{-

Copyright © 2010-2011 Jon Kristensen.

This file is part of Pontarius XMPP.

Pontarius XMPP is free software: you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free
Software Foundation, either version 3 of the License, or (at your option) any
later version.

Pontarius XMPP 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 Lesser General Public License for more
details.

You should have received a copy of the GNU Lesser General Public License along
with Pontarius XMPP. If not, see <http://www.gnu.org/licenses/>.

-}


-- TODO: Move away from stringprep for all three profiles.

-- TODO: When no longer using stringprep, do appropriate testing. (Including
-- testing addresses like a@b/c@d/e, a/b@c, a@/b, a/@b...)

-- TODO: Unicode 3.2 should be used.


-- |
-- Module:      $Header$
-- Description: Data type and utility functions for XMPP addresses (JIDs)
-- Copyright:   Copyright © 2010-2011 Jon Kristensen
-- License:     LGPL-3
--
-- Maintainer:  info@pontarius.org
-- Stability:   unstable
-- Portability: portable
--
-- This module deals with XMPP addresses (also known as JIDs and JabberIDs). For
-- more information on XMPP addresses, see RFC 6122: XMPP: Address Format.
--
-- Provided hostnames may contain international characters; Pontarius XMPP will
-- try to convert such hostnames to internationalized hostnames.


module Network.XMPP.Address (fromString, fromStrings, isBare, isFull) where

import Network.XMPP.Types

import Data.Maybe (fromJust, isJust)
import Text.Parsec ((<|>), anyToken, char, eof, many, noneOf, parse)
import Text.Parsec.ByteString (GenParser)

import Text.StringPrep (StringPrepProfile (..), a1, b1, b2, c11, c12, c21, c22,
                        c3, c4, c5, c6, c7, c8, c9, runStringPrep)
import Text.NamePrep (namePrepProfile)

import Data.Text.IDNA2008 (toASCII)

import Network.URI (isIPv4address, isIPv6address)

import qualified Data.ByteString.Char8 as DBC (pack)
import qualified Data.Text as DT (pack, unpack)


-- |
-- Converts a string to an XMPP address.

fromString :: String -> Maybe Address

fromString s = fromStrings localpart serverpart resourcepart
    where
        Right (localpart, serverpart, resourcepart) =
            parse addressParts "" (DBC.pack s)


-- |
-- Converts localpart, serverpart, and resourcepart strings to an XMPP address.

-- Runs the appropriate stringprep profiles and validates the parts.

fromStrings :: Maybe String -> String -> Maybe String -> Maybe Address

fromStrings l s r
    | serverpart == Nothing = Nothing
    | otherwise = if validateNonServerpart localpart &&
                     isJust serverpart' &&
                     validateNonServerpart resourcepart
                  then Just (Address localpart (fromJust serverpart') resourcepart)
                  else Nothing
    where

        -- Applies the nodeprep profile on the localpart string, if any.
        localpart :: Maybe String
        localpart = case l of
            Just l' -> case runStringPrep nodeprepProfile (DT.pack l') of
                Just l'' -> Just $ DT.unpack l''
                Nothing -> Nothing
            Nothing -> Nothing

        -- Applies the nameprep profile on the serverpart string.
        -- TODO: Allow unassigned?
        serverpart :: Maybe String
        serverpart = case runStringPrep (namePrepProfile False) (DT.pack s) of
            Just s' -> Just $ DT.unpack s'
            Nothing -> Nothing

        -- Applies the resourceprep profile on the resourcepart string, if any.
        resourcepart :: Maybe String
        resourcepart = case r of
            Just r' -> case runStringPrep resourceprepProfile (DT.pack r') of
                Just r'' -> Just $ DT.unpack r''
                Nothing -> Nothing
            Nothing -> Nothing

        -- Returns the serverpart if it was a valid IP or if the toASCII
        -- function was successful, or Nothing otherwise.
        serverpart' :: Maybe String
        serverpart' | isIPv4address s || isIPv6address s = Just s
                    | otherwise = toASCII s

        -- Validates that non-serverpart strings have an appropriate length.
        validateNonServerpart :: Maybe String -> Bool
        validateNonServerpart Nothing = True
        validateNonServerpart (Just l) = validPartLength l
            where
                validPartLength :: String -> Bool
                validPartLength p = length p > 0 && length p < 1024


-- | Returns True if the address is `bare', and False otherwise.

isBare :: Address -> Bool

isBare j | resourcepart j == Nothing = True
         | otherwise                 = False


-- | Returns True if the address is `full', and False otherwise.

isFull :: Address -> Bool

isFull jid = not $ isBare jid


-- Parses an address string and returns its three parts. It performs no
-- validation or transformations. We are using Parsec to parse the address.
-- There is no input for which 'addressParts' fails.

addressParts :: GenParser Char st (Maybe String, String, Maybe String)

addressParts = do

    -- Read until we reach an '@', a '/', or EOF.
    a <- many $ noneOf ['@', '/']

    -- Case 1: We found an '@', and thus the localpart. At least the serverpart
    -- is remaining. Read the '@' and until a '/' or EOF.
    do
        char '@'
        b <- many $ noneOf ['/']

        -- Case 1A: We found a '/' and thus have all the address parts. Read the
        -- '/' and until EOF.
        do
            char '/' -- Resourcepart remaining
            c <- many $ anyToken -- Parse resourcepart
            eof
            return (Just a, b, Just c)

        -- Case 1B: We have reached EOF; the address is in the form
        -- localpart@serverpart.
            <|> do
                eof
                return (Just a, b, Nothing)

        -- Case 2: We found a '/'; the address is in the form
        -- serverpart/resourcepart.
        <|> do
            char '/'
            b <- many $ anyToken
            eof
            return (Nothing, a, Just b)

        -- Case 3: We have reached EOF; we have an address consisting of only a
        -- serverpart.
        <|> do
            eof
            return (Nothing, a, Nothing)


nodeprepProfile :: StringPrepProfile

nodeprepProfile = Profile { maps = [b1, b2]
                          , shouldNormalize = True
                          , prohibited = [a1] ++ [c11, c12, c21, c22, c3, c4, c5, c6, c7, c8, c9]
                          , shouldCheckBidi = True }


-- These needs to be checked for after normalization. We could also look up the
-- Unicode mappings and include a list of characters in the prohibited field
-- above. Let's defer that until we know that we are going to use stringprep.

nodeprepExtraProhibitedCharacters = ['\x22', '\x26', '\x27', '\x2F', '\x3A',
                                     '\x3C', '\x3E', '\x40']



resourceprepProfile :: StringPrepProfile

resourceprepProfile = Profile { maps = [b1]
                          , shouldNormalize = True
                          , prohibited = [a1] ++ [c12, c21, c22, c3, c4, c5, c6, c7, c8, c9]
                          , shouldCheckBidi = True }