{-# LANGUAGE CPP #-}

-- Copyright (C) 2010-2011 John Millikin <jmillikin@gmail.com>
-- 
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- any later version.
-- 
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-- GNU General Public License for more details.
-- 
-- You should have received a copy of the GNU General Public License
-- along with this program.  If not, see <http://www.gnu.org/licenses/>.

module Network.Protocol.XMPP.JID
	( JID (..)
	, Node (..)
	, Domain (..)
	, Resource (..)

	, parseJID
	, parseJID_
	, formatJID
	) where

import           Data.Maybe (fromMaybe)
import qualified Data.Text
import           Data.Text (Text)
import qualified Data.Text.IDN.StringPrep as SP
import qualified Data.Text.IDN.IDNA as IDNA
import           Data.String (IsString, fromString)

newtype Node = Node { strNode :: Text }
newtype Domain = Domain { strDomain :: Text }
newtype Resource = Resource { strResource :: Text }

instance Show Node where
	showsPrec d (Node x) = showParen (d > 10) $
		showString "Node " . shows x

instance Show Domain where
	showsPrec d (Domain x) = showParen (d > 10) $
		showString "Domain " . shows x

instance Show Resource where
	showsPrec d (Resource x) = showParen (d > 10) $
		showString "Resource " . shows x

instance Eq Node where
	(==) = equaling strNode

instance Eq Domain where
	(==) = equaling strDomain

instance Eq Resource where
	(==) = equaling strResource

data JID = JID
	{ jidNode :: Maybe Node
	, jidDomain :: Domain
	, jidResource :: Maybe Resource
	}
	deriving (Eq)

instance Show JID where
	showsPrec d jid =  showParen (d > 10) $
		showString "JID " . shows (formatJID jid)

instance IsString JID where
	fromString = parseJID_ . fromString

parseJID :: Text -> Maybe JID
parseJID str = maybeJID where
	(bare, resource) = case textSpanBy (/= '/') str of
		(x, y) -> if Data.Text.null y
			then (x, Nothing)
			else (x, Just $ Data.Text.drop 1 y)
	(node, domain) = case textSpanBy (/= '@') bare of
		(x, y) -> if Data.Text.null y
			then (Nothing, x)
			else (Just x, Data.Text.drop 1 y)
	nullable Nothing _ = Just Nothing
	nullable (Just x) f = if Data.Text.null x
		then Nothing
		else fmap Just (f x)
	maybeJID = do
		preppedNode <- nullable node (stringprepM SP.xmppNode)
		preppedDomain <- fmap (IDNA.toUnicode IDNA.defaultFlags)
			(rightToJust $ IDNA.toASCII IDNA.defaultFlags domain)
		preppedResource <- nullable resource (stringprepM SP.xmppResource)
		if Data.Text.null preppedDomain
			then Nothing
			else return $ JID
				(fmap Node preppedNode)
				(Domain preppedDomain)
				(fmap Resource preppedResource)
	rightToJust (Left _) = Nothing
	rightToJust (Right y) = Just y
	stringprepM p x = rightToJust $ SP.stringprep p SP.defaultFlags x

parseJID_ :: Text -> JID
parseJID_ = fromMaybe (error "Malformed JID") . parseJID

formatJID :: JID -> Text
formatJID (JID node (Domain domain) resource) = formatted where
	formatted = Data.Text.concat [node', domain, resource']
	node' = maybe Data.Text.empty (\(Node x) -> Data.Text.snoc x '@') node
	resource' = maybe Data.Text.empty (\(Resource x) -> Data.Text.cons '/' x) resource

-- Similar to 'comparing'
equaling :: Eq a => (b -> a) -> b -> b -> Bool
equaling f x y = f x == f y

-- multi-version 'text' compatibility
textSpanBy :: (Char -> Bool) -> Text -> (Text, Text)
#if MIN_VERSION_text(0,11,0)
textSpanBy = Data.Text.span
#else
textSpanBy = Data.Text.spanBy
#endif