local array = require "util.array";

local it = require "util.iterators";

local jid = require "util.jid";

local sha256 = require "util.hashes".sha256;

local set = require "util.set";

local st = require "util.stanza";

local rtbl_service_jid = assert(module:get_option_string("muc_rtbl_jid"), "No RTBL JID supplied");

local rtbl_node = module:get_option_string("muc_rtbl_node", "muc_bans_sha256");

local banned_hashes = module:shared("banned_hashes");

module:depends("pubsub_subscription");

module:add_item("pubsub-subscription", {

	service = rtbl_service_jid;

	node = rtbl_node;

	-- Callbacks:

	on_subscribed = function()

		module:log("info", "RTBL active");

	end;

	on_error = function(err)

		module:log("error", "Failed to subscribe to RTBL: %s::%s:  %s", err.type, err.condition, err.text);

	end;

	on_item = function(event)

		local hash = event.item.attr.id;

		if not hash then return; end

		module:log("debug", "Received new hash: %s", hash);

		banned_hashes[hash] = true;

	end;

	on_retract = function (event)

		local hash = event.item.attr.id;

		if not hash then return; end

		module:log("debug", "Retracted hash: %s", hash);

		banned_hashes[hash] = nil;

	end;

});

function request_list()

	local items_request = st.iq({ to = rtbl_service_jid, from = module.host, type = "get", id = "rtbl-request" })

		:tag("pubsub", { xmlns = "http://jabber.org/protocol/pubsub" })

			:tag("items", { node = rtbl_node }):up()

		:up();

	module:send(items_request);

end

function update_list(event)

	local from_jid = event.stanza.attr.from;

	if from_jid ~= rtbl_service_jid then

		module:log("debug", "Ignoring RTBL response from unknown sender");

		return;

	end

	local items_el = event.stanza:find("{http://jabber.org/protocol/pubsub}pubsub/items");

	if not items_el then

		module:log("warn", "Invalid items response from RTBL service");

		return;

	end

	local old_entries = set.new(array.collect(it.keys(banned_hashes)));

	local n_added, n_removed, n_total = 0, 0, 0;

	for item in items_el:childtags("item") do

		local hash = item.attr.id;

		if hash then

			n_total = n_total + 1;

			if not old_entries:contains(hash) then

				-- New entry

				n_added = n_added + 1;

				banned_hashes[hash] = true;

			else

				-- Entry already existed

				old_entries:remove(hash);

			end

		end

	end

	-- Remove old entries that weren't in the received list

	for hash in old_entries do

		n_removed = n_removed + 1;

		banned_hashes[hash] = nil;

	end

	module:log("info", "%d RTBL entries received from %s (%d added, %d removed)", n_total, from_jid, n_added, n_removed);

	return true;

end

module:hook("iq-result/host/rtbl-request", update_list);

module:hook("muc-occupant-pre-join", function (event)

	local from_bare = jid.bare(event.stanza.attr.from);

	local affiliation = event.room:get_affiliation(from_bare);

	if affiliation and affiliation ~= "none" then

		-- Skip check for affiliated users

		return;

	end

	local bare_hash = sha256(jid.bare(event.stanza.attr.from), true);

	local host_hash = sha256(jid.host(event.stanza.attr.from), true);

	if banned_hashes[bare_hash] or banned_hashes[host_hash] then

		module:log("info", "Blocked user <%s> from room <%s> due to RTBL match", from_bare, event.stanza.attr.to);

		local error_reply = st.error_reply(event.stanza, "cancel", "forbidden", "You are banned from this service", event.room.jid);

		event.origin.send(error_reply);

		return true;

	end

end);

if prosody.start_time then

	request_list();

else

	module:hook_global("server-started", function ()

		request_list();

	end);

end