{-# LANGUAGE DeriveGeneric #-}

{-# LANGUAGE FlexibleInstances #-}

{-# LANGUAGE OverloadedStrings #-}

{-# LANGUAGE RecordWildCards #-}

-- | Nix types.

module Stack.Types.Nix where

import Control.Applicative

import Data.Aeson.Extended

import Data.Monoid

import Data.Text (Text)

import GHC.Generics (Generic)

import Generics.Deriving.Monoid (mappenddefault, memptydefault)

import Prelude

-- | Nix configuration. Parameterize by resolver type to avoid cyclic

-- dependency.

data NixOpts = NixOpts

{nixEnable :: !Bool

,nixPureShell :: !Bool

,nixPackages :: ![Text]

-- ^ The system packages to be installed in the environment before it runs

,nixInitFile :: !(Maybe FilePath)

-- ^ The path of a file containing preconfiguration of the environment (e.g shell.nix)

,nixShellOptions :: ![Text]

-- ^ Options to be given to the nix-shell command line

,nixAddGCRoots :: !Bool

-- ^ Should we register gc roots so running nix-collect-garbage doesn't remove nix dependencies

}

deriving (Show)

-- | An uninterpreted representation of nix options.

-- Configurations may be "cascaded" using mappend (left-biased).

data NixOptsMonoid = NixOptsMonoid

{nixMonoidDefaultEnable :: !Any

-- ^ Should nix-shell be defaulted to enabled (does @nix:@ section exist in the config)?

,nixMonoidEnable :: !(First Bool)

-- ^ Is using nix-shell enabled?

,nixMonoidPureShell :: !(First Bool)

-- ^ Should the nix-shell be pure

,nixMonoidPackages :: !(First [Text])

-- ^ System packages to use (given to nix-shell)

,nixMonoidInitFile :: !(First FilePath)

-- ^ The path of a file containing preconfiguration of the environment (e.g shell.nix)

,nixMonoidShellOptions :: !(First [Text])

-- ^ Options to be given to the nix-shell command line

,nixMonoidPath :: !(First [Text])

-- ^ Override parts of NIX_PATH (notably 'nixpkgs')

,nixMonoidAddGCRoots :: !(First Bool)

-- ^ Should we register gc roots so running nix-collect-garbage doesn't remove nix dependencies

}

deriving (Eq, Show, Generic)

-- | Decode uninterpreted nix options from JSON/YAML.

instance FromJSON (WithJSONWarnings NixOptsMonoid) where

parseJSON = withObjectWarnings "NixOptsMonoid"

(\o -> do nixMonoidDefaultEnable <- pure (Any False)

nixMonoidEnable <- First <$> o ..:? nixEnableArgName

nixMonoidPureShell <- First <$> o ..:? nixPureShellArgName

nixMonoidPackages <- First <$> o ..:? nixPackagesArgName

nixMonoidInitFile <- First <$> o ..:? nixInitFileArgName

nixMonoidShellOptions <- First <$> o ..:? nixShellOptsArgName

nixMonoidPath <- First <$> o ..:? nixPathArgName

nixMonoidAddGCRoots <- First <$> o ..:? nixAddGCRootsArgName

return NixOptsMonoid{..})

-- | Left-biased combine Nix options

instance Monoid NixOptsMonoid where

mempty = memptydefault

mappend = mappenddefault

-- | Nix enable argument name.

nixEnableArgName :: Text

nixEnableArgName = "enable"

-- | Nix run in pure shell argument name.

nixPureShellArgName :: Text

nixPureShellArgName = "pure"

-- | Nix packages (build inputs) argument name.

nixPackagesArgName :: Text

nixPackagesArgName = "packages"

-- | shell.nix file path argument name.

nixInitFileArgName :: Text

nixInitFileArgName = "shell-file"

-- | Extra options for the nix-shell command argument name.

nixShellOptsArgName :: Text

nixShellOptsArgName = "nix-shell-options"

-- | NIX_PATH override argument name

nixPathArgName :: Text

nixPathArgName = "path"

-- | Add GC roots arg name

nixAddGCRootsArgName :: Text

nixAddGCRootsArgName = "add-gc-roots"