import Text.CSV
import Graphics.Gloss

data Command = 
      Go Float
    | TurnLeft
    | TurnRight
    | Say String
    deriving Show

toCommand ["GO",n] = Go (read n)
toCommand ["LEFT"] = TurnLeft
toCommand ["RIGHT"] = TurnRight
toCommand ["SAY",something] = Say something
toCommand record = error $ "Can not parse record " ++ show record

{-
1. try 

commandsToPicture = pictures . map toPicture

toPicture (Go length) = line [(0,0), (0, length)]
toPicture TurnLeft = blank
toPicture TurnRight = blank
toPicture (Say something) = scale 0.3 0.3 (text something)
-}

{-
2. try

commandsToPicture [] = blank
commandsToPicture (Go length : cmds) = pictures
    [ line [(0,0), (0, length)]
    , translate 0 length (commandsToPicture cmds)
    ]
commandsToPicture (TurnLeft  : cmds) = rotate (-90) (commandsToPicture cmds)
commandsToPicture (TurnRight : cmds) = rotate 90 (commandsToPicture cmds)
commandsToPicture (Say something : cmds) = pictures
    [ scale 0.3 0.3 (text something)
    , commandsToPicture cmds
    ]

-}

{-
3. try
commandsToPicture [] = blank
commandsToPicture ((n,Go length) : cmds) = annotate n $ pictures
    [ line [(0,0), (0, length)]
    , translate 0 length (commandsToPicture cmds)
    ]
commandsToPicture ((n,TurnLeft) : cmds) = annotate n $ rotate (-90) (commandsToPicture cmds)
commandsToPicture ((n,TurnRight) : cmds) = annotate n $ rotate 90 (commandsToPicture cmds)
commandsToPicture ((n,Say something) : cmds) = annotate n $ pictures
    [ scale 0.3 0.3 (text something)
    , commandsToPicture cmds
    ]
-}

annotate n picture = pictures [ scale 0.1 0.1 (text (show n)) , picture ]

commandsToPicture = toPicture commandToPicture

toPicture conv [] = blank
toPicture conv ((n,x):xs) = annotate n (conv x (toPicture conv xs))

commandToPicture (Go length) pics =  pictures
    [ line [(0,0), (0, length)]
    , translate 0 length pics
    ]
commandToPicture TurnLeft pics = rotate (-90) pics
commandToPicture TurnRight pics = rotate 90 pics
commandToPicture (Say something) pics = pictures
    [ scale 0.3 0.3 (text something)
    , pics
    ]

main = do
    csvOrError <- parseCSVFromFile "pen.csv"
    case csvOrError of
      Left error -> print error
      Right records ->
        displayInWindow "Pen demo" (400, 400) (800, 300) white $
            commandsToPicture $
            zip [1..] $
            map toCommand $
            records