import Data.Complex
import System.Environment(getArgs)

type C = Complex(Double)

mandelbrot_eval::Int->C->Int
mandelbrot_eval max_iter c =
  length
  $ (takeWhile (\z -> (magnitude z) < 2))
  $ (take max_iter)
  $ (iterate (\z ->  z*z+c) (0:+0) )

-- half_width_pixels::Int
-- half_width_pixels = 10240

-- at 12800: 9162 seconds (153 minutes)
-- at 10240: 99m 44s

scaling:: Int -> Double->Int->Double
scaling half_width_pixels width = (* (width
            /(fromIntegral half_width_pixels)))
          . fromIntegral
range:: Int -> Double->[Double]
range half_width_pixels width= map (scaling half_width_pixels width)
    [1-half_width_pixels .. half_width_pixels]

-- the "28" was discovered by trial and error for zoom 6.

-- Also consider zoom 5.42 if only the center section is going to be cut out to create a rectangular image
iterations::Int
iterations = 100000;
-- 310+28 -- 310;
--  perl -plwe 'next unless /^\d+$/;if($_>255){$_=255}' fileout | xloadimage stdin
--  perl -plwe 'next unless /^-?\d+$/;if($_>255){$_=255}elsif($_<0){$_=0}' fileout | xloadimage stdin

truncrange :: Int -> Int
truncrange i = if (i>255) then 255 else if (i<0) then 0 else i;

color :: Int -> Int -> [Int];
color max_iter i = if i==max_iter then [0,0,0] else
                       [i-55,i-55,i]
-- (\i -> [i-55-28,i-55-28,i-28]) -- (\i -> [i-55,i-55,i])

main::IO ()
main = do
   args <- getArgs
   let half_width_pixels :: Int
       half_width_pixels = read $ args !! 1
       s = show $ 2*half_width_pixels
   putStrLn ("P3\n"++s++" "++s++"\n"++"255");

   let side::Double
       side  = exp(-(read (head args)))
       the_range :: [Double]
       the_range = range half_width_pixels side
   putStr $ unlines $ map (show.truncrange)
    $ concatMap ((color iterations)
                . (mandelbrot_eval iterations)
                . (+ center) )
    $ [x:+y | x<- the_range, y<- the_range]


center::C
center =  0.4245127190 :+ 0.2075302281

-- Fenway House is looking for new residents!