import           Ai.Evolutionary    (evolve)
import           Codec.Picture      (DynamicImage, convertRGB8, readImage)
import           Data.Colour        (lab2rgb)
import qualified Data.Vector        as V
import           Stylix.Output      (makeOutputTable)
import           Stylix.Palette     ()
import           System.Environment (getArgs)
import           System.Exit        (die)
import           System.Random      (mkStdGen, setStdGen)
import           Text.JSON          (encode)

-- | Load an image file.
loadImage :: String -- ^ Path to the file
          -> IO DynamicImage
loadImage input = either error id <$> readImage input

mainProcess :: (String, String, String) -> IO ()
mainProcess (polarity, input, output) = do
  putStrLn $ "Processing " ++ input

  -- Random numbers must be deterministic when running inside Nix.
  setStdGen $ mkStdGen 0

  image <- loadImage input
  palette <- evolve (polarity, convertRGB8 image)
  let outputTable = makeOutputTable $ V.map lab2rgb palette

  writeFile output $ encode outputTable
  putStrLn $ "Saved to " ++ output

parseArguments :: [String] -> Either String (String, String, String)
parseArguments [polarity, input, output] = Right (polarity, input, output)
parseArguments [_, _] = Left "Please specify an output file"
parseArguments [_] = Left "Please specify an image"
parseArguments [] = Left "Please specify a polarity: either, light or dark"
parseArguments _ = Left "Too many arguments"

main :: IO ()
main = either die mainProcess . parseArguments =<< getArgs