From 2838568ea4447c4fe820a02f216a58bacfee0238 Mon Sep 17 00:00:00 2001
From: Johannes Hilden <hildenjohannes@gmail.com>
Date: Fri, 1 Sep 2023 01:31:55 +0300
Subject: [PATCH] Fix https://github.com/sqids/sqids-haskell/issues/4

---
 src/Web/Sqids/Internal.hs        | 5 +++--
 test/Web/Sqids/BlocklistTests.hs | 8 ++++++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/Web/Sqids/Internal.hs b/src/Web/Sqids/Internal.hs
index 2fa39ce..d59fb07 100644
--- a/src/Web/Sqids/Internal.hs
+++ b/src/Web/Sqids/Internal.hs
@@ -225,8 +225,9 @@ instance (MonadSqids m) => MonadSqids (SelectT r m) where
 --   3. Remove words that contain characters that are not in the alphabet
 --
 filteredBlocklist :: Text -> [Text] -> [Text]
-filteredBlocklist alph ws = (Text.map toLower) <$> filter isValid ws where
-  isValid w = Text.length w >= 3 && Text.all (`Text.elem` alph) w
+filteredBlocklist alph ws = filter isValid (Text.map toLower <$> ws) where
+  isValid w = Text.length w >= 3 && Text.all (`Text.elem` lowercaseAlphabet) w
+  lowercaseAlphabet = Text.map toLower alph
 
 decodeStep :: (Text, Text) -> Maybe (Int, (Text, Text))
 decodeStep (sqid, alph)
diff --git a/test/Web/Sqids/BlocklistTests.hs b/test/Web/Sqids/BlocklistTests.hs
index fb9b3f6..60d1e39 100644
--- a/test/Web/Sqids/BlocklistTests.hs
+++ b/test/Web/Sqids/BlocklistTests.hs
@@ -61,3 +61,11 @@ testBlocklist = do
 
     it "match against a short blocklist word" $
       withCustomBlocklist [ "pPQ" ] ((encode >=> decode) [1000]) `shouldBe` Right [1000]
+
+    it "blocklist filtering in constructor" $ do
+      let options = defaultSqidsOptions { alphabet = "ABCDEFGHIJKLMNOPQRSTUVWXYZ", blocklist = ["sqnmpn"] } 
+          testFn = do
+            p <- encode [1, 2, 3]
+            q <- decode p
+            pure (p, q)
+      runSqids options testFn `shouldBe` Right ("ULPBZGBM", [1, 2, 3])