{- Copyright 2016 Joey Hess <id@joeyh.name>
 -
 - Licensed under the GNU AGPL version 3 or higher.
 -}

{-# LANGUAGE OverloadedStrings #-}

module Storage.Network (Server(..), networkServers, networkStorage) where

import Types
import Types.Storage
import HTTP
import HTTP.Client
import Servant.Client
import Network.Wai.Handler.Warp (Port)
import Network.HTTP.Client (Manager, newManager, defaultManagerSettings)
import Control.Monad.Trans.Except (ExceptT, runExceptT)

data Server = Server
	{ serverName :: String
	, serverPort :: Port
	}

serverUrl :: Server -> BaseUrl
serverUrl srv = BaseUrl Http (serverName srv) (serverPort srv) ""

networkServers :: IO [Server]
networkServers = return 
	[ Server "localhost" 8080
	, Server "localhost" 8080
	, Server "localhost" 8080
	]

networkStorage :: Server -> Storage
networkStorage server = Storage
	{ storeShare = store server
	, retrieveShare = retrieve server
	, obscureShares = obscure server
	, countShares = count server
	, moveShares = move server
	}

store :: Server -> StorableObjectIdent -> Share -> IO StoreResult
store srv i (Share _n o) = 
	serverRequest srv StoreFailure id $ \pow ->
		putObject i pow o

retrieve :: Server -> ShareNum -> StorableObjectIdent -> IO RetrieveResult
retrieve srv n i = 
	serverRequest srv RetrieveFailure (RetrieveSuccess . Share n) $
		getObject i

-- | Servers should automatically obscure, so do nothing.
-- (Could upload chaff.)
obscure :: Server -> IO ObscureResult
obscure _ = return ObscureSuccess

count :: Server -> IO CountResult
count srv = serverRequest srv CountFailure id countObjects

-- | Not needed for servers.
move :: Server -> Storage -> IO ()
move _ _ = error "move is not implemented for servers"

serverRequest
	:: Server
	-> (String -> a)
	-> (r -> a)
	-> (Maybe ProofOfWork -> Manager -> BaseUrl -> ExceptT ServantError IO (ProofOfWorkRequirement r))
	-> IO a
serverRequest srv onerr onsuccess a =
	go Nothing =<< newManager defaultManagerSettings
  where
	url = serverUrl srv
	go pow manager = do
		res <- runExceptT $ a pow manager url
		case res of
			Left err -> return $ onerr $ 
				"server failure: " ++ show err
			Right (Result r) -> return $ onsuccess r
			Right needpow -> error "NEEDPOW" -- loop with pow