<?php
/**
 * @file include/datetime.php
 * @brief Some functions for date and time related tasks.
 */


/**
 * @brief Two-level sort for timezones.
 *
 * Can be used in usort() to sort timezones.
 *
 * @param string $a
 * @param string $b
 * @return number
 */
function timezone_cmp($a, $b) {
	if(strstr($a,'/') && strstr($b,'/')) {
		if ( t($a) == t($b)) return 0;
		return ( t($a) < t($b)) ? -1 : 1;
	}
	if (strstr($a,'/')) return -1;
	if (strstr($b,'/')) return  1;
	if ( t($a) == t($b)) return 0;

	return ( t($a) < t($b)) ? -1 : 1;
}

function is_null_date($s) {
	if($s === '0000-00-00 00:00:00' || $s === '0001-01-01 00:00:00')
		return true;

	return false;
}

/**
 * @brief Return timezones grouped (primarily) by continent.
 *
 * @see timezone_cmp()
 * @return array
 */
function get_timezones( ){
	$timezone_identifiers = DateTimeZone::listIdentifiers();

	usort($timezone_identifiers, 'timezone_cmp');
	$continent = '';
	$continents = array();
	foreach ($timezone_identifiers as $value) {
		$ex = explode("/", $value);
		if (count($ex) > 1) {
			$continent = t($ex[0]);
			if (count($ex) > 2)
				$city = substr($value, strpos($value, '/')+1);
			else
				$city = $ex[1];
		} else {
			$city = $ex[0];
			$continent = t('Miscellaneous');
		}
		$city = str_replace('_', ' ', t($city));

		if (!x($continents, $ex[0])) $continents[$ex[0]] = array();
		$continents[$continent][$value] = $city;
	}

	return $continents;
}

/**
 * @brief General purpose date parse/convert function.
 *
 * @param string $from source timezone
 * @param string $to dest timezone
 * @param string $s some parseable date/time string
 * @param string $fmt output format recognised from php's DateTime class
 *   http://www.php.net/manual/en/datetime.format.php
 * @return string
 */
function datetime_convert($from = 'UTC', $to = 'UTC', $s = 'now', $fmt = "Y-m-d H:i:s") {

	// Defaults to UTC if nothing is set, but throws an exception if set to empty string.
	// Provide some sane defaults regardless.

	if($from === '')
		$from = 'UTC';
	if($to === '')
		$to = 'UTC';
	if( ($s === '') || (! is_string($s)) )
		$s = 'now';

	if(is_null_date($s)) {
		$d = new DateTime('0001-01-01 00:00:00', new DateTimeZone('UTC'));
		return $d->format($fmt);
	}

	try {
		$from_obj = new DateTimeZone($from);
	} catch(Exception $e) {
		$from_obj = new DateTimeZone('UTC');
	}

	try {
		$d = new DateTime($s, $from_obj);
	} catch(Exception $e) {
		logger('exception: ' . $e->getMessage());
		$d = new DateTime('now', $from_obj);
	}

	try {
		$to_obj = new DateTimeZone($to);
	} catch(Exception $e) {
		$to_obj = new DateTimeZone('UTC');
	}

	$d->setTimeZone($to_obj);

	return($d->format($fmt));
}

/**
 * @brief Wrapper for date selector, tailored for use in birthday fields.
 *
 * @param string $dob Date of Birth
 * @return string Parsed HTML with selector
 */
function dob($dob) {

	$y = substr($dob,0,4);
	if((! ctype_digit($y)) || ($y < 1900))
		$ignore_year = true;
	else
		$ignore_year = false;

	if ($dob === '0000-00-00' || $dob === '')
		$value = '';
	else
		$value = (($ignore_year) ? datetime_convert('UTC','UTC',$dob,'m-d') : datetime_convert('UTC','UTC',$dob,'Y-m-d'));

	$o = replace_macros(get_markup_template("field_input.tpl"), [
		'$field' => [ 'dob', t('Birthday'), $value, ((intval($value)) ? t('Age: ') . age($value,App::$user['timezone'],App::$user['timezone']) : ''), '', 'placeholder="' . t('YYYY-MM-DD or MM-DD') .'"' ]
	]);


	return $o;
}

/**
 * @brief Returns a datetime selector.
 *
 * @param string $format
 *   format string, e.g. 'ymd' or 'mdy'. Not currently supported
 * @param DateTime $min
 *   unix timestamp of minimum date
 * @param DateTime $max
 *   unix timestap of maximum date
 * @param DateTime $default
 *   unix timestamp of default date
 * @param string $label
 * @param string $id
 *   id and name of datetimepicker (defaults to "datetimepicker")
 * @param boolean $pickdate
 *   true to show date picker (default)
 * @param boolean $picktime
 *   true to show time picker (default)
 * @param DateTime $minfrom
 *   set minimum date from picker with id $minfrom (none by default)
 * @param DateTime $maxfrom
 *   set maximum date from picker with id $maxfrom (none by default)
 * @param boolean $required default false
 * @param int $first_day (optional) default 0
 * @return string Parsed HTML output.
 *
 * @todo Once browser support is better this could probably be replaced with
 * native HTML5 date picker.
 */
function datetimesel($format, $min, $max, $default, $label, $id = 'datetimepicker', $pickdate = true, $picktime = true, $minfrom = '', $maxfrom = '', $required = false, $first_day = 0) {

	$o = '';
	$dateformat = '';

	if($pickdate) $dateformat .= 'Y-m-d';
	if($pickdate && $picktime) $dateformat .= ' ';
	if($picktime) $dateformat .= 'H:i';

	$minjs = $min->getTimestamp() ? ",minDate: new Date({$min->getTimestamp()}*1000), yearStart: " . $min->format('Y') : '';
	$maxjs = $max->getTimestamp() ? ",maxDate: new Date({$max->getTimestamp()}*1000), yearEnd: " . $max->format('Y') : '';

	$input_text = $default->getTimestamp() ? date($dateformat, $default->getTimestamp()) : '';
	$defaultdatejs = $default->getTimestamp() ? ",defaultDate: new Date({$default->getTimestamp()}*1000)" : '';

	$pickers = '';
	if(!$pickdate) $pickers .= ',datepicker: false';
	if(!$picktime) $pickers .= ',timepicker: false, closeOnDateSelect:true';

	$extra_js = '';
	if($minfrom != '')
		$extra_js .= "\$('#id_$minfrom').data('xdsoft_datetimepicker').setOptions({onChangeDateTime: function (currentDateTime) { \$('#id_$id').data('xdsoft_datetimepicker').setOptions({minDate: currentDateTime})}})";

	if($maxfrom != '')
		$extra_js .= "\$('#id_$maxfrom').data('xdsoft_datetimepicker').setOptions({onChangeDateTime: function (currentDateTime) { \$('#id_$id').data('xdsoft_datetimepicker').setOptions({maxDate: currentDateTime})}})";

	$readable_format = $dateformat;
	$readable_format = str_replace('Y','yyyy',$readable_format);
	$readable_format = str_replace('m','mm',$readable_format);
	$readable_format = str_replace('d','dd',$readable_format);
	$readable_format = str_replace('H','HH',$readable_format);
	$readable_format = str_replace('i','MM',$readable_format);

	$tpl = get_markup_template('field_input.tpl');
	$o .= replace_macros($tpl,array(
			'$field' => array($id, $label, $input_text, (($required) ? t('Required') : ''), (($required) ? '*' : ''), 'placeholder="' . $readable_format . '"'),
		));
	$o .= "<script>\$(function () {var picker = \$('#id_$id').datetimepicker({step:15,format:'$dateformat' $minjs $maxjs $pickers $defaultdatejs,dayOfWeekStart:$first_day}); $extra_js})</script>";

	return $o;
}

/**
 * @brief Returns a relative date string.
 *
 * Implements "3 seconds ago" etc.
 * Based on $posted_date, (UTC).
 * Results relative to current timezone.
 * Limited to range of timestamps.
 *
 * @param string $posted_date
 * @param string $format (optional) parsed with sprintf()
 *    <tt>%1$d %2$s ago</tt>, e.g. 22 hours ago, 1 minute ago
 * @return string with relative date
 */
function relative_date($posted_date, $format = null) {

	$localtime = datetime_convert('UTC', date_default_timezone_get(), $posted_date);

	$abs = strtotime($localtime);

	if (is_null($posted_date) || is_null_date($posted_date) || $abs === false) {
		return t('never');
	}

	$etime = time() - $abs;

	if ($etime < 1) {
		return t('less than a second ago');
	}

	$a = array( 12 * 30 * 24 * 60 * 60  =>  'y',
				30 * 24 * 60 * 60       =>  'm',
				7  * 24 * 60 * 60       =>  'w',
				24 * 60 * 60            =>  'd',
				60 * 60                 =>  'h',
				60                      =>  'i',
				1                       =>  's'
	);


	foreach ($a as $secs => $str) {
		$d = $etime / $secs;
		if ($d >= 1) {
			$r = round($d);
			if (! $format)
				$format = t('%1$d %2$s ago', 'e.g. 22 hours ago, 1 minute ago');

			return sprintf($format, $r, plural_dates($str,$r));
		}
	}
}

function plural_dates($k,$n) {

	switch($k) {
		case 'y':
			return tt('year','years',$n,'relative_date');
			break;
		case 'm':
			return tt('month','months',$n,'relative_date');
			break;
		case 'w':
			return tt('week','weeks',$n,'relative_date');
			break;
		case 'd':
			return tt('day','days',$n,'relative_date');
			break;
		case 'h':
			return tt('hour','hours',$n,'relative_date');
			break;
		case 'i':
			return tt('minute','minutes',$n,'relative_date');
			break;
		case 's':
			return tt('second','seconds',$n,'relative_date');
			break;
		default:
			return;
	}
}

/**
 * @brief Returns timezone correct age in years.
 *
 * Returns the age in years, given a date of birth, the timezone of the person
 * whose date of birth is provided, and the timezone of the person viewing the
 * result.
 *
 * Why? Bear with me. Let's say I live in Mittagong, Australia, and my birthday
 * is on New Year's. You live in San Bruno, California.
 * When exactly are you going to see my age increase?
 *
 * A: 5:00 AM Dec 31 San Bruno time. That's precisely when I start celebrating
 * and become a year older. If you wish me happy birthday on January 1
 * (San Bruno time), you'll be a day late.
 *
 * @param string $dob Date of Birth
 * @param string $owner_tz (optional) timezone of the person of interest
 * @param string $viewer_tz (optional) timezone of the person viewing
 * @return number
 */
function age($dob, $owner_tz = '', $viewer_tz = '') {
	if (! intval($dob))
		return 0;
	if (! $owner_tz)
		$owner_tz = date_default_timezone_get();
	if (! $viewer_tz)
		$viewer_tz = date_default_timezone_get();

	$birthdate = datetime_convert('UTC', $owner_tz, $dob . ' 00:00:00+00:00','Y-m-d');
	list($year,$month,$day) = explode("-", $birthdate);
	$year_diff  = datetime_convert('UTC', $viewer_tz, 'now', 'Y') - $year;
	$curr_month = datetime_convert('UTC', $viewer_tz, 'now', 'm');
	$curr_day   = datetime_convert('UTC', $viewer_tz, 'now', 'd');

	if (($curr_month < $month) || (($curr_month == $month) && ($curr_day < $day)))
		$year_diff--;

	return $year_diff;
}

/**
 * @brief Get days of a month in a given year.
 *
 * Returns number of days in the month of the given year.
 * $m = 1 is 'January' to match human usage.
 *
 * @param int $y year
 * @param int $m month (1=January, 12=December)
 * @return int number of days in the given month
 */
function get_dim($y, $m) {
	$dim = array( 0,
			31, 28, 31, 30, 31, 30,
			31, 31, 30, 31, 30, 31
	);

	if ($m != 2)
		return $dim[$m];

	if (((($y % 4) == 0) && (($y % 100) != 0)) || (($y % 400) == 0))
		return 29;

	return $dim[2];
}

/**
 * @brief Returns the first day in month for a given month, year.
 *
 * Months start at 1.
 *
 * @param int $y Year
 * @param int $m Month (1=January, 12=December)
 * @return string day 0 = Sunday through 6 = Saturday
 */
function get_first_dim($y, $m) {
	$d = sprintf('%04d-%02d-01 00:00', intval($y), intval($m));

	return datetime_convert('UTC', 'UTC', $d, 'w');
}

/**
 * @brief Output a calendar for the given month, year.
 *
 * If $links are provided (array), e.g. $links[12] => 'http://mylink' ,
 * date 12 will be linked appropriately. Today's date is also noted by
 * altering td class.
 * Months count from 1.
 *
 * @param number $y Year
 * @param number $m Month
 * @param string $links (default false)
 * @param string $class
 * @return string
 *
 * @todo provide (prev,next) links, define class variations for different size calendars
 */
function cal($y = 0, $m = 0, $links = false, $class='') {

	// month table - start at 1 to match human usage.

	$mtab = [ ' ', 'January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December' ];

	$thisyear = datetime_convert('UTC',date_default_timezone_get(),'now','Y');
	$thismonth = datetime_convert('UTC',date_default_timezone_get(),'now','m');
	if (! $y)
		$y = $thisyear;
	if (! $m)
		$m = intval($thismonth);

	$dn = [ 'Sunday', 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday' ];
	$f = get_first_dim($y, $m);
	$l = get_dim($y, $m);
	$d = 1;
	$dow = 0;
	$started = false;

	if (($y == $thisyear) && ($m == $thismonth))
		$tddate = intval(datetime_convert('UTC',date_default_timezone_get(),'now','j'));

	$str_month = day_translate($mtab[$m]);
	$o = '<table class="calendar' . $class . '">';
	$o .= "<caption>$str_month $y</caption><tr>";
	for ($a = 0; $a < 7; $a ++)
		$o .= '<th>' . mb_substr(day_translate($dn[$a]),0,3,'UTF-8') . '</th>';

	$o .= '</tr><tr>';

	while ($d <= $l) {
		if (($dow == $f) && (! $started))
			$started = true;

		$today = (((isset($tddate)) && ($tddate == $d)) ? "class=\"today\" " : '');
		$o .= "<td $today>";
		$day = str_replace(' ','&nbsp;',sprintf('%2.2d', $d));
		if ($started) {
			if (is_array($links) && isset($links[$d]))
				$o .=  "<a href=\"{$links[$d]}\">$day</a>";
			else
				$o .= $day;

			$d ++;
		} else {
			$o .= '&nbsp;';
		}

		$o .= '</td>';
		$dow ++;
		if (($dow == 7) && ($d <= $l)) {
			$dow = 0;
			$o .= '</tr><tr>';
		}
	}
	if ($dow)
		for ($a = $dow; $a < 7; $a ++)
			$o .= '<td>&nbsp;</td>';

	$o .= '</tr></table>'."\r\n";

	return $o;
}

/**
 * @brief Return the next birthday, converted from the owner's timezone to UTC.
 *
 * This makes it globally portable.
 * If the provided birthday lacks a month and or day, return an empty string.
 * A missing year is acceptable.
 *
 * @param string $dob Date of Birth
 * @param string $tz Timezone
 * @param string $format
 * @return string
 */
function z_birthday($dob, $tz, $format="Y-m-d H:i:s") {

	if (! strlen($tz))
		$tz = 'UTC';

	$birthday = '';
	$tmp_dob = substr($dob,5);
	$tmp_d = substr($dob,8);
	if (intval($tmp_dob) && intval($tmp_d)) {
		$y = datetime_convert($tz,$tz,'now','Y');
		$bd = $y . '-' . $tmp_dob . ' 00:00';
		$t_dob = strtotime($bd);
		$now = strtotime(datetime_convert($tz,$tz,'now'));
		if ($t_dob < $now)
			$bd = $y + 1 . '-' . $tmp_dob . ' 00:00';

		$birthday = datetime_convert($tz,'UTC',$bd,$format);
	}

	return $birthday;
}

/**
 * @brief Create a birthday event for any connections with a birthday in the next 1-2 weeks.
 *
 * Update the year so that we don't create another event until next year.
 */
function update_birthdays() {

	require_once('include/event.php');
	require_once('include/permissions.php');

	$r = q("SELECT * FROM abook left join xchan on abook_xchan = xchan_hash
		WHERE abook_dob > %s + interval %s and abook_dob < %s + interval %s",
		db_utcnow(), db_quoteinterval('7 day'),
		db_utcnow(), db_quoteinterval('14 day')
	);
	if ($r) {
		foreach ($r as $rr) {
			if (! perm_is_allowed($rr['abook_channel'], $rr['xchan_hash'], 'send_stream'))
				continue;

			$ev = [
				'uid'         => $rr['abook_channel'],
				'account'     => $rr['abook_account'],
				'event_xchan' => $rr['xchan_hash'],
				'dtstart'     => datetime_convert('UTC', 'UTC', $rr['abook_dob']),
				'dtend'       => datetime_convert('UTC', 'UTC', $rr['abook_dob'] . ' + 1 day '),
				'adjust'      => 0,
				'summary'     => sprintf( t('%1$s\'s birthday'), $rr['xchan_name']),
				'description' => sprintf( t('Happy Birthday %1$s'), '[zrl=' . $rr['xchan_url'] . ']' . $rr['xchan_name'] . '[/zrl]'),
				'etype'       => 'birthday',
			];

			$z = event_store_event($ev);

			if ($z) {
				$item_id = event_store_item($ev, $z);
				q("update abook set abook_dob = '%s' where abook_id = %d",
					dbesc(intval($rr['abook_dob']) + 1 . substr($rr['abook_dob'], 4)),
					intval($rr['abook_id'])
				);
			}
		}
	}
}

/**
 *
 * Calculate a due by interval
 * based on the current datetime the interval is added/subtracted
 * @author Hilmar Runge
 * @since  2020-02-20
 * @param  $duri the interval in the format n[n]i
 *		   where n is a 1-2 digit numeric amount and i is a unit
 *         example $duri='1w' represents one week
 *         unit may be one of i(minutes), h(hours), d(days), w(weeks), m(months, y(years))
 * @return array['due']  computed datetime in format 'Y-m-d H:i:s'
 * 				['durn'] the amount
 *				['duru'] the unit
 *		   or false
 */
	function calculate_adue($duri=false, $sign='+') {
		if ( preg_match( '/^[0-9]{1,2}[ihdwmy]{1}$/', $duri ) && ($sign == '+' || $sign == '-')  ) {
			$duru = substr( $duri, -1);
			$durn = substr( $duri, 0, -1);
			$due  = date( 'Y-m-d H:i:s', strtotime(
					'+' . $durn . ' ' 
				  . str_replace( array(':i',':h',':d',':w',':m',':y'), 
			 				 	 array('minutes', 'hours', 'days', 'weeks', 'months', 'years'),
			 					 ( ':'. $duru ) 
			 					) 
					)
			);
			return array( 'durn' => $durn, 'duru' => $duru, 'due' => $due);
		}
		return false;
	}