{-# LANGUAGE QuasiQuotes #-}
{-# LANGUAGE TypeFamilies #-}
{-# LANGUAGE FlexibleContexts #-}
{-# LANGUAGE OverloadedStrings #-}
{-# LANGUAGE CPP #-}
-- | Provide the user with a rich text editor.
module Yesod.Form.Nic
    ( YesodNic (..)
    , nicHtmlField
    ) where

import Yesod.Core
import Yesod.Form
import Text.HTML.SanitizeXSS (sanitizeBalance)
import Text.Hamlet (Html, shamlet)
import Text.Julius (julius, rawJS)
import Text.Blaze (preEscapedToMarkup)
import Text.Blaze.Html.Renderer.String (renderHtml)
import Data.Text (Text, pack)
import Data.Maybe (listToMaybe)

class Yesod a => YesodNic a where
    -- | NIC Editor Javascript file.
    urlNicEdit :: a -> Either (Route a) Text
    urlNicEdit _ = Right "http://js.nicedit.com/nicEdit-latest.js"

nicHtmlField :: YesodNic site => Field (HandlerT site IO) Html
nicHtmlField = Field
    { fieldParse = \e _ -> return . Right . fmap (preEscapedToMarkup . sanitizeBalance) . listToMaybe $ e
    , fieldView = \theId name attrs val _isReq -> do
        toWidget [shamlet|
$newline never
    <textarea id="#{theId}" *{attrs} name="#{name}" .html>#{showVal val}
|]
        addScript' urlNicEdit
        master <- getYesod
        toWidget $
          case jsLoader master of
            BottomOfHeadBlocking -> [julius|
bkLib.onDomLoaded(function(){new nicEditor({fullPanel:true}).panelInstance("#{rawJS theId}")});
|]
            _ -> [julius|
(function(){new nicEditor({fullPanel:true}).panelInstance("#{rawJS theId}")})();
|]
    , fieldEnctype = UrlEncoded
    }
  where
    showVal = either id (pack . renderHtml)

addScript' :: (MonadWidget m, HandlerSite m ~ site)
           => (site -> Either (Route site) Text)
           -> m ()
addScript' f = do
    y <- getYesod
    addScriptEither $ f y