-- The code in this file should be self-explanatory, though the logic is horrible

-- for more info on that, see doc/stanza_routing.txt, which attempts to condense

-- the rules from the RFCs (mainly 3921)

require "core.servermanager"

local log = require "util.logger".init("stanzarouter")

local st = require "util.stanza";

local send = require "core.sessionmanager".send_to_session;

function core_process_stanza(origin, stanza)

	log("debug", "Received: "..tostring(stanza))

	-- TODO verify validity of stanza (as well as JID validity)

	if stanza.name == "iq" and not(#stanza.tags == 1 and stanza.tags[1].attr.xmlns) then

		error("Invalid IQ");

	end

	if origin.type == "c2s" and not origin.full_jid

		and not(stanza.name == "iq" and stanza.tags[1].name == "bind"

				and stanza.tags[1].attr.xmlns == "urn:ietf:params:xml:ns:xmpp-bind") then

		error("Client MUST bind resource after auth");

	end

	local to = stanza.attr.to;

	stanza.attr.from = origin.full_jid -- quick fix to prevent impersonation

	if not to or (hosts[to] and hosts[to].type == "local") then

		core_handle_stanza(origin, stanza);

	elseif to and stanza.name == "iq" and not select(3, jid_split(to)) then

		core_handle_stanza(origin, stanza);

	elseif origin.type == "c2s" then

		core_route_stanza(origin, stanza);

	end

end

function core_handle_stanza(origin, stanza)

	-- Handlers

	if origin.type == "c2s" or origin.type == "c2s_unauthed" then

		local session = origin;

		stanza.attr.from = session.full_jid;

		log("debug", "Routing stanza");

		-- Stanza has no to attribute

		--local to_node, to_host, to_resource = jid_split(stanza.attr.to);

		--if not to_host then error("Invalid destination JID: "..string.format("{ %q, %q, %q } == %q", to_node or "", to_host or "", to_resource or "", stanza.attr.to or "nil")); end

		-- Stanza is to this server, or a user on this server

		log("debug", "Routing stanza to local");

		handle_stanza(session, stanza);

	end

end

function core_route_stanza(origin, stanza)

	-- Hooks

	--- ...later

	-- Deliver

	local node, host, resource = jid_split(stanza.attr.to);

	local host_session = hosts[host]

	if host_session and host_session.type == "local" then

		-- Local host

		local user = host_session.sessions[node];

		if user then

			local res = user.sessions[resource];

			-- TODO do something about presence broadcast

			if not res then

				-- if we get here, resource was not specified or was unavailable

				for k in pairs(user.sessions) do

					res = user.sessions[k];

					break;

				end

				-- TODO find resource with greatest priority

			end

			stanza.attr.to = res.full_jid;

			send(res, stanza); -- Yay \o/

		else

			-- user not found

			send(origin, st.error_reply(stanza, "cancel", "service-unavailable"));

		end

	else

		-- Remote host

		if host_session then

			-- Send to session

		else

			-- Need to establish the connection

		end

	end

end

function handle_stanza_nodest(stanza)

	if stanza.name == "iq" then

		handle_stanza_iq_no_to(session, stanza);

	elseif stanza.name == "presence" then

		-- Broadcast to this user's contacts

		handle_stanza_presence_broadcast(session, stanza);

		-- also, if it is initial presence, send out presence probes

		if not session.last_presence then

			handle_stanza_presence_probe_broadcast(session, stanza);

		end

		session.last_presence = stanza;

	elseif stanza.name == "message" then

		-- Treat as if message was sent to bare JID of the sender

		handle_stanza_to_local_user(stanza);

	end

end

function handle_stanza_tolocal(stanza)

	local node, host, resource = jid.split(stanza.attr.to);

	if host and hosts[host] and hosts[host].type == "local" then

			-- Is a local host, handle internally

			if node then

				-- Is a local user, send to their session

				log("debug", "Routing stanza to %s@%s", node, host);

				if not session.username then return; end --FIXME: Correct response when trying to use unauthed stream is what?

				handle_stanza_to_local_user(stanza);

			else

				-- Is sent to this server, let's handle it...

				log("debug", "Routing stanza to %s", host);

				handle_stanza_to_server(stanza, session);

			end

	end

end

function handle_stanza_toremote(stanza)

	log("error", "Stanza bound for remote host, but s2s is not implemented");

end

--[[

local function route_c2s_stanza(session, stanza)

	stanza.attr.from = session.full_jid;

	if not stanza.attr.to and session.username then

		-- Has no 'to' attribute, handle internally

		if stanza.name == "iq" then

			handle_stanza_iq_no_to(session, stanza);

		elseif stanza.name == "presence" then

			-- Broadcast to this user's contacts

			handle_stanza_presence_broadcast(session, stanza);

			-- also, if it is initial presence, send out presence probes

			if not session.last_presence then

				handle_stanza_presence_probe_broadcast(session, stanza);

			end

			session.last_presence = stanza;

		elseif stanza.name == "message" then

			-- Treat as if message was sent to bare JID of the sender

			handle_stanza_to_local_user(stanza);

		end

	end

	local node, host, resource = jid.split(stanza.attr.to);

	if host and hosts[host] and hosts[host].type == "local" then

			-- Is a local host, handle internally

			if node then

				-- Is a local user, send to their session

				if not session.username then return; end --FIXME: Correct response when trying to use unauthed stream is what?

				handle_stanza_to_local_user(stanza);

			else

				-- Is sent to this server, let's handle it...

				handle_stanza_to_server(stanza, session);

			end

	else

		-- Is not for us or a local user, route accordingly

		route_s2s_stanza(stanza);

	end

end

function handle_stanza_no_to(session, stanza)

	if not stanza.attr.id then log("warn", "<iq> without id attribute is invalid"); end

	local xmlns = (stanza.tags[1].attr and stanza.tags[1].attr.xmlns);

	if stanza.attr.type == "get" or stanza.attr.type == "set" then

		if iq_handlers[xmlns] then

			if iq_handlers[xmlns](stanza) then return; end; -- If handler returns true, it handled it

		end

		-- Oh, handler didn't handle it. Need to send service-unavailable now.

		log("warn", "Unhandled namespace: "..xmlns);

		session:send(format("<iq type='error' id='%s'><error type='cancel'><service-unavailable/></error></iq>", stanza.attr.id));

		return; -- All done!

	end

end

function handle_stanza_to_local_user(stanza)

	if stanza.name == "message" then

		handle_stanza_message_to_local_user(stanza);

	elseif stanza.name == "presence" then

		handle_stanza_presence_to_local_user(stanza);

	elseif stanza.name == "iq" then

		handle_stanza_iq_to_local_user(stanza);

	end

end

function handle_stanza_message_to_local_user(stanza)

	local node, host, resource = stanza.to.node, stanza.to.host, stanza.to.resource;

	local destuser = hosts[host].sessions[node];

	if destuser then

		if resource and destuser[resource] then

			destuser[resource]:send(stanza);

		else

			-- Bare JID, or resource offline

			local best_session;

			for resource, session in pairs(destuser.sessions) do

				if not best_session then best_session = session;

				elseif session.priority >= best_session.priority and session.priority >= 0 then

					best_session = session;

				end

			end

			if not best_session then

				offlinemessage.new(node, host, stanza);

			else

				print("resource '"..resource.."' was not online, have chosen to send to '"..best_session.username.."@"..best_session.host.."/"..best_session.resource.."'");

				destuser[best_session]:send(stanza);

			end

		end

	else

		-- User is offline

		offlinemessage.new(node, host, stanza);

	end

end

function handle_stanza_presence_to_local_user(stanza)

	local node, host, resource = stanza.to.node, stanza.to.host, stanza.to.resource;

	local destuser = hosts[host].sessions[node];

	if destuser then

		if resource then

			if destuser[resource] then

				destuser[resource]:send(stanza);

			else

				return;

			end

		else

			-- Broadcast to all user's resources

			for resource, session in pairs(destuser.sessions) do

				session:send(stanza);

			end

		end

	end

end

function handle_stanza_iq_to_local_user(stanza)

end

function foo()

		local node, host, resource = stanza.to.node, stanza.to.host, stanza.to.resource;

		local destuser = hosts[host].sessions[node];

		if destuser and destuser.sessions then

			-- User online

			if resource and destuser.sessions[resource] then

				stanza.to:send(stanza);

			else

				--User is online, but specified resource isn't (or no resource specified)

				local best_session;

				for resource, session in pairs(destuser.sessions) do

					if not best_session then best_session = session;

					elseif session.priority >= best_session.priority and session.priority >= 0 then

						best_session = session;

					end

				end

				if not best_session then

					offlinemessage.new(node, host, stanza);

				else

					print("resource '"..resource.."' was not online, have chosen to send to '"..best_session.username.."@"..best_session.host.."/"..best_session.resource.."'");

					resource = best_session.resource;

				end

			end

			if destuser.sessions[resource] == session then

				log("warn", "core", "Attempt to send stanza to self, dropping...");

			else

				print("...sending...", tostring(stanza));

				--destuser.sessions[resource].conn.write(tostring(data));

				print("   to conn ", destuser.sessions[resource].conn);

				destuser.sessions[resource].conn.write(tostring(stanza));

				print("...sent")

			end

		elseif stanza.name == "message" then

			print("   ...will be stored offline");

			offlinemessage.new(node, host, stanza);

		elseif stanza.name == "iq" then

			print("   ...is an iq");

			stanza.from:send(st.reply(stanza)

				:tag("error", { type = "cancel" })

					:tag("service-unavailable", { xmlns = "urn:ietf:params:xml:ns:xmpp-stanzas" }));

		end

end

-- Broadcast a presence stanza to all of a user's contacts

function handle_stanza_presence_broadcast(session, stanza)

	if session.roster then

		local initial_presence = not session.last_presence;

		session.last_presence = stanza;

		-- Broadcast presence and probes

		local broadcast = st.presence({ from = session.full_jid, type = stanza.attr.type });

		for child in stanza:childtags() do

			broadcast:add_child(child);

		end

		for contact_jid in pairs(session.roster) do

			broadcast.attr.to = contact_jid;

			send_to(contact_jid, broadcast);

			if initial_presence then

				local node, host = jid.split(contact_jid);

				if hosts[host] and hosts[host].type == "local" then

					local contact = hosts[host].sessions[node]

					if contact then

						local pres = st.presence { to = session.full_jid };

						for resource, contact_session in pairs(contact.sessions) do

							if contact_session.last_presence then

								pres.tags = contact_session.last_presence.tags;

								pres.attr.from = contact_session.full_jid;

								send(pres);

							end

						end

					end

					--FIXME: Do we send unavailable if they are offline?

				else

					probe.attr.to = contact;

					send_to(contact, probe);

				end

			end

		end

		-- Probe for our contacts' presence

	end

end

-- Broadcast presence probes to all of a user's contacts

function handle_stanza_presence_probe_broadcast(session, stanza)

end

-- 

function handle_stanza_to_server(stanza)

end

function handle_stanza_iq_no_to(session, stanza)

end

]]