{-# 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           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
        (node, postNode) = case textSpanBy (/= '@') str of
                (x, y) -> if Data.Text.null y
                        then (Data.Text.empty, x)
                        else (x, Data.Text.drop 1 y)
        (domain, resource) = case textSpanBy (/= '/') postNode of
                (x, y) -> if Data.Text.null y
                        then (x, Data.Text.empty)
                        else (x, Data.Text.drop 1 y)
        nullable x f = if Data.Text.null x
                then Just Nothing
                else fmap Just (f x)
        maybeJID = do
                preppedNode <- nullable node (stringprepM SP.xmppNode)
                preppedDomain <- stringprepM SP.nameprep domain
                preppedResource <- nullable resource (stringprepM SP.xmppResource)
                return $ JID
                        (fmap Node preppedNode)
                        (Domain preppedDomain)
                        (fmap Resource preppedResource)
        stringprepM p x = case SP.stringprep p SP.defaultFlags x of
                Left _ -> Nothing
                Right y -> Just y

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