Subversion Repositories Integrator Subversion

<?php

//--------------------------------------------------------------------------------------------------
// Utilities for our event-fetching scripts.
//
// Requires PHP 5.2.0 or higher.
//--------------------------------------------------------------------------------------------------

// PHP will fatal error if we attempt to use the DateTime class without this being set.
date_default_timezone_set('UTC');


class Event {

        // Tests whether the given ISO8601 string has a time-of-day or not
        const ALL_DAY_REGEX = '/^\d{4}-\d\d-\d\d$/'; // matches strings like "2013-12-29"

        public $title;
        public $allDay; // a boolean
        public $start; // a DateTime
        public $end; // a DateTime, or null
        public $properties = array(); // an array of other misc properties


        // Constructs an Event object from the given array of key=>values.
        // You can optionally force the timezone of the parsed dates.
        public function __construct($array, $timezone=null) {

                $this->title = $array['title'];

                if (isset($array['allDay'])) {
                        // allDay has been explicitly specified
                        $this->allDay = (bool)$array['allDay'];
                }
                else {
                        // Guess allDay based off of ISO8601 date strings
                        $this->allDay = preg_match(self::ALL_DAY_REGEX, $array['start']) &&
                                (!isset($array['end']) || preg_match(self::ALL_DAY_REGEX, $array['end']));
                }

                if ($this->allDay) {
                        // If dates are allDay, we want to parse them in UTC to avoid DST issues.
                        $timezone = null;
                }

                // Parse dates
                $this->start = parseDateTime($array['start'], $timezone);
                $this->end = isset($array['end']) ? parseDateTime($array['end'], $timezone) : null;

                // Record misc properties
                foreach ($array as $name => $value) {
                        if (!in_array($name, array('title', 'allDay', 'start', 'end'))) {
                                $this->properties[$name] = $value;
                        }
                }
        }


        // Returns whether the date range of our event intersects with the given all-day range.
        // $rangeStart and $rangeEnd are assumed to be dates in UTC with 00:00:00 time.
        public function isWithinDayRange($rangeStart, $rangeEnd) {

                // Normalize our event's dates for comparison with the all-day range.
                $eventStart = stripTime($this->start);
                $eventEnd = isset($this->end) ? stripTime($this->end) : null;

                if (!$eventEnd) {
                        // No end time? Only check if the start is within range.
                        return $eventStart < $rangeEnd && $eventStart >= $rangeStart;
                }
                else {
                        // Check if the two ranges intersect.
                        return $eventStart < $rangeEnd && $eventEnd > $rangeStart;
                }
        }


        // Converts this Event object back to a plain data array, to be used for generating JSON
        public function toArray() {

                // Start with the misc properties (don't worry, PHP won't affect the original array)
                $array = $this->properties;

                $array['title'] = $this->title;

                // Figure out the date format. This essentially encodes allDay into the date string.
                if ($this->allDay) {
                        $format = 'Y-m-d'; // output like "2013-12-29"
                }
                else {
                        $format = 'c'; // full ISO8601 output, like "2013-12-29T09:00:00+08:00"
                }

                // Serialize dates into strings
                $array['start'] = $this->start->format($format);
                if (isset($this->end)) {
                        $array['end'] = $this->end->format($format);
                }

                return $array;
        }

}


// Date Utilities
//----------------------------------------------------------------------------------------------


// Parses a string into a DateTime object, optionally forced into the given timezone.
function parseDateTime($string, $timezone=null) {
        $date = new DateTime(
                $string,
                $timezone ? $timezone : new DateTimeZone('UTC')
                        // Used only when the string is ambiguous.
                        // Ignored if string has a timezone offset in it.
        );
        if ($timezone) {
                // If our timezone was ignored above, force it.
                $date->setTimezone($timezone);
        }
        return $date;
}


// Takes the year/month/date values of the given DateTime and converts them to a new DateTime,
// but in UTC.
function stripTime($datetime) {
        return new DateTime($datetime->format('Y-m-d'));
}