{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE TypeOperators #-}

-- | Provides `madlang` runMadlangutable
module Text.Madlibs.Exec.Main where

import Text.Madlibs.Cata.Run
import Text.Madlibs.Ana.Parse
import Text.Madlibs.Internal.Types
import Text.Madlibs.Internal.Utils
import qualified Data.Text as T
import qualified Data.Text.IO as TIO
import Text.Megaparsec
import Options.Generic

-- | datatype for the program
data Program = Program { input :: FilePath <?> "filepath to template"
                       , debug :: Bool <?> "whether to display parsed RandTok" --also: display crontab in that case?
                       , rep :: Maybe Int <?> "How many times to repeat"
                       } deriving (Generic)

-- | Generated automatically by optparse-generic.
instance ParseRecord Program where

-- | Main program action
runMadlang :: IO ()
runMadlang = do
    x <- getRecord "Text.Madlibs templating DSL"
    case unHelpful . rep $ x of
        (Just n) -> sequence_ . (take n) . repeat $ template x
        Nothing -> template x

-- | given a parsed record perform the appropriate IO action
template :: Program -> IO ()
template rec = do
    let filepath = unHelpful . input $ rec
    parsed <- parseFile filepath
    runFile filepath >>= TIO.putStrLn
    if unHelpful . debug $ rec then
        print parsed
    else
        pure ()

-- | Generate randomized text from a template
templateGen :: T.Text -> Either (ParseError Char Dec) (IO T.Text)
templateGen txt = run <$> parseTok txt

-- | Generate randomized text from a file conatining a template
runFile :: FilePath -> IO T.Text
runFile filepath = do
    txt <- readFile' filepath
    either (pure . parseErrorPretty') (>>= (pure . show')) (templateGen txt)

-- | Parse a template file into the `RandTok` data type
parseFile :: FilePath -> IO (Either (ParseError Char Dec) RandTok)
parseFile filepath = do
    txt <- readFile' filepath
    let val = parseTok txt
    pure val