module Util where

import Prelude ()
import BasicPrelude
import Control.Applicative (many)

import Data.Time (getCurrentTime)
import Data.XML.Types (Element(..), Node(NodeElement), isNamed, elementText, elementChildren, attributeText)
import qualified Data.Text as T
import qualified Network.Protocol.XMPP as XMPP
import qualified Data.Attoparsec.Text as Atto

log :: (Show a, MonadIO m) => String -> a -> m ()
log tag x = liftIO $ do
	time <- getCurrentTime
	putStr (show time ++ s" " ++ fromString tag ++ s" :: ") >> print x >> putStrLn mempty

s :: (IsString a) => String -> a
s = fromString

escapeJid :: Text -> Text
escapeJid txt = mconcat result
	where
	Right result = Atto.parseOnly (many (
			slashEscape <|>
			replace ' ' "\\20" <|>
			replace '"' "\\22" <|>
			replace '&' "\\26" <|>
			replace '\'' "\\27" <|>
			replace '/' "\\2f" <|>
			replace ':' "\\3a" <|>
			replace '<' "\\3c" <|>
			replace '>' "\\3e" <|>
			replace '@' "\\40" <|>
			fmap T.singleton Atto.anyChar
		) <* Atto.endOfInput) txt
	replace c str = Atto.char c *> pure (fromString str)
	-- XEP-0106 says to only escape \ when absolutely necessary
	slashEscape =
		fmap (s"\\5c"++) $
		Atto.char '\\' *> Atto.choice escapes
	escapes = map (Atto.string . fromString) [
			"20", "22", "26", "27", "2f", "3a", "3c", "3e", "40", "5c"
		]

unescapeJid :: Text -> Text
unescapeJid txt = fromString result
	where
	Right result = Atto.parseOnly (many (
			(Atto.char '\\' *> Atto.choice unescapes) <|>
			Atto.anyChar
		) <* Atto.endOfInput) txt
	unescapes = map (\(str, c) -> Atto.string (fromString str) *> pure c) [
			("20", ' '), ("22", '"'), ("26", '&'), ("27", '\''), ("2f", '/'), ("3a", ':'), ("3c", '<'), ("3e", '>'), ("40", '@'), ("5c", '\\')
		]

bareTxt (XMPP.JID (Just node) domain _) = mconcat [XMPP.strNode node, s"@", XMPP.strDomain domain]
bareTxt (XMPP.JID Nothing domain _) = XMPP.strDomain domain

getFormField form var =
		listToMaybe $ mapMaybe (\node ->
			case node of
				NodeElement el
					| elementName el == s"{jabber:x:data}field" &&
					  (attributeText (s"{jabber:x:data}var") el == Just var ||
					  attributeText (s"var") el == Just var) ->
						Just $ mconcat $
						elementText =<< isNamed (s"{jabber:x:data}value") =<< elementChildren el
				_ -> Nothing
		) (elementNodes form)