<?php
/**********************************************************************
    Copyright (C) FrontAccounting, LLC.
	Released under the terms of the GNU General Public License, GPL, 
	as published by the Free Software Foundation, either version 3 
	of the License, or (at your option) any later version.
    This program 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 License here <http://www.gnu.org/licenses/gpl-3.0.html>.
***********************************************************************/
include_once($path_to_root . "/includes/db/references_db.inc");
//---------------------------------------------------------------------------------------------
//
// For now (2.3) the references system has somewhat inconsistent design scheme.
// Most transactions store references in respective table, but this is not the case
// for journal entries. All references regardless of type are stored also in refs table. 
// Reference uniquness now can be checked with is_new_reference() for all transactions. 
// In near future this should be fixed either with removing reference fields 
// in transaction tables, or adding ref in bank transaction/journal and removing refs table.
//

class references 
{
	//
	//	Get reference from refs table for given transaction.
	//	Used for transactions which do not hold references (journal and bank).
	//
	function get($type, $id) 
	{
		return get_reference($type, $id);
	}
	//
	// Check if reference is used for any non voided transaction (used for ST_JOURNALENTRY type)
	//
	function exists($type, $reference) 
	{
		return (find_reference($type, $reference) != null);
	}
	//
	// Get default reference on new transaction creation.
	//
	function get_next($type) 
	{
		return get_next_reference($type);
	}
	//
	// Check reference is valid before add/update transaction.
	//
	function is_valid($reference) 
	{
		return strlen(trim($reference)) > 0;
	}
	//
	//	Save reference (and prepare next) on write transaction.
	//
	function save($type, $id, $reference) 
	{
		update_reference($type, $id, $reference); // store in refs table
		if ($reference == $this->get_next($type)) { // if reference was not changed from default
			$next = $this->_increment($reference);	// increment default
			save_next_reference($type, $next);
		}
	}
	//
	// Restore previous reference (if possible) after voiding transaction.
	//
	function restore_last($type, $id) 
	{
		$reference = get_reference($type, $id);
		$prev = $this->_increment($this->get_next($type), true); //decrement
		if ($reference==$prev) {
			save_next_reference($type, $prev);
		}
	}
	//-----------------------------------------------------------------------
	//
	//	Increments (or decrements if $back==true) reference template
	//
	function _increment($reference, $back=false) 
	{
		// New method done by Pete. So f.i. WA036 will increment to WA037 and so on.
       	// If $reference contains at least one group of digits,
        // extract first didgits group and add 1, then put all together.
        // NB. preg_match returns 1 if the regex matches completely 
        // also $result[0] holds entire string, 1 the first captured, 2 the 2nd etc.
        //
        if (preg_match('/^(\D*?)(\d+)(.*)/', $reference, $result) == 1) 
        {
			list($all, $prefix, $number, $postfix) = $result;
			$dig_count = strlen($number); // How many digits? eg. 0003 = 4
			$fmt = '%0' . $dig_count . 'd'; // Make a format string - leading zeroes
			$val = intval($number + ($back ? ($number<1 ? 0 : -1) : 1));
			$nextval =  sprintf($fmt, $val); // Add one on, and put prefix back on

			return $prefix.$nextval.$postfix;
        }
        else 
            return $reference;
	}
}

//----------------------------------------------------------------------------
//
//	Check if reference was not used so far (for other transaction than $trans_no)
//
function is_new_reference($ref, $type, $trans_no=0)
{
	$db_info = get_systype_db_info($type);
	$db_name = $db_info[0];
	$db_type = $db_info[1];
	$db_trans = $db_info[2];
	$db_ref = $db_info[3];
	
	$ref = db_escape(trim($ref));
	$type = db_escape($type);
	
	if ($db_ref == null) { // journal or bank trans store references in refs table
		$db_ref = TB_PREF."refs";
		$db_type = 'type';
		$db_trans = 'id';
		$rb_ref = 'reference';
	}

	if ($db_type != null) {
		$sql = "SELECT $db_ref FROM $db_name 
			LEFT JOIN ".TB_PREF."voided v ON 
				$db_name.$db_type=v.type AND $db_name.$db_trans=v.id
			WHERE $db_name.$db_ref=$ref AND ISNULL(v.id)
				AND $db_name.$db_type=$type";
	} else {
		$sql = "SELECT $db_ref FROM $db_name 
			LEFT JOIN ".TB_PREF."voided v ON 
				v.type=$type AND $db_name.$db_trans=v.id
			WHERE $db_ref=$ref AND ISNULL(v.id)";
	}

	if ($trans_no)
	{
		$sql .= " AND $db_name.$db_trans != ".db_escape($trans_no);
	}
	$result = db_query($sql, "could not test for unique reference");

	return (db_num_rows($result) == 0);

}


?>