      "#default_value" => variable_get("carbon_money_units", "$"),
      "#description" => t("Used only for carbon trades."),
      "#maxlength" => "10",
      "#size" => "10");


  return system_settings_form($form);
}


function _get_carbon_chart_providers()
{
  return array('internal'); //,'google','openflashchart','fusioncharts');
}

function _set_title($account)
{
  drupal_set_title($account->title);
}

/**
 * This function hides most of an account name so users need not reveal their
 * fullname but enough of it that their friends recognise the name.
 *
 * @param $name
 * @return name which has been hideen
 */

function carbon_anonomize($name)
{
  return substr($name, 0, 5)."..." ;
}

/**
 * Because carbon_stamps don't have their own protection (too
 * difficult to manage), when we to show a link to a carbon_stamp,
 * test the protection of the account supplied.
 *
 * In other words carbon stamps are private be default. But they
 * can be made public if attached to a carbon_account.
 *
 * Also used by carbon_transfers.
 *
 * @param $node is the object that you want to link to (e.g. a carbon stamp)
 * @param $account is the object that you want to evaluate protection (e.g. a carbon account)
 */

function carbon_link_from_title($node, $account, $extra)
{
  $access = carbon_access("view", $account);  // $node->type must be set!
  $title = empty($node->title)  ? '('.$node->nid.')'
  :  ($access ? $node->title : carbon_anonomize($node->title)) ;
  return $access ? l($title,"node/".$node->nid. "/". $extra) : $title;
}


/**
 * format the edit clone buttons
 *
 * @param $node  the node that might be editable
 * @param $query the query to initiate edir
 * @return html
 */


function carbon_format_edit_ops($node, $query)
{
  return
  _fancy_link($node,"","edit all fields on stamp", "node/".$node->nid."/edit", $query, "edit");
}


function carbon_format_add_new_op($node, $query)
{
  return _fancy_link($node, "new", "add new carbon stamp", "node/add/carbon_stamp", $query, "add");
}


/**
 * Similar to carbon_link_from_title except that you can insert
 * the link in colour and in reverse video.
 */


function carbon_highlighted_link($node, $text, $title, $path, $query, $text_class)
{
  return _fancy_link($node, $text, $title, $path, $query, $text_class);
}


function _fancy_link($node, $text, $title, $path, $query, $class)
{
//  $access = carbon_access(is_object($node) ? "update":"create", $node_type);  // $node->type must be set!
//  if (!$access)
//  return "" ;

  $attributes = array('title'=>$title, 'class'=>$class);
  $html = l($text, $path, $options = array('attributes'=>$attributes, 'query'=> $query, $html=false));

  return $html ;
}


/*
 * hm probably not necessary to define this class
 */

class Node
{

}


//  Shared date functions


/**
 * Format a date range. Show a date range using as few as
 * characters as possible so that it takes little space
 * on the screen but without being ambiguous.
 */

function _format_date_range($firstdate, $lastdate)
{
  $y1 = date('y', $firstdate);  $y2 = date('y', $lastdate);
  $m1 = date('m', $firstdate);  $m2 = date('m', $lastdate);

  if ($y1 == $y2)
  {
    if ($m1 == $m2)
    return date("M Y", $firstdate);

    return date("M", $firstdate)." to ". date("M Y", $lastdate);
  }
  return date("M Y", $firstdate)." to ". date("M Y", $lastdate);
}


/**
 * Bypass Drupal's format_date() which deals only with offsets and
 * appears to not understand daylight savings time.
 *
 * It is really important that dates are handled consistently.
 * Otherwise you end up accepting dates with one offset e.g. BST
 * and displaying them with another e.g. GMT which is what happened
 * with early software versions.
 *
 * Print time if it's any value other than 00:00
 *
 * @param $timestamp
 * @param $type
 * @return unknown_type
 */

function _format_date_only($timestamp)
{
  if (empty($timestamp)) return '' ;
  $datetimeformat = variable_get('date_format_short', 'm/d/Y');
  // trim the format string down to just the date part see http://uk.php.net/manual/en/function.date.php
  $len = strspn($datetimeformat, "-dDjlNSwz-W-FmMnt-LoyY-/");
  $dateformat = substr($datetimeformat, 0 , $len);
  return date($dateformat, $timestamp);
}

/**
 * Print time if it's any value other than 00:00
 * @param $timestamp
 * @return unknown_type
 */


function _format_date($timestamp)
{
  if (empty($timestamp)) return '' ;

  if (idate('H', $timestamp) || idate('i', $timestamp))
  {
    return _format_date_time($timestamp);  // time not midnight, so add hours
  }
  return _format_date_only($timestamp);
}

/**
 * Format date time string and always show time
 *
 * @param $timestamp
 * @return unknown_type
 */

function _format_date_time($timestamp)
{
  if (empty($timestamp)) return '' ;
  $format = variable_get('date_format_short', 'm/d/Y - H:i');  // drupal default date
  return date($format, $timestamp);
}

/**
 * This class is used to convert between dates embedded in URLs
 * and the unix timestamp.
 *
 * @author johna
 *
 */


class CarbonDate
{
  /*
   * return a unix timestamp from a string
   */
  static function fromYYYYMMDD($s)
  {
    return mktime(0, 0, 0, substr($s,4,2), substr($s,6,2), substr($s,0,4));
  }

  /*
   * return a string from a unix timestamp
   */

  static function asYYYYMMDD($time)
  {
    return sprintf("%04d%02d%02d", date('Y', $time), date('m', $time), date('d', $time));
  }

  /**
   * return time
   * @return unknown_type
   */
  static function today()
  {
    return mktime(0, 0, 0, idate('m'), idate('d'), idate('Y'));
  }
}


/**
 * Add whole years onto a date
 *
 * @param unix timestamp (secs from 1970)
 * @param integer number of months
 * @return the new date (secs from 1970)
 */

function _add_months($date, $num)
{
  return strtotime($num." month", $date);
}


?>