{-# LANGUAGE EmptyDataDecls #-}
{-# LANGUAGE NoImplicitPrelude #-}

-- | The home page script:
-- 
--  1) Make sure that the language samples are highlighted.
--  2) Add a show/hide button for the JS output on all samples.
--  3) For code samples that are too large, hide them.
-- 
-- Because dogfood. This is not necessarily a good example, indeed, it
-- may very well be a very bad example of how to write client
-- code. But that's the point, really. Even the quick scripts that
-- you'd just whip up in JS should be also done in Fay. Alright?
--

module Home (main) where

import Language.Fay.FFI
import Language.Fay.Prelude

-- | Main entry point.
main :: Fay ()
main = do
  ready (jquery [thedocument]) $ do
    samples <- query ".language-javascript"
    forM_ samples $ \this ->
      let sample = jquery [this]
      in do text <- getText sample
            setText sample
                    (beautify text 2)
    setTabReplace hljs "    "
    initHighlightingOnLoad hljs
    wrapwidth <- query ".wrap" >>= getWidth . jquery
    each ".example" $ \this -> do
      tr <- getFind this "tr"
      left <- getFind tr "td" >>= getFirst
      addClass left "left"
      right <- getNext left
      toggle <- makeElement "<a class='toggle' href='javascript:'>Show JavaScript</a>"
      toggleButton <- return $ do
        visible <- getIs right ":visible"
        if visible
           then do setText toggle "Hide JavaScript"
                   swapClasses toggle "toggle-hide" "toggle-show"
           else do setText toggle "Show JavaScript"
                   swapClasses toggle "toggle-show" "toggle-hide"
      setClick toggle $ fadeToggle right $ toggleButton
      width <- getWidth tr
      when (width > wrapwidth + 20*wrapwidth/100) $ hide right
      toggleButton
      panel <- getFind left ".panel"
      prepend panel toggle
      return ()

--------------------------------------------------------------------------------
-- Window object

-- | Console log.
print :: (Show a,Foreign a) => a -> Fay ()
print = foreignFay "console.log" FayNone

-- | Pop-up an alert.
alert :: String -> Fay ()
alert = foreignFay "window.alert" FayNone

--------------------------------------------------------------------------------
-- DOM

data Element
instance Foreign Element
instance Show Element

-- | The document.
thedocument :: Element
thedocument = foreignValue "window.document" FayNone

--------------------------------------------------------------------------------
-- jQuery

data JQuery
instance Foreign JQuery
instance Show JQuery

-- | Make a jQuery object out of an element.
jquery :: [Element] -> JQuery
jquery = foreignPure "window['jQuery']" FayNone

-- | Bind a handler for when the element is ready.
ready :: JQuery -> Fay () -> Fay ()
ready = foreignMethodFay "ready" FayNone

-- | Query for elements.
query :: String -> Fay [Element]
query = foreignFay "window['jQuery']" FayList

-- | Set the text of the given object.
setText :: JQuery -> String -> Fay ()
setText = foreignMethodFay "text" FayNone

-- | Set the click of the given object.
setClick :: JQuery -> Fay () -> Fay ()
setClick = foreignMethodFay "click" FayNone

-- | Toggle the visibility of an element, faded.
fadeToggle :: JQuery -> Fay () -> Fay ()
fadeToggle = foreignMethodFay "fadeToggle" FayNone

-- | Hide an element.
hide :: JQuery -> Fay ()
hide = foreignMethodFay "hide" FayNone

-- | Add a class to the given object.
addClass :: JQuery -> String -> Fay ()
addClass = foreignMethodFay "addClass" FayNone

-- | Remove a class from the given object.
removeClass :: JQuery -> String -> Fay ()
removeClass = foreignMethodFay "removeClass" FayNone

-- | Swap the given classes on the object.
swapClasses :: JQuery -> String -> String -> Fay ()
swapClasses obj addme removeme = do
  addClass obj addme
  removeClass obj removeme

-- | Get the text of the given object.
getText :: JQuery -> Fay String
getText = foreignMethodFay "text" FayString

-- | Get the text of the given object.
getIs :: JQuery -> String -> Fay Bool
getIs = foreignMethodFay "is" FayBool

-- | Get the next of the given object.
getNext :: JQuery -> Fay JQuery
getNext = foreignMethodFay "next" FayNone

-- | Get the first of the given object.
getFirst :: JQuery -> Fay JQuery
getFirst = foreignMethodFay "first" FayNone

-- | Get the find of the given object.
getFind :: JQuery -> String -> Fay JQuery
getFind = foreignMethodFay "find" FayNone

-- | Prepend an element to this one.
prepend :: JQuery -> JQuery -> Fay JQuery
prepend = foreignMethodFay "prepend" FayNone

-- | Make a new element.
makeElement :: String -> Fay JQuery
makeElement = foreignFay "window['jQuery']" FayNone

-- | Get the width of the given object.
getWidth :: JQuery -> Fay Double
getWidth = foreignMethodFay "width" FayNone

-- | For each element in a query set do something.
each :: String -> (JQuery -> Fay ()) -> Fay ()
each q go = do
  results <- query q
  forM_ results $ \result -> go (jquery [result])

--------------------------------------------------------------------------------
-- Pretty printing / highlighting

-- | Pretty print the given JS code.
beautify :: String -- ^ The JS code.
         -> Double -- ^ The indentation level.
         -> String -- ^ The reformatted JS code.
beautify = foreignPure "$jsBeautify" FayString

data Highlighter
instance Foreign Highlighter

-- | Get the highlighter.
hljs :: Highlighter
hljs = foreignValue "window['hljs']" FayNone

-- | Init syntax highlighting on load.
initHighlightingOnLoad :: Highlighter -> Fay ()
initHighlightingOnLoad = foreignMethodFay "initHighlightingOnLoad" FayNone

-- | Init syntax highlighting on load.
setTabReplace :: Highlighter -> String -> Fay ()
setTabReplace = foreignSetProp "tabReplace"