{-# LANGUAGE RecordWildCards, OverloadedStrings #-}

module Development.Bake.Core.Message(
    Message(..), Ping(..), Question(..), Answer(..),
    sendMessage, messageToInput, messageFromInput, questionToOutput
    ) where

import Development.Bake.Core.Type
import General.Web
import Control.Applicative
import Control.Monad
import Control.DeepSeq
import Data.Aeson hiding (Success)
import System.Time.Extra
import Safe
import qualified Data.Text.Lazy as TL
import qualified Data.ByteString.Lazy.Char8 as LBS
import Prelude


data Message
    -- Send by the user
    = SetState Author State
    | AddPatch Author Patch
    | DelPatch Patch
    | Requeue
    | Pause
    | Unpause
    | AddSkip Author Test
    | DelSkip Test
    -- Sent by the client
    | Pinged Ping
    | Finished {question :: Question, answer :: Answer}
    deriving (Show,Eq)

instance NFData Message where
    rnf (AddPatch x y) = rnf x `seq` rnf y
    rnf (DelPatch x) = rnf x
    rnf Requeue = ()
    rnf (SetState x y) = rnf x `seq` rnf y
    rnf Pause = ()
    rnf Unpause = ()
    rnf (AddSkip x y) = rnf x `seq` rnf y
    rnf (DelSkip x) = rnf x
    rnf (Pinged x) = rnf x
    rnf (Finished x y) = rnf x `seq` rnf y

data Question = Question
    {qCandidate :: (State, [Patch])
    ,qTest :: Maybe Test
    ,qThreads :: Int
    ,qClient :: Client
    }
    deriving (Show,Eq,Ord)

instance NFData Question where
    rnf (Question a b c d) = rnf (a,b,c,d)

data Answer = Answer
    {aStdout :: TL.Text
    ,aDuration :: Maybe Seconds -- Nothing for a skip
    ,aTests :: [Test]
    ,aSuccess :: Bool
    }
    deriving (Show,Eq)

instance NFData Answer where
    rnf (Answer a b c d) = rnf a `seq` rnf b `seq` rnf c `seq` rnf d

data Ping = Ping
    {pClient :: Client
    ,pAuthor :: Author
    ,pProvide :: [String] -- matches with testRequire
    ,pMaxThreads :: Int
    ,pNowThreads :: Int
    }
    deriving (Show,Eq)

instance NFData Ping where
    rnf (Ping a b c d e) = rnf a `seq` rnf b `seq` rnf c `seq` rnf d `seq` rnf e

-- JSON instance is only true for Finished
instance ToJSON Message where
    toJSON (Finished q a) = object ["question" .= q, "answer" .= a]
    toJSON _ = error "ToJSON Message is only supported for Finished"

instance FromJSON Message where
    parseJSON (Object v) = Finished <$>
        (v .: "question") <*> (v .: "answer")
    parseJSON _ = mzero

instance ToJSON Question where
    toJSON Question{..} = object
        ["candidate" .= toJSONCandidate qCandidate
        ,"test" .= qTest
        ,"threads" .= qThreads
        ,"client" .= qClient]

instance FromJSON Question where
    parseJSON (Object v) = Question <$>
        (fromJSONCandidate =<< (v .: "candidate")) <*> (v .: "test") <*> (v .: "threads") <*> (v .: "client")
    parseJSON _ = mzero

toJSONCandidate (s, ps) = object ["state" .= s, "patches" .= ps]

fromJSONCandidate (Object v) = (,) <$> (v .: "state") <*> (v .: "patches")
fromJSONCandidate _ = mzero

instance ToJSON Answer where
    toJSON Answer{..} = object
        ["stdout" .= aStdout
        ,"duration" .= aDuration
        ,"tests" .= aTests
        ,"success" .= aSuccess]

instance FromJSON Answer where
    parseJSON (Object v) = Answer <$>
        (v .: "stdout") <*> (v .: "duration") <*> (v .: "tests") <*> (v .: "success")
    parseJSON _ = mzero


messageToInput :: Message -> Input
messageToInput (AddPatch author patch) = Input ["api","add"] [("author",author),("patch",fromPatch patch)] ""
messageToInput (DelPatch patch) = Input ["api","del"] [("patch",fromPatch patch)] ""
messageToInput Requeue = Input ["api","requeue"] [] ""
messageToInput (SetState author state) = Input ["api","set"] [("author",author),("state",fromState state)] ""
messageToInput Pause = Input ["api","pause"] [] ""
messageToInput Unpause = Input ["api","unpause"] [] ""
messageToInput (AddSkip author test) = Input ["api","addskip"] [("author",author),("test",fromTest test)] ""
messageToInput (DelSkip test) = Input ["api","delskip"] [("test",fromTest test)] ""
messageToInput (Pinged Ping{..}) = Input ["api","ping"] 
    ([("client",fromClient pClient),("author",pAuthor)] ++
     [("provide",x) | x <- pProvide] ++
     [("maxthreads",show pMaxThreads),("nowthreads",show pNowThreads)]) ""
messageToInput x@Finished{} = Input ["api","finish"] [] $ encode x


-- return either an error message (not a valid message), or a message
messageFromInput :: Input -> Either String Message
messageFromInput (Input [msg] args body)
    | msg == "add" = AddPatch <$> str "author" <*> (toPatch <$> str "patch")
    | msg == "del" = DelPatch <$> (toPatch <$> str "patch")
    | msg == "addskip" = AddSkip <$> str "author" <*> (toTest <$> str "test")
    | msg == "delskip" = DelSkip <$> (toTest <$> str "test")
    | msg == "requeue" = pure Requeue
    | msg == "set" = SetState <$> str "author" <*> (toState <$> str "state")
    | msg == "pause" = pure Pause
    | msg == "unpause" = pure Unpause
    | msg == "ping" = Pinged <$> (Ping <$> (toClient <$> str "client") <*>
        str "author" <*> strs "provide" <*> int "maxthreads" <*> int "nowthreads")
    | msg == "finish" = eitherDecode body
    where strs x = Right $ map snd $ filter ((==) x . fst) args
          str x | Just v <- lookup x args = Right v
                | otherwise = Left $ "Missing field " ++ show x ++ " from " ++ show msg
          int x = readNote "messageFromInput, expecting Int" <$> str x
messageFromInput (Input msg args body) = Left $ "Invalid API call, got " ++ show msg


questionToOutput :: Maybe Question -> Output
questionToOutput = OutputString . LBS.unpack . encode


sendMessage :: (Host,Port) -> Message -> IO (Maybe Question)
sendMessage hp msg = do
    res <- send hp $ messageToInput msg
    return $ decode res