module VM where

import Data.Set (Set)
import qualified Data.Set as Set
import Test.QuickCheck

type Cell = (Int, Int)

data Board = Board {
           boardWidth :: Int,
           boardHeight :: Int,
           filled :: Set Cell
           }

data Unit = Unit {
          unitMembers :: Set Cell,
          unitPivot :: Cell
          }
          deriving Show

data Command = MoveW
             | MoveE
             | MoveSW
             | MoveSE
             | RotateClockwise
             | RotateCounterclockwise


data Game = Game Board Unit
-- data Game = Game { board :: Board, unit :: Unit }

-- isValidPosition :: Unit -> Board

data Notes = OK
           | Collision
           | CollisionWithRowElision

-- step :: Game -> Command -> (Game, Notes)
-- step game inst

applyWholeUnit :: Unit -> (Cell -> Cell) -> Unit
applyWholeUnit (Unit members pivot) f = Unit (Set.map f members) (f pivot)

applyCommand :: Unit -> Command -> Unit

applyCommand unit MoveW = applyWholeUnit unit move where
    move (x, y) = (x - 1, y)
applyCommand unit MoveE = applyWholeUnit unit move where
    move (x, y) = (x + 1, y)
applyCommand unit MoveSW = applyWholeUnit unit move where
    move (x, y) = (x - ((y + 1) `mod` 2), y + 1)
applyCommand unit MoveSE = applyWholeUnit unit move where
    move (x, y) = (x + (y `mod` 2), y + 1)
applyCommand (Unit members pivot) RotateClockwise = Unit (Set.map transform members) pivot where
    transform cell = rotateCell pivot cell
applyCommand (Unit members pivot) RotateCounterclockwise = Unit (Set.map transform members) pivot where
    transform cell = counterRotateCell pivot cell

rotateCell :: Cell -> Cell -> Cell
rotateCell (px, py) (x, y) = (px - ddiag + (doriz + px `mod` 2) `div` 2, py + doriz) where
    (ddiag, doriz) = relativePosition (px, py) (x, y)

counterRotateCell :: Cell -> Cell -> Cell
counterRotateCell pivot = rp . rp . rp . rp . rp where
    rp = rotateCell pivot

relativePosition :: Cell -> Cell -> (Int, Int)
relativePosition (px, py) (x, y) = (diagDir, horizDir) where
    diagDir = y - py
    horizDir = x - px + (if py `mod` 2 == 0 then diagDir + diagDir `mod` 2 else diagDir - diagDir `mod` 2) `div` 2

test :: (Cell -> Cell) -> [Bool]
test f = [f (0,3) == (2,5), f (1,3) == (3, 6), f (2,3) == (3,7), f (3, 3) == (4,8), f (2, 4) == (2,7)]

test2 :: (Cell -> Cell) -> [Bool]
test2 f = [f (2,5) == (3,6), f (3,6) == (2, 7), f (2,7) == (1,7), f (1, 7) == (1,6), f (1, 6) == (1,5), f (1, 5) == (2, 5)]

deepCheck p = quickCheckWith (stdArgs { maxSuccess = 10000 }) p

testTutto = do
        deepCheck (\pivot cell -> let r2 = rotateCell pivot in (r2 . r2 . r2 . r2 . r2 . r2) cell == cell)
        deepCheck (\pivot cell -> cell == counterRotateCell pivot (rotateCell pivot cell))