Generate calendar in php

index.php

<?php
// My target is to create script to generate something like this:
//
// ------------------------
// | January              |
// | s  m  t  w  t  f  s  |
// |          1  2  3  4  |
// | 5  6  7  8  9  10 11 |
// | 12 13 14 15 16 17 18 |
// | 19 20 21 22 23 24 25 |
// | 26 27 28 29 30 31    |
// ------------------------
//
//


// $startingDay - number 0 to 7
// $days - how many days to render
// $month - Name of month
function createCalendar($startingDay, $days, $month) {
    $spaces = '                        ';
    $out = [];
    $out[] = '------------------------'; // length is 24
    $out[] = '| '.substr($month.$spaces,0,20).' |';
    $out[] = '| s  m  t  w  t  f  s  |';
    $calday = 0;
    $day = $startingDay*-1+1;
    while ($day <= $days) {
        if ($day <= 0) {
            $dtp = '   ';
        } else {
            $dtp = substr("$day   ",0,3);
        }
        if ($calday % 7 == 0) {
            $out[] .= "| $dtp";
        } else if ($calday % 7 == 6) {
            $out[count($out)-1] .= "$dtp|";
        } else {
            $out[count($out)-1] .= $dtp;
        }
        $day++;
        $calday++;
    }
    //$out[] = '------------------------';
    while (strlen($out[count($out)-1]) < 23) {
        echo "";
        $out[count($out)-1] .= ' ';
    }
    $out[count($out)-1] .= '|';
    $out[] = '------------------------';
    return implode($out,PHP_EOL);
}
echo createCalendar($argv[1], $argv[2], $argv[3]);

cyjan@ubudubu ~/P/phpCalendar> php index.php 1 31 January
------------------------
| January              |
| s  m  t  w  t  f  s  |
|    1  2  3  4  5  6  |
| 7  8  9  10 11 12 13 |
| 14 15 16 17 18 19 20 |
| 21 22 23 24 25 26 27 |
| 28 29 30 31          |
------------------------⏎```