{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE DataKinds #-}
{-# LANGUAGE TypeSynonymInstances #-}

module IHaskell.Display.Widgets.Selection.SelectMultiple (
-- * The SelectMultiple Widget
SelectMultiple, 
                -- * Constructor
                mkSelectMultiple) where

-- To keep `cabal repl` happy when running from the ihaskell repo
import           Prelude

import           Control.Monad (fmap, join, sequence, void)
import           Data.Aeson
import qualified Data.HashMap.Strict as HM
import           Data.IORef (newIORef)
import           Data.Text (Text)
import qualified Data.Vector as V
import           Data.Vinyl (Rec(..), (<+>))

import           IHaskell.Display
import           IHaskell.Eval.Widgets
import           IHaskell.IPython.Message.UUID as U

import           IHaskell.Display.Widgets.Types
import           IHaskell.Display.Widgets.Common

-- | A 'SelectMultiple' represents a SelectMultiple widget from IPython.html.widgets.
type SelectMultiple = IPythonWidget SelectMultipleType

-- | Create a new SelectMultiple widget
mkSelectMultiple :: IO SelectMultiple
mkSelectMultiple = do
  -- Default properties, with a random uuid
  uuid <- U.random
  let widgetState = WidgetState $ defaultMultipleSelectionWidget "SelectMultipleView"

  stateIO <- newIORef widgetState

  let widget = IPythonWidget uuid stateIO

  -- Open a comm for this widget, and store it in the kernel state
  widgetSendOpen widget $ toJSON widgetState

  -- Return the widget
  return widget

instance IHaskellDisplay SelectMultiple where
  display b = do
    widgetSendView b
    return $ Display []

instance IHaskellWidget SelectMultiple where
  getCommUUID = uuid
  comm widget (Object dict1) _ = do
    let key1 = "sync_data" :: Text
        key2 = "selected_labels" :: Text
        Just (Object dict2) = HM.lookup key1 dict1
        Just (Array labels) = HM.lookup key2 dict2
        labelList = map (\(String x) -> x) $ V.toList labels
    opts <- getField widget Options
    case opts of
      OptionLabels _ -> void $ do
        setField' widget SelectedLabels labelList
        setField' widget SelectedValues labelList
      OptionDict ps ->
        case sequence $ map (`lookup` ps) labelList of
          Nothing -> return ()
          Just valueList -> void $ do
            setField' widget SelectedLabels labelList
            setField' widget SelectedValues valueList
    triggerSelection widget