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

-- Copyright (C) 2011-2014 Kim Alvefur

--

-- This file is MIT/X11 licensed.

local xmlns_mam     = "urn:xmpp:mam:0";

local xmlns_delay   = "urn:xmpp:delay";

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

local muc_form_enable_logging = "muc#roomconfig_enablelogging"

local st = require "util.stanza";

local rsm = module:require "mod_mam/rsm";

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

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

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

local it = require"util.iterators";

-- Support both old and new MUC code

local mod_muc = module:depends"muc";

local rooms = rawget(mod_muc, "rooms");

local each_room = rawget(mod_muc, "each_room") or function() return it.values(rooms); end;

local new_muc = not rooms;

if new_muc then

	rooms = module:shared"muc/rooms";

end

local get_room_from_jid = rawget(mod_muc, "get_room_from_jid") or

	function (jid)

		return rooms[jid];

	end

local getmetatable = getmetatable;

local function is_stanza(x)

	return getmetatable(x) == st.stanza_mt;

end

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 max_history_length = module:get_option_number("max_history_messages", 1000);

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

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

	module:log("error", "Could not open archive storage");

	return

elseif not archive.find then

	module:log("error", "mod_%s does not support archiving, switch to mod_storage_sql2", archive._provided_by);

	return

end

local function logging_enabled(room)

	if log_all_rooms then

		return true;

	end

	local enabled = room._data.logging;

	if enabled == nil then

		return log_by_default;

	end

	return enabled;

end

local send_history, save_to_history;

	-- Override history methods for all rooms.

if not new_muc then -- 0.10 or older

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

		local room = event.room;

		if logging_enabled(room) then

			room.send_history = send_history;

			room.save_to_history = save_to_history;

		end

	end);

	function module.load()

		for room in each_room() do

			if logging_enabled(room) then

				room.send_history = send_history;

				room.save_to_history = save_to_history;

			end

		end

	end

	function module.unload()

		for room in each_room() do

			if room.send_history == send_history then

				room.send_history = nil;

				room.save_to_history = nil;

			end

		end

	end

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_logging,

			type = "boolean",

			label = "Enable Logging?",

			value = logging_enabled(room),

		}

		);

	end);

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

		local room, fields, changed = event.room, event.fields, event.changed;

		local new = fields[muc_form_enable_logging];

		if new ~= room._data.logging then

			room._data.logging = new;

			if type(changed) == "table" then

				changed[muc_form_enable_logging] = true;

			else

				event.changed = true;

			end

			if new then

				room.send_history = send_history;

				room.save_to_history = save_to_history;

			else

				room.send_history = nil;

				room.save_to_history = nil;

			end

		end

	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 = stanza.attr.to;

	local room_node = jid_split(room);

	local orig_from = stanza.attr.from;

	local query = stanza.tags[1];

	local room_obj = get_room_from_jid(room);

	if not room_obj then

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

	end

	local from = jid_bare(orig_from);

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

	local from_affiliation = room_obj:get_affiliation(from);

	if from_affiliation == "outcast" -- banned

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

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

	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

	-- 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;

		total = true;

		with = "message<groupchat";

	});

	if not data then

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

	end

	local total = err;

	origin.send(st.reply(stanza))

	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();

		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

	end

	-- That's all folks!

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

	if reverse then first, last = last, first; end

	origin.send(st.message(msg_reply_attr)

		: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 logging_enabled(room) then return end

	local room_jid = room.jid;

	local maxstanzas = event.maxstanzas;

	local maxchars = event.maxchars;

	local since = event.since;

	local to = event.to;

	-- Load all the data!

	local query = {

		limit = m_min(maxstanzas or 20, max_history_length);

		start = since;

		reverse = true;

		with = "message<groupchat";

	}

	module:log("debug", require"util.serialization".serialize(query))

	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 _, 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

		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);

function send_history(self, to, stanza)

	local maxchars, maxstanzas, seconds, since;

	local history_tag = stanza:find("{http://jabber.org/protocol/muc}x/history")

	if history_tag then

		module:log("debug", tostring(history_tag));

		local history_attr = history_tag.attr;

		maxchars = tonumber(history_attr.maxchars);

		maxstanzas = tonumber(history_attr.maxstanzas);

		seconds = tonumber(history_attr.seconds);

		since = history_attr.since;

		if since then

			since = timestamp_parse(since);

		end

		if seconds then

			since = math.max(os.time() - seconds, since or 0);

		end

	end

	local event = {

		room = self;

		to = to; -- `to` is required to calculate the character count for `maxchars`

		maxchars = maxchars, maxstanzas = maxstanzas, since = since;

		next_stanza = function() end; -- events should define this iterator

	};

	module:fire_event("muc-get-history", event);

	for msg in event.next_stanza, event do

		self:_route_stanza(msg);

	end

end

-- Handle messages

function save_to_history(self, stanza)

	local room = jid_split(self.jid);

	-- Policy check

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

	module:log("debug", "We're logging this")

	-- And stash it

	local with = stanza.name

	if stanza.attr.type then

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

	end

	archive:append(room, nil, time_now(), with, stanza);

end

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

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

	if stanza:get_child("body") then

		save_to_history(room, stanza);

	end

end);