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diff --git a/src/Mail.hs b/src/Mail.hs
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+{-# LANGUAGE OverloadedStrings #-}
+
+module Mail
+  ( mailSubject
+  , mailBody
+  ) where
+
+import Data.Text (Text)
+import qualified Data.Text as T
+
+import Date
+import Birthdate
+
+mailSubject :: [Birthdate] -> Text
+mailSubject birthdates =
+  let count = length birthdates
+  in  T.concat
+        [ "Hey, "
+        , if count > 1 then "there are" else "there is"
+        , " "
+        , T.pack . show $ count
+        , " birthday"
+        , if count > 1 then "s" else ""
+        , " today!"
+        ]
+
+mailBody :: Date -> [Birthdate] -> Text
+mailBody currentDate birthdates =
+  let count = length birthdates
+      birthdatesWithLines = map (mapFst getLine) . zip [1..] $ birthdates
+      getLine 1 = if count == 1 then SingleLine else FirstLine
+      getLine line = if line == count then LastLine else MiddleLine
+  in  T.concat $ map (mailLine currentDate) birthdatesWithLines
+
+mapFst :: (a -> c) -> (a, b) -> (c, b)
+mapFst f (x, y) = (f x, y)
+
+data Line =
+  SingleLine
+  | FirstLine
+  | MiddleLine
+  | LastLine
+  deriving (Eq, Show)
+
+mailLine :: Date -> (Line, Birthdate) -> Text
+mailLine date (SingleLine, birthdate) =
+  T.concat
+    [ fullname birthdate
+    , " is now "
+    , T.pack . show $ age date birthdate
+    , " years old."
+    ]
+mailLine date (FirstLine, birthdate) =
+  T.concat
+    [ fullname birthdate
+    , " is now "
+    , T.pack . show $ age date birthdate
+    , " years old"
+    ]
+mailLine date (MiddleLine, birthdate) =
+  T.concat
+    [ ", "
+    , fullname birthdate
+    , " is "
+    , T.pack . show $ age date birthdate
+    , " years old"
+    ]
+mailLine date (LastLine, birthdate) =
+  T.concat
+    [ " and "
+    , fullname birthdate
+    , " is "
+    , T.pack . show $ age date birthdate
+    , " years old."
+    ]