Incredible behaviour with strftime - php

Question

I have this code:
function calendarDay ($month, $year)
{
$num = cal_days_in_month(CAL_GREGORIAN, $month, $year);
$today = strtotime(date("Y-m-d"));
$result = array();
$str = "";
$strMonth = "";
for ($i = 0; $i < $num; $i++) {
$date = strtotime($year . "-" . $month . "-" . ($i + 1));
$day=strftime("%a", $date);
$month = strftime("%b", $date);
if ($today == $date) {
if ($day == "Sat" || $day == "Sun") {
$str .= "<th style='background-color:mediumseagreen'>" . $day. "</th>";
$strMonth = $strMonth . "<th style='background-color:mediumseagreen'>".($i + 1) . "-" . $month." ". "</th>";
}
else {
$str .= "<th style='background-color:#888888'>" . $day. "</th>";
$strMonth = $strMonth . "<th style='background-color:#888888'>".($i + 1) . "-" . $month." ". "</th>";
}
}
else if ($today != $date) {
if ($day == "Sat" || $day == "Sun") {
$str .= "<th style='background-color:mediumseagreen'>" . $day. "</th>";
$strMonth = $strMonth . "<th style='background-color:mediumseagreen'>".($i + 1) . "-" . $month." ". "</th>";
}
else {
$str .= "<th>" . $day. "</th>";
$strMonth = $strMonth . "<th>".($i + 1) . "-" . $month." ". "</th>";
}
}
$result = array_merge($result, array("Month" => $strMonth));
$result = array_merge($result, array("Day" => $str));
}
return $result;
}
When I delete the line which convert my numeric $month from parameters to string with strftime("%b", $date), It gives the good behaviour.
And when I add this line the var $day began to repeat 9 times the first day of the month... which is Tuesday, and can't get the solution, its a bug for me...

Answer 1

You're replacing the variable that you use in:
$date = strtotime($year . "-" . $month . "-" . ($i + 1));
So on the 2nd day of the month, instead of trying to parse 2019-1-2 you're parsing 2019-Jan-1. I'm not sure why, but when you use this format with a single-digit day, it always parses as if it's 2019-01-01.
The solution is to use a different variable.
function calendarDay ($month, $year)
{
$num = cal_days_in_month(CAL_GREGORIAN, $month, $year);
$today = strtotime(date("Y-m-d"));
$result = array();
$str = "";
$strMonth = "";
for ($i = 0; $i < $num; $i++) {
$date = strtotime($year . "-" . $month . "-" . ($i + 1));
$day=strftime("%a", $date);
$monthName = strftime("%b", $date);
if ($today == $date) {
if ($day == "Sat" || $day == "Sun") {
$str .= "<th style='background-color:mediumseagreen'>" . $day. "</th>";
$strMonth = $strMonth . "<th style='background-color:mediumseagreen'>".($i + 1) . "-" . $monthName." ". "</th>";
}
else {
$str .= "<th style='background-color:#888888'>" . $day. "</th>";
$strMonth = $strMonth . "<th style='background-color:#888888'>".($i + 1) . "-" . $monthName." ". "</th>";
}
}
else if ($today != $date) {
if ($day == "Sat" || $day == "Sun") {
$str .= "<th style='background-color:mediumseagreen'>" . $day. "</th>";
$strMonth = $strMonth . "<th style='background-color:mediumseagreen'>".($i + 1) . "-" . $monthName." ". "</th>";
}
else {
$str .= "<th>" . $day. "</th>";
$strMonth = $strMonth . "<th>".($i + 1) . "-" . $monthName." ". "</th>";
}
}
$result = array_merge($result, array("Month" => $strMonth));
$result = array_merge($result, array("Day" => $str));
}
return $result;
}

Answer 2

Replace the code
$date = strtotime($year . "-" . $month . "-" . ($i + 1));
into
$date = strtotime($year . "-" . $month . "-" .str_pad(($i + 1), 2, '0', STR_PAD_LEFT) );

Answer 3

Oh my go thanks you all !!! a lot, i was searching what i'm doing wrong since several days...
Just a var name conflict with my numeric $month and the string month with strftime. So i replaced the name of the string one.
Bad mistake ! ^^