-----------------------------------------------------------------------------
-- |
-- Module      :  Control.Distributed.Node
-- Copyright   :  (c) 2020-2021 EMQ Technologies Co., Ltd.
-- License     :  BSD-style (see the LICENSE file)
--
-- Maintainer  :  Feng Lee, feng@emqx.io
--                Yang M, yangm@emqx.io
-- Stability   :  experimental
-- Portability :  portable
--
-- The Distributed Node module.
--
-----------------------------------------------------------------------------
module Control.Distributed.Node
  ( Cookie
  , Node
  , NodeType(..)
  , nodes
  , nodesOf
  , nodeOfPid
  , nodeOfRef
  , selfNode
  , disconnect
    -- * cookie
  , getCookie
  , setCookie
  , isAlive
  , monitorNode
  ) where

import Control.Monad (IO)
import Data.Maybe (Maybe)
import Data.Ref (Reference)
import Data.Pid (Pid)
import Data.Unit (Unit)
import Foreign (ffiIO0, ffiIO1)

type Cookie = String

-- A distributed Node.
type Node = Atom

data NodeType = Hidden | Connected | Known | Visible

nodes :: IO [Node]
nodes = ffiIO0 :erlang :nodes

foreign import nodesOf :: NodeType -> IO [Node]

-- Return the name of this node.
selfNode :: IO Node
selfNode = ffiIO0 :erlang :node

nodeOfPid :: Pid -> IO Node
nodeOfPid = ffiIO1 :erlang :node

nodeOfRef :: Reference -> IO Node
nodeOfRef = ffiIO1 :erlang :node

foreign import disconnect :: Node -> IO (Maybe Boolean)

foreign import getCookie :: IO Cookie

foreign import setCookie :: Node -> Cookie -> IO ()

foreign import isAlive :: IO Boolean

foreign import monitorNode :: Node -> Boolean -> IO Boolean

-- spawn[_link|_opt](Node, Fun): Creates a process at a remote node.
-- spawn[_link|opt](Node, Module, FunctionName, Args): Creates a process at a remote node.