From 10ad8d65c4635aa793a16bd17931e693c028a531 Mon Sep 17 00:00:00 2001
From: Smuuf <premavansmuuf@gmail.com>
Date: Sat, 13 Jul 2019 13:12:07 +0200
Subject: [PATCH] Fixed string_shuffle function for unicode characters.

---
 src/extensions/psl/StringExtension.php | 15 ++++++++++++++-
 tests/unit/value.string.phpt           |  7 +++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/extensions/psl/StringExtension.php b/src/extensions/psl/StringExtension.php
index 2cf45642..f3739338 100644
--- a/src/extensions/psl/StringExtension.php
+++ b/src/extensions/psl/StringExtension.php
@@ -15,7 +15,20 @@
 class StringExtension extends Extension {
 
 	public static function string_shuffle(StringValue $str): StringValue {
-		return new StringValue(str_shuffle((string) $str->value));
+
+		// str_shuffle() doesn't work with unicode, so let's do this ourselves.
+		$original = $str->value;
+		$length = mb_strlen($original);
+		$indices = range(0, $length - 1);
+		shuffle($indices);
+		$result = "";
+
+		while (($i = array_pop($indices)) !== null) {
+			$result .= mb_substr($original, $i, 1);
+		}
+
+		return new StringValue($result);
+
 	}
 
 	public static function string_length(StringValue $str): NumberValue {
diff --git a/tests/unit/value.string.phpt b/tests/unit/value.string.phpt
index 89d57c5c..63f247e1 100644
--- a/tests/unit/value.string.phpt
+++ b/tests/unit/value.string.phpt
@@ -252,6 +252,13 @@ Assert::same(2, get_val($fns['string_number_of']->invoke([$string, new StringVal
 Assert::same(0, get_val($fns['string_number_of']->invoke([$string, new StringValue("xoxoxo")])));
 Assert::same(0, get_val($fns['string_number_of']->invoke([$string, new NumberValue(1)])));
 
+//
+// Test shuffle.
+//
+
+Assert::same(17, mb_strlen(get_val($fns['string_shuffle']->invoke([$string]))));
+Assert::same(17, mb_strlen(get_val($fns['string_shuffle']->invoke([$unicode]))));
+
 //
 // Test length.
 //