How to create a new FLEXIcontent item or update an existing item by calling the FLEXIcontent item model in custom code

NOTE:
- the following was test but it may be incomplete if you have a fix / suggestion for the following then post in our forums

// Create a log file
$user = JFactory::getUser();
$log_filename = 'item_creation_'.($user->id).'.php';
jimport('joomla.log.log');
JLog::addLogger(array('text_file' => $log_filename));

error_reporting(E_ALL & ~E_STRICT);
ini_set('display_errors',1);


// **************************************
// Include the needed classes and helpers
// **************************************

if (!defined('DS'))  define('DS',DIRECTORY_SEPARATOR);
require_once (JPATH_SITE.DS.'components'.DS.'com_flexicontent'.DS.'classes'.DS.'flexicontent.helper.php');
require_once (JPATH_SITE.DS.'components'.DS.'com_flexicontent'.DS.'classes'.DS.'flexicontent.categories.php');
require_once (JPATH_SITE.DS.'components'.DS.'com_flexicontent'.DS.'classes'.DS.'flexicontent.fields.php');
require_once (JPATH_SITE.DS.'components'.DS.'com_flexicontent'.DS.'helpers'.DS.'permission.php');
require_once (JPATH_SITE.DS.'components'.DS.'com_flexicontent'.DS.'helpers'.DS.'route.php');

// Add component's table directory to the include path
JTable::addIncludePath(JPATH_ADMINISTRATOR.DS.'components'.DS.'com_flexicontent'.DS.'tables');



// *******************
// Load language files
// *******************

// (BACKEND) Load english language file for 'com_content' component then override with current language file
JFactory::getLanguage()->load('com_content', JPATH_ADMINISTRATOR, 'en-GB', true);
JFactory::getLanguage()->load('com_content', JPATH_ADMINISTRATOR, null, true);
// (BACKEND) Load english language file for 'com_flexicontent' component then override with current language file
JFactory::getLanguage()->load('com_flexicontent', JPATH_ADMINISTRATOR, 'en-GB', true);
JFactory::getLanguage()->load('com_flexicontent', JPATH_ADMINISTRATOR, null, true);


// (FRONTEND) Load english language file for 'com_content' component then override with current language file
JFactory::getLanguage()->load('com_content', JPATH_SITE, 'en-GB', true);
JFactory::getLanguage()->load('com_content', JPATH_SITE, null, true);
// (FRONTEND) Load english language file for 'com_flexicontent' component then override with current language file
JFactory::getLanguage()->load('com_flexicontent', JPATH_SITE, 'en-GB', true);
JFactory::getLanguage()->load('com_flexicontent', JPATH_SITE, null, true);



// ****************************
// Create the item model object
// ****************************
JFactory::getApplication()->isAdmin()
  ? require_once(JPATH_ADMINISTRATOR.DS.'components'.DS.'com_flexicontent'.DS.'models'.DS.'item.php')
  : require_once(JPATH_SITE.DS.'components'.DS.'com_flexicontent'.DS.'models'.DS.'item.php');
$item_model = new FlexicontentModelItem();


// Create the new item data
$data = array();

// 444 is the id of the item that you want to load, or set it to zero for new item
$item_ID = 0;   // 444;

if ($item_ID)
{
  // EITHER Load existing item into the ITEM model
  $item = $item_model->getItem($item_ID, $check_view_access=false, $no_cache=true, $force_version=0);
  // You can use $item to get existing values
  if (!$item) die('item '.$item_ID.' not found');

  // IMPORTANT: Get existing field values for the item
  $items = array($item);
  $items_custom_values = FlexicontentFields::getCustomFieldValues($items, 'item');
  $data['custom'] = reset($items_custom_values); // Get data of first item

  // Indicate which item to update
  $data['id'] = $item_ID;
}
else
{
  // OR indicate a new item will be created
  $data['id'] = 0;
}

// Type and language
$data['type_id'] = ...; // e.g. 1 for article, !! DO NOT CHANGE for existing item
$data['language']= ...; // e.g. 'en-GB'

// main category, secondary categories and tags
$data['catid']   = ...; // INTEGER ... the main category of the item
$data['cid']     = ...; // e.g. array() or ... array(55,117,56)  an array of the secondary categories of the item
$data['tag']     = ...; // e.g. array() or ... array(13,43,34)  an array of the tags of the item

$data['vstate']  = 2;  // item version is approved
$data['state']   = 1;  // 1 for published ...

$data['title']   = 'this is the title of the item';
$data['text']    = 'this is the description of the item';

// Custom fields
$data['custom']['field1'] = 'this value of field 1';
$data['custom']['field2'][0] = 'this value 0 of field 2';
$data['custom']['field2'][1] = 'this value 1 of field 2';
$data['custom']['field2'][2] = 'this value 2 of field 2';


// Store the new / existing item and log the result in file and on screen
if ( !$item_model->store($data) )
{
	$msg = 'Failed to store item: '. $item_model->getError();
	JLog::add($msg);
	echo $msg."<br/>";
}

Also if the above IS NOT inside a Joomla extension, then you will need to load the Joomla Framework before calling the above code, by using:

// Get Joomla! framework
define( '_JEXEC', 1 );
define( '_VALID_MOS', 1 );
define( 'JPATH_BASE', realpath(dirname(__FILE__)) );
define( 'DS', DIRECTORY_SEPARATOR );
require_once ( JPATH_BASE .DS.'includes'.DS.'defines.php' );
require_once ( JPATH_BASE .DS.'includes'.DS.'framework.php' );

$app = JFactory::getApplication('site');
$app->initialise();

// Define component paths IF FLEXIcontent v3.1.0 or older
// You do not need them for v3.1.1 or later !!
define( 'JPATH_COMPONENT_SITE', JPATH_SITE.DS.'components'.DS.'com_flexicontent' );
define( 'JPATH_COMPONENT_ADMINISTRATOR', JPATH_ADMINISTRATOR.DS.'components'.DS.'com_flexicontent' );

In the above we assume that you custom script is located in your site root, if it is located in a subfolder: custom/myscripts/ then use:

define( 'JPATH_BASE', realpath(dirname(__FILE__).'/../..' ));