module Main (main) where

import qualified Data.ByteString.Lazy as ByteString
import qualified Data.YAML as YAML
import qualified Data.Text.Lazy.IO as Text
import qualified Options.Applicative as Opt
import Control.Applicative
import SinglePage

data Options =
    SinglePage {
      file        :: FilePath,
      includeNsfw :: Bool,
      output      :: Maybe FilePath
    }
  | GalleryPage {
      directory   :: FilePath,
      includeNsfw :: Bool,
      output      :: Maybe FilePath
    }

optionsParser :: Opt.ParserInfo Options
optionsParser =
  (Opt.hsubparser (single <> gallery) <**> Opt.helper) `Opt.info` mainInfo
 where
  single = Opt.command "single" $ singleOpts `Opt.info` singleInfo
  singleOpts = SinglePage <$> fileArg <*> nsfwSwitch <*> outputOpt
  fileArg = Opt.strArgument $
    Opt.metavar "FILE" <> Opt.help "yaml file to read"
  nsfwSwitch = Opt.switch $
    Opt.short 'n' <> Opt.long "nsfw" <>
    Opt.help "include nsfw versions"
  outputOpt = Opt.option (Just <$> Opt.str) $
    Opt.short 'o' <> Opt.long "output" <>
    Opt.value Nothing <>
    Opt.help "output file (default: stdout)"
  singleInfo = Opt.progDesc "generate a page for a single work"

  gallery = Opt.command "gallery" $ galleryOpts `Opt.info` galleryInfo
  galleryOpts = GalleryPage <$> dirArg <*> nsfwSwitch <*> outputOpt
  dirArg = Opt.strArgument $
    Opt.metavar "DIR" <> Opt.help "directory to search for yaml files"
  galleryInfo = Opt.progDesc "generate a gallery page"

  mainInfo = Opt.progDesc "static gallery site generator" <> Opt.fullDesc


main :: IO ()
main = main2 =<< Opt.execParser optionsParser

main2 :: Options -> IO ()
main2 (SinglePage {file, includeNsfw, output}) = do
  txt <- ByteString.readFile file
  let Right info = YAML.decode1 txt
  let page = make info
  case output of
    Nothing  -> Text.putStr page
    Just out -> Text.writeFile out page
main2 (GalleryPage {}) = do
  error "surprise! this doesn't exist yet"