{-# LANGUAGE FlexibleInstances #-}
{-# LANGUAGE DeriveDataTypeable #-}
{-# LANGUAGE RankNTypes #-}
{-# LANGUAGE MultiParamTypeClasses #-}
{-# LANGUAGE FunctionalDependencies #-}

-- | Van Laarhoven lenses for XMPP types. The lenses are designed to work with
-- the lens library. This module also provides 3 simple accessors ('view',
-- 'modify', 'set') so you don't need to pull in the lens library to get some
-- use out of them.
module Network.Xmpp.Lens
       ( Lens
       , Traversal
         -- * Accessors
         -- | Reimplementation of the basic lens functions so you don't have to
         -- bring in all of lens library in to use the lenses
       , view
       , modify
       , set
         -- * Lenses
         -- ** Stanzas
       , IsStanza(..)
       , HasStanzaPayload(..)
       , IsErrorStanza(..)
       , messageTypeL
       , presenceTypeL
       , iqRequestTypeL
         -- ** StanzaError
       , stanzaErrorTypeL
       , stanzaErrorConditionL
       , stanzaErrorTextL
       , stanzaErrorApplL
         -- ** StreamConfiguration
       , preferredLangL
       , toJidL
       , connectionDetailsL
       , resolvConfL
       , establishSessionL
       , tlsBehaviourL
       , tlsParamsL
         -- ** SessionConfiguration
       , streamConfigurationL
       , onConnectionClosedL
       , sessionStanzaIDsL
       , ensableRosterL
       , pluginsL
       )
       where

import           Control.Applicative
import           Data.Functor.Identity(Identity(..))
import qualified Data.Text as Text
import           Data.Text(Text)
import           Data.XML.Types(Element)
import           Network.DNS(ResolvConf)
import           Network.TLS (TLSParams)
import           Network.Xmpp.Types
import           Network.Xmpp.Concurrent.Types

-- | Van-Laarhoven lenses.
type Lens a b = Functor f => (b -> f b) -> a -> f a

type Traversal a b = Applicative f => (b -> f b) -> a -> f a

class IsStanza s where
    -- | From-attribute of the stanza
    from :: Lens s (Maybe Jid)
    -- | To-attribute of the stanza
    to   :: Lens s (Maybe Jid)
    -- | Langtag of the stanza
    lang :: Lens s (Maybe LangTag)
    -- | Stanza ID. Setting this to /Nothing/ for IQ* stanzas will set the id to
    -- the empty Text.
    sid :: Lens s (Maybe Text)
    -- | Traversal over the payload elements.
    payloadT :: Traversal s Element

traverseList :: Traversal [a] a
traverseList _inj [] = pure []
traverseList inj  (x:xs) = (:) <$> inj x <*> traverseList inj xs

instance IsStanza Message where
    from inj m@(Message{messageFrom=f}) = (\f' -> m{messageFrom = f'}) <$> inj f
    to inj m@(Message{messageTo=t}) = (\t' -> m{messageTo = t'}) <$> inj t
    lang inj m@(Message{messageLangTag=t}) =
        (\t' -> m{messageLangTag = t'}) <$> inj t
    sid inj m@(Message{messageID = i}) =
        ((\i' -> m{messageID = i'}) <$> inj i)
    payloadT inj m@(Message{messagePayload=pl}) =
        (\pl' -> m{messagePayload=pl'}) <$> traverseList inj pl


instance IsStanza MessageError where
    from inj m@(MessageError{messageErrorFrom=f}) =
        (\f' -> m{messageErrorFrom = f'}) <$> inj f
    to inj m@(MessageError{messageErrorTo=t}) =
        (\t' -> m{messageErrorTo = t'}) <$> inj t
    lang inj m@(MessageError{messageErrorLangTag=t}) =
        (\t' -> m{messageErrorLangTag = t'}) <$> inj t
    sid inj m@(MessageError{messageErrorID = i}) =
        ((\i' -> m{messageErrorID = i'}) <$> inj i)
    payloadT inj m@(MessageError{messageErrorPayload=pl}) =
        (\pl' -> m{messageErrorPayload=pl'}) <$> traverseList inj pl

instance IsStanza Presence where
    from inj m@(Presence{presenceFrom=f}) = (\f' -> m{presenceFrom = f'}) <$> inj f
    to inj m@(Presence{presenceTo=t}) = (\t' -> m{presenceTo = t'}) <$> inj t
    lang inj m@(Presence{presenceLangTag=t}) =
        (\t' -> m{presenceLangTag = t'}) <$> inj t
    sid inj m@(Presence{presenceID = i}) =
        ((\i' -> m{presenceID = i'}) <$> inj i)
    payloadT inj m@(Presence{presencePayload=pl}) =
        (\pl' -> m{presencePayload=pl'}) <$> traverseList inj pl

instance IsStanza PresenceError where
    from inj m@(PresenceError{presenceErrorFrom=f}) =
        (\f' -> m{presenceErrorFrom = f'}) <$> inj f
    to inj m@(PresenceError{presenceErrorTo=t}) =
        (\t' -> m{presenceErrorTo = t'}) <$> inj t
    lang inj m@(PresenceError{presenceErrorLangTag=t}) =
        (\t' -> m{presenceErrorLangTag = t'}) <$> inj t
    sid inj m@(PresenceError{presenceErrorID = i}) =
        ((\i' -> m{presenceErrorID = i'}) <$> inj i)
    payloadT inj m@(PresenceError{presenceErrorPayload=pl}) =
        (\pl' -> m{presenceErrorPayload=pl'}) <$> traverseList inj pl

instance IsStanza IQRequest where
    from inj m@(IQRequest{iqRequestFrom=f}) =
        (\f' -> m{iqRequestFrom = f'}) <$> inj f
    to inj m@(IQRequest{iqRequestTo=t}) =
        (\t' -> m{iqRequestTo = t'}) <$> inj t
    lang inj m@(IQRequest{iqRequestLangTag=t}) =
        (\t' -> m{iqRequestLangTag = t'}) <$> inj t
    sid inj m@(IQRequest{iqRequestID = i}) =
        ((\i' -> m{iqRequestID = i'}) <$> maybeNonempty inj i)
    payloadT inj m@(IQRequest{iqRequestPayload=pl}) =
        (\pl' -> m{iqRequestPayload=pl'}) <$> inj pl

instance IsStanza IQResult where
    from inj m@(IQResult{iqResultFrom=f}) =
        (\f' -> m{iqResultFrom = f'}) <$> inj f
    to inj m@(IQResult{iqResultTo=t}) =
        (\t' -> m{iqResultTo = t'}) <$> inj t
    lang inj m@(IQResult{iqResultLangTag=t}) =
        (\t' -> m{iqResultLangTag = t'}) <$> inj t
    sid inj m@(IQResult{iqResultID = i}) =
        ((\i' -> m{iqResultID = i'}) <$> maybeNonempty inj i)
    payloadT inj m@(IQResult{iqResultPayload=pl}) =
        (\pl' -> m{iqResultPayload=pl'}) <$> maybe (pure Nothing)
                                                   (fmap Just . inj) pl

instance IsStanza IQError where
    from inj m@(IQError{iqErrorFrom=f}) =
        (\f' -> m{iqErrorFrom = f'}) <$> inj f
    to inj m@(IQError{iqErrorTo=t}) =
        (\t' -> m{iqErrorTo = t'}) <$> inj t
    lang inj m@(IQError{iqErrorLangTag=t}) =
        (\t' -> m{iqErrorLangTag = t'}) <$> inj t
    sid inj m@(IQError{iqErrorID = i}) =
        ((\i' -> m{iqErrorID = i'}) <$> maybeNonempty inj i)
    payloadT inj m@(IQError{iqErrorPayload=pl}) =
        (\pl' -> m{iqErrorPayload=pl'}) <$> maybe (pure Nothing)
                                                  (fmap Just . inj) pl

liftLens :: (forall s. IsStanza s => Lens s a) -> Lens Stanza a
liftLens f inj (IQRequestS     s) = IQRequestS     <$> f inj s
liftLens f inj (IQResultS      s) = IQResultS      <$> f inj s
liftLens f inj (IQErrorS       s) = IQErrorS       <$> f inj s
liftLens f inj (MessageS       s) = MessageS       <$> f inj s
liftLens f inj (MessageErrorS  s) = MessageErrorS  <$> f inj s
liftLens f inj (PresenceS      s) = PresenceS      <$> f inj s
liftLens f inj (PresenceErrorS s) = PresenceErrorS <$> f inj s

liftTraversal :: (forall s. IsStanza s => Traversal s a) -> Traversal Stanza a
liftTraversal f inj (IQRequestS     s) = IQRequestS     <$> f inj s
liftTraversal f inj (IQResultS      s) = IQResultS      <$> f inj s
liftTraversal f inj (IQErrorS       s) = IQErrorS       <$> f inj s
liftTraversal f inj (MessageS       s) = MessageS       <$> f inj s
liftTraversal f inj (MessageErrorS  s) = MessageErrorS  <$> f inj s
liftTraversal f inj (PresenceS      s) = PresenceS      <$> f inj s
liftTraversal f inj (PresenceErrorS s) = PresenceErrorS <$> f inj s

instance IsStanza Stanza where
    from     = liftLens from
    to       = liftLens to
    lang     = liftLens lang
    sid      = liftLens sid
    payloadT = liftTraversal payloadT

maybeNonempty :: Lens Text (Maybe Text)
maybeNonempty inj x = (maybe Text.empty id)
                      <$> inj (if Text.null x then Nothing else Just x)


class IsErrorStanza s where
    -- | Error element of the stanza
    stanzaError :: Lens s StanzaError

instance IsErrorStanza IQError where
    stanzaError inj m@IQError{iqErrorStanzaError = i} =
        (\i' -> m{iqErrorStanzaError = i'}) <$> inj i

instance IsErrorStanza MessageError where
    stanzaError inj m@MessageError{messageErrorStanzaError = i} =
        (\i' -> m{messageErrorStanzaError = i'}) <$> inj i

instance IsErrorStanza PresenceError where
    stanzaError inj m@PresenceError{presenceErrorStanzaError = i} =
        (\i' -> m{presenceErrorStanzaError = i'}) <$> inj i

class HasStanzaPayload s p | s -> p where
    -- | Payload element(s) of the stanza. Since the amount of elements possible
    -- in a stanza vary by type, this lens can't be used with a general
    -- 'Stanza'. There is, however, a more general Traversable that works with
    -- all stanzas (including 'Stanza'): 'payloadT'
    payload :: Lens s p

instance HasStanzaPayload IQRequest Element where
    payload inj m@IQRequest{iqRequestPayload = i} =
        (\i' -> m{iqRequestPayload = i'}) <$> inj i

instance HasStanzaPayload IQResult (Maybe Element) where
    payload inj m@IQResult{iqResultPayload = i} =
        (\i' -> m{iqResultPayload = i'}) <$> inj i

instance HasStanzaPayload IQError (Maybe Element) where
    payload inj m@IQError{iqErrorPayload = i} =
        (\i' -> m{iqErrorPayload = i'}) <$> inj i

instance HasStanzaPayload Message [Element] where
    payload inj m@Message{messagePayload = i} =
        (\i' -> m{messagePayload = i'}) <$> inj i

instance HasStanzaPayload MessageError [Element] where
    payload inj m@MessageError{messageErrorPayload = i} =
        (\i' -> m{messageErrorPayload = i'}) <$> inj i

instance HasStanzaPayload Presence [Element] where
    payload inj m@Presence{presencePayload = i} =
        (\i' -> m{presencePayload = i'}) <$> inj i

instance HasStanzaPayload PresenceError [Element] where
    payload inj m@PresenceError{presenceErrorPayload = i} =
        (\i' -> m{presenceErrorPayload = i'}) <$> inj i

iqRequestTypeL :: Lens IQRequest IQRequestType
iqRequestTypeL inj p@IQRequest{iqRequestType = tp} =
    (\tp' -> p{iqRequestType = tp'}) <$> inj tp


messageTypeL :: Lens Message MessageType
messageTypeL inj p@Message{messageType = tp} =
    (\tp' -> p{messageType = tp'}) <$> inj tp

presenceTypeL :: Lens Presence PresenceType
presenceTypeL inj p@Presence{presenceType = tp} =
    (\tp' -> p{presenceType = tp'}) <$> inj tp


-- StanzaError
-----------------------

stanzaErrorTypeL :: Lens StanzaError StanzaErrorType
stanzaErrorTypeL inj se@StanzaError{stanzaErrorType = x} =
    (\x' -> se{stanzaErrorType = x'}) <$> inj x

stanzaErrorConditionL :: Lens StanzaError StanzaErrorCondition
stanzaErrorConditionL inj se@StanzaError{stanzaErrorCondition = x} =
    (\x' -> se{stanzaErrorCondition = x'}) <$> inj x

stanzaErrorTextL :: Lens StanzaError (Maybe (Maybe LangTag, Text))
stanzaErrorTextL inj se@StanzaError{stanzaErrorText = x} =
    (\x' -> se{stanzaErrorText = x'}) <$> inj x

stanzaErrorApplL  :: Lens StanzaError (Maybe Element)
stanzaErrorApplL inj se@StanzaError{stanzaErrorApplicationSpecificCondition = x} =
    (\x' -> se{stanzaErrorApplicationSpecificCondition = x'}) <$> inj x


-- StreamConfiguration
-----------------------

preferredLangL :: Lens StreamConfiguration (Maybe LangTag)
preferredLangL inj sc@StreamConfiguration{preferredLang = x}
    = (\x' -> sc{preferredLang = x'}) <$> inj x

toJidL :: Lens StreamConfiguration (Maybe (Jid, Bool))
toJidL inj sc@StreamConfiguration{toJid = x}
    = (\x' -> sc{toJid = x'}) <$> inj x

connectionDetailsL :: Lens StreamConfiguration ConnectionDetails
connectionDetailsL inj sc@StreamConfiguration{connectionDetails = x}
    = (\x' -> sc{connectionDetails = x'}) <$> inj x

resolvConfL :: Lens StreamConfiguration ResolvConf
resolvConfL inj sc@StreamConfiguration{resolvConf = x}
    = (\x' -> sc{resolvConf = x'}) <$> inj x

establishSessionL :: Lens StreamConfiguration Bool
establishSessionL inj sc@StreamConfiguration{establishSession = x}
    = (\x' -> sc{establishSession = x'}) <$> inj x

tlsBehaviourL :: Lens StreamConfiguration TlsBehaviour
tlsBehaviourL inj sc@StreamConfiguration{tlsBehaviour = x}
    = (\x' -> sc{tlsBehaviour = x'}) <$> inj x

tlsParamsL :: Lens StreamConfiguration TLSParams
tlsParamsL inj sc@StreamConfiguration{tlsParams = x}
    = (\x' -> sc{tlsParams = x'}) <$> inj x

-- SessioConfiguration
-----------------------
streamConfigurationL :: Lens SessionConfiguration StreamConfiguration
streamConfigurationL inj sc@SessionConfiguration{sessionStreamConfiguration = x}
    = (\x' -> sc{sessionStreamConfiguration = x'}) <$> inj x

onConnectionClosedL :: Lens SessionConfiguration (Session -> XmppFailure -> IO ())
onConnectionClosedL inj sc@SessionConfiguration{onConnectionClosed = x}
    = (\x' -> sc{onConnectionClosed = x'}) <$> inj x

sessionStanzaIDsL :: Lens SessionConfiguration (IO (IO Text))
sessionStanzaIDsL inj sc@SessionConfiguration{sessionStanzaIDs = x}
    = (\x' -> sc{sessionStanzaIDs = x'}) <$> inj x

ensableRosterL :: Lens SessionConfiguration Bool
ensableRosterL inj sc@SessionConfiguration{enableRoster = x}
    = (\x' -> sc{enableRoster = x'}) <$> inj x

pluginsL :: Lens SessionConfiguration [Plugin]
pluginsL inj sc@SessionConfiguration{plugins = x}
    = (\x' -> sc{plugins = x'}) <$> inj x

-- | Read the value the lens is pointing to
view :: Lens a b -> a -> b
view l x = getConst $ l Const x

-- | Modify the value the lens is pointing to
modify :: Lens a b -> (b -> b) -> a -> a
modify l f x = runIdentity $ l (fmap f . Identity) x

-- | Replace the value the lens is pointing to
set :: Lens a b -> b -> a -> a
set l b x = modify l (const b) x