From f20e37360674d48c164ad95ce0105d7f5f5014ef Mon Sep 17 00:00:00 2001
From: =?utf8?q?Rapha=C3=ABl=20Gertz?= <git@rapsys.eu>
Date: Fri, 8 Mar 2024 02:08:30 +0100
Subject: [PATCH] Add getEastern member function

---
 Util/IntlUtil.php | 40 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 40 insertions(+)

diff --git a/Util/IntlUtil.php b/Util/IntlUtil.php
index eb7711f..b37169d 100644
--- a/Util/IntlUtil.php
+++ b/Util/IntlUtil.php
@@ -84,6 +84,46 @@ class IntlUtil {
 		return $formatter->formatCurrency($number, $currency);
 	}
 
+	/**
+	 * Compute eastern for selected year
+	 *
+	 * @param string $year The eastern year
+	 *
+	 * @return DateTime The eastern date
+	 */
+	public function getEastern(string $year): \DateTime {
+		//Set static results
+		static $results = [];
+
+		//Check if already computed
+		if (isset($results[$year])) {
+			//Return computed eastern
+			return $results[$year];
+		}
+
+		$d = (19 * ($year % 19) + 24) % 30;
+
+		$e = (2 * ($year % 4) + 4 * ($year % 7) + 6 * $d + 5) % 7;
+
+		$day = 22 + $d + $e;
+
+		$month = 3;
+
+		if ($day > 31) {
+			$day = $d + $e - 9;
+			$month = 4;
+		} elseif ($d == 29 && $e == 6) {
+			$day = 10;
+			$month = 4;
+		} elseif ($d == 28 && $e == 6) {
+			$day = 18;
+			$month = 4;
+		}
+
+		//Store eastern in data
+		return ($results[$year] = new \DateTime(sprintf('%04d-%02d-%02d', $year, $month, $day)));
+	}
+
 	/**
 	 * Gets number formatter instance matching locale and style.
 	 *
-- 
2.41.0