module BenchVerticalScroll where

import Graphics.Vty hiding ( pad )
import Verify

import Control.Concurrent( threadDelay )
import Control.Monad( liftM2 )

import Data.Default (def)
import Data.List
import Data.Word

import System.Environment( getArgs )
import System.IO
import System.Random

bench0 = do 
    let fixedGen = mkStdGen 0
    setStdGen fixedGen
    return $ Bench (return ()) (\() -> mkVty def >>= liftM2 (>>) run shutdown)

run vt  = mapM_ (\p -> update vt p) . benchgen =<< displayBounds (outputIface vt)

-- Currently, we just do scrolling.
takem :: (a -> Int) -> Int -> [a] -> ([a],[a])
takem len n [] = ([],[])
takem len n (x:xs) | lx > n = ([], x:xs)
                   | True = let (tk,dp) = takem len (n - lx) xs in (x:tk,dp)
    where lx = len x

fold :: (a -> Int) -> [Int] -> [a] -> [[a]]
fold len [] xs = []
fold len (ll:lls) xs = let (tk,dp) = takem len ll xs in tk : fold len lls dp

lengths :: Int -> StdGen -> [Int]
lengths ml g =
    let (x,g2) = randomR (0,ml) g
        (y,g3) = randomR (0,x) g2
    in y : lengths ml g3

nums :: StdGen -> [(Attr, String)]
nums g = let (x,g2) = (random g :: (Int, StdGen))
             (c,g3) = random g2
         in ( if c then defAttr `withForeColor` red else defAttr
            , shows x " "
            ) : nums g3

pad :: Int -> Image -> Image
pad ml img = img <|> charFill defAttr ' ' (ml - imageWidth img) 1

clines :: StdGen -> Int -> [Image]
clines g maxll = map (pad maxll . horizCat . map (uncurry string)) 
                 $ fold (length . snd) (lengths maxll g1) (nums g2)
  where (g1,g2)  = split g

benchgen :: DisplayRegion -> [Picture]
benchgen (w,h) 
    = take 2000 $ map ((\i -> picForImage i) . vertCat . take (fromEnum h))
        $ tails
        $ clines (mkStdGen 80) w