Support for Taiwan holidays (#124)

* support Taiwan holidays

* Refactor lunarCalendar method to handle parsing errors

* Update variableHolidays to correctly return converted dates

* Refactor variableHolidays to combine array_map and array_filter

* use the Taiwanese language to label the holiday

---------

Co-authored-by: Takeshi Yu <[email protected]>

composer.json

@@ -21,8 +21,8 @@
     ],
     "require": {
         "php": "^8.1",
-        "nesbot/carbon": "^2.72.1",
-        "ext-calendar": "*"
+        "ext-intl": "*",
+        "nesbot/carbon": "^2.72.1"
     },
     "require-dev": {
         "laravel/pint": "^1.0",

src/Countries/Taiwan.php

@@ -0,0 +1,63 @@
+<?php
+
+namespace Spatie\Holidays\Countries;
+
+use DateTime;
+use DateTimeZone;
+use IntlDateFormatter;
+
+class Taiwan extends Country
+{
+    protected string $timezone = 'Asia/Taipei';
+
+    public function countryCode(): string
+    {
+        return 'tw';
+    }
+
+    protected function allHolidays(int $year): array
+    {
+        return array_merge([
+            '元旦' => '01-01',
+            '228和平紀念日' => '02-28',
+            '兒童節' => '04-04',
+            '雙十國慶' => '10-10',
+        ], $this->variableHolidays($year));
+    }
+
+    /** @return array<string, string> */
+    protected function variableHolidays(int $year): array
+    {
+        return array_filter(array_map(fn ($date) => $this->lunarCalendar($date, $year), [
+            '農曆春節-正月初一' => '01-01',
+            '農曆春節-正月初二' => '01-02',
+            '農曆春節-正月初三' => '01-03',
+            '端午節' => '05-05',
+            '中秋節' => '08-15',
+        ]));
+    }
+
+    protected function lunarCalendar(string $input, int $year): ?string
+    {
+        $formatter = new IntlDateFormatter(
+            locale: 'zh-TW@calendar=chinese',
+            dateType: IntlDateFormatter::SHORT,
+            timeType: IntlDateFormatter::NONE,
+            timezone: $this->timezone,
+            calendar: IntlDateFormatter::TRADITIONAL
+        );
+
+        $lunarDateStr = $year . '-' . $input;
+        $parsedTimestamp = $formatter->parse($lunarDateStr);
+
+        if ($parsedTimestamp === false) {
+            return null;
+        }
+
+        $dateTime = new DateTime;
+        $dateTime->setTimestamp($parsedTimestamp);
+        $dateTime->setTimezone(new DateTimeZone($this->timezone));
+
+        return $dateTime->format('m-d');
+    }
+}

tests/.pest/snapshots/Countries/TaiwanTest/it_can_calculate_taiwan_holidays.snap

@@ -0,0 +1,38 @@
+[
+    {
+        "name": "\u5143\u65e6",
+        "date": "2024-01-01"
+    },
+    {
+        "name": "\u8fb2\u66c6\u6625\u7bc0-\u6b63\u6708\u521d\u4e00",
+        "date": "2024-02-10"
+    },
+    {
+        "name": "\u8fb2\u66c6\u6625\u7bc0-\u6b63\u6708\u521d\u4e8c",
+        "date": "2024-02-11"
+    },
+    {
+        "name": "\u8fb2\u66c6\u6625\u7bc0-\u6b63\u6708\u521d\u4e09",
+        "date": "2024-02-12"
+    },
+    {
+        "name": "228\u548c\u5e73\u7d00\u5ff5\u65e5",
+        "date": "2024-02-28"
+    },
+    {
+        "name": "\u5152\u7ae5\u7bc0",
+        "date": "2024-04-04"
+    },
+    {
+        "name": "\u7aef\u5348\u7bc0",
+        "date": "2024-06-10"
+    },
+    {
+        "name": "\u4e2d\u79cb\u7bc0",
+        "date": "2024-09-17"
+    },
+    {
+        "name": "\u96d9\u5341\u570b\u6176",
+        "date": "2024-10-10"
+    }
+]

tests/Countries/TaiwanTest.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Spatie\Holidays\Tests\Countries;
+
+use Carbon\CarbonImmutable;
+use Spatie\Holidays\Holidays;
+
+it('can calculate taiwan holidays', function () {
+    CarbonImmutable::setTestNowAndTimezone('2024-01-01');
+
+    $holidays = Holidays::for(country: 'tw')->get();
+
+    expect($holidays)
+        ->toBeArray()
+        ->not()->toBeEmpty();
+
+    expect(formatDates($holidays))->toMatchSnapshot();
+
+});