-- XEP-0313: Message Archive Management for Prosody

-- Copyright (C) 2011-2012 Kim Alvefur

--

-- This file is MIT/X11 licensed.

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

local xmlns_delay   = "urn:xmpp:delay";

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

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 jid_prep = require "util.jid".prep;

local host = module.host;

local dm_load = require "util.datamanager".load;

local dm_store = require "util.datamanager".store;

local rm_load_roster = require "core.rostermanager".load_roster;

local serialize, deserialize = require"util.json".encode, require"util.json".decode;

local unpack = unpack;

local tostring = tostring;

local time_now = os.time;

local t_insert = table.insert;

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 global_default_policy = module:get_option("default_archive_policy", false);

-- TODO Should be possible to enforce it too

local sql, setsql, getsql = {};

do -- SQL stuff

local dburi;

local connection;

local connections = module:shared "/*/sql/connection-cache";

local build_url = require"socket.url".build;

local resolve_relative_path = require "core.configmanager".resolve_relative_path;

local params = module:get_option("mam_sql", module:get_option("sql"));

local function db2uri(params)

	return build_url{

		scheme = params.driver,

		user = params.username,

		password = params.password,

		host = params.host,

		port = params.port,

		path = params.database,

	};

end

local connect

local function test_connection()

	if not connection then return nil; end

	if connection:ping() then

		return true;

	else

		module:log("debug", "Database connection closed");

		module:log("debug", "Attempting to reconnect");

		connection = nil;

		return connect();

	end

end

function connect()

	if not test_connection() then

		prosody.unlock_globals();

		local dbh, err = DBI.Connect(

			params.driver, params.database,

			params.username, params.password,

			params.host, params.port

		);

		prosody.lock_globals();

		if not dbh then

			module:log("debug", "Database connection failed: %s", tostring(err));

			return nil, err;

		end

		module:log("debug", "Successfully connected to database");

		dbh:autocommit(false); -- don't commit automatically

		connection = dbh;

		connections[dburi] = dbh;

	end

	return connection;

end

do -- process options to get a db connection

	local ok;

	prosody.unlock_globals();

	ok, DBI = pcall(require, "DBI");

	if not ok then

		package.loaded["DBI"] = {};

		module:log("error", "Failed to load the LuaDBI library for accessing SQL databases: %s", DBI);

		module:log("error", "More information on installing LuaDBI can be found at http://prosody.im/doc/depends#luadbi");

	end

	prosody.lock_globals();

	if not ok or not DBI.Connect then

		return; -- Halt loading of this module

	end

	params = params or { driver = "SQLite3" };

	if params.driver == "SQLite3" then

		params.database = resolve_relative_path(prosody.paths.data or ".", params.database or "prosody.sqlite");

	end

	assert(params.driver and params.database, "Both the SQL driver and the database need to be specified");

	dburi = db2uri(params);

	connection = connections[dburi];

	assert(connect());

end

function getsql(sql, ...)

	if params.driver == "PostgreSQL" then

		sql = sql:gsub("`", "\"");

	end

	if not connection then

		return nil, 'connection failed';

	end

	if not test_connection() then

		return nil, 'connection failed';

	end

	-- do prepared statement stuff

	local stmt, err = connection:prepare(sql);

	if not stmt and not test_connection() then

		return nil, "connection failed";

	end

	if not stmt then module:log("error", "QUERY FAILED: %s %s", err, debug.traceback()); return nil, err; end

	-- run query

	local ok, err = stmt:execute(...);

	if not ok and not test_connection() then

		return nil, "connection failed";

	end

	if not ok then return nil, err; end

	return stmt;

end

function setsql(sql, ...)

	local stmt, err = getsql(sql, ...);

	if not stmt then return stmt, err; end

	return stmt:affected();

end

function sql.rollback(...)

	if connection then connection:rollback(); end -- FIXME check for rollback error?

	return ...;

end

function sql.commit(...)

	if not connection:commit() then return nil, "SQL commit failed"; end

	return ...;

end

end

-- For translating preference names from string to boolean and back

local default_attrs = {

	always = true, [true] = "always",

	never = false, [false] = "never",

	roster = "roster",

}

do

	local prefs_format = {

		[false] = "roster",

		-- default ::= true | false | "roster"

		-- true = always, false = never, nil = global default

		["romeo@montague.net"] = true, -- always

		["montague@montague.net"] = false, -- newer

	};

end

local archive_store = "archive2";

local prefs_store = archive_store .. "_prefs";

local function get_prefs(user)

	return dm_load(user, host, prefs_store) or

		{ [false] = global_default_policy };

end

local function set_prefs(user, prefs)

	return dm_store(user, host, prefs_store, prefs);

end

-- Handle prefs.

module:hook("iq/self/"..xmlns_mam..":prefs", function(event)

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

	local user = origin.username;

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

		local prefs = get_prefs(user);

		local default = prefs[false];

		default = default ~= nil and default_attrs[default] or global_default_policy;

		local reply = st.reply(stanza):tag("prefs", { xmlns = xmlns_mam, default = default })

		local always = st.stanza("always");

		local never = st.stanza("never");

		for k,v in pairs(prefs) do

			if k then

				(v and always or never):tag("jid"):text(k):up();

			end

		end

		reply:add_child(always):add_child(never);

		origin.send(reply);

		return true

	else -- type == "set"

		local prefs = {};

		local new_prefs = stanza:get_child("prefs", xmlns_mam);

		local new_default = new_prefs.attr.default;

		if new_default then

			prefs[false] = default_attrs[new_default];

		end

		local always = new_prefs:get_child("always");

		if always then

			for rule in always:childtags("jid") do

				local jid = rule:get_text();

				prefs[jid] = true;

			end

		end

		local never = new_prefs:get_child("never");

		if never then

			for rule in never:childtags("jid") do

				local jid = rule:get_text();

				prefs[jid] = false;

			end

		end

		local ok, err = set_prefs(user, prefs);

		if not ok then

			origin.send(st.error_reply(stanza, "cancel", "internal-server-error", "Error storing preferences: "..tostring(err)));

		else

			origin.send(st.reply(stanza));

		end

		return true

	end

end);

-- Handle archive queries

module:hook("iq/self/"..xmlns_mam..":query", function(event)

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

	local query = stanza.tags[1];

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

		local qid = query.attr.queryid;

		-- Search query parameters

		local qwith = query:get_child_text("with");

		local qstart = query:get_child_text("start");

		local qend = query:get_child_text("end");

		local qset = rsm.get(query);

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

			tostring(qid), qwith or "anyone", qstart or "the dawn of time", qend or "now");

		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

		local qres;

		if qwith then -- Validate the 'with' jid

			local pwith = qwith and jid_prep(qwith);

			if pwith and not qwith then -- it failed prepping

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

				return true

			end

			local _, _, resource = jid_split(qwith);

			qwith = jid_bare(pwith);

			qres = resource;

		end

		-- RSM stuff

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

		local last;

		local sql_query = ([[

		SELECT `id`, `when`, `stanza`

		FROM `prosodyarchive`

		WHERE `host` = ? AND `user` = ? AND `store` = ?

		AND `when` BETWEEN ? AND ?

		%s %s

		AND `id` > ?

		LIMIT ?;

		]]):format(qwith and [[AND `with` = ?]] or "", qres and [[AND `resource` = ?]] or "")

		local p = {

			host, origin.username, archive_store,

			qstart or 0, qend or time_now(),

			qset and tonumber(qset.after) or 0,

			qmax

		};

		if qwith then

			if qres then

				t_insert(p, 6, qres);

			end

			t_insert(p, 6, qwith);

		end

		local data, err = getsql(sql_query, unpack(p));

		if not data then

			origin.send(st.error_reply(stanza, "cancel", "internal-server-error", "Error loading archive: "..tostring(err)));

			return true

		end

		for item in data:rows() do

			local id, when, orig_stanza = unpack(item);

			--module:log("debug", "id is %s", id);

			local fwd_st = st.message{ to = origin.full_jid }

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

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

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

			orig_stanza = st.deserialize(deserialize(orig_stanza));

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

			fwd_st:add_child(orig_stanza);

			origin.send(fwd_st);

			last = id;

		end

		-- That's all folks!

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

		local reply = st.reply(stanza);

		if last then

			-- This is a bit redundant, isn't it?

			reply:query(xmlns_mam):add_child(rsm.generate{last = last});

		end

		origin.send(reply);

		return true

	end

end);

local function has_in_roster(user, who)

	local roster = rm_load_roster(user, host);

	module:log("debug", "%s has %s in roster? %s", user, who, roster[who] and "yes" or "no");

	return roster[who];

end

local function shall_store(user, who)

	-- TODO Cache this?

	local prefs = get_prefs(user);

	local rule = prefs[who];

	module:log("debug", "%s's rule for %s is %s", user, who, tostring(rule))

	if rule ~= nil then

		return rule;

	else -- Below could be done by a metatable

		local default = prefs[false];

		module:log("debug", "%s's default rule is %s", user, tostring(default))

		if default == nil then

			default = global_default_policy;

			module:log("debug", "Using global default rule, %s", tostring(default))

		end

		if default == "roster" then

			return has_in_roster(user, who);

		end

		return default;

	end

end

-- Handle messages

local function message_handler(event, c2s)

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

	local orig_type = stanza.attr.type or "normal";

	local orig_to = stanza.attr.to;

	local orig_from = stanza.attr.from;

	if not orig_from and c2s then

		orig_from = origin.full_jid;

	end

	orig_to = orig_to or orig_from; -- Weird corner cases

	-- Don't store messages of these types

	if orig_type == "error"

	or orig_type == "headline"

	or orig_type == "groupchat"

	or not stanza:get_child("body") then

		return;

		-- TODO Maybe headlines should be configurable?

	end

	local store_user, store_host = jid_split(c2s and orig_from or orig_to);

	local target_jid = c2s and orig_to or orig_from;

	local target_bare = jid_bare(target_jid);

	local _, _, target_resource = jid_split(target_jid);

	if shall_store(store_user, target_bare) then

		module:log("debug", "Archiving stanza: %s", stanza:top_tag());