{-# LANGUAGE OverloadedStrings, DeriveGeneric #-}
module JSONDeser where

import Data.Maybe
import Data.ByteString.Lazy
import Data.Aeson
import GHC.Generics


data Cell = Cell { x :: Int, y :: Int}
            deriving (Show, Generic)
                    
data Unit = Unit { members :: [Cell], pivot :: Cell}
            deriving (Show, Generic)
            
data Input = Input { id :: Int,
                     units :: [Unit],
                     width :: Int,
                     height :: Int,
                     filled :: [Cell],
                     sourceLength :: Int,
                     sourceSeeds :: [Int]
                   }
             deriving (Show, Generic)


instance FromJSON Cell
instance ToJSON Cell

instance FromJSON Unit
instance ToJSON Unit

instance FromJSON Input
instance ToJSON Input

readInputInternal :: ByteString -> Input
readInputInternal str = if isJust result
                        then fromJust result
                        else error "Error during JSON parsing"
                          where
                            result = (decode str :: Maybe Input)