get_tzid_fallbacks()

Complexity

Conditions	9
Paths	36

Size

Total Lines	137
Code Lines	69

Duplication

Lines	0
Ratio	0 %

Importance

Changes	1
Bugs	0	Features	0

<?php
function get_tzid_fallbacks($tzids, $when = 'now')
{
	$tzids = (array) $tzids;

	$when = is_numeric($when) ? intval($when) : (is_int(@strtotime($when)) ? strtotime($when) : time());

The condition is_int(@strtotime($when)) is always true.

	// 'ts' is the timestamp when the substitution first becomes valid.
	// 'tzid' is the alternative time zone identifier to use.
	$fallbacks = array(
		// 1. Simple renames. PHP_INT_MIN because these are valid for all dates.
		'Asia/Kolkata' => array(
			array(
				'ts' => PHP_INT_MIN,
				'tzid' => 'Asia/Calcutta',
			),
		),
		'Pacific/Chuuk' => array(
			array(
				'ts' => PHP_INT_MIN,
				'tzid' => 'Pacific/Truk',
			),
		),
		'Pacific/Pohnpei' => array(
			array(
				'ts' => PHP_INT_MIN,
				'tzid' => 'Pacific/Ponape',
			),
		),
		'Asia/Yangon' => array(
			array(
				'ts' => PHP_INT_MIN,
				'tzid' => 'Asia/Rangoon',
			),
		),
		'America/Nuuk' => array(
			array(
				'ts' => PHP_INT_MIN,
				'tzid' => 'America/Godthab',
			),
		),

		// 2. Newly created time zones.

		// The same as Tasmania, except it stayed on DST all year in 2010.
		// Australia/Tasmania is an otherwise unused backwards compatibility
		// link to Australia/Hobart, so we can borrow it here without conflict.
		'Antarctica/Macquarie' => array(
			array(
				'ts' => PHP_INT_MIN,
				'tzid' => 'Australia/Tasmania',
			),
			array(
				'ts' => strtotime('2010-04-03T16:00:00+0000'),
				'tzid' => 'Etc/GMT-11',
			),
			array(
				'ts' => strtotime('2011-04-07T17:00:00+0000'),
				'tzid' => 'Australia/Tasmania',
			),
		),

		// This place uses two hours for DST. No substitutes are possible.
		'Antarctica/Troll' => array(
			array(
				'ts' => PHP_INT_MIN,
				'tzid' => '',
			),
		),

		// Diverged from Pacific/Port_Moresby in version 2014i.
		'Pacific/Bougainville' => array(
			// Before the divergence, we don't actually need this one at all.
			array(
				'ts' => PHP_INT_MIN,
				'tzid' => '',
			),
			// For dates after divergence, it is the same as Pacific/Kosrae.
			// If this ever ceases to be true, add another entry.
			array(
				'ts' => strtotime('2014-12-27T16:00:00+0000'),
				'tzid' => 'Pacific/Kosrae',
			),
		),

		// Diverged from America/Santiago in version 2017a.
		'America/Punta_Arenas' => array(
			// Before the divergence, we don't actually need this one at all.
			array(
				'ts' => PHP_INT_MIN,
				'tzid' => '',
			),
			// For dates after divergence, it is the same as Antarctica/Palmer.
			// If this ever ceases to be true, add another entry.
			array(
				'ts' => strtotime('2017-05-14T03:00:00+0000'),
				'tzid' => 'Antarctica/Palmer',
			),
		),
	);

	$missing = array_diff($tzids, timezone_identifiers_list(DateTimeZone::ALL_WITH_BC));

It seems like timezone_identifiers_list(DateTimeZone::ALL_WITH_BC) can also be of type false; however, parameter $array2 of array_diff() does only seem to accept array, maybe add an additional type check?

	call_integration_hook('integrate_timezone_fallbacks', array(&$fallbacks, &$missing, $tzids, $when));

	$replacements = array();

	foreach ($tzids as $tzid)
	{
		// Not missing.
		if (!in_array($tzid, $missing))
			$replacements[$tzid] = $tzid;

		// Missing and we have no fallback.
		elseif (empty($fallbacks[$tzid]))
			$replacements[$tzid] = '';

		// Missing, but we have a fallback.
		else
		{
			usort($fallbacks[$tzid], function ($a, $b) {
				return $a['ts'] > $b['ts'];
			});

			foreach ($fallbacks[$tzid] as $alt)
			{
				if ($when < $alt['ts'])
					break;

				$replacements[$tzid] = $alt['tzid'];
			}

			if (empty($replacements[$tzid]))
				$replacements[$tzid] = '';
		}
	}

	return $replacements;
}
?>