local mt = dofile "/lib/multitask.lua"
local p = mt.newPool({crash_on_error = true})
local spudnet = {}
local api = {}
spudnet.api = api
spudnet.init = function(o)
	o = o or {}
	o.on_init = o.on_init or function() end
	if not o.channel then
		error("no channel specified")
	end
	if not o.mode then
		error("no mode specified")
	end
	o.subchannels = o.subchannels or {} 
	local url = "wss://spudnet.osmarks.net/v4?enc=json&force_binary=true"
	local ws = nil
	local since_last_ping = os.epoch"utc"
	local init
	for i,v in ipairs(o.subchannels) do
		o.subchannels[i]=o.mode..":"..o.channel.."/"..v
	end
	local get_spudmsg = function(filter)
		while true do
			local e, url_, data = coroutine.yield("websocket_message")
			data = textutils.unserializeJSON(data)
			if url_ == url then
				if not filter or filter == data.type then
					return data
				end
			end
		end
	end
	
	api.send_raw = function(data)
		return p.add(function(this)
			local x = pcall(ws.send,textutils.serializeJSON(data),true)
			if not x then
				p.clear()
				p.add(init,{name="spudnet_init"})
			end
		end)
	end
	
	api.send_raw_sync = function(data)
		local id = math.random(1,0xFFFFFF)
		data.cid = id
		p.await(api.send_raw(data))
		while true do
			local m = get_spudmsg("ok")
			if m.cid == id then
				return true
			end
		end
	end
	
	api.receive = function(filter)
		while true do
			local m = get_spudmsg("message").data
			if filter then
				if m.type == filter then
					return m
				end
			else
				return m
			end
		end
	end
	api.send = function(data,subchannel)
		api.send_raw({
			type="send",
			data=data,
			channel=o.mode..":"..o.channel.."/"..subchannel
		})
	end
	
	api.send_sync = function(data,subchannel)
		api.send_raw_sync({
			type="send",
			data=data,
			channel=o.mode..":"..o.channel.."/"..subchannel
		})
	end
	
	local error_handler = function()
		while true do
			local a = get_spudmsg("error")
			if a.error == "timeout" then
				p.clear()
				p.add(init,{name="spudnet_init"})
			else
				error("Error from SPUDNET ('"..(a["error"] or a["for"]).."'): "..a.detail)
			end
		end
	end
	
	local ping_handler = function()
		while true do
			local a = get_spudmsg("ping").seq
			since_last_ping = os.epoch"utc"
			api.send_raw({
				type="pong",
				seq = a,
			})
			os.queueEvent("spudnet_ping",seq)
		end
	end
	local terminate_handler = function()
		local x = os.pullEventRaw("terminate")
		if ws then ws.close() end
		p.clear()
	end
	local timeout_handler = function()
		while true do
			sleep(1)
			if os.epoch"utc" - since_last_ping >= 15000 then
				p.clear()
				p.add(init,{name="spudnet_init"})
				os.queueEvent("spudnet_timeout")
			end
		end
	end
	init = function()
		p.add(terminate_handler,{name="spudnet_termination_handler"})
		if ws then ws.close() end
		ws = nil
		while true do
			ws = http.websocket(url)
			if ws then
				break
			end
			sleep(0.3)
		end
		p.add(error_handler,{name="spudnet_error_handler"})
		p.add(ping_handler,{name="spudnet_ping_handler"})
		p.add(timeout_handler,{name="spudnet_timeout_handler"})
		api.send_raw_sync({
			type="identify",
			key=o.key,
			channels=o.subchannels,
		})
		p.add(o.on_init)
		os.queueEvent("spudnet_ready")
	end
	p.add(init,{name="spudnet_init"})
	p.run(false)
end

spudnet.pool = p

return spudnet