calendar.php

<?php

function get_next_day_of_Y_m_d($input) {
    return \DateTime::createFromFormat('Y-m-d', $input)->add(new \DateInterval('P1D'))->format('Y-m-d');
}

$start = <<<EOF
BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//Decitre//decitre.Calendar.Export 1.0//EN

EOF;

$format = <<<EOF
BEGIN:VEVENT
DTSTART;VALUE=DATE:{date}
DTEND;VALUE=DATE:{date_end}
TRANSP:TRANSPARENT
SUMMARY: {label}
DESCRIPTION:
UID:astreinte-{date}
END:VEVENT

EOF;

$end = <<<EOF
END:VCALENDAR
EOF;

header('Content-Type: text/Calendar; charset=UTF-8');
header('Content-Disposition: inline; filename=iCal.vcs');
header('Cache-Control: no-cache');
header('Pragma: no-cache');

$gdocUrl = 'https://docs.google.com/spreadsheets/d/IDDOCUMENT/export?format=csv';
$events = [];
$fp = fopen($gdocUrl, 'rb');
if (!$fp) {
    http_response_code(503);
    die("Unable to load Google Spreadsheet document");
}
$cpt = 0;
$displayedItems = 60;
$currentDate = date('Y-m-d');
$events = [];
$filter = isset($_GET['filter']) ? $_GET['filter'] : null;
$oneEventPerDay = ($_GET['oneEventPerDay'] ?? 1) == 1;
$previousRow = null;
$currentEvent = [];
while (false !== ($row = fgetcsv($fp))) {
    if (count($row) < 2 || !preg_match('/^\d{4}-\d{2}-\d{2}$/', $row[0])) {
        continue; // invalid line
    }
    list ($date, $onDuty) = $row;
    $eventDate = str_replace('-', '', $date);
    $eventLabel = $onDuty;
    if (0 === strlen(trim($eventLabel))) {
        continue;
    }
    if ($date < $currentDate) {
        continue;
    }
    if (null !== $filter && $eventLabel != $filter) {
        continue;
    }
    if (null !== $filter) {
        $eventLabel = 'Astreinte';
    }

    if ($oneEventPerDay) {
        $events[] = [
            'start' => $eventDate,
            'label' => $eventLabel,
            'end' => str_replace('-', '', get_next_day_of_Y_m_d($date)) // +1 jour à la date de fin pour que ca apparaisse correctement
        ];
    } else {
        if ($previousRow === null) {
            $currentEvent['start'] = $eventDate;
            $currentEvent['label'] = $eventLabel;
        } elseif ($onDuty !== $previousRow[1] || get_next_day_of_Y_m_d($previousRow[0]) !== $date) {
            // Si le nom de la personne est différent de la ligne précédente
            // OU que le lendemain de la date précédente n'est pas ce jour ci
            // => on finalise l'event qu'on construisait
            $currentEvent['end'] = str_replace('-', '', get_next_day_of_Y_m_d($previousRow[0])); // +1 jour à la date de fin pour que ca apparaisse correctement
            $events[] = $currentEvent;

            $currentEvent['start'] = $eventDate;
            $currentEvent['label'] = $eventLabel;
        }

        $previousRow = $row;
    }

    $cpt++;
    if ($cpt === $displayedItems) {
        break;
    }
}

// On fini de construire le dernier event
if (isset($currentEvent['start']) && $previousRow !== null) {
    $currentEvent['end'] = str_replace('-', '', get_next_day_of_Y_m_d($previousRow[0])); // +1 jour à la date de fin pour que ca apparaisse correctement
    $events[] = $currentEvent;
}

$content = $start;
foreach ($events as $event) {
   $content .= strtr($format, ['{date}' => $event['start'], '{date_end}' => $event['end'], '{label}' => $event['label']]);
}
$content .= $end;

echo str_replace("\n", "\r\n", $content);