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 (Applicative ((<*>)), Alternative ((<|>)))
import "base" Data.Function (($))
import "base" Data.Functor ((<$>))
import "base" Data.Int (Int)
import "base" Text.Show (Show)

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