{-|
Module      : Headroom.FileType
Description : Supported source code file types
Copyright   : (c) 2019-2020 Vaclav Svejcar
License     : BSD-3
Maintainer  : vaclav.svejcar@gmail.com
Stability   : experimental
Portability : POSIX

This application can generate source code headers from templates for various
type of source code files. Such headers are usually represented as a top level
comment, the application must render such header with correct syntax.
The 'FileType' represents such type of source code file, which is recognized by
this application and for which the license headers can be manipulated.
-}
{-# LANGUAGE LambdaCase        #-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}
module Headroom.FileType
  ( FileType(..)
  , fileTypeByExt
  , listExtensions
  , fileTypeByName
  )
where

import           Headroom.Types.Utils           ( allValues
                                                , readEnumCI
                                                )
import           RIO
import qualified RIO.List                      as L
import qualified RIO.Text                      as T
import           Text.Read                      ( readsPrec )


-- | Represents supported type of source code file, where license headers may
-- be added, replaced or removed.
data FileType
  = CSS     -- ^ /CSS/ source code file
  | Haskell -- ^ /Haskell/ source code file
  | HTML    -- ^ /HTML/ source code file
  | Java    -- ^ /Java/ source code file
  | JS      -- ^ /JavaScript/ source code file
  | Scala   -- ^ /Scala/ source code file
  deriving (Bounded, Enum, Eq, Ord, Show)

instance Read FileType where
  readsPrec _ = readEnumCI

-- | Returns 'FileType' for given file extension (without dot).
--
-- >>> fileTypeByExt "hs"
-- Just Haskell
fileTypeByExt :: Text           -- ^ file extension to search for
              -> Maybe FileType -- ^ corresponding 'FileType' (if found)
fileTypeByExt ext =
  L.find (elem ext . listExtensions) (allValues :: [FileType])

-- | Lists all recognized file extensions for given 'FileType'.
--
-- >>> listExtensions Haskell
-- ["hs"]
listExtensions :: FileType -- ^ 'FileType' to list extensions for
               -> [Text]   -- ^ list of found file extensions
listExtensions = \case
  CSS     -> ["css"]
  Haskell -> ["hs"]
  HTML    -> ["html", "htm"]
  Java    -> ["java"]
  JS      -> ["js"]
  Scala   -> ["scala"]

-- | Reads 'FileType' from its textual representation.
--
-- >>> fileTypeByName "haskell"
-- Just Haskell
fileTypeByName :: Text           -- ^ textual representation of 'FileType'
               -> Maybe FileType -- ^ corresponding 'FileType' (if found)
fileTypeByName = readMaybe . T.unpack