module RPGEngine.Render.Core where

import Graphics.Gloss ( Picture, translate )
import GHC.IO (unsafePerformIO)
import Graphics.Gloss.Juicy (loadJuicyPNG)
import Data.Maybe (fromJust)
import Graphics.Gloss.Data.Picture (scale)

----------------------------- Constants ------------------------------

-- Default scale
zoom :: Float
zoom = 5.0

-- Resolution of the texture
resolution :: Float
resolution = 16

assetsFolder :: FilePath
assetsFolder = "assets/"

unknownImage :: FilePath
unknownImage = "unkown.png"

allEntities :: [(String, FilePath)]
allEntities = [
    ("player", "player.png"),
    ("door", "door.png")
    ]

allItems :: [(String, FilePath)]
allItems = [
    ("dagger", "dagger.png"),
    ("key",    "key.png"   )
    ]

-- Map of all renders
library :: [(String, Picture)]
library = unknown:entities ++ environment ++ gui ++ items
    where unknown     = ("unkown", renderPNG (assetsFolder ++ unknownImage))
          entities    = map (\(f, s) -> (f, renderPNG (assetsFolder ++ "entities/" ++ s))) allEntities
          environment = []
          gui         = []
          items       = map (\(f, s) -> (f, renderPNG (assetsFolder ++ "items/" ++ s))) allItems

----------------------------------------------------------------------

-- Turn a path to a .png file into a Picture.
renderPNG :: FilePath -> Picture
renderPNG path = scale zoom zoom $ fromJust $ unsafePerformIO $ loadJuicyPNG path

-- Retrieve an image from the library. If the library does not contain
-- the requested image, a default is returned.
getRender :: String -> Picture
getRender id = get filtered
    where filtered         = filter ((== id) . fst) library
          get []           = snd $ head library
          get ((_, res):_) = res

setRenderPos :: Int -> Int -> Picture -> Picture
setRenderPos x y = translate floatX floatY
    where floatX = fromIntegral x * zoom * resolution
          floatY = fromIntegral y * zoom * resolution