Validate birthdates and show an error message if there are invalid ones

1 files changed, 16 insertions, 3 deletions

diff --git a/src/Model/BirthdateParser.hs b/src/Model/BirthdateParser.hs
index c9ac3b9..8e8489b 100644
--- a/src/Model/BirthdateParser.hs
+++ b/src/Model/BirthdateParser.hs
@@ -1,3 +1,5 @@
+{-# LANGUAGE OverloadedStrings #-}
+
 module Model.BirthdateParser
   ( parseBirthdates
   ) where
@@ -14,9 +16,20 @@ import Model.Date
 
 parseBirthdates :: Text -> Either Text [Birthdate]
 parseBirthdates input =
-  left
-    (T.pack . show)
-    (parse birthdatesParser "" (T.unpack input))
+  left (T.pack . show) (parse birthdatesParser "" (T.unpack input)) >>= validateBirthdates
+
+validateBirthdates :: [Birthdate] -> Either Text [Birthdate]
+validateBirthdates birthdates =
+  let invalid = filter (not . isValid . date) birthdates
+  in  if null invalid
+        then
+          Right birthdates
+        else
+          Left $
+             T.concat
+               [ "Invalid birthdates: "
+               , T.intercalate ", " (map renderBirthdate invalid)
+               ]
 
 birthdatesParser :: Parser [Birthdate]
 birthdatesParser = many (many newline >> birthdateParser <* many newline)