{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE LambdaCase        #-}
{-# LANGUAGE OverloadedStrings #-}

module Util
  ( mkProxy
  , PrettyPrint(..)
  , printPretty
  , naiveEscapeHTML
  , ellipsis
  ) where

import           Universum

import           Data.Aeson as Aeson
import qualified Data.Set   as S
import qualified Data.Text  as T
import           Data.Tiled (Layer, PropertyValue (..),
                             Tileset (tilesetName), layerName)

-- | helper function to create proxies
mkProxy :: a -> Proxy a
mkProxy = const Proxy

-- | a class to address all the string conversions necessary
-- when using Show to much that just uses Text instead
class PrettyPrint a where
  prettyprint :: a -> Text

-- | let's see if this is a good idea or makes type inference bite us
instance PrettyPrint Text where
  prettyprint text = "\"" <> text <> "\""

-- | same as show json, but without the "String" prefix for json strings
instance PrettyPrint Aeson.Value where
  prettyprint = \case
    Aeson.String s -> prettyprint s
    v              -> show v

instance PrettyPrint t => PrettyPrint (Set t) where
  prettyprint = prettyprint . S.toList

instance PrettyPrint PropertyValue where
  prettyprint = \case
    StrProp str     -> str
    BoolProp bool   -> if bool then "true" else "false"
    IntProp int     -> show int
    FloatProp float -> show float

-- | here since Unit is sometimes used as dummy type
instance PrettyPrint () where
  prettyprint _ = error "shouldn't pretty-print Unit"

instance PrettyPrint Layer where
  prettyprint = (<>) "layer " . layerName

instance PrettyPrint Tileset where
  prettyprint = (<>) "tileset " . tilesetName

instance PrettyPrint a => PrettyPrint [a] where
  prettyprint = T.intercalate ", " . fmap prettyprint

printPretty :: PrettyPrint a => a -> IO ()
printPretty = putStr . toString . prettyprint


-- | for long lists which shouldn't be printed out in their entirety
ellipsis :: Int -> [Text] -> Text
ellipsis i texts
  | i < l     = prettyprint (take i texts) <> " ... (and " <> show (l-i) <> " more)"
  | otherwise = prettyprint texts
  where l = length texts



-- | naive escaping of html sequences, just to be sure that
-- | workadventure won't mess things up again …
naiveEscapeHTML :: Text -> Text
naiveEscapeHTML = T.replace "<" "&lt;" . T.replace ">" "&gt;"