From 95cb563d471420fe7f0030c14f7d625e5accb6fa Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9ia=20Bohner?= <andreiabohner@gmail.com>
Date: Wed, 27 Mar 2024 15:27:35 -0300
Subject: [PATCH] Add options to list timezones by country or region

---
 README.md                           | 27 +++++++++++++-
 src/Concerns/HasTimezoneOptions.php | 57 ++++++++++++++++++++++++++++-
 src/Enums/Region.php                | 25 +++++++++++++
 3 files changed, 106 insertions(+), 3 deletions(-)
 create mode 100644 src/Enums/Region.php

diff --git a/README.md b/README.md
index e7479b7..bca6a6f 100644
--- a/README.md
+++ b/README.md
@@ -54,7 +54,32 @@ public static function form(Form $form): Form
 }
 ```
 
-All [Filament select field](https://filamentphp.com/docs/2.x/forms/fields#select) methods are available to use:
+To list only the timezones for a country, you can pass the country code to `->byCountry()` method. For example, to list only United States timezones:
+
+```php
+TimezoneSelect::make('timezone')
+    ->byCountry('US')
+```
+
+It's also possible to list the timezones for a region using `->byRegion()` method. You can specify a region with a [Region enum value](src/Enums/Region.php):
+
+```php
+use Tapp\FilamentTimezoneField\Enums\Region;
+
+TimezoneSelect::make('timezone')
+    ->byRegion(Region::Australia)
+```
+
+or you can use one of the [PHP's DateTimeZone predifined constants](https://www.php.net/manual/en/class.datetimezone.php):
+
+```php
+use DateTimeZone;
+
+TimezoneSelect::make('timezone')
+    ->byRegion(DateTimeZone::AUSTRALIA)
+```
+
+Also all [Filament select field](https://filamentphp.com/docs/2.x/forms/fields#select) methods are available to use:
 
 ```php
 use Tapp\FilamentTimezoneField\Forms\Components\TimezoneSelect;
diff --git a/src/Concerns/HasTimezoneOptions.php b/src/Concerns/HasTimezoneOptions.php
index c11bdc7..43707e6 100644
--- a/src/Concerns/HasTimezoneOptions.php
+++ b/src/Concerns/HasTimezoneOptions.php
@@ -4,9 +4,14 @@
 
 use DateTime;
 use DateTimeZone;
+use Tapp\FilamentTimezoneField\Enums\Region;
 
 trait HasTimezoneOptions
-{    
+{
+    protected string | Closure | null $byCountry = null;
+
+    protected Region | int | Closure | null $byRegion = null;
+
     public function getOptions(): array
     {
         $options = $this->getTimezones();
@@ -18,7 +23,11 @@ public function getOptions(): array
 
     public function getTimezones(): array
     {
-        $timezones = DateTimeZone::listIdentifiers(DateTimeZone::ALL);
+        $timezones = match(true) {
+            !empty($this->byCountry) => $this->listTimezonesByCountry($this->byCountry),
+            !empty($this->byRegion) => $this->listTimezonesByRegion($this->byRegion),
+            default => $this->listAllTimezones(),
+        };
 
         $data = [];
 
@@ -40,4 +49,48 @@ public function getTimezones(): array
 
         return $data;
     }
+
+    public function byCountry(string | Closure | null $countryCode): static
+    {
+        $this->byCountry = $countryCode;
+
+        return $this;
+    }
+
+    public function getByCountry(): string | null
+    {
+        return $this->evaluate($this->byCountry);
+    }
+
+    public function byRegion(Region | int | Closure | null $region): static
+    {
+        $this->byRegion = $region;
+
+        return $this;
+    }
+
+    public function getByRegion(): Region | int | null
+    {
+        return $this->evaluate($this->byRegion);
+    }
+
+    protected function listTimezonesByCountry($countryCode)
+    {
+        return DateTimeZone::listIdentifiers(
+            timezoneGroup: DateTimeZone::PER_COUNTRY,
+            countryCode: $countryCode,
+        );
+    }
+
+    protected function listTimezonesByRegion($region)
+    {
+        return DateTimeZone::listIdentifiers(
+            timezoneGroup: $region?->value ?? $region,
+        );
+    }
+
+    protected function listAllTimezones()
+    {
+        return DateTimeZone::listIdentifiers(DateTimeZone::ALL);
+    }
 }
diff --git a/src/Enums/Region.php b/src/Enums/Region.php
new file mode 100644
index 0000000..b30be3d
--- /dev/null
+++ b/src/Enums/Region.php
@@ -0,0 +1,25 @@
+<?php
+
+namespace Tapp\FilamentTimezoneField\Enums;
+
+use DateTimeZone;
+use Filament\Support\Contracts\HasLabel;
+
+enum Region: int implements HasLabel
+{
+    case Africa = DateTimeZone::AFRICA;
+    case America = DateTimeZone::AMERICA;
+    case Antarctica = DateTimeZone::ANTARCTICA;
+    case Arctic = DateTimeZone::ARCTIC;
+    case Asia = DateTimeZone::ASIA;
+    case Atlantic = DateTimeZone::ATLANTIC;
+    case Australia = DateTimeZone::AUSTRALIA;
+    case Europe = DateTimeZone::EUROPE;
+    case Indian = DateTimeZone::INDIAN;
+    case Pacific = DateTimeZone::PACIFIC;
+
+    public function getLabel(): ?string
+    {
+        return $this->name;
+    }
+}