PHP Calendar - start week numbers counting from the week that has the first Monday in April

[mds1256]

I currently have the below code that I have hacked together using various sources on the internet.

 

I am trying to get it where the week numbers start counting from the week that has the first Monday in each April.

 

So when you move to the next year it will restart counting again from the week that contains the first Monday in April.

 

I have been on for hours trying to get the logic right but not making much progress - any tips on what the logic should be?

<?php
	
$monthNames = Array("January", "February", "March", "April", "May", "June", "July", 
"August", "September", "October", "November", "December");

if (!isset($_REQUEST["month"]))
{
	$_REQUEST["month"] = date("n");
}
if (!isset($_REQUEST["year"]))
{
	$_REQUEST["year"] = date("Y");
}

$cMonth = $_REQUEST["month"];
$cYear = $_REQUEST["year"];
 
$prev_year = $cYear;
$next_year = $cYear;
$prev_month = $cMonth-1;
$next_month = $cMonth+1;
 
if ($prev_month == 0 ) {
    $prev_month = 12;
    $prev_year = $cYear - 1;
}
if ($next_month == 13 ) {
    $next_month = 1;
    $next_year = $cYear + 1;
}

?>

<table width="250">
<tr align="center">
<td bgcolor="#999999" style="color:#FFFFFF">
<table width="100%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td width="50%" align="left">  <a href="<?php echo $_SERVER["PHP_SELF"] . "?month=". $prev_month . "&year=" . $prev_year; ?>" style="color:#FFFFFF">Previous</a></td>
<td width="50%" align="right"><a href="<?php echo $_SERVER["PHP_SELF"] . "?month=". $next_month . "&year=" . $next_year; ?>" style="color:#FFFFFF">Next</a>  </td>
</tr>
</table>
</td>
</tr>
<tr>
<td align="center">
<table width="100%" border="0" cellpadding="2" cellspacing="2">
<tr align="center">
<td colspan="8" bgcolor="#999999" style="color:#FFFFFF"><strong><?php echo $monthNames[$cMonth-1].' '.$cYear; ?></strong></td>
</tr>
<tr>
<td align="center" bgcolor="#999999" style="color:#FFFFFF"><strong>M</strong></td>
<td align="center" bgcolor="#999999" style="color:#FFFFFF"><strong>T</strong></td>
<td align="center" bgcolor="#999999" style="color:#FFFFFF"><strong>W</strong></td>
<td align="center" bgcolor="#999999" style="color:#FFFFFF"><strong>T</strong></td>
<td align="center" bgcolor="#999999" style="color:#FFFFFF"><strong>F</strong></td>
<td align="center" bgcolor="#999999" style="color:#FFFFFF"><strong>S</strong></td>
<td align="center" bgcolor="#999999" style="color:#FFFFFF"><strong>S</strong></td>
<td align="center" bgcolor="#999999" style="color:#FFFFFF"><strong>Week No</strong></td>
</tr>


<?php 
$timestamp = mktime(0,0,0,$cMonth,1,$cYear);
$maxday = date("t",$timestamp);
$thismonth = getdate ($timestamp);
$startday = $thismonth['wday']-1;
$firstDateMonth = 0;

function roundToNearestW($int, $i) {
        return ceil($int / $i) * $i;
    }
    
if ($startday == -1)
{
	$startday = 6;
}
$complete_cells = roundToNearestW($maxday+$startday,7);
for ($i=0; $i<($complete_cells); $i++)
{
    if(($i % 7) == 0 )
    {
	    echo "<tr>
	    ";
	}
	
    if($i < $startday || $i >= $maxday+$startday)
    {
	    echo "<td></td>
	    ";
	}
    else
    {
	    if(($i - $startday + 1) > $firstDateMonth)
	    {
		    $firstDateMonth = ($i - $startday + 1);
	    }
	    echo "<td align='center' valign='middle' height='20px'>". ($i - $startday + 1) . "</td>
	    ";
	}
	
    if(($i % 7) == 6 )
    {
	    $weekDate = $cYear."-".$cMonth."-".$firstDateMonth;
		$Caldate = new DateTime($weekDate);
		$week = $Caldate->format("W");
	    echo "<td align='center' valign='middle' height='20px'>WK ".$week."</td>
	    ";
	}
    if(($i % 7) == 6 )
    {
	    echo "</tr>";
	}
    
}
?>



</table>
</td>
</tr>
</table>

[ginerjm]

To find the date of the first Monday in April, I did this:

 

//  check this year
$curr_yr = 2020;
//  start by looking for 4/1
$dd = 1;
$date_found = '';
while($date_found == '')
{
$testdt = mktime(0, 0, 0, 4, $dd, $curr_yr);
if (date('N',$testdt) == 1)  // is it a Monday?
{
  $date_found = date('m/d/y', $testdt);
  break;
}
else
  $dd++;  // bump up the calendar date to look for
}
echo "Date found is $date_found<br>";

 

I didn't try to understand what the rest of your code did.  I figure that once you know the date of the first monday in April, you can move on with that knowledge.

 

PS - Try to learn to write your scripts to do ALL YOUR PHP coding before you start outputting the HTML.

[requinix]

Maybe I'm too tired, but if the question is finding the first Monday of April then

$ts = strtotime("March 31 {$year} next Monday");

[Barand]

try

function weeknum (DateTime $dt_input) 
{
    $year = $dt_input->format('Y');
    $basedate = new datetime("first monday of april $year");

    if ($dt_input < $basedate) {
        $year--;
        $basedate = new datetime("first monday of april $year");
    }

    return 1 + floor($basedate->diff($dt_input)->days / 7);
}
[/code

To test
[code]$sdate = new DateTime('2017-02-01');
$di = new DateInterval('P7D');
$dp = new DatePeriod($sdate,$di,60);

foreach ($dp as $d) {
	printf("%s WEEK : %d<br>", $d->format('D d M Y'), weeknum($d) );
}

[ginerjm]

I like your approach.  Started with that thought but didn't follow-thru once I thought of my little looping process.