{-# LANGUAGE ConstraintKinds   #-}
{-# LANGUAGE FlexibleContexts  #-}
{-# LANGUAGE NoImplicitPrelude #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE TemplateHaskell   #-}
-- | Commandline options tools.
module Hbro.Options (
      Command(..)
    , CliOptions()
    , startURI_
    , socketPath_
    , uiFile_
    , dyreMode_
    , dyreDebug_
    , logLevel_
    , parseOptions
    ) where

-- {{{ Imports
import qualified Hbro.Dyre                   as Dyre
import           Hbro.Error
import           Hbro.Prelude

import           Control.Monad.Logger

import           Lens.Micro.Platform

import           Network.URI

import           Options.Applicative.Builder
import           Options.Applicative.Extra
import           Options.Applicative.Types
-- }}}

-- * Types
-- | Available commands
data Command = Rebuild | Version

-- | Available options
data CliOptions = CliOptions
  { _startURI   :: Maybe URI
  , _socketPath :: Maybe FilePath
  , _uiFile     :: Maybe FilePath
  , _dyreMode   :: Dyre.Mode
  , _dyreDebug  :: Bool
  , _logLevel   :: LogLevel
  } deriving(Eq)

makeLensesWith (lensRules & lensField .~ lensGen) ''CliOptions

instance Describable CliOptions where
  describe opts = unwords $ catMaybes
    [ ("URI=" <>) . show <$> (opts^.startURI_)
    , ("SOCKET=" <>) . pack  <$> (opts^.socketPath_)
    , ("UI=" <>) . pack <$> (opts^.uiFile_)
    , Just . ("DYRE_MODE=" <>) . show $ opts^.dyreMode_
    , if opts^.dyreDebug_ then Just "DYRE_DEBUG" else Nothing
    , Just . ("LOG-LEVEL=" <>) . show $ opts^.logLevel_
    ]

instance Default CliOptions where
    def = CliOptions
            {- startURI   -} Nothing
            {- socketPath -} Nothing
            {- uiFile     -} Nothing
            {- dyreMode   -} def
            {- dyreDebug  -} False
            {- logLevel   -} LevelInfo

-- * High level
parseOptions :: (MonadIO m) => m (Either Command CliOptions)
parseOptions = io $ customExecParser (prefs noBacktrack) (info parser $ progDesc "Minimal extensible web-browser")

-- * Low level
-- ** URI options
startURI :: Parser URI
startURI = option (eitherReader $ note "Invalid URI" . parseURIReference) $ long "uri" <> short 'u' <> metavar "START-URI" <> help "URI to load at start-up."

socketURI, uiURI :: Parser FilePath
socketURI = option (eitherReader $ Right . fromString) $ long "socket" <> short 'S' <> metavar "SOCKET-URI" <> help "URI to open IPC's listening socket."
uiURI     = option (eitherReader $ Right . fromString) $ long "ui" <> short 'U' <> metavar "UI-FILE" <> help "Path to UI descriptor (XML file)"

-- ** Dyre options
vanillaFlag, forceReconfFlag, denyReconfFlag :: Parser Dyre.Mode
vanillaFlag      = flag def Dyre.Vanilla $ long "vanilla" <> short '1' <> help "Do not read custom configuration file"
forceReconfFlag  = flag def Dyre.ForceReconfiguration $ long "force-reconf" <> help "Recompile configuration file before starting the program"
denyReconfFlag   = flag def Dyre.IgnoreReconfiguration $ long "deny-reconf" <> help "Do not recompile configuration file even if it has changed"

dyreDebug :: Parser Bool
dyreDebug = switch $ long "dyre-debug" <> help "Use './cache/' as the cache directory and ./ as the configuration directory. Useful to debug the program."

dyreMasterBinary :: Parser String
dyreMasterBinary = strOption $ long "dyre-master-binary" <> metavar "PATH" <> hidden <> internal <> help "Internal flag used for dynamic reconfiguration."

-- ** Log level options
verboseFlag, quietFlag, logLevel :: Parser LogLevel
verboseFlag = flag LevelInfo LevelDebug $ long "verbose" <> short 'v' <> help "Set log level to DEBUG."
quietFlag   = flag LevelInfo LevelError $ long "quiet" <> short 'q' <> help "Set log level to ERROR."
logLevel    = option auto $ long "log-level" <> short 'l' <> metavar "LOG-LEVEL" <> value LevelInfo <> completeWith ["LevelDebug", "LevelInfo", "LevelWarn", "LevelError"] <> help "Set log level. Available values: LevelDebug, LevelInfo, LevelWarn, LevelError."

-- |

-- ** Commands
rebuildOptions, versionOptions :: Parser Command
rebuildOptions = pure Rebuild
versionOptions = pure Version

rebuildCommand, versionCommand :: Mod CommandFields Command
rebuildCommand = command "rebuild" $ info rebuildOptions $ progDesc "Rebuild configuration file."
versionCommand = command "version" $ info versionOptions $ progDesc "Print version."

commands :: Parser Command
commands = subparser $ rebuildCommand <> versionCommand

-- ** Aggregated parsers
cliOptions :: Parser CliOptions
cliOptions = CliOptions
    <$> optional startURI
    <*> optional socketURI
    <*> optional uiURI
    <*> (vanillaFlag <|> forceReconfFlag <|> denyReconfFlag)
    <*> dyreDebug
    <*> (verboseFlag <|> quietFlag <|> logLevel)

parser :: Parser (Either Command CliOptions)
parser = helper <*> optional dyreMasterBinary *> ((Left <$> commands) <|> (Right <$> cliOptions))