module Controller.Menu.Statistics.FrequencyDistribution (eventHandler)
    where

import Control.Monad (forM_)
import Data.List (nub)
import Controller (Controller,onGridView)
import View.Component.Grid (getColumnValues)
import Util (justWhen)
import qualified Controller.Grid as Grid
import Controller.Canonical (addRow)
import Controller.Menu.Table.Add (addColumn)
import Controller.Dialog (chooseColumnDialog)
import I18n (__)

eventHandler :: Controller ()
eventHandler = do
  selection <- chooseColumnDialog $ __ "Frequency Distribution"
  justWhen selection $ \colIndex ->
      do values <- onGridView $ getColumnValues colIndex
         Grid.new Nothing
         addColumn $ Just $ __ "Frequency"
         addColumn $ Just $ __ "Percentage"

         forM_ (freqDist values) $ \(value,freq,perc) ->
             do addRow (Just value,[show freq, show perc])

freqDist :: [String] -> [(String,Int,Double)]
freqDist values =
    let unique = nub values
        frequency = map (\s -> length $ filter ((==) s) values) unique
        numValues = length values
        percentage = map (\f -> fromIntegral f / (fromIntegral numValues)) frequency
    in
      zip3 unique frequency percentage