{-# LANGUAGE OverloadedStrings
  , BangPatterns
  , MultiWayIf
  , LambdaCase
  , TemplateHaskell
#-}
module Main where


import           Control.Monad                  ( void )

import qualified Graphics.UI.FLTK.LowLevel.FL  as FL
import           Graphics.UI.FLTK.LowLevel.Fl_Types
import           Graphics.UI.FLTK.LowLevel.FLTKHS as FL

import           Control.Lens

import           Graphics.Rendering.Chart.Easy as Ch
import           Graphics.Rendering.Chart.Backend.FLTKHS


values :: [ (String,Double,Bool) ]
values = [ ("Mexico City",19.2,False), ("Mumbai",12.9,False), ("Sydney",4.3,False), ("London",8.3,False), ("New York",8.2,True) ]

pitem (s,v,o) = pitem_value .~ v
              $ pitem_label .~ s
              $ pitem_offset .~ (if o then 25 else 0)
              $ def

chart = toRenderable layout
    where
        values = [ ("Mexico City",19.2,e), ("Mumbai",12.9,e), ("Sydney",4.3,e), ("London",8.3,e), ("New York",8.2,e1) ]
        e = 0
        e1 = 25
        pitem (s,v,o) = pitem_value .~ v
                        $ pitem_label .~ s
                        $ pitem_offset .~ o
                        $ def

        layout = pie_title .~ "Relative Population"
                $ pie_plot . pie_data .~ map pitem values
                $ def



drawChart ::  Ref Widget -> IO ()
drawChart widget = do
    rectangle' <- getRectangle widget
    withFlClip rectangle' $
        renderToWidgetEC widget $ do
            pie_title .= "Relative Population"
            pie_plot . pie_data .= map pitem values



main :: IO ()
main = do
    let width  = 800
        height = 600

    window' <- doubleWindowNew (Size (Width width) (Height height))
                               Nothing
                               Nothing
    begin window'
    widget' <- widgetCustom
        (FL.Rectangle (Position (X 0) (Y 0)) (Size (Width width) (Height height)))
        Nothing
        drawChart
        defaultCustomWidgetFuncs
    end window'
    showWidget window'
    void FL.run