{-# LANGUAGE BangPatterns #-}
{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE DeriveGeneric #-}
{-# OPTIONS -fno-warn-unused-do-bind #-}

-- | Package identifier (name-version).

module Stack.Types.PackageIdentifier
  ( PackageIdentifier(..)
  , toTuple
  , fromTuple
  , parsePackageIdentifier
  , parsePackageIdentifierFromString
  , packageIdentifierParser
  , packageIdentifierString
  , packageIdentifierText )
  where

import           Control.Applicative
import           Control.DeepSeq
import           Control.Exception (Exception)
import           Control.Monad.Catch (MonadThrow, throwM)
import           Data.Aeson.Extended
import           Data.Attoparsec.Text
import           Data.Data
import           Data.Hashable
import           Data.Store (Store)
import           Data.Text (Text)
import qualified Data.Text as T
import           GHC.Generics
import           Prelude hiding (FilePath)
import           Stack.Types.PackageName
import           Stack.Types.Version

-- | A parse fail.
data PackageIdentifierParseFail
  = PackageIdentifierParseFail Text
  deriving (Typeable)
instance Show PackageIdentifierParseFail where
    show (PackageIdentifierParseFail bs) = "Invalid package identifier: " ++ show bs
instance Exception PackageIdentifierParseFail

-- | A pkg-ver combination.
data PackageIdentifier = PackageIdentifier
  { -- | Get the name part of the identifier.
    packageIdentifierName    :: !PackageName
    -- | Get the version part of the identifier.
  , packageIdentifierVersion :: !Version
  } deriving (Eq,Ord,Generic,Data,Typeable)

instance NFData PackageIdentifier where
  rnf (PackageIdentifier !p !v) =
      seq (rnf p) (rnf v)

instance Hashable PackageIdentifier
instance Store PackageIdentifier

instance Show PackageIdentifier where
  show = show . packageIdentifierString

instance ToJSON PackageIdentifier where
  toJSON = toJSON . packageIdentifierString
instance FromJSON PackageIdentifier where
  parseJSON = withText "PackageIdentifier" $ \t ->
    case parsePackageIdentifier t of
      Left e -> fail $ show (e, t)
      Right x -> return x

-- | Convert from a package identifier to a tuple.
toTuple :: PackageIdentifier -> (PackageName,Version)
toTuple (PackageIdentifier n v) = (n,v)

-- | Convert from a tuple to a package identifier.
fromTuple :: (PackageName,Version) -> PackageIdentifier
fromTuple (n,v) = PackageIdentifier n v

-- | A parser for a package-version pair.
packageIdentifierParser :: Parser PackageIdentifier
packageIdentifierParser =
  do name <- packageNameParser
     char '-'
     version <- versionParser
     return (PackageIdentifier name version)

-- | Convenient way to parse a package identifier from a 'Text'.
parsePackageIdentifier :: MonadThrow m => Text -> m PackageIdentifier
parsePackageIdentifier x = go x
  where go =
          either (const (throwM (PackageIdentifierParseFail x))) return .
          parseOnly (packageIdentifierParser <* endOfInput)

-- | Convenience function for parsing from a 'String'.
parsePackageIdentifierFromString :: MonadThrow m => String -> m PackageIdentifier
parsePackageIdentifierFromString =
  parsePackageIdentifier . T.pack

-- | Get a string representation of the package identifier; name-ver.
packageIdentifierString :: PackageIdentifier -> String
packageIdentifierString (PackageIdentifier n v) = show n ++ "-" ++ show v

-- | Get a Text representation of the package identifier; name-ver.
packageIdentifierText :: PackageIdentifier -> Text
packageIdentifierText = T.pack .  packageIdentifierString