<?php
	$LinkStatus=1;

	function doSync()
	{	GLOBAL $mLink, $rLink;

//		if ($rLink !== false and $_SESSION['instance']['sync'])
		if ($rLink)
		{	// we have a remote connection, so we can do a sync
			$r = sqlReplace("touches", "tdate='".date("Ymd")."',remote_unit='".$_SESSION['instance']['prefix']."'","tdate='".date("Ymd")."' and remote_unit='".$_SESSION['instance']['prefix']."'");

			$curRemMod = mysql_query("select NOW() + 0 as curRemMod", $rLink);
			$curRemMod = mysql_fetch_assoc($curRemMod);
			$curRemMod = substr($curRemMod['curRemMod'], 0, 14);

			$lastmod = getSystemLastMod();
//			$lastmod = mysql_query("select lastmod from system", $mLink);
//			$lastmod = mysql_fetch_assoc($lastmod);
//			$lastmod = $lastmod['lastmod'];

			$_SESSION['update']['lastmod'] = $lastmod;

			// get all changes from both the local copy and from the main server before sending anything
			// UPDATE: collecting both send and receive before starting sync allows a bug where (example)
			// an order can be close, but is reopened by sync
			// separating the send and receive -- this will cause the master to send back all the changes
			// submitted by the remote, but that is better than it being incorrect

			// integrity for when the table does not yet exist on another client, table existance is checked
			// if the table does not exist, data is not sent - on in the case of receiving, the block is stored
			// in a backlog to be retried once each session.

			$sndQuery = "select * from `transaction_log` order by lastmod";
			$toSnd = mysql_query($sndQuery, $mLink);

			// we're going to keep track of each TID we send so that we can NOT re-receive them later
			// store this list in the array "doNotRcvList"
			$doNotRcvList = array();
//~~ potential problem: if a different client modifies this TID between send and recieve, that change may be ignored
//   if this does become a problem, remove the "doNotRcvList" lines (272, 299, 324 and 353)
			// remote has priority, so send to master FIRST

			while ($snd = mysql_fetch_assoc($toSnd))
			{	$tbl = $snd['tble'];
				$tid = $snd['tid'];
				$r = mysql_query("show tables like '$tbl'", $rLink);
				if (mysql_num_rows($r))
				{
					$str = "";
					$q = "select * from $tbl where tid='$tid'";
					if (($data = mysql_query($q, $mLink)) !== false)
					{	$data = mysql_fetch_assoc($data);
						if (is_array($data))
						{	foreach ($data as $k => $v)
							{	if ($str) $str .=", ";
								$str .= "$k = '".addslashes($v)."'";
							}
							$q = "replace into $tbl set $str";
							mysql_query($q, $rLink);
							$q = "replace into `transaction_mstr_log` set tble='$tbl', tid='$tid', lastmod='$curRemMod', chgby = '{$snd['chgby']}'";
							mysql_query($q, $rLink);
							// the info has to be put itno the regular trans-log as well so that it will be relayed to the server if this is a cross sync session
							$q = "replace into `transaction_log` set tble='$tbl', tid='$tid', lastmod='$curRemMod', chgby = '{$snd['chgby']}'";
							mysql_query($q, $rLink);
							mysql_query("delete from `transaction_log` where tid='$tid'", $mLink); // remove from the log
							$doNotRcvList[] = $tid;
						}
						else
						{	$q = "delete from `transaction_log` where tid='$tid'";
							mysql_query($q, $mLink);
						}
					}
					else
					{	$q = "delete from `transaction_log` where tid='$tid'";
						mysql_query($q, $mLink);
					}
				}
			}

			// 20110912: receive collection moved to this point: see note above (line 255)
			// get the reference for all transactions newer than the last one received and NOT originating from THIS computer
			$rcvQuery = "select * from `transaction_mstr_log` where lastmod >= '$lastmod' and chgby != '{$_SESSION['instance']['prefix']}' order by lastmod asc, tid asc limit 250";
			$toRcv = mysql_query($rcvQuery, $rLink);

			while ($rcv = mysql_fetch_assoc($toRcv))
			{	// block all receiving TID's that were just sent
				if (array_search($rcv['tid'], $doNotRcvList) === false)
				{	$tbl = $rcv['tble'];
					$tid = $rcv['tid'];
					$lastmod = $rcv['lastmod'];
					$chgby = $rcv['chgby'];
					$r = mysql_query("show tables like '$tbl'", $mLink);
					if (mysql_num_rows($r))
					{
						$str = "";
						$q = "select * from $tbl where tid='$tid'";
						if (($data = mysql_query($q, $rLink)) !== false)
						{	$data = mysql_fetch_assoc($data);
							if (is_array($data))
							{	foreach ($data as $k => $v)
								{	if ($str) $str .=", ";
									$str .= "$k = '".addslashes($v)."'";
								}
								mysql_query("replace into $tbl set $str", $mLink);
//								mysql_query("replace into `transaction_log` set tid='$tid', lastmod = '$lastmod', tble = '$tbl', chgby = '$chgby'", $mLink);
								mysql_query("replace into `transaction_mstr_log` set tid='$tid', lastmod = '$lastmod', tble = '$tbl', chgby = '$chgby'", $mLink);
								mysql_query("update system set lastmod ='$lastmod'", $mLink);
							}
						}
					}
					else
					{	mysql_query("replace into `transaction_backlog` set tid = '$tid', lastmod = '$lastmod', tble = '$tbl', chgby = '$chgby'", $mLink);
					}
				}
			}
			// to ensure that the block list ($doNotRcvList) resets every time, remove it now
			unset($sendList);
		}
	}

	if (($rLink = @mysql_connect($_SESSION['instance']['sdbIfce'], $_SESSION['instance']['sdbUser'], $_SESSION['instance']['sdbPass'], true)) !== false)
	{
		mysql_select_db($_SESSION['instance']['sdbName'], $rLink) or die("Could not select remote database");

		// try to get sync backlog ... ONCE per session
		if (!isset($_SESSION['instance']['backlog'])) // we haven't tried to send backlog yet in this session
		{	$_SESSION['instance']['backlog'] = true;
			$tList = mysql_query("select tble from `transaction_backlog` group by tble", $mLink);
			while ($l = mysql_fetch_assoc($tList))
			{	$r = mysql_query("show tables like '{$l['tble']}'", $mLink);
				if (mysql_num_rows($r))
				{	// this table now exists, so process these entries
					$pList = mysql_query("select * from `transaction_backlog` where tble = '{$l['tble']}' order by tid", $mLink);
					while (list($tid, $lastmod, , $chgby) = mysql_fetch_row($pList))
					{
						$str = "";
						$q = "select * from $tbl where tid='$tid'";
						if (($data = mysql_query($q, $rLink)) !== false)
						{	$data = mysql_fetch_assoc($data);
							if (is_array($data))
							{	foreach ($data as $k => $v)
								{	if ($str) $str .=", ";
									$str .= "$k = '".addslashes($v)."'";
								}
								mysql_query("replace into $tbl set $str", $mLink);
//								mysql_query("replace into `transaction_log` set tid='$tid', lastmod = '$lastmod', tble = '$tbl', chgby = '$chgby'", $mLink);
								mysql_query("replace into `transaction_mstr_log` set tid='$tid', lastmod = '$lastmod', tble = '$tbl', chgby = '$chgby'", $mLink);
								mysql_query("update system set lastmod ='$lastmod'", $mLink);
							}
						}
					}
				}
			}
		}
	}
?>