-- 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;

local user_exists = require "core.usermanager".user_exists;

local jid_split = require "util.jid".split;

local print = print;

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

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

			error("Invalid IQ");

		elseif #stanza.tags > 1 or not(stanza.attr.type == "error" or stanza.attr.type == "result") then

			error("Invalid IQ");

		end

	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 (FIXME this would be incorrect when the origin is not c2s)

	-- TODO also, stazas should be returned to their original state before the function ends

	-- TODO presence subscriptions

	if not to then

			core_handle_stanza(origin, stanza);

	elseif hosts[to] and hosts[to].type == "local" then

		core_handle_stanza(origin, stanza);

	elseif 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

-- This function handles stanzas which are not routed any further,

-- that is, they are handled by this server

function core_handle_stanza(origin, stanza)

	-- Handlers

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

		local session = origin;

		if stanza.name == "presence" and origin.roster then

			if stanza.attr.type == nil or stanza.attr.type == "available" or stanza.attr.type == "unavailable" then

				for jid in pairs(origin.roster) do -- broadcast to all interested contacts

					local subscription = origin.roster[jid].subscription;

					if subscription == "both" or subscription == "from" then

						stanza.attr.to = jid;

						core_route_stanza(origin, stanza);

					end

				end

				--[[local node, host = jid_split(stanza.attr.from);

				for _, res in pairs(hosts[host].sessions[node].sessions) do -- broadcast to all resources

					if res.full_jid then

						res = user.sessions[k];

						break;

					end

				end]]

				if not origin.presence then -- presence probes on initial presence

					local probe = st.presence({from = origin.full_jid, type = "probe"});

					for jid in pairs(origin.roster) do

						local subscription = origin.roster[jid].subscription;

						if subscription == "both" or subscription == "to" then

							probe.attr.to = jid;

							core_route_stanza(origin, probe);

						end

					end

				end

				origin.presence = stanza;

				stanza.attr.to = nil; -- reset it

			else

				-- TODO error, bad type

			end

		else

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

			handle_stanza(session, stanza);

		end

	end

end

-- TODO: Does this function belong here?

function is_authorized_to_see_presence(origin, username, host)

	local roster = datamanager.load(username, host, "roster") or {};

	local item = roster[origin.username.."@"..origin.host];

	return item and (item.subscription == "both" or item.subscription == "from");

end

function core_route_stanza(origin, stanza)

	-- Hooks

	--- ...later

	-- Deliver

	local to = stanza.attr.to;

	local node, host, resource = jid_split(to);

	if stanza.name == "presence" and stanza.attr.type == "probe" then resource = nil; end

	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];

			if not res then

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

				if stanza.name == "presence" then

					if stanza.attr.type == "probe" then

						if is_authorized_to_see_presence(origin, node, host) then

							for k in pairs(user.sessions) do -- return presence for all resources

								if user.sessions[k].presence then

									local pres = user.sessions[k].presence;

									pres.attr.to = origin.full_jid;

									pres.attr.from = user.sessions[k].full_jid;

									send(origin, pres);

									pres.attr.to = nil;

									pres.attr.from = nil;

								end

							end

						else

							send(origin, st.presence({from = user.."@"..host, to = origin.username.."@"..origin.host, type = "unsubscribed"}));

						end

					else

						for k in pairs(user.sessions) do -- presence broadcast to all user resources

							if user.sessions[k].full_jid then

								stanza.attr.to = user.sessions[k].full_jid;

								send(user.sessions[k], stanza);

							end

						end

					end

				elseif stanza.name == "message" then -- select a resource to recieve message

					for k in pairs(user.sessions) do

						if user.sessions[k].full_jid then

							res = user.sessions[k];

							break;

						end

					end

					-- TODO find resource with greatest priority

					send(res, stanza);

				else

					-- TODO send IQ error

				end

			else

				-- User + resource is online...

				stanza.attr.to = res.full_jid;

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

			end

		else

			-- user not online

			if user_exists(node, host) then

				if stanza.name == "presence" then

					if stanza.attr.type == "probe" and is_authorized_to_see_presence(origin, node, host) then -- FIXME what to do for not c2s?

						-- TODO send last recieved unavailable presence

					else

						-- TODO send unavailable presence

					end

				elseif stanza.name == "message" then

					-- TODO send message error, or store offline messages

				elseif stanza.name == "iq" then

					-- TODO send IQ error

				end

			else -- user does not exist

				-- TODO we would get here for nodeless JIDs too. Do something fun maybe? Echo service? Let plugins use xmpp:server/resource addresses?

				if stanza.name == "presence" then

					if stanza.attr.type == "probe" then

						send(origin, st.presence({from = user.."@"..host, to = origin.username.."@"..origin.host, type = "unsubscribed"}));

					end

					-- else ignore

				else

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

				end

			end

		end

	else

		-- Remote host

		send_s2s(origin.host, host, stanza);

	end

	stanza.attr.to = to; -- reset

end

function handle_stanza_toremote(stanza)

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

end