local jid = require "util.jid";

local st = require "util.stanza";

local datetime = require "util.datetime";

local jid_resource = require "util.jid".resource;

local notify_unaffiliated_users = module:get_option("muc_mmn_notify_unaffiliated_users", false)

local muc_affiliation_store = module:open_store("config", "map");

local mmn_xmlns = "urn:xmpp:mmn:0";

local reference_xmlns = "urn:xmpp:reference:0";

local forwarded_xmlns = "urn:xmpp:forward:0";

local deplay_xmlns = "urn:xmpp:delay";

-- Returns a set of rooms the user is affiliated to

local function get_user_rooms(user_bare_jid)

	return muc_affiliation_store:get_all(user_bare_jid);

end

local function is_eligible(user_bare_jid, room)

	if notify_unaffiliated_users then return true; end

	local user_rooms, err = get_user_rooms(user_bare_jid);

	if not user_rooms then

		if err then

			return false, err;

		end

		return false;

	end

	local room_node = jid.node(room.jid)

	if user_rooms[room_node] then

		return true;

	end

	return false

end

-- Send a single notification for a room, updating data structures as needed

local function send_single_notification(user_bare_jid, room_jid, mention_stanza)

	local notification = st.message({ to = user_bare_jid, from = room_jid })

		:tag("mentions", { xmlns = mmn_xmlns })

		:tag("forwarded", {xmlns = forwarded_xmlns})

		:tag("delay", {xmlns = deplay_xmlns, stamp = datetime.datetime()}):up()

		:add_child(mention_stanza)

		:reset();

	module:log("debug", "Sending mention notification from %s to %s", room_jid, user_bare_jid);

	return module:send(notification);

end

local function notify_mentioned_users(room, client_mentions, mention_stanza)

	module:log("debug", "NOTIFYING FOR %s", room.jid)

	for mentioned_jid in pairs(client_mentions) do

		local user_bare_jid = mentioned_jid;

		if (string.match(mentioned_jid, room.jid)) then

			local nick = jid_resource(mentioned_jid);

			user_bare_jid = room:get_registered_jid(nick);

		end

		if is_eligible(user_bare_jid, room) then

			send_single_notification(user_bare_jid, room.jid, mention_stanza);

		end

	end

end

local function get_mentions(stanza)

	local has_mentions = false

	local client_mentions = {}

	for element in stanza:childtags("reference", reference_xmlns) do

		if element.attr.type == "mention" then

			local user_bare_jid = element.attr.uri:match("^xmpp:(.+)$");

			if user_bare_jid then

				client_mentions[user_bare_jid] = user_bare_jid;

				has_mentions = true

			end

		end

	end

	return has_mentions, client_mentions

end

module:hook("muc-broadcast-message", function (event)

	local room, stanza = event.room, event.stanza;

	local body = stanza:get_child_text("body")

	if not body or #body < 1 then return; end

	local correction = stanza:get_child("replace", "urn:xmpp:message-correct:0");

	if correction then return; end -- Do not notify on message corrections

	local has_mentions, client_mentions = get_mentions(stanza)

	if not has_mentions then return; end

	-- Notify any users that need to be notified

	notify_mentioned_users(room, client_mentions, stanza);

end, -1);