Add local holidays to date/time calculation in PHP - php

Question

I want to show an estimated delivery time in my shop.
If a customer orders before 4pm, he gets his order the next day.
But if the order is on a friday or on the weekend, he gets the order on the next monday.
That all works fine. But I need to add some holidays like christmas, new year and local holidays based on a state in my country.
I found a solution to identify the fixed and flexible (like easter) holidays in my state.
But I don't know how to work with them in the current function.
If an order is placed before one of these holidays I need to move the future date some days ahead.
Here's the current code (based on this code):
date_default_timezone_set( 'Europe/Berlin' );
$current_year = date('Y');
$next_year = date('Y', strtotime( $current_year." + 1 year" ));
// Holidays
$neujahr = date('d.m.Y',strtotime(date($next_year.'-01-01')));
$ostern = date('d.m.Y', easter_date($current_year));
$karfreitag = date( "l jS F", strtotime( $ostern." - 2 days" ) );
$ostermontag = date( "l jS F", strtotime( $ostern." + 1 days" ) );
$tagderarbeit = date('d.m.Y',strtotime(date('Y-05-01')));
$himmelfahrt = date( "l jS F", strtotime( $ostern." + 39 days" ) );
$pfingstmontag = date( "l jS F", strtotime( $ostern." + 50 days" ) );
$fronleichnam = date( "l jS F", strtotime( $ostern." + 60 days" ) );
$einheit = date('d.m.Y',strtotime(date('Y-10-03')));
$allerheiligen = date('d.m.Y',strtotime(date('Y-11-01')));
$weihnachten1 = date('d.m.Y',strtotime(date('Y-12-25')));
$weihnachten2 = date('d.m.Y',strtotime(date('Y-12-26')));
// if FRI/SAT/SUN delivery will be MON
if ( date( 'N' ) >= 5 ) {
$del_day = date( "l jS F", strtotime( "next monday" ) );
$order_by = "Monday";
}
// if MON/THU after 4PM delivery will be TOMORROW
elseif ( date( 'H' ) >= 16 ) {
$del_day = date( "l jS F", strtotime( "tomorrow" ) );
$order_by = "tomorrow";
}
// if MON/THU before 4PM delivery will be TODAY
else {
$del_day = date( "l jS F", strtotime( "today" ) );
$order_by = "today";
}
$html = "<br><div class='woocommerce-message' style='clear:both'>Order by 4PM {$order_by} for delivery on {$del_day}</div>";
echo $html;

Answer 1

The working method you are currently applying can work with multiple different if / else statements to check all conditions, so I prefer a different approach.
It goes as follows
As of today date 8 possible delivery dates are generated (expl: today = 14/07/2020,
possible dates are 14, 15, 16, 17, 18, 19, 20 & 21/07/2020
If today is already after 4 pm, the date of today expires (14/07/2020)
Less than 4 pm but a Friday, Saturday or Sunday, remove date
Then remove the (other) dates from the weekend: friday, saturday & sunday (17, 18, 19/07/2020)
Then all holidays (if any) are filtered out of the result
In the last step, the first value in the result is used and shown in the output message.
Note: It is easy to test by adjusting $today = date( 'd.m.Y' ); values ​​to any date in the future, like $today = date( '25.12.2024' ); which would return
Delivery on Monday 30th December
25, 26 = holidays. 27, 28 & 29/12/2024 = friday, saturday & sunday
date_default_timezone_set( 'Europe/Berlin' );
// Today
$today = date( 'd.m.Y' );
// Possible delivery dates from today
for ( $i = 0; $i <= 7; $i++) {
$possible_delivery_dates[] = date( 'd.m.Y', strtotime( $today . '+' . $i . 'days' ) );
}
// Today ?
if ( date( 'H', strtotime( $today ) ) >= 16 ) {
// Today NOT possible
unset( $possible_delivery_dates[0] );
} elseif ( date( 'N', strtotime( $today ) ) >= 5 ) {
// Today (weekend) NOT possible
unset( $possible_delivery_dates[0] );
}
// Next Fri, Sat & Sun
$next_friday = date( 'd.m.Y', strtotime( $today . 'next friday' ) );
$next_saturday = date( 'd.m.Y', strtotime( $today . 'next saturday' ) );
$next_sunday = date( 'd.m.Y', strtotime( $today . 'next sunday' ) );
// Remove next fri, sat & sun
$possible_delivery_dates = array_diff( $possible_delivery_dates, [ $next_friday, $next_saturday, $next_sunday ] );
// Current & next year
$current_year = date( 'Y', strtotime( $today ) );
$next_year = date( 'Y', strtotime( $today . '+ 1 year' ));
// Holidays
$neujahr = date( 'd.m.Y', strtotime( date( $next_year . '-01-01' ) ) );
$ostern = date( 'd.m.Y', easter_date( $current_year ) );
$karfreitag = date( 'd.m.Y', strtotime( $ostern . '- 2 days' ) );
$ostermontag = date( 'd.m.Y', strtotime( $ostern . '+ 1 days' ) );
$tagderarbeit = date( 'd.m.Y', strtotime( date( $current_year . '-05-01') ) );
$himmelfahrt = date( 'd.m.Y', strtotime( $ostern . '+ 39 days' ) );
$pfingstmontag = date( 'd.m.Y', strtotime( $ostern . '+ 50 days' ) );
$fronleichnam = date( 'd.m.Y', strtotime( $ostern . '+ 60 days' ) );
$einheit = date( 'd.m.Y', strtotime( date( $current_year . '-10-03' ) ) );
$allerheiligen = date( 'd.m.Y', strtotime( date( $current_year . '-11-01' ) ) );
$weihnachten1 = date( 'd.m.Y', strtotime( date( $current_year . '-12-25' ) ) );
$weihnachten2 = date( 'd.m.Y', strtotime( date( $current_year . '-12-26' ) ) );
// Holidays (array)
$holidays = array( $neujahr, $ostern, $karfreitag, $ostermontag, $tagderarbeit, $himmelfahrt, $pfingstmontag, $fronleichnam, $einheit, $allerheiligen, $weihnachten1, $weihnachten2 );
// Remove holidays
$possible_delivery_dates = array_diff( $possible_delivery_dates, $holidays );
// First value
$first_val = reset( $possible_delivery_dates );
$html = 'Delivery on ' . date( 'l jS F', strtotime( $first_val ) );
echo $html;