date.php

<?php

date_default_timezone_set('Europe/London');

$dayInterval = new DateInterval('P1D');
$startDate = new DateTime('2013-07-01');
$duration = null;

if (isset($_GET['duration'])) {
    $duration = $_GET['duration'];
    $days = 1;

    $endDate = clone $startDate;

    if (!(preg_match('/^(\d+) (min(ute)?s?)$/i', $duration, $match) && preg_match('/^(\d+) (hours?)$/i', $duration, $match))) {
        if ($duration == 'half day') {
            $days = 1;
        } elseif (preg_match('/^(\d+) (weeks?)$/i', $duration, $match)) {
            $days = intval(5 * $match[1]);
        } elseif (preg_match('/^(\d+) (days?)$/i', $duration, $match)) {
            $days = $match[1];
        } elseif (preg_match('/^(\d+) (months?)$/i', $duration, $match)) {
            $days = intval(25 * $match[1]);
        }

        if ($days > 1) {
            $endDate->modify(sprintf('%d weekdays', $days - 1));
        }
    }
} else {
    $endDate = new DateTime($_GET['endDate']);
    
    if ($endDate->format('N') == 6) {
        $endDate->modify('1 weekdays');
    } elseif ($endDate->format('N') == 7) {
        $endDate->modify('2 weekdays');
    }
}

$days = 0;
foreach(new DatePeriod($startDate, $dayInterval, $endDate->add($dayInterval)) as $day) {
    /* 'N' number days 1 (mon) to 7 (sun) */
    if ($day->format('N') < 6) {
        $days++;
        echo sprintf('Day %d: %s (%d)', $days, $day->format('l jS'), $day->format('N')).'<br>';
    }
}

if ($days == 1) {
    $duration = '1 day';
} elseif ($days < 5) {
    $duration = sprintf('%d days', $days);
} elseif ($days < 25) {
    $weeks = intval($days / 5);
    $mod = $days % 5;

    if ($mod > 0) {
        $duration = sprintf('%d weeks, %d days', $weeks, $mod);
    } else {
        $duration = sprintf('%d weeks', $weeks);
    }
} else {
    $months = intval($days / 25);
    $weeksMod = $days % 25;
    $weeks = intval($weeksMod / 5);
    $daysMod = $weeksMod % 5;
    $daysValue = intval($daysMod);

    if ($daysMod > 0) {
        $duration = sprintf('%d months, %d weeks, %d days', $months, $weeks, $daysValue);
    } elseif ($weeksMod > 0) {
        $duration = sprintf('%d months, %d weeks', $months, $weeks);
    } else {
        $duration = sprintf('%d months', $months);
    }
}

$endDate->sub($dayInterval);

printf("Start date: %s<br>", $startDate->format('jS F'));
printf("End date: %s<br>", $endDate->format('jS F'));
printf("Days: %d<br>", $days);
printf("Duration: %s<br>", $duration);

Not working properly for 24 days.... but is for 23 and 25....... WTF

Looks like it's sorted....