-- Draws nested squares.  Solution to SA-3, with input added.
-- Demonstrates how to read and use numbers.
-- by Scot Drysdale on 10/1/07, modified 2/9/09

module Main where

import Graphics.SOE.Gtk

type Radius = Int

-- Creates a colored square centered at (x,y) with "radius" r
-- (where radius is half the side length)
makeSquare             :: Color -> Point -> Radius -> Graphic
makeSquare clr (x, y) r = withColor clr
  (polyline [(x-r, y-r), (x+r, y-r), (x+r, y+r), (x-r, y+r), (x-r, y-r)])
  
squareDraw = runGraphics (
       do w <- openWindow "One Square" (300, 300)
          drawInWindow w (makeSquare Blue (100,100) 50)
          spaceClose w)

-- Creates a group of nested squares, all centered at ctr, with
-- smallest radius sm, largest radius lg, step size step, and color clr.
makeNestedSquares  :: Point -> Radius -> Radius -> Int -> Color -> [Graphic]
makeNestedSquares ctr sm lg step clr 
  = map makeSq [sm, (sm+step) .. lg]
    where makeSq r = (makeSquare clr ctr r) 

-- Creates a list of draw commands from a list of Graphics
graphicsToIO       :: Window -> [Graphic] -> [IO ()]
graphicsToIO w list = map drawGraphic list
  where drawGraphic g = drawInWindow w g

main = runGraphics (
         do w <- openWindow "Nested Squares" (300, 300)
            putStr "Smallest radius = "
            small <- getLine
            let sm = read small
            putStr "Largest radius = "
            large <- getLine
            let lg = read large
            putStr "Increment = "
            incr <- getLine
            let inc = read incr
            let nest1 = makeNestedSquares (150, 150) sm lg inc Red
            sequence_ (graphicsToIO w nest1)
            spaceClose w)
            

-- This version uses readInt
main2 = runGraphics (
         do w <- openWindow "Nested Squares" (300, 300)
            sm <- readInt "Smallest radius = "
            lg <- readInt "Largest radius = "
            inc <- readInt "Increment = "
            
            let nest1 = makeNestedSquares (150, 150) sm lg inc Red
            sequence_ (graphicsToIO w nest1)
            spaceClose w)
       
-- A function to read an Int from the keyboard, using given prompt.  
-- Note that it returns IO Int, not Int.
readInt :: String -> IO Int
readInt prompt = 
  do
    putStr prompt
    numStr <- getLine
    let num = read numStr
    return num
     

-- From SOE
spaceClose :: Window -> IO ()
spaceClose w
  = do k <- getKey w
       if k==' ' || k == '\x0'
          then closeWindow w
          else spaceClose w