From 613f3fd56eef40b00e81283c1cbd8cf553f1bf01 Mon Sep 17 00:00:00 2001
From: Ben Sherred <ben@sherred.co.uk>
Date: Tue, 28 Nov 2023 08:32:40 +0000
Subject: [PATCH] feat: add shuffle key

---
 README.md              |  2 +-
 config/sqids.php       | 13 +++++++++++++
 src/Sqids.php          | 11 ++++++-----
 src/Support/Config.php | 11 +++++++++++
 4 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/README.md b/README.md
index f48bbc1..32bd66c 100644
--- a/README.md
+++ b/README.md
@@ -10,7 +10,7 @@
 Laravel Sqids (pronounced "squids") allows you to easily generate Stripe/YouTube looking IDs for your Laravel models.
 These IDs are short and are guaranteed to be Collision free.
 
-For more information on Sqids, we recommend checking out the official Sqids (formerly Hashids) webiste: [https://sqids.org](https://sqids.org).
+For more information on Sqids, we recommend checking out the official Sqids (formerly Hashids) website: [https://sqids.org](https://sqids.org).
 
 ## Installation
 
diff --git a/config/sqids.php b/config/sqids.php
index f2b3b3e..1957c44 100644
--- a/config/sqids.php
+++ b/config/sqids.php
@@ -4,6 +4,19 @@
 
 return [
 
+    /*
+    |--------------------------------------------------------------------------
+    | Shuffle Key
+    |--------------------------------------------------------------------------
+    |
+    | This option is used to control the "shuffle key" for your Sqids. This
+    | ensures that your Sqids are unique to your application. Changing
+    | this value will result in all Sqids having a new value.
+    |
+    */
+
+    'shuffle_key' => env('APP_KEY'),
+
     /*
     |--------------------------------------------------------------------------
     | Alphabet
diff --git a/src/Sqids.php b/src/Sqids.php
index f19d432..db0c40a 100644
--- a/src/Sqids.php
+++ b/src/Sqids.php
@@ -79,18 +79,19 @@ public static function encoder(string $model): SqidsCore
     public static function alphabetForModel(string $model): string
     {
         $alphabet = Config::alphabet();
-        $modelLength = mb_strlen(string: $model);
+        $shuffle = $model . Config::shuffleKey();
+        $shuffleLength = mb_strlen(string: $shuffle);
 
-        if (!$modelLength) {
+        if (!$shuffleLength) {
             return Config::alphabet();
         }
 
         $alphabetArray = static::multiByteSplit(string: Config::alphabet());
-        $modelArray = static::multiByteSplit(string: $model);
+        $shuffleArray = static::multiByteSplit(string: $shuffle);
 
         for ($i = mb_strlen($alphabet) - 1, $v = 0, $p = 0; $i > 0; $i--, $v++) {
-            $v %= $modelLength;
-            $p += $int = mb_ord($modelArray[$v], 'UTF-8');
+            $v %= $shuffleLength;
+            $p += $int = mb_ord($shuffleArray[$v], 'UTF-8');
             $j = ($int + $v + $p) % $i;
 
             $temp = $alphabetArray[$j];
diff --git a/src/Support/Config.php b/src/Support/Config.php
index bd75d9d..9dec0fa 100644
--- a/src/Support/Config.php
+++ b/src/Support/Config.php
@@ -18,6 +18,17 @@ class Config
 
     protected static string $defaultPrefixCase = 'lower';
 
+    public static function shuffleKey(): ?string
+    {
+        $shuffleKey = config(key: 'sqids.shuffle_key');
+
+        if (!is_string($shuffleKey)) {
+            return null;
+        }
+
+        return $shuffleKey;
+    }
+
     public static function alphabet(): string
     {
         $alphabet = config(key: 'sqids.alphabet');