module Types
  ( Action(..)
  , FormatResult
  , FormatError(..)
  , Formatted(..)
  , HaskellSource(..)
  , RunResult(..)
  , SourceFile(..)
  , SourceFileWithContents(..)
  ) where

import Data.Semigroup          (Semigroup, (<>))
import Language.Haskell.Format

data Action
  = PrintDiffs
  | PrintSources
  | PrintFilePaths
  | WriteSources
  deriving (Eq)

data SourceFile
  = SourceFilePath FilePath
  | StdinSource

instance Show SourceFile where
  show (SourceFilePath path) = path
  show StdinSource           = "-"

data SourceFileWithContents =
  SourceFileWithContents SourceFile HaskellSource

type FormatResult = Either FormatError Formatted

data FormatError =
  FormatError SourceFile String

instance Show FormatError where
  show (FormatError input errorString) =
    "Error reformatting " ++ show input ++ ": " ++ errorString

data Formatted =
  Formatted SourceFile HaskellSource Reformatted

data RunResult
  = OperationalFailure
  | SourceParseFailure
  | HadDifferences
  | NoDifferences

instance Semigroup RunResult where
  x <> NoDifferences      = x
  NoDifferences <> x      = x
  OperationalFailure <> _ = OperationalFailure
  SourceParseFailure <> _ = SourceParseFailure
  HadDifferences <> _     = HadDifferences

instance Monoid RunResult where
  mempty = NoDifferences
  mappend = (<>)