-- XEP-0313: Message Archive Management for Prosody MUC

-- Copyright (C) 2011-2017 Kim Alvefur

--

-- This file is MIT/X11 licensed.

if module:get_host_type() ~= "component" then

	module:log("error", "mod_%s should be loaded only on a MUC component, not normal hosts", module.name);

	return;

end

local xmlns_mam     = "urn:xmpp:mam:2";

local xmlns_delay   = "urn:xmpp:delay";

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

local xmlns_st_id   = "urn:xmpp:sid:0";

local xmlns_muc_user = "http://jabber.org/protocol/muc#user";

local muc_form_enable = "muc#roomconfig_enablearchiving"

local st = require "util.stanza";

local rsm = require "util.rsm";

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

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

local jid_prep = require "util.jid".prep;

local dataform = require "util.dataforms".new;

local mod_muc = module:depends"muc";

local get_room_from_jid = mod_muc.get_room_from_jid;

local is_stanza = st.is_stanza;

local tostring = tostring;

local time_now = os.time;

local m_min = math.min;

local timestamp, timestamp_parse = require "util.datetime".datetime, require "util.datetime".parse;

local default_max_items, max_max_items = 20, module:get_option_number("max_archive_query_results", 50);

local default_history_length = 20;

local max_history_length = module:get_option_number("max_history_messages", math.huge);

local function get_historylength(room)

	return math.min(room._data.history_length or default_history_length, max_history_length);

end

local log_all_rooms = module:get_option_boolean("muc_log_all_rooms", false);

local log_by_default = module:get_option_boolean("muc_log_by_default", true);

local archive_store = "muc_log";

local archive = module:open_store(archive_store, "archive");

if archive.name == "null" or not archive.find then

	if not archive.find then

		module:log("error", "Attempt to open archive storage returned a driver without archive API support");

		module:log("error", "mod_%s does not support archiving",

			archive._provided_by or archive.name and "storage_"..archive.name.."(?)" or "<unknown>");

	else

		module:log("error", "Attempt to open archive storage returned null driver");

	end

	module:log("info", "See https://prosody.im/doc/storage and https://prosody.im/doc/archiving for more information");

	return false;

end

local function archiving_enabled(room)

	if log_all_rooms then

		return true;

	end

	local enabled = room._data.archiving;

	if enabled == nil then

		return log_by_default;

	end

	return enabled;

end

if not log_all_rooms then

	module:hook("muc-config-form", function(event)

		local room, form = event.room, event.form;

		table.insert(form,

		{

			name = muc_form_enable,

			type = "boolean",

			label = "Enable archiving?",

			value = archiving_enabled(room),

		}

		);

	end);

	module:hook("muc-config-submitted/"..muc_form_enable, function(event)

		event.room._data.archiving = event.value;

	end);

end

-- Note: We ignore the 'with' field as this is internally used for stanza types

local query_form = dataform {

	{ name = "FORM_TYPE"; type = "hidden"; value = xmlns_mam; };

	{ name = "with"; type = "jid-single"; };

	{ name = "start"; type = "text-single" };

	{ name = "end"; type = "text-single"; };

};

-- Serve form

module:hook("iq-get/bare/"..xmlns_mam..":query", function(event)

	local origin, stanza = event.origin, event.stanza;

	origin.send(st.reply(stanza):add_child(query_form:form()));

	return true;

end);

-- Handle archive queries

module:hook("iq-set/bare/"..xmlns_mam..":query", function(event)

	local origin, stanza = event.origin, event.stanza;

	local room_jid = stanza.attr.to;

	local room_node = jid_split(room_jid);

	local orig_from = stanza.attr.from;

	local query = stanza.tags[1];

	local room = get_room_from_jid(room_jid);

	if not room then

		origin.send(st.error_reply(stanza, "cancel", "item-not-found"))

		return true;

	end

	local from = jid_bare(orig_from);

	-- Banned or not a member of a members-only room?

	local from_affiliation = room:get_affiliation(from);

	if from_affiliation == "outcast" -- banned

		or room:get_members_only() and not from_affiliation then -- members-only, not a member

		origin.send(st.error_reply(stanza, "auth", "forbidden"))

		return true;

	end

	local qid = query.attr.queryid;

	-- Search query parameters

	local qstart, qend;

	local form = query:get_child("x", "jabber:x:data");

	if form then

		local err;

		form, err = query_form:data(form);

		if err then

			origin.send(st.error_reply(stanza, "modify", "bad-request", select(2, next(err))));

			return true;

		end

		qstart, qend = form["start"], form["end"];

	end

	if qstart or qend then -- Validate timestamps

		local vstart, vend = (qstart and timestamp_parse(qstart)), (qend and timestamp_parse(qend))

		if (qstart and not vstart) or (qend and not vend) then

			origin.send(st.error_reply(stanza, "modify", "bad-request", "Invalid timestamp"))

			return true;

		end

		qstart, qend = vstart, vend;

	end

	module:log("debug", "Archive query id %s from %s until %s)",

		tostring(qid),

		qstart and timestamp(qstart) or "the dawn of time",

		qend and timestamp(qend) or "now");

	-- RSM stuff

	local qset = rsm.get(query);

	local qmax = m_min(qset and qset.max or default_max_items, max_max_items);

	local reverse = qset and qset.before or false;

	local before, after = qset and qset.before, qset and qset.after;

	if type(before) ~= "string" then before = nil; end

	-- Load all the data!

	local data, err = archive:find(room_node, {

		start = qstart; ["end"] = qend; -- Time range

		limit = qmax + 1;

		before = before; after = after;

		reverse = reverse;

		with = "message<groupchat";

	});

	if not data then

		origin.send(st.error_reply(stanza, "cancel", "internal-server-error"));

		return true;

	end

	local total = tonumber(err);

	local msg_reply_attr = { to = stanza.attr.from, from = stanza.attr.to };

	local results = {};

	-- Wrap it in stuff and deliver

	local first, last;

	local count = 0;

	local complete = "true";

	for id, item, when in data do

		count = count + 1;

		if count > qmax then

			complete = nil;

			break;

		end

		local fwd_st = st.message(msg_reply_attr)

			:tag("result", { xmlns = xmlns_mam, queryid = qid, id = id })

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

					:tag("delay", { xmlns = xmlns_delay, stamp = timestamp(when) }):up();

		-- Strip <x> tag, containing the original senders JID, unless the room makes this public

		if room:get_whois() ~= "anyone" then

			item:maptags(function (tag)

				if tag.name == "x" and tag.attr.xmlns == xmlns_muc_user then

					return nil;

				end

				return tag;

			end);

		end

		if not is_stanza(item) then

			item = st.deserialize(item);

		end

		item.attr.xmlns = "jabber:client";

		fwd_st:add_child(item);

		if not first then first = id; end

		last = id;

		if reverse then

			results[count] = fwd_st;

		else

			origin.send(fwd_st);

		end

	end

	if reverse then

		for i = #results, 1, -1 do

			origin.send(results[i]);

		end

		first, last = last, first;

	end

	-- That's all folks!

	module:log("debug", "Archive query %s completed", tostring(qid));

	origin.send(st.reply(stanza)

		:tag("fin", { xmlns = xmlns_mam, queryid = qid, complete = complete })

			:add_child(rsm.generate {

				first = first, last = last, count = total }));

	return true;

end);

module:hook("muc-get-history", function (event)

	local room = event.room;

	if not archiving_enabled(room) then return end

	local room_jid = room.jid;

	local maxstanzas = event.maxstanzas or math.huge;

	local maxchars = event.maxchars;

	local since = event.since;

	local to = event.to;

	-- Load all the data!

	local query = {

		limit = math.min(maxstanzas, get_historylength(room));

		start = since;

		reverse = true;

		with = "message<groupchat";

	}

	local data, err = archive:find(jid_split(room_jid), query);

	if not data then

		module:log("error", "Could not fetch history: %s", tostring(err));

		return

	end

	local history, i = {}, 1;

	for id, item, when in data do

		item.attr.to = to;

		item:tag("delay", { xmlns = "urn:xmpp:delay", from = room_jid, stamp = timestamp(when) }):up(); -- XEP-0203

		item:tag("stanza-id", { xmlns = xmlns_st_id, by = room_jid, id = id }):up();

		if room:get_whois() ~= "anyone" then

			item:maptags(function (tag)

				if tag.name == "x" and tag.attr.xmlns == xmlns_muc_user then

					return nil;

				end

				return tag;

			end);

		end

		if maxchars then

			local chars = #tostring(item);

			if maxchars - chars < 0 then

				break

			end

			maxchars = maxchars - chars;

		end

		history[i], i = item, i+1;

		-- module:log("debug", tostring(item));

	end

	function event.next_stanza()

		i = i - 1;

		return history[i];

	end

	return true;

end, 1);

-- Handle messages

local function save_to_history(self, stanza)

	local room_node, room_host = jid_split(self.jid);

	-- Filter out <stanza-id> that claim to be from us

	stanza:maptags(function (tag)

		if tag.name == "stanza-id" and tag.attr.xmlns == xmlns_st_id

		and jid_prep(tag.attr.by) == self.jid then

			return nil;

		end

		if tag.name == "x" and tag.attr.xmlns == xmlns_muc_user then

			return nil;

		end

		return tag;

	end);

	local stored_stanza = stanza;

	if stanza.name == "message" and self:get_whois() == "anyone" then

		stored_stanza = st.clone(stanza);

		local actor = jid_bare(self._occupants[stanza.attr.from].jid);

		local affiliation = self:get_affiliation(actor) or "none";

		local role = self:get_role(actor) or self:get_default_role(affiliation);

		stored_stanza:add_direct_child(st.stanza("x", { xmlns = xmlns_muc_user })

			:tag("item", { affiliation = affiliation; role = role; jid = actor }));

	end

	-- Policy check

	if not archiving_enabled(self) then return end -- Don't log

	-- And stash it

	local with = stanza.name

	if stanza.attr.type then

		with = with .. "<" .. stanza.attr.type

	end

	local id = archive:append(room_node, nil, stored_stanza, time_now(), with);

	if id then

		stanza:add_direct_child(st.stanza("stanza-id", { xmlns = xmlns_st_id, by = self.jid, id = id }));

	end

end

module:hook("muc-add-history", function (event)

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

	save_to_history(room, stanza);

end);

if module:get_option_boolean("muc_log_presences", true) then

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

	end);

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

		save_to_history(event.room, st.stanza("presence", { type = "unavailable", from = event.nick }));

	end);

end

if not archive.delete then

	module:log("warn", "Storage driver %s does not support deletion", archive._provided_by);

	module:log("warn", "Archived message will persist after a room has been destroyed");

else

	module:hook("muc-room-destroyed", function(event)

		local room_node = jid_split(event.room.jid);

		archive:delete(room_node);

	end);

end

-- And role/affiliation changes?

module:add_feature(xmlns_mam);

module:hook("muc-disco#info", function(event)

	event.reply:tag("feature", {var=xmlns_mam}):up();

end);