<?
/* $Id: expiration.inc.php,v 1.10 2001/03/02 21:47:48 phord Exp $ */

/* estimated end of clients adviews */
/* -------------------------------- */
/* placed to GNU by martin@braun.cc */

/* this function calculates the estimated end of a clients credits in clicks or views
   based on used views and clicks, the time from the first to the last view and click 
   and the current date. If the client has an expiration date this one will have
   priority.

   The return value is an array which returns a ready to use string with expiration and
   left days contents based on language string settings, a string with the date und an 
   integer value with the amount of days left for alternate usage
   
   usage: list($desc,$enddate,$daysleft)=days_left($clientID)

   Disclaimer:
   This function will temporarily not work properly, if statistics are reset or the 
   amount of the credit in views or clicks or left days is modified
*/
function days_left($clientID)
{
	global $phpAds_db, $phpAds_tbl_banners, $phpAds_tbl_clients, $phpAds_tbl_adviews, $phpAds_tbl_adclicks, $date_format;
    global $phpAds_tbl_adstats, $phpAds_compact_stats;

	// uses the following language settings:
	global $strExpiration, $strDaysLeft, $strEstimated;

	// preset return values
	$estimated_end = "-";
	$days_left="-";
	$description="";
	$absolute=0;
   
	// get client record
	$client_query="
		SELECT
			views,
			clicks,                                     
			DATE_FORMAT(expire, '".$date_format."') as expire,
			TO_DAYS(expire)-TO_DAYS(NOW()) as days_left
		FROM
			$phpAds_tbl_clients
		WHERE 
			clientID = ".$clientID;
	$res_client = db_query($client_query) or mysql_die() ;
	if ( mysql_num_rows($res_client)==1)
	{
		$row_client = mysql_fetch_array($res_client);

		$rawexpire=$row_client["expire"];
	
		// handle things when client works with credit days
		if ( $row_client["expire"] )
		{
			$days_left = sprintf("%d",$row_client["days_left"]);
			$estimated_end = $row_client["expire"];
			$absolute = 1;
  		}
		else // client has (had) credits in views/clicks
		{
            // Note: only one of these queries will run.  It will not get the
            // true total if some are in verbose stats format and some are in compact

            // get views
            $view_query="
				SELECT
					count(*) as total_views,
					MAX(TO_DAYS(v.t_stamp))-TO_DAYS(NOW()) as days_since_last_view,
					TO_DAYS(NOW())-MIN(TO_DAYS(v.t_stamp)) as days_since_start
				FROM
					$phpAds_tbl_adviews AS v, 
					$phpAds_tbl_banners AS b 
				WHERE
					b.clientID = $clientID 
					AND
					b.bannerID = v.bannerID";

                if ($phpAds_compact_stats) {
                    $view_query="
                        SELECT
                            SUM(views) as total_views,
                            MAX(TO_DAYS(day))-TO_DAYS(NOW()) as days_since_last_view,
                            TO_DAYS(NOW())-MIN(TO_DAYS(day)) as days_since_start
                        FROM
                            $phpAds_tbl_adstats AS v
                                LEFT JOIN $phpAds_tbl_banners AS b USING (bannerID)
                        WHERE
                            b.clientID = $clientID";
                }
			$res_views = db_query($view_query) or mysql_die() ;
			if ( mysql_num_rows($res_views)==1 )
			{
				$row_views = mysql_fetch_array($res_views);
				// calculate estimated end of views
				if ($row_views["days_since_start"] == 0 || $row_views["days_since_start"] == null )
				{
					// to avoid division by zero
					$row_views["days_since_start"]=1;
				}
				if ( $row_views["total_views"] > 0 )
				{
					$days_left = sprintf("%d",$row_client["views"]/($row_views["total_views"]/$row_views["days_since_start"]));
					// get clicks
					$click_query="
						SELECT
							count(*) as total_clicks,
							MAX(TO_DAYS(c.t_stamp))- TO_DAYS(NOW()) as days_since_last_click,
							TO_DAYS(NOW())-MIN(TO_DAYS(c.t_stamp)) as days_since_start
						FROM
							$phpAds_tbl_adclicks AS c, 
							$phpAds_tbl_banners AS b 
						WHERE 
							b.clientID = $clientID
							AND
							b.bannerID = c.bannerID";

                        if ($phpAds_compact_stats) 
                        {
                            $view_query="
                                SELECT
                                    SUM(clicks) as total_clicks,
                                    MAX(TO_DAYS(day))-TO_DAYS(NOW()) as days_since_last_click,
                                    TO_DAYS(NOW())-MIN(TO_DAYS(day)) as days_since_start
                                FROM
                                    $phpAds_tbl_adstats
                                        LEFT JOIN $phpAds_tbl_banners USING (bannerID)
                                WHERE
                                    clientID = $clientID AND
                                    clicks > 0";
                        }
					$res_clicks = db_query($click_query) or mysql_die() ;
					if ( mysql_num_rows($res_clicks)==1)
					{
						$row_clicks = mysql_fetch_array($res_clicks);
						// all credits finished already?
						if ( $row_client["views"]==0 && $row_client["clicks"]==0  )
						{
							$days_left = $row_views["days_since_last_view"]>$row_clicks["days_since_last_click"]?$row_views["days_since_last_view"]:$row_clicks["days_since_last_click"];
							$absolute = 1;
						}
						else
						{
							// calculate estimated end of clicks
							if ( $row_clicks["total_clicks"] > 0 && $row_clicks["days_since_start"] > 0 )
							{
								$click_days_left = $row_client["clicks"]/($row_clicks["total_clicks"]/$row_clicks["days_since_start"]);
								$days_left = sprintf("%d",max(strval($days_left),$click_days_left));
							}
						}
					}
					$estimated_end = strftime($date_format,mktime(0,0,0,date("m"),date("d")+$days_left,date("Y")));
				}
			}
		}
	}
   
	// build return value
	$ret_val = array();
	$days_left = $days_left>0?$days_left:0;
	if (my_substr_count($rawexpire,"0")==8)
	{
		$ret_val[] = $strExpiration.": No expiration date set";
	} else
	{
		if ( $absolute )
		{
			$ret_val[] = $strExpiration.": ".$estimated_end." (".$strDaysLeft.": ".$days_left.")";
		}
		else
		{
			$ret_val[] = $strEstimated.": ".$estimated_end." (".$strDaysLeft.": ".$days_left.")";
		}
		$ret_val[]=$estimated_end;
		$ret_val[]=$days_left;
	}
	return $ret_val;
}

// for php3 compatibility
function my_substr_count($string,$search) 
{ 
    $temp = str_replace($search,$search."a",$string); 
    return strlen($temp)-strlen($string); 
}