module UI (drawUI) where

import State
import Data.IORef
import Board
import Raylib.Core
import Raylib.Types
import Raylib.Core.Shapes
import Raylib.Util.Math

drawUI :: IORef AppState -> IO ()
drawUI r = do
    state <- readIORef r
    winW <- getRenderWidth
    winH <- getRenderHeight
    let act = state'action state
        brd = state'board  state
        pth = state'path   state
        (Point off) = state'offset state
        zoom = state'zoom   state
        (Board ti bg pths) = brd
    drawBG off zoom winW winH bg
    mapM_ (drawPath off zoom) pths
    case act of
        ActionDraw p -> drawPath off zoom p
        _ -> return ()
    drawInterface act pth ti winW winH
    
drawPath :: Vector2 -> Float -> Path -> IO ()
drawPath offset zoom path =
    let points = path'points path
        segments = zip points (init points)
        col = unBoardColor $ path'color path
        thick = (path'thickness path) * zoom
    in
    mapM_ (\(s, e) ->
        let s' = (offset |+| unPoint s) |* zoom
            e' = (offset |+| unPoint e) |* zoom
        in
        drawLineEx s' e' thick col
    ) segments

drawBG :: Vector2 -> Float -> Int -> Int -> BackgroundPattern -> IO ()
drawBG _ _ _ _ (BGPatternPlain (BoardColor col)) = clearBackground col
drawBG off zoom maxx' maxy' (BGPatternGrid fc' dc' hs' vs' th) =
    let fc = unBoardColor fc'
        dc = unBoardColor dc'
        hs = fromIntegral hs' * zoom
        vs = fromIntegral vs' * zoom
        offx = fromIntegral ((truncate $ vector2'x off) `rem` hs') * zoom
        offy = fromIntegral ((truncate $ vector2'y off) `rem` vs') * zoom
        maxx = fromIntegral maxx'
        maxy = fromIntegral maxy'
    in do
        clearBackground fc
        mapM_ (\x -> drawLineEx (Vector2 x 0) (Vector2 x  maxy) th dc)
            [offx, offx+hs .. maxx]
        mapM_ (\y -> drawLineEx (Vector2 0 y) (Vector2 maxx y) th dc)
            [offy, offy+vs .. maxy]
drawBG _ _ _ _ _ = undefined 

drawInterface :: Action -> String -> String -> Int -> Int -> IO ()
drawInterface act pth ti winW winH = do
    return ()