-- Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

-- 

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

local log = module._log;

local require = require;

local pairs, ipairs = pairs, ipairs;

local t_concat, t_insert = table.concat, table.insert;

local s_find = string.find;

local tonumber = tonumber;

local st = require "util.stanza";

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

local jid_bare = require "util.jid".bare;

local hosts = hosts;

local NULL = {};

local rostermanager = require "core.rostermanager";

local sessionmanager = require "core.sessionmanager";

local offlinemanager = require "core.offlinemanager";

local function select_top_resources(user)

	local priority = 0;

	local recipients = {};

	for _, session in pairs(user.sessions) do -- find resource with greatest priority

		if session.presence then

			-- TODO check active privacy list for session

			local p = session.priority;

			if p > priority then

				priority = p;

				recipients = {session};

			elseif p == priority then

				t_insert(recipients, session);

			end

		end

	end

	return recipients;

end

local function recalc_resource_map(user)

	if user then

		user.top_resources = select_top_resources(user);

		if #user.top_resources == 0 then user.top_resources = nil; end

	end

end

local ignore_presence_priority = module:get_option("ignore_presence_priority");

function handle_normal_presence(origin, stanza)

	if ignore_presence_priority then

		local priority = stanza:child_with_name("priority");

		if priority and priority[1] ~= "0" then

			for i=#priority.tags,1,-1 do priority.tags[i] = nil; end

			for i=#priority,1,-1 do priority[i] = nil; end

			priority[1] = "0";

		end

	end

	if full_sessions[origin.full_jid] then -- if user is still connected

		origin.send(stanza); -- reflect their presence back to them

	end

	local roster = origin.roster;

	local node, host = origin.username, origin.host;

	local user = bare_sessions[node.."@"..host];

	for _, res in pairs(user and user.sessions or NULL) do -- broadcast to all resources

		if res ~= origin and res.presence then -- to resource

			stanza.attr.to = res.full_jid;

			core_post_stanza(origin, stanza, true);

		end

	end

	for jid, item in pairs(roster) do -- broadcast to all interested contacts

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

			stanza.attr.to = jid;

			core_post_stanza(origin, stanza, true);

		end

	end

	if stanza.attr.type == nil and not origin.presence then -- initial presence

		origin.presence = stanza; -- FIXME repeated later

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

		for jid, item in pairs(roster) do -- probe all contacts we are subscribed to

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

				probe.attr.to = jid;

				core_post_stanza(origin, probe, true);

			end

		end

		for _, res in pairs(user and user.sessions or NULL) do -- broadcast from all available resources

			if res ~= origin and res.presence then

				res.presence.attr.to = origin.full_jid;

				core_post_stanza(res, res.presence, true);

				res.presence.attr.to = nil;

			end

		end

		if roster.pending then -- resend incoming subscription requests

			for jid in pairs(roster.pending) do

				origin.send(st.presence({type="subscribe", from=jid})); -- TODO add to attribute? Use original?

			end

		end

		local request = st.presence({type="subscribe", from=origin.username.."@"..origin.host});

		for jid, item in pairs(roster) do -- resend outgoing subscription requests

			if item.ask then

				request.attr.to = jid;

				core_post_stanza(origin, request, true);

			end

		end

		local offline = offlinemanager.load(node, host);

		if offline then

			for _, msg in ipairs(offline) do

				origin.send(msg); -- FIXME do we need to modify to/from in any way?

			end

			offlinemanager.deleteAll(node, host);

		end

	end

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

		origin.presence = nil;

		if origin.priority then

			origin.priority = nil;

			recalc_resource_map(user);

		end

		if origin.directed then

			for jid in pairs(origin.directed) do

				stanza.attr.to = jid;

				core_post_stanza(origin, stanza, true);

			end

			origin.directed = nil;

		end

	else

		origin.presence = stanza;

		local priority = stanza:child_with_name("priority");

		if priority and #priority > 0 then

			priority = t_concat(priority);

			if s_find(priority, "^[+-]?[0-9]+$") then

				priority = tonumber(priority);

				if priority < -128 then priority = -128 end

				if priority > 127 then priority = 127 end

			else priority = 0; end

		else priority = 0; end

		if origin.priority ~= priority then

			origin.priority = priority;

			recalc_resource_map(user);

		end

	end

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

end

function send_presence_of_available_resources(user, host, jid, recipient_session, stanza)

	local h = hosts[host];

	local count = 0;

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

		local u = h.sessions[user];

		if u then

			for k, session in pairs(u.sessions) do

				local pres = session.presence;

				if pres then

					if stanza then pres = stanza; pres.attr.from = session.full_jid; end

					pres.attr.to = jid;

					core_post_stanza(session, pres, true);

					pres.attr.to = nil;

					count = count + 1;

				end

			end

		end

	end

	log("debug", "broadcasted presence of "..count.." resources from "..user.."@"..host.." to "..jid);

	return count;

end

function handle_outbound_presence_subscriptions_and_probes(origin, stanza, from_bare, to_bare)

	local node, host = jid_split(from_bare);

	if to_bare == origin.username.."@"..origin.host then return; end -- No self contacts

	local st_from, st_to = stanza.attr.from, stanza.attr.to;

	stanza.attr.from, stanza.attr.to = from_bare, to_bare;

	log("debug", "outbound presence "..stanza.attr.type.." from "..from_bare.." for "..to_bare);

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

		stanza.attr.from, stanza.attr.to = st_from, st_to;

		return;

	elseif stanza.attr.type == "subscribe" then

		-- 1. route stanza

		-- 2. roster push (subscription = none, ask = subscribe)

		if rostermanager.set_contact_pending_out(node, host, to_bare) then

			rostermanager.roster_push(node, host, to_bare);

		end -- else file error

		core_post_stanza(origin, stanza);

	elseif stanza.attr.type == "unsubscribe" then

		-- 1. route stanza

		-- 2. roster push (subscription = none or from)

		if rostermanager.unsubscribe(node, host, to_bare) then

			rostermanager.roster_push(node, host, to_bare); -- FIXME do roster push when roster has in fact not changed?

		end -- else file error

		core_post_stanza(origin, stanza);

	elseif stanza.attr.type == "subscribed" then

		-- 1. route stanza

		-- 2. roster_push ()

		-- 3. send_presence_of_available_resources

		if rostermanager.subscribed(node, host, to_bare) then

			rostermanager.roster_push(node, host, to_bare);

		end

		core_post_stanza(origin, stanza);

		send_presence_of_available_resources(node, host, to_bare, origin);

	elseif stanza.attr.type == "unsubscribed" then

		-- 1. route stanza

		-- 2. roster push (subscription = none or to)

		if rostermanager.unsubscribed(node, host, to_bare) then

			rostermanager.roster_push(node, host, to_bare);

		end

		core_post_stanza(origin, stanza);

	end

	stanza.attr.from, stanza.attr.to = st_from, st_to;

	return true;

end

function handle_inbound_presence_subscriptions_and_probes(origin, stanza, from_bare, to_bare)

	local node, host = jid_split(to_bare);

	local st_from, st_to = stanza.attr.from, stanza.attr.to;

	stanza.attr.from, stanza.attr.to = from_bare, to_bare;

	log("debug", "inbound presence "..stanza.attr.type.." from "..from_bare.." for "..to_bare);

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

		local result, err = rostermanager.is_contact_subscribed(node, host, from_bare);

		if result then

			if 0 == send_presence_of_available_resources(node, host, st_from, origin) then

				core_post_stanza(hosts[host], st.presence({from=to_bare, to=st_from, type="unavailable"}), true); -- TODO send last activity

			end

		elseif not err then

			core_post_stanza(hosts[host], st.presence({from=to_bare, to=from_bare, type="unsubscribed"}), true);

		end

	elseif stanza.attr.type == "subscribe" then

		if rostermanager.is_contact_subscribed(node, host, from_bare) then

			core_post_stanza(hosts[host], st.presence({from=to_bare, to=from_bare, type="subscribed"}), true); -- already subscribed

			-- Sending presence is not clearly stated in the RFC, but it seems appropriate

			if 0 == send_presence_of_available_resources(node, host, from_bare, origin) then

				core_post_stanza(hosts[host], st.presence({from=to_bare, to=from_bare, type="unavailable"}), true); -- TODO send last activity

			end

		else

			core_post_stanza(hosts[host], st.presence({from=to_bare, to=from_bare, type="unavailable"}), true); -- acknowledging receipt

			if not rostermanager.is_contact_pending_in(node, host, from_bare) then

				if rostermanager.set_contact_pending_in(node, host, from_bare) then

					sessionmanager.send_to_available_resources(node, host, stanza);

				end -- TODO else return error, unable to save

			end

		end

	elseif stanza.attr.type == "unsubscribe" then

		if rostermanager.process_inbound_unsubscribe(node, host, from_bare) then

			sessionmanager.send_to_interested_resources(node, host, stanza);

			rostermanager.roster_push(node, host, from_bare);

		end

	elseif stanza.attr.type == "subscribed" then

		if rostermanager.process_inbound_subscription_approval(node, host, from_bare) then

			sessionmanager.send_to_interested_resources(node, host, stanza);

			rostermanager.roster_push(node, host, from_bare);

		end

	elseif stanza.attr.type == "unsubscribed" then

		if rostermanager.process_inbound_subscription_cancellation(node, host, from_bare) then

			sessionmanager.send_to_interested_resources(node, host, stanza);

			rostermanager.roster_push(node, host, from_bare);

		end

	end -- discard any other type

	stanza.attr.from, stanza.attr.to = st_from, st_to;

	return true;

end

local outbound_presence_handler = function(data)

	-- outbound presence recieved

	local origin, stanza = data.origin, data.stanza;

	local to = stanza.attr.to;

	if to then

		local t = stanza.attr.type;

		if t ~= nil and t ~= "unavailable" and t ~= "error" then -- check for subscriptions and probes

			return handle_outbound_presence_subscriptions_and_probes(origin, stanza, jid_bare(stanza.attr.from), jid_bare(stanza.attr.to));

		end

		local to_bare = jid_bare(to);

			origin.directed = origin.directed or {};

			if t then -- removing from directed presence list on sending an error or unavailable

				origin.directed[to] = nil; -- FIXME does it make more sense to add to_bare rather than to?

			else

				origin.directed[to] = true; -- FIXME does it make more sense to add to_bare rather than to?

			end

		end

	end -- TODO maybe handle normal presence here, instead of letting it pass to incoming handlers?

end

module:hook("pre-presence/full", outbound_presence_handler);

module:hook("pre-presence/bare", outbound_presence_handler);

module:hook("pre-presence/host", outbound_presence_handler);

module:hook("presence/bare", function(data)

	-- inbound presence to bare JID recieved

	local origin, stanza = data.origin, data.stanza;

	local to = stanza.attr.to;

	local t = stanza.attr.type;

	if to then

		if t ~= nil and t ~= "unavailable" and t ~= "error" then -- check for subscriptions and probes sent to bare JID

			return handle_inbound_presence_subscriptions_and_probes(origin, stanza, jid_bare(stanza.attr.from), jid_bare(stanza.attr.to));

		end

		local user = bare_sessions[to];

		if user then

			for _, session in pairs(user.sessions) do

				if session.presence then -- only send to available resources

					session.send(stanza);

				end

			end

		end -- no resources not online, discard

	elseif not t or t == "unavailable" then

		handle_normal_presence(origin, stanza);

	end

	return true;

end);

module:hook("presence/full", function(data)

	-- inbound presence to full JID recieved

	local origin, stanza = data.origin, data.stanza;

	local t = stanza.attr.type;

	if t ~= nil and t ~= "unavailable" and t ~= "error" then -- check for subscriptions and probes sent to full JID

		return handle_inbound_presence_subscriptions_and_probes(origin, stanza, jid_bare(stanza.attr.from), jid_bare(stanza.attr.to));

	end

	local session = full_sessions[stanza.attr.to];

	if session then

		-- TODO fire post processing event

		session.send(stanza);

	end -- resource not online, discard

	return true;

end);

module:hook("presence/host", function(data)

	-- inbound presence to the host

	local origin, stanza = data.origin, data.stanza;

	local from_bare = jid_bare(stanza.attr.from);

	local t = stanza.attr.type;

	if t == "probe" then

		core_post_stanza(hosts[module.host], st.presence({ from = module.host, to = from_bare, id = stanza.attr.id }));

	elseif t == "subscribe" then

		core_post_stanza(hosts[module.host], st.presence({ from = module.host, to = from_bare, id = stanza.attr.id, type = "subscribed" }));

		core_post_stanza(hosts[module.host], st.presence({ from = module.host, to = from_bare, id = stanza.attr.id }));