{-# LANGUAGE OverloadedStrings #-}

-- |
-- License: GPL-3.0-or-later
-- Copyright: Oleg Grenrus
module CabalGild.Fields.Modules
  ( otherModulesF,
    exposedModulesF,
  )
where

import CabalGild.Fields
import CabalGild.Prelude
import qualified Distribution.FieldGrammar as C
import qualified Distribution.ModuleName as C
import qualified Distribution.Parsec as C
import qualified Distribution.Pretty as C
import qualified Text.PrettyPrint as PP

exposedModulesF :: FieldDescrs () ()
exposedModulesF = singletonF "exposed-modules" pretty parse

otherModulesF :: FieldDescrs () ()
otherModulesF = singletonF "other-modules" pretty parse

parse :: (C.CabalParsing m) => m [C.ModuleName]
parse = unpack' (C.alaList' C.VCat C.MQuoted) <$> C.parsec

pretty :: [C.ModuleName] -> PP.Doc
pretty =
  PP.vcat
    . map C.pretty
    . nub
    . sortBy (cmp `on` map strToLower . C.components)
  where
    cmp :: (Ord a) => [a] -> [a] -> Ordering
    cmp a b = case dropCommonPrefix a b of
      ([], []) -> EQ
      ([], _ : _) -> LT
      (_ : _, []) -> GT
      (a', b') -> compare a' b'

strToLower :: String -> String
strToLower = map toLower

dropCommonPrefix :: (Eq a) => [a] -> [a] -> ([a], [a])
dropCommonPrefix [] [] = ([], [])
dropCommonPrefix [] ys = ([], ys)
dropCommonPrefix xs [] = (xs, [])
dropCommonPrefix xs@(x : xs') ys@(y : ys')
  | x == y = dropCommonPrefix xs' ys'
  | otherwise = (xs, ys)