{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}

-- | Commonly useful functions, a Prelude replacement.
--
-- This is designed to be imported everywhere, unqualified (generally
-- the only unqualified import you should use).
--
-- Alpha can be opinionated and break with other Haskell idioms. For
-- example, we define our own operators which have a pattern to their
-- characters:
--
-- - `|` normal function-level applications
-- - `/` indicates doing something inside a functor
-- - `<` and `>` indicate the direction in which values flow
--   between functions
--
-- It seems unnecessarily different at first but it makes things easier
-- to read quickly.
module Alpha
  ( -- * Re-export Protolude
    module X,

    -- * Applying
    (<|),
    (|>),

    -- * Mapping
    (/>),
    (</),
    (<//),

    -- * Bool
    don't,

    -- * Text
    chomp,
    lchomp,
    joinWith,

    CanSnakeCase(snake),

    -- * Debugging tools
    say,
  )
where

import Data.Function ((&))
import Data.Functor ((<&>))
import Data.String
import Data.Text (Text)
import qualified Data.Text as Text
import qualified Data.Text.Lazy as LazyText
import Protolude as X

-- | Debugging printf
say :: Text -> IO ()
say = putText

-- | Alias for map, fmap, <$>
(</) :: Functor f => (a -> b) -> f a -> f b
(</) = fmap

-- | Double fmap. A function on the left goes "into" two functors
-- (i.e. it goes "two levels deep"), applies the function to the inner
-- values, then returns the result wrapped in the two functors.
(<//) :: (Functor f0, Functor f1) => (a -> b) -> f0 (f1 a) -> f0 (f1 b)
(<//) = fmap . fmap

-- | Normal function application. Do the right side, then pass the
-- return value to the function on the left side.
(<|) :: (a -> b) -> a -> b
(<|) = ($)

infixr 0 <|

-- | Reverse function application. Do the left side, then pass the
-- return value to the function on the right side.
(|>) :: a -> (a -> b) -> b
(|>) = (&)

-- | Alias for <&>. Can be read as "and then". Basically does into a
-- functor, does some computation, then returns the same kind of
-- functor. Could also be defined as `f >>= return . g`
(/>) :: Functor f => f a -> (a -> b) -> f b
(/>) = (<&>)

-- | Removes newlines from text.
chomp :: Text -> Text
chomp = Text.filter (/= '\n')

-- | Removes newlines from lazy text.
lchomp :: LazyText.Text -> LazyText.Text
lchomp = LazyText.filter (/= '\n')

-- | Join a list of things with a separator.
joinWith :: [a] -> [[a]] -> [a]
joinWith = intercalate

-- | can you just not
don't :: Bool -> Bool
don't = do not
{-# ANN don't ("HLint: ignore Redundant do" :: String) #-}

-- | Class for turning different string types to snakeCase.
class CanSnakeCase str where
  snake :: str -> str

instance CanSnakeCase Text where
  snake = Text.replace " " "-" . Text.toLower