{-# LANGUAGE TupleSections, OverloadedStrings #-}
module Handler.Home where

import Import

import qualified Data.Text as T
import Text.Julius
import Yesod.WebSockets
import Turing.Examples
import Turing.Machine

data Cmd = Beginning | Backward | Forward | Poll deriving Read

wsTuring :: WebSocketsT Handler ()
wsTuring = evalLoop defaultMachine [defaultConfig]
    where defaultMachine = mWriteStr "Hello!"
          defaultConfig = mkConfig . map charToSym $  "_"
          evalLoop m [] = evalLoop m [defaultConfig]
          evalLoop m cfgs@(c:cs) = do
            sendTextData . T.pack . show $ c
            cmd <- receiveData
            case (read . T.unpack $ cmd) of
              Beginning -> evalLoop defaultMachine [defaultConfig]
              Backward -> evalLoop m cs
              Forward -> case step c (delta m) of
                           Just c' -> evalLoop m (c':cfgs)
                           Nothing -> evalLoop m cfgs
              Poll -> evalLoop m cfgs

getHomeR :: Handler Html
getHomeR = do
  webSockets wsTuring
  defaultLayout $ do
    setTitle "Turing simulator"

    -- JQuery
    addScriptRemote "https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"
    -- Bootstrap CSS
    addStylesheetRemote "https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/css/bootstrap.min.css"
    -- Bootstrap JS
    addScriptRemote "https://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"

    -- Identifiers used in HTML/JS code
    results <- newIdent
    butBeginning <- newIdent
    butBackward <- newIdent
    butTogglePlay <- newIdent
    butForward <- newIdent

    $(widgetFile "home")