{-# Language TemplateHaskell, MultiWayIf #-}
{-|
Module      : Client.Options
Description : Processing of command-line options
Copyright   : (c) Eric Mertens, 2016
License     : ISC
Maintainer  : emertens@gmail.com

This module process command-line options provided when launching the client.

-}
module Client.Options
  (
  -- * Command-line options
    Options(..)

  -- * Lenses
  , optConfigFile
  , optInitialNetworks
  , optNoConnect

  -- * Options loader
  , getOptions
  ) where

import           Control.Lens
import           Data.Foldable
import           Data.Text (Text)
import qualified Data.Text as Text
import           Data.Version
import           Development.GitRev (gitHash, gitDirty)
import           System.Console.GetOpt
import           System.Environment
import           System.Exit
import           System.IO
import           Paths_glirc (version)

-- | Command-line options
data Options = Options
  { _optConfigFile      :: Maybe FilePath -- ^ configuration file path
  , _optInitialNetworks :: [Text]         -- ^ initial networks
  , _optNoConnect       :: Bool           -- ^ disable autoconnect
  , _optShowHelp        :: Bool           -- ^ show help message
  , _optShowVersion     :: Bool           -- ^ show version message
  }

makeLenses ''Options

-- | Default values for 'Options'
defaultOptions :: Options
defaultOptions = Options
  { _optConfigFile      = Nothing
  , _optInitialNetworks = []
  , _optShowHelp        = False
  , _optShowVersion     = False
  , _optNoConnect       = False
  }

-- | Option descriptions
options :: [OptDescr (Options -> Options)]
options =
  [ Option "c" ["config"]  (ReqArg (set optConfigFile . Just) "PATH")
    "Configuration file path"
  , Option "!" ["noconnect"] (NoArg (set optNoConnect True))
    "Disable autoconnecting"
  , Option "h" ["help"]    (NoArg (set optShowHelp True))
    "Show help"
  , Option "v" ["version"] (NoArg (set optShowVersion True))
    "Show version"
  ]

optOrder :: ArgOrder (Options -> Options)
optOrder = ReturnInOrder (\x -> optInitialNetworks <>~ [Text.pack x])

-- | Load command line options. This action will terminate early
-- in the case of the version flag, help flag, or an error.
getOptions :: IO Options
getOptions =
  do (flags, _, errors) <- getOpt optOrder options <$> getArgs

     let opts = foldl' (\acc f -> f acc) defaultOptions flags

         bullet x = "• " ++ x

         reportErrors =
           do hPutStrLn stderr "Errors processing command-line options:"
              traverse_ (hPutStr stderr) (map bullet errors)
              hPutStrLn stderr tryHelpTxt

     if | view optShowHelp    opts -> putStr helpTxt    >> exitSuccess
        | view optShowVersion opts -> putStr versionTxt >> exitSuccess
        | null errors              -> return opts
        | otherwise                -> reportErrors      >> exitFailure

helpTxt :: String
helpTxt = usageInfo "glirc2 [FLAGS] INITIAL_NETWORKS..." options

tryHelpTxt :: String
tryHelpTxt =
  "Run 'glirc2 --help' to see a list of available command line options."

versionTxt :: String
versionTxt = unlines
  [ "glirc-" ++ showVersion version ++ gitHashTxt ++ gitDirtyTxt
  , "Copyright 2016 Eric Mertens"
  ]

-- git version information ---------------------------------------------

-- | Returns @"-SOMEHASH"@ when in a git repository, @""@ otherwise.
gitHashTxt :: String
gitHashTxt
  | hashTxt == "UNKNOWN" = ""
  | otherwise            = '-':hashTxt
  where
    hashTxt = $gitHash

-- | Returns @"-dirty"@ when in a dirty git repository, @""@ otherwise.
gitDirtyTxt :: String
gitDirtyTxt
  | $gitDirty = "-dirty"
  | otherwise = ""