path: root/src/router.moon

-- Network router, implements RAFT consensus with modificationes
net = require("net")
log = require("log")

router = {}

-- Election messages
net.register_message("Prevote",{required:{peer:"string"}})
net.register_message("SurveyElection",{})
net.register_message("ResponseElection",{required:{candidate: "string"}})
net.register_message("CompleteElection",{required:{elected: "string"}})

-- Cluster state
net.register_message("RequestClusterInfo",{})
net.register_message("RespondClusterInfo",{required:{
	peerlist: "table"
	elected: "string"
	term:"number"
	prevotes: "table"
}})

net.register_message("RequestWorldInfo",{})
net.register_message("RespondWorldInfo",{required:{
	entities: "table"
}})

--Heartbeat
net.register_message("RequestHeartbeat",{required:{n1:"number",n2:"number"}})
net.register_message("RespondHeartbeat",{required:{n:"number",time:"number"}})

--Suggestion/commit, use ("peer","entity","time") as key to find messages later to commit.
-- -> peers can only suggest 1 state change per entity, per time
--Suggestions are broadcast from peers
net.register_message("Suggest",{required:{
	entity:"number"
	state:"table"
	peer:"string"
	time:"number"
}})
--Commits are broadcast from the elected peer
net.register_message("Commit",{required:{
	nonce: "number"
	entity:"number"
	peer:"string"
	suggest_time:"number"
	commit_time:"number"
}})
-- When a peer misses a committed message, re-request it
net.register_message("RequestReplay",{required:{nonce: "number"}})
net.register_message("RespondReplay",{required:{
	nonce: "number"
	entity: "number"
	peer: "string"
	state: "table"
	suggest_time: "number"
	commit_time: "number"
}})
--Rejections are also broadcast from the elected peer
net.register_message("Reject",{required:{
	nonce: "number"
	entity:"number"
	peer:"string"
	suggest_time:"number"
	reject_time:"number"
}})
--Suggest + commit from the elected peer, so we can throw away old state.
net.register_message("Simplify",{required:{
	entity:"number"
	state:"table"
	time:"number"
}})

--Testing
net.register_message("Raw",{optional:{s:"string"}})
router_singleton = nil
class Queue
	new: () =>
		@queue = {}
	push: (item) =>
		table.insert(@queue, item)
	pop: () =>
		table.remove(@queue, 1)

class Router
	new: () =>
		@peerlist = {}
		@routes = {}

		-- "uninitialized", "peer", "candidate", "elected"
		@state = "uninitialized"

		-- [peerid] = "votes for peerid"
		@nonce = 0
		@prevotes = {}
		@term = 0

		-- The uncommited queue
		@uncommited = Queue!
		router_singleton = @

	initalize: (id) =>
		@set_route("RequestClusterInfo",(conn, message) =>
			print("Requested cluster info:", message)
			peerlist = {}
			for peerid, _ in pairs(@peerlist)
				table.insert(peerlist, peerid)
			conn\send("RespondClusterInfo",{
				peerlist: peerlist
				elected: @elected
				term: @term
				prevotes: @prevotes
			})
			true
		)
		peer_setup = (peer) ->
			peer\on("error",(message) =>
				if message.data.type == "unavailable-id"
					peer\replace_id!
					peer_setup(peer)
					return
				error("Peer setup error: " .. tostring(message))
			)
			peer\on("open",(message) =>
				print("Peer",peer.id, "opened:",message)
				peer.open = true
			)
		peer = net.Peer!
		@peer = peer
		peer_setup(peer)
		while not peer.open
			coroutine.yield("Waiting for open")
			net.pump!
		peerlist = @peerlist
		router = @
		peer\on("connection",(message) =>
			print("Peer",peer.id, "got connection", message)
			assert(message.data.dest == peer.id)
			peerlist[message.data.source] = message.data
			message.data\send("Raw",{s: "Hello after conn"})
			message.data\on("data",(datamsg) =>
				print("Peer ",peer.id," got data:",datamsg)
				router\route(message.data, datamsg.data[1], datamsg.data[2])
				print("done routing")
			)
			message.data\on("error",(msg) =>
				error(msg)
			)
		)
		if id
			print("Doing id fork")
			connected = false
			conn = peer\connect(id)
			conn\on("open", (message) =>
				print("Conn got open message")
				connected = true
			)
			while not connected
				coroutine.yield("Waiting for client to connect")
				net.pump!
			conn\on("error", (message) =>
				error(message)
			)
			--Assume we vote for ourselves, and our peer votes for themselves
			@prevotes[peer.id] = peer.id
			@prevotes[id] = id
			@state = "peer"
			log.info("Peer passed, I'm a peer of " .. id, {"net"})
			--while not connected
			--	coroutine.yield("Give it a second to connect")
			--	net.pump!
			got_hello = false
			conn\on("data", (message) =>
				print("Peer got message:", message)
				got_hello = true
			)
			while not got_hello
				coroutine.yield("Waiting for hello")
				net.pump!
			@peerlist[peer.id] = peer
			@peerlist[id] = conn
			clusterinfo = @sync(conn, "RequestClusterInfo", {})
			print("Got cluster info:", clusterinfo)

		else
			log.info("No peer passed, I'm the elected peer: " .. peer.id, {"net"})
			@state = "elected"
			@elected = peer.id
			@term += 1
			-- Vote for ourselves
			@prevotes[peer.id] = peer.id
			-- Add ourselves to the peerlist
			@peerlist[peer.id] = peer
			while true
				coroutine.yield(peer.id)
				net.pump!

	sync: (conn, msgfmt, msg) =>
		ret = nil
		conn\on("data", (message) =>
			ret = message
		)
		conn\send(msgfmt, msg)
		while not ret
			coroutine.yield("Waiting on " .. msgfmt)
			net.pump!
		return ret

	broadcast: (msgfmt, message) =>
		for peerid, conn in pairs(@peerlist)
			if peerid ~= @peer.id
				conn\send(msgfmt, message)
	
	send_elected: (msgfmt, message) =>
		elected_conn = @peerlist[@elected]
		elected_conn\send(msgfmt, message)

	set_route: (msgfmt, callback) =>
		if @routes[msgfmt]
			log.warn("Overwriting callback for message " .. msgfmt, {"net"})
		@routes[msgfmt] = {callback}

	listen: (msgfmt, callback, id) =>
		id = id or {}
		@routes[msgfmt] = @routes[msgfmt] or {}
		@routes[msgfmt][id] = callback
	
	defen: (msgfmt, id) =>
		assert(@routes[msgfmt])
		assert(@routes[msgfmt][id])
		@routes[msgfmt][id] = nil

	route: (conn, msgfmt, message) =>
		print("Got route",conn,msgfmt,message)
		assert(type(msgfmt) == "string", "Message format must be a string")
		assert(type(message) == "table", "Message must be a table")
		if @routes[msgfmt]
			routed_any = false
			for _, r in pairs(@routes[msgfmt])
				routed_any = true
				if r(@, conn, message)
					break
			if not routed_any
				log.warn("No routes found for message format:" .. msgfmt, {"net"})
		else
			log.warn("No message callback registered for format " .. msgfmt .. " routes are: " .. tostring(@routes), {"net"})

node = am.group!
node\update(() ->
	if router_singleton and router_singleton.state ~= "uninitalized"
		net.pump!
		coroutine.yield!
)
{:Router, :node}