{-# LANGUAGE NamedFieldPuns #-}
{-# LANGUAGE TemplateHaskell #-}

module Parser.Types (
  Atom (..),
  FormatArg (..),
  Flag (..),
  adjustmentFlags,
  Adjustment (..),
  FormatStr,
  MaySpecify (..),
  emptyFlagSet,
  toFlagSet,
  FlagSet (..),
  LengthSpecifier (..),
  flags_,
  spec_,
  signed_,
  prefixed_,
  spaced_,
  adjustment_,
) where

import Data.Foldable (
  elem,
  notElem,
 )
import Data.Set (Set)
import qualified Data.Set as S
import Language.Haskell.TH.Lift
import Lens.Micro.Platform
import Prelude hiding (
  elem,
  notElem,
 )

data Atom
  = Arg FormatArg
  | Str String
  deriving (Show)

data LengthSpecifier
  = HH
  | H
  | BigL
  | LL
  | L
  | J
  | Z
  | T
  deriving (Eq)

instance Show LengthSpecifier where
  show HH = "hh"
  show H = "h"
  show BigL = "L"
  show LL = "ll"
  show L = "l"
  show J = "j"
  show Z = "z"
  show T = "t"

data Flag
  = FlagLJust
  | FlagSigned
  | FlagSpaced
  | FlagPrefixed
  | FlagZeroPadded
  deriving (Show, Eq, Ord)

adjustmentFlags :: Set Flag
adjustmentFlags = S.fromList [FlagLJust, FlagZeroPadded]

data Adjustment
  = LeftJustified
  | ZeroPadded
  deriving (Show, Eq)

data MaySpecify
  = Given Integer
  | Need
  deriving (Show)

data FormatArg = FormatArg
  { flags :: FlagSet
  , width :: Maybe MaySpecify
  , precision :: Maybe MaySpecify
  , spec :: Char
  , lengthSpec :: Maybe LengthSpecifier
  }
  deriving (Show)

type FormatStr = [Atom]

data FlagSet = FlagSet
  { adjustment :: Maybe Adjustment
  , signed :: Bool
  , spaced :: Bool
  , prefixed :: Bool
  }
  deriving (Show)

emptyFlagSet :: FlagSet
emptyFlagSet = FlagSet Nothing False False False

toFlagSet :: Set Flag -> FlagSet
toFlagSet fs = set'
 where
  adjustment
    | FlagLJust `S.member` fs = Just LeftJustified
    | FlagZeroPadded `S.member` fs = Just ZeroPadded
    | otherwise = Nothing
  set' =
    FlagSet
      { signed = FlagSigned `elem` fs
      , prefixed = FlagPrefixed `elem` fs
      , adjustment
      , spaced = FlagSpaced `elem` fs && FlagSigned `notElem` fs
      }

makeLensesFor
  [ ("adjustment", "adjustment_")
  , ("signed", "signed_")
  , ("spaced", "spaced_")
  , ("prefixed", "prefixed_")
  ]
  ''FlagSet

makeLensesFor
  [ ("flags", "flags_")
  , ("spec", "spec_")
  ]
  ''FormatArg

deriveLiftMany [''Adjustment, ''FlagSet, ''LengthSpecifier]