module Turbo where

import Data.Map.Strict (Map)
import Data.Map.Strict qualified as Map
import Prelude hiding (fmap, pure, (<*>), (<*), (*>), (>>=))
import TurboDef


-- "Run" a Turbo program to produce SVG path commands.
-- This is the only function that will be tested.
runTurbo :: Stmt -> [SVGPathCmd]
runTurbo stmt = snd (unTurbo (turbo stmt) initTurboMem)
-- But the actual execution engine and recursion are in "turbo" and "evalReal"
-- below.


-- Evaluate an expression.
evalReal :: RealExpr -> Turbo Double
evalReal (RLit r) = pure r
evalReal (RVar var) = getVar var
evalReal (e1 :+: e2) = liftA2 (+) (evalReal e1) (evalReal e2)
evalReal (e1 :-: e2) = liftA2 (-) (evalReal e1) (evalReal e2)
evalReal (e1 :*: e2) = liftA2 (*) (evalReal e1) (evalReal e2)
evalReal (e1 :/: e2) = liftA2 (/) (evalReal e1) (evalReal e2)


-- Turbo interpreter. Return SVG path commands.
turbo :: Stmt -> Turbo [SVGPathCmd]
turbo = error "TODO"


-- If you could code up the following helpers, your turbo implementation could
-- be much less repetitive and higher-level.  fmap, get, modify, Map.lookup, and
-- Map.insert will get you a long way.  getPen and setPen are provided as examples.

-- Get current direction.
getAngle :: Turbo Double
getAngle = error "TODO"

-- Change direction by adding the given angle.
turn :: Double -> Turbo ()
turn t = error "TODO"

-- Get pen state.
getPen :: Turbo Bool
getPen = fmap (\(TurboMem _ _ p) -> p) get

-- Set pen state.
setPen :: Bool -> Turbo ()
setPen b = modify (\(TurboMem vs a _) -> TurboMem vs a b)

-- Get a variable's current value. (If not found, give 0 for simplicity.)
getVar :: String -> Turbo Double
getVar = error "TODO"

-- Set a variable to value.
setVar :: String -> Double -> Turbo ()
setVar = error "TODO"