module Main where

import qualified Paths_hydrogen_cli as Paths

import Hydrogen.Prelude.System
import Hydrogen.CliArgs

import H.Common (LogLevel)

import qualified H.Dump as Dump
import qualified H.Init as Init
import qualified H.Run as Run


showVersion :: IO ()
showVersion = putStrLn ("hydrogen v" ++ show (fromDataVersion Paths.version))

unknownCommand :: String -> IO ()
unknownCommand =
    printf "Unknown command \"%s\". Use \"help\" for a list of available commands.\n"

unknownTopic :: String -> IO ()
unknownTopic =
    printf "Unknown topic \"%s\". Use \"help\" for a list of available topics.\n"

showHelp :: String -> IO ()
showHelp topic = do
    
    let topic' = if null topic then "help" else topic

    filename <- Paths.getDataFileName ("help" </> topic' <.> "txt")
    exists <- doesFileExist filename

    if | exists -> readFile filename >>= putStr
       | otherwise -> unknownTopic topic

main :: IO ()
main = do

    (options, switches, args) <- getOpts [
        'h' ~: switch "help"
      , 'V' ~: switch "version"
      , 'v' ~: switch "verbose"
      , 'v' ~: optarg "verbose" ~= "^(v{1,3}|[0-4])$"
      ]
    
    let (command, topic, _) = safeHeadAndTail2 "help" "" args
        vs = case options ! "verbose" of
          [x] -> x
          _ -> ""
        verbosity
          | switches ? "verbose" = 1
          | null vs = 0
          | all (== 'v') vs = 1 + length vs
          | otherwise = read vs
        logger (lvl :: LogLevel)
          | fromEnum lvl <= verbosity = hPutStrLn stderr
          | otherwise = void . return
        run f = f logger (drop 1 args)

    if | switches ? "version" -> showVersion
       | switches ? "help" -> showHelp command
       | otherwise -> case command of

        "help" -> showHelp topic

        "escape"    -> mapM_ (putStrLn . escapeFileName) (drop 1 args)
        "unescape"  -> mapM_ (maybe (return ()) putStrLn . unescapeFileName) (drop 1 args)

        "dump"  -> run Dump.main
        "init"  -> run Init.main
        "run"   -> run Run.main

        cmd -> unknownCommand cmd