Add TimezoneSelect component for timezone selection in forms

src/Filament/Forms/Components/TimezoneSelect.php

@@ -0,0 +1,178 @@
+<?php
+
+/*
+<COPYRIGHT>
+
+    Copyright © 2016-2026, Canyon GBS LLC. All rights reserved.
+
+    Canyon GBS Common is licensed under the Elastic License 2.0. For more details,
+    see https://github.com/canyongbs/common/blob/main/LICENSE.
+
+    Notice:
+
+    - You may not provide the software to third parties as a hosted or managed
+      service, where the service provides users with access to any substantial set of
+      the features or functionality of the software.
+    - You may not move, change, disable, or circumvent the license key functionality
+      in the software, and you may not remove or obscure any functionality in the
+      software that is protected by the license key.
+    - You may not alter, remove, or obscure any licensing, copyright, or other notices
+      of the licensor in the software. Any use of the licensor’s trademarks is subject
+      to applicable law.
+    - Canyon GBS LLC respects the intellectual property rights of others and expects the
+      same in return. Canyon GBS™ and Canyon GBS Common are registered trademarks of
+      Canyon GBS LLC, and we are committed to enforcing and protecting our trademarks
+      vigorously.
+    - The software solution, including services, infrastructure, and code, is offered as a
+      Software as a Service (SaaS) by Canyon GBS LLC.
+    - Use of this software implies agreement to the license terms and conditions as stated
+      in the Elastic License 2.0.
+
+    For more information or inquiries please visit our website at
+    https://www.canyongbs.com or contact us via email at legal@canyongbs.com.
+
+</COPYRIGHT>
+*/
+
+namespace CanyonGBS\Common\Filament\Forms\Components;
+
+use DateTime;
+use DateTimeZone;
+use Filament\Forms\Components\Select;
+
+class TimezoneSelect
+{
+    protected const EXCLUDED_PREFIXES = [
+        'US/',
+        'Canada/',
+        'Mexico/',
+        'Brazil/',
+        'Chile/',
+        'Australia/',
+        'NZ/',
+        'Etc/GMT',
+        'Etc/UTC',
+    ];
+
+    protected const EXCLUDED_IDENTIFIERS = [
+        'America/Edmonton',
+        'America/Whitehorse',
+        'America/Inuvik',
+        'America/Fort_Nelson',
+        'America/Coral_Harbour',
+        'America/Atikokan',
+        'America/Shiprock',
+        'America/Indiana/Indianapolis',
+        'America/Knox_IN',
+    ];
+
+    protected const US_TIMEZONES = [
+        'Pacific/Honolulu',
+        'America/Anchorage',
+        'America/Los_Angeles',
+        'America/Denver',
+        'America/Phoenix',
+        'America/Chicago',
+        'America/New_York',
+        'America/Puerto_Rico',
+    ];
+
+    public static function make(string $name = 'timezone'): Select
+    {
+        $now = new DateTime('now', new DateTimeZone('UTC'));
+
+        $identifiers = DateTimeZone::listIdentifiers(DateTimeZone::ALL);
+
+        $usTimezones = [];
+        $otherTimezones = [];
+
+        foreach ($identifiers as $id) {
+            if (! self::isCanonical($id)) {
+                continue;
+            }
+
+            $timezone = new DateTimeZone($id);
+            $offset = $timezone->getOffset($now);
+
+            $entry = [
+                'id' => $id,
+                'offset' => $offset,
+                'label' => self::formatLabel($id, $offset),
+            ];
+
+            if (in_array($id, self::US_TIMEZONES, true)) {
+                $usTimezones[] = $entry;
+            } else {
+                $otherTimezones[] = $entry;
+            }
+        }
+
+        $sortByOffset = static function (array $first, array $second): int {
+            return $first['offset'] <=> $second['offset']
+                ?: strcmp($first['id'], $second['id']);
+        };
+
+        usort($usTimezones, $sortByOffset);
+        usort($otherTimezones, $sortByOffset);
+
+        return Select::make($name)
+            ->searchable()
+            ->optionsLimit(PHP_INT_MAX)
+            ->options([
+                'United States' => self::toOptions($usTimezones),
+                'Other Timezones' => self::toOptions($otherTimezones),
+            ]);
+    }
+
+    protected static function isCanonical(string $id): bool
+    {
+        if ((! str_contains($id, '/')) && ($id !== 'UTC')) {
+            return false;
+        }
+
+        foreach (self::EXCLUDED_PREFIXES as $prefix) {
+            if (str_starts_with($id, $prefix)) {
+                return false;
+            }
+        }
+
+        return ! in_array($id, self::EXCLUDED_IDENTIFIERS, true);
+    }
+
+    /**
+     * @param array<int, array{id: string, label: string}> $zones
+     *
+     * @return array<string, string>
+     */
+    protected static function toOptions(array $zones): array
+    {
+        $options = [];
+
+        foreach ($zones as $zone) {
+            $options[$zone['id']] = $zone['label'];
+        }
+
+        return $options;
+    }
+
+    protected static function formatLabel(string $id, int $offset): string
+    {
+        if ($id === 'UTC') {
+            return 'UTC';
+        }
+
+        $sign = $offset >= 0 ? '+' : '-';
+        $hours = intdiv(abs($offset), 3600);
+        $minutes = intdiv(abs($offset) % 3600, 60);
+
+        $utc = sprintf('UTC%s%02d:%02d', $sign, $hours, $minutes);
+
+        [, $city] = array_pad(explode('/', $id, 2), 2, null);
+
+        $city = $city
+            ? str_replace('_', ' ', $city)
+            : $id;
+
+        return sprintf('(%s) %s (%s)', $utc, $id, $city);
+    }
+}