-- Handles the bridge to javascript to do peer-to-peer connections

log = require("log")
rng = require("rng")
util = require("util")

net = {}

initialized = false
initialize = () ->
	am.eval_js(require("js_bridge"))
	initialized = true

net.call = (method, args) ->
	if not initialized
		initialize!
	args = args or {}
	json_str = am.to_json(args)
	log.info("Json string sent to javascript:" .. tostring(json_str), {"net"})
	result = am.eval_js("window.PEER." .. method .. "(" .. am.to_json(args) .. ")")
	result

net.pull_peers = () ->
	if not initialized
		initialize!
	messages = am.eval_js("window.PEER.peer_message_queue")
	am.eval_js("window.PEER.peer_message_queue = []")
	messages

net.pull_connections = () ->
	if not initialized
		initialize!
	messages = am.eval_js("window.PEER.connection_message_queue")
	am.eval_js("window.PEER.connection_message_queue = []")
	messages

net.pull_creation = () ->
	if not initialized
		initialize!
	creations = am.eval_js("window.PEER.creation_queue")
	am.eval_js("window.PEER.creation_queue = []")
	creations

-- Sequence of function(peer, message) | function(connection, message)
-- functions of (peer,message) for peer "open","connection","call","close","disconnected","error"
-- functions of (connection, message) for connection "data","open","close","error"
callbacks = {}
callback_info = {}
-- Map of [string peerid] = Peer
peers = {}

--Connections are always create js side, this is just it's lua representation
class Connection
	@connections = {}
	@methods = util.reverse({"data","open","close","error"})
	new: (source, dest) =>
		@source = source
		@dest = dest
	@get: (source, dest) =>
		key = table.concat({source,dest},",")
		if @connections[key]
			return @connections[key]
		@@connections[key] = Connection(source,dest)
		@@connections[key]
	on: (event, callback) =>
		if not @@methods[event]
			error("Tried to set an unknown event (" .. event .. ") on a connection")
		newid = #callbacks + 1
		callbacks[newid] = callback
		callback_info[newid] = debug.getinfo(callback)
		-- Wait until the JS-side directional connection [source,dest] is ready
		while am.eval_js('window.PEER.connections[["' .. @source .. '","' .. @dest .. '"]] == null')
			coroutine.yield("Waiting for peer")
		-- Attach handler to this directional connection (source -> dest)
		net.call("conn_on", {source: @source, dest: @dest, e: event, message: newid})
	send: (msgname, msg) =>
		-- Send as array: [msgname, msg]
		log.info("Sending",{"net"})
		res = net.call("send",{source: @source, dest: @dest, data: {msgname, msg}})
		res

class Peer
	@methods = util.reverse({"open","connection","call","close","disconnected","error"})
	@max_attempts = 4
	@create_timeout = 10
	new: () =>
		log.info("Creating peer...", {"net"})
		net.call("create")
		creations = {}
		starttime = am.eval_js("Date.now()")
		attempts = 0
		while #creations == 0 and attempts < @@max_attempts
			creations = net.pull_creation()
			if #creations > 1
				error("Created more than 1 peer at a time, we don't know which one we are")
			messages = net.pull_connections()
			log.info("Creating peer " .. attempts .. "/" .. tostring(@@max_attempts), {"net"})
			if #messages > 0
				if messages[1] and messages[1].data and messages[1].data.message.type == "network"
					-- Try again
					net.call("create")
					attempts += 1
					starttime = am.eval_js("Date.now()")
				else
					error(tostring(messages))
			if am.eval_js("Date.now()") - starttime > (@@create_timeout * 1000)
				net.call("create")
				attempts += 1
				starttime = am.eval_js("Date.now()")
			if attempts > @@max_attempts
				error("Failed to create host after 4 attempts")
			coroutine.yield!
		if attempts == @@max_attempts
			error("Failed to create peer, check https://status.peerjs.com")
		@id = creations[1]
		peers[@id] = @
		log.info("Creating peer: " .. @id, {"net"})
	generate_id: () =>
		os.date("%Y%e") .. rng.numstring(4)
	replace_id: () =>
		log.info("Regenerating id for peer: " .. @id, {"net"})
		-- peers[@id] = nil TODO: uncomment, this breaks when running multiple peers from the same tab.
		net.call("delete_peer",{name: @id})
		@id = @generate_id!
		peers[@id] = @
		net.call("create", {name: @id})
	on: (event, callback) =>
		if not @@methods[event]
			error("Tried to set an unknown event (" .. event .. ") on a peer.")
		newid = #callbacks + 1
		callbacks[newid] = callback
		net.call("on",{name: @id, message:newid, e: event})
	
	connect: (id, options) =>
		conn = net.call("connect", {source: @id, dest: id})
		log.info("Got connection: " .. tostring(conn), {"net"})
		Connection\get(conn[1],conn[2])


net.Peer = Peer

-- A fake peer for testing
fakepeers = {}
fakeconnections = {}
fakecallbacks = {}
channel = require("channel")

class FakePeer
	new: (id) =>
		if id
			@id = id
			fakepeers[id] = @
	on: (event, callback) =>
		newid = #fakecallbacks + 1
		fakecallbacks[newid] = callback
	
	connect: (id, options) =>
		conn = channel.FaultyChannel({
			avg_latency: 200
			latency_std: 100
			loss: 0.1
		})
		conn


messages = {}
formatcache = {}
message_callbacks = {}
net.register_message = (name, format) ->
	assert(type(format) == "table", "Format must be a table")
	format.required = format.required or {}
	format.optional = format.optional or {}
	if not (next(format.required) or next(format.optional))
		log.warn("Message " .. name .. " registered with no fields.")
	for set in *({format.required, format.optional})
		for field, type_ in pairs(set)
			if type(type_) == "string"
				key = string.format("%s\0%s\0%s",name,field,type_)
				if not formatcache[key]
					formatcache[key] = (any) ->
						assert(type(any) == type_, string.format("In message %q %q must be a %q, but was a %q", name, field, type_, type(any)))
				set[field] = formatcache[key]
	messages[name] = format
	message_callbacks[name] = {}
	log.info("Registered message type:" .. name, {"net"})

net.validate = (name, message) ->
	log.debug("Validating message:" .. tostring(message), {"net"})
	assert(type(message) == "table", "Message must be a table")
	format = messages[name]
	assert(format, "Failed to find a format: " .. name)
	required = {}
	for field, validate in pairs(format.required)
		required[field] = validate
	for field, value in pairs(message)
		if format.required[field]
			required[field](value)
			required[field] = nil
		if format.optional[field]
			format.optional[field](value)
	missing = next(required)
	if missing
		error("Missing required field: " .. missing)
	true

net.listen = (name, callback, id) ->
	id = id or {}
	message_callbacks[name] = message_callbacks[name] or {}
	message_callbacks[name][id] = callback
	id

net.defen = (name, id) ->
	message_callbacks[name][id] = nil

-- net.route = (conn, name, data) ->
-- 	if message_callbacks[name]
-- 		for id, callback in pairs(message_callbacks[name])
-- 			ret = message_callbacks[name](conn,

net.rewrite_events = {
	connection: (message) ->
		-- message.data.data is [server, client]; build Hub-side Connection(server->client)
		conn = Connection\get(message.data.data[1], message.data.data[2])
		assert(conn, "Failed to build conn?")
		assert(conn.source and conn.dest)
		message.data.data = conn
}

net.pump = () ->
	msg_ = net.pull_peers!
	if #msg_ > 0
		log.info("Processing " .. tostring(#msg_) .. " peer messages", {"net"})
	for message in *msg_
		--log.info(tostring(message), {"net", message.data.peer})
		if net.rewrite_events[message.data.e]
			log.info("Rewriting data due to " .. message.data.e .. " event", {"net", message.data.peer})
			net.rewrite_events[message.data.e](message)
			log.info(tostring(message), {"net", message.data.peer})
		if not message.data.peer and message.data.e == "open"
			log.info("Setting peerid for a peer that didn't have one " ..tostring(message), {"net"})
		peer = peers[message.data.peer]
		assert(peer, "Failed to find peer:" .. message.data.peer .. " peers:" .. tostring(net.peers!))
		callback = callbacks[message.message]
		assert(callback, "Failed to find callback " .. message.message .. " on peer " .. message.data.peer)
		callback(peer,message.data)
	msg_ = net.pull_connections!
	if #msg_ > 0
		log.info("Processing " .. tostring(#msg_) .. " connection messages", {"net"})
	for message in *msg_
		--log.info(tostring(message), {"net", message.data.peer})
		-- Extra debug for connection routing
		peer  = message.data and message.data.peer or "nil"
		dest  = message.data and message.data.dest or "nil"
		inner = message.data and message.data.data or nil
		log.debug("NET connection msg peer=" .. tostring(peer) ..
			" dest=" .. tostring(dest) ..
			" inner=" .. tostring(inner), {"net", "debug"})
		-- For connection events, message.data is a wrapper from JS bridge.
		-- The actual payload from Connection:send is in message.data.data.
		payload = inner or message.data
		-- message.data.peer is the source, message.data.dest is the dest from JS bridge
		connection = Connection\get(message.data.peer, message.data.dest)
		callback = callbacks[message.message]
		if callback
			wcall = () ->
				callback(connection, payload)
			handler = (err) ->
				info = callback_info[message.message]
				string.format("Failed to call callback defined at %s:%d:\n%s", info.short_src, info.linedefined, debug.traceback(err))
			assert(xpcall(wcall, handler))
		else
			log.warn("Failed to find callback for message:" .. tostring(message),{"net"})
		--assert(callback, "Failed to find callback " .. tostring(message.message) .. " for message" .. tostring(message))

net.peers = () ->
	peers

net.node = am.group!
initialize!

net