module Network.Telegram.API.Bot.Object.Update (Update (..)) where

import "aeson" Data.Aeson (FromJSON (parseJSON), withObject, (.:))
import "aeson" Data.Aeson.Types (Object, Parser)
import "base" Control.Applicative (Alternative ((<|>)))

import Network.Telegram.API.Bot.Access (Access (access))
import Network.Telegram.API.Bot.Object.Callback (Callback)
import Network.Telegram.API.Bot.Object.Chat (Chat)
import Network.Telegram.API.Bot.Object.Moving (Moving)
import Network.Telegram.API.Bot.Object.Message (Message)
import Network.Telegram.API.Bot.Property.Identifiable
        (Identifiable (identificator), Identificator)

data Update
        = Query Int Callback
        | Membership Int Moving
        | Incoming Int Message
        deriving Show

type instance Identificator Update = Int

instance Identifiable Update where
        identificator (Query i _) = i
        identificator (Membership i _) = i
        identificator (Incoming i _) = i

instance FromJSON Update where
        parseJSON = withObject "Update" $ \v ->
                query v <|> membership v <|> incoming v where

                query :: Object -> Parser Update
                query v = Query <$> v .: "update_id" <*> v .: "callback_query"

                membership :: Object -> Parser Update
                membership v = Membership <$> v .: "update_id" <*> v .: "message"

                incoming :: Object -> Parser Update
                incoming v = Incoming <$> v .: "update_id" <*> v .: "message"

instance Access Chat Update where
        access f (Incoming upd_id msg) = Incoming upd_id <$> access f msg
        access f (Query upd_id cb) = Query upd_id <$> access f cb
        access f (Membership upd_id mmb) = Membership upd_id <$> access f mmb