{-# LANGUAGE OverloadedStrings #-}

import Text.DocTemplates

import Test.Hspec

import Data.Text

import Data.Aeson

data Employee = Employee { firstName :: String

                         , lastName  :: String

                         , salary    :: Maybe Integer }

instance ToJSON Employee where

  toJSON e = object [ "name" .= object [ "first" .= firstName e

                                       , "last"  .= lastName e ]

                    , "salary" .= salary e ]

employees :: [Employee]

employees = [ Employee "John" "Doe" Nothing

            , Employee "Omar" "Smith" (Just 30000)

            , Employee "Sara" "Chen" (Just 60000) ]

template :: Text

template =

  "$for(employee)$Hi, $employee.name.first$. $if(employee.salary)$You make $$$employee.salary$.$else$No salary data.$endif$$sep$\n$endfor$"

main :: IO ()

main = hspec $ do

  describe "applyTemplate" $ do

    it "works" $ do

      applyTemplate template (object ["employee" .= employees])

        `shouldBe`

        (Right "Hi, John. No salary data.\nHi, Omar. You make $30000.\nHi, Sara. You make $60000." :: Either String Text)

    it "renders numbers appropriately as integer or floating" $ do

      applyTemplate "$m$ and $n$"

        (object ["m" .= (5 :: Integer), "n" .= (7.3 :: Double)])

        `shouldBe`

        (Right "5 and 7.3" :: Either String Text)

    it "handles comments" $ do

      applyTemplate "hello $--there and $m$\n$-- comment\nbar"

        (object ["m" .= (5 :: Integer)])

        `shouldBe`

        (Right "hello \nbar" :: Either String Text)

    it "fails with an incorrect template" $ do

      applyTemplate "$if(x$and$endif$" (object [])

        `shouldBe`

        (Left "\"template\" (line 1, column 6):\nunexpected \"$\"\nexpecting \".\" or \")$\"" :: Either String Text)