New sharer ident checked for CI-uniqueness

src/Vervis/Field/Person.hs

@@ -19,9 +19,11 @@ module Vervis.Field.Person
     )
 where
 
-import Vervis.Import
+import Vervis.Import hiding ((==.))
 
 import Data.Char (isDigit)
+import Database.Esqueleto
+
 import Data.Char.Local (isAsciiLetter)
 
 checkLoginTemplate :: Field Handler Text -> Field Handler Text
@@ -40,13 +42,12 @@ checkLoginTemplate =
     in  checkBool ok msg
 
 checkLoginUnique :: Field Handler Text -> Field Handler Text
-checkLoginUnique = checkM $ \ login -> runDB $ do
-    let sharer = Sharer
-            { sharerIdent = login
-            , sharerName  = Nothing
-            }
-    mus <- checkUnique sharer
-    return $ if isNothing mus
+checkLoginUnique = checkM $ \ login -> do
+    sames <- runDB $ select $ from $ \ sharer -> do
+        where_ $ lower_ (sharer ^. SharerIdent) ==. lower_ (val login)
+        limit 1
+        return ()
+    return $ if null sames
         then Right login
         else Left ("This username is already in use" :: Text)
 
@@ -63,7 +64,7 @@ checkPassLength =
             \alternative, such as a client TLS certificate, that can work \
             \somewhat like SSH and GPG keys."
         minlen = 8
-    in  checkBool  ((>= minlen) . length) msg
+    in  checkBool ((>= minlen) . length) msg
 
 passConfirmField :: Field Handler Text
 passConfirmField = Field