module Html (
  html_tests,
  replace_entities )
where

import Test.Tasty ( TestTree, testGroup )
import Test.Tasty.HUnit ( (@?=), testCase )
import Text.HTML.TagSoup.Entity ( lookupEntity )

replace_entities :: String -> String
replace_entities [] = []
replace_entities ('&':xs) =
  let (b, a) = break (== ';') xs in
  case (lookupEntity b, a) of
    (Just s, ';':as) ->  s ++ replace_entities as
    _                -> '&' : replace_entities xs
replace_entities (x:xs) = x : replace_entities xs


html_tests :: TestTree
html_tests =
  testGroup "HTML Tests" [ test_replace_entities ]


test_replace_entities :: TestTree
test_replace_entities =
  testCase description $ actual @?= expected
  where
    description = "all entities are replaced correctly."
    actual =
      replace_entities $
        ""The moon is gay……" " ++
        "said <insert the current president of the " ++
        "United States of America>. “It’s " ++
        "OK—–he’s not a real doctor.”"
    expected =
      "\"The moon is gay……\" said <insert " ++
      "the current president of the United States of America>. " ++
      "“It’s OK—–he’s not a real doctor.”"