-- Prosody IM

-- Copyright (C) 2008-2010 Matthew Wild

-- Copyright (C) 2008-2010 Waqas Hussain

--

-- This project is MIT/X11 licensed. Please see the

-- COPYING file in the source package for more information.

--

-- luacheck: globals prosody.full_sessions prosody.bare_sessions

local tostring, setmetatable = tostring, setmetatable;

local pairs, next= pairs, next;

local prosody, hosts = prosody, prosody.hosts;

local full_sessions = prosody.full_sessions;

local bare_sessions = prosody.bare_sessions;

local logger = require "prosody.util.logger";

local log = logger.init("sessionmanager");

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

local config_get = require "prosody.core.configmanager".get;

local resourceprep = require "prosody.util.encodings".stringprep.resourceprep;

local nodeprep = require "prosody.util.encodings".stringprep.nodeprep;

local generate_identifier = require "prosody.util.id".short;

local sessionlib = require "prosody.util.session";

local initialize_filters = require "prosody.util.filters".initialize;

local gettime = require "socket".gettime;

local _ENV = nil;

-- luacheck: std none

local function new_session(conn)

	local session = sessionlib.new("c2s");

	sessionlib.set_id(session);

	sessionlib.set_logger(session);

	sessionlib.set_conn(session, conn);

	session.conntime = gettime();

	local filter = initialize_filters(session);

	local w = conn.write;

	function session.rawsend(t)

		t = filter("bytes/out", tostring(t));

		if t then

			local ret, err = w(conn, t);

			if not ret then

				session.log("debug", "Error writing to connection: %s", err);

				return false, err;

			end

		end

		return true;

	end

	session.send = function (t)

		session.log("debug", "Sending[%s]: %s", session.type, t.top_tag and t:top_tag() or t:match("^[^>]*>?"));

		if t.name then

			t = filter("stanzas/out", t);

		end

		if t then

			return session.rawsend(t);

		end

		return true;

	end

	session.ip = conn:ip();

	local conn_name = "c2s"..tostring(session):match("[a-f0-9]+$");

	session.log = logger.init(conn_name);

	return session;

end

local resting_session = { -- Resting, not dead

		destroyed = true;

		type = "c2s_destroyed";

		close = function (session)

			session.log("debug", "Attempt to close already-closed session");

		end;

		filter = function (type, data) return data; end; --luacheck: ignore 212/type

	}; resting_session.__index = resting_session;

local function retire_session(session)

	local log = session.log or log; --luacheck: ignore 431/log

	for k in pairs(session) do

		if k ~= "log" and k ~= "id" then

			session[k] = nil;

		end

	end

	function session.send(data) log("debug", "Discarding data sent to resting session: %s", data); return false; end

	function session.rawsend(data) log("debug", "Discarding data sent to resting session: %s", data); return false; end

	function session.data(data) log("debug", "Discarding data received from resting session: %s", data); end

	session.thread = { run = function (_, data) return session.data(data) end };

	return setmetatable(session, resting_session);

end

-- Update a session with a new one (transplanting connection, filters, etc.)

-- new_session should be discarded after this call returns

local function update_session(to_session, from_session)

	to_session.log("debug", "Updating with parameters from session %s", from_session.id);

	from_session.log("debug", "Session absorbed into %s", to_session.id);

	local replaced_conn = to_session.conn;

	if replaced_conn then

		to_session.conn = nil;

	end

	to_session.since = from_session.since;

	to_session.ip = from_session.ip;

	to_session.conn = from_session.conn;

	to_session.rawsend = from_session.rawsend;

	to_session.rawsend.session = to_session;

	to_session.rawsend.conn = to_session.conn;

	to_session.send = from_session.send;

	to_session.send.session = to_session;

	to_session.close = from_session.close;

	to_session.filter = from_session.filter;

	to_session.filter.session = to_session;

	to_session.filters = from_session.filters;

	to_session.send.filter = to_session.filter;

	to_session.sasl_handler = from_session.sasl_handler;

	to_session.stream = from_session.stream;

	to_session.secure = from_session.secure;

	to_session.hibernating = nil;

	to_session.resumption_counter = (to_session.resumption_counter or 0) + 1;

	from_session.log = to_session.log;

	from_session.type = to_session.type;

	-- Inform xmppstream of the new session (passed to its callbacks)

	to_session.stream:set_session(to_session);

	-- Notify modules, allowing them to copy further fields or update state

	prosody.events.fire_event("c2s-session-updated", {

		session = to_session;

		from_session = from_session;

		replaced_conn = replaced_conn;

	});

	-- Retire the session we've pulled from, to avoid two sessions on the same connection

	retire_session(from_session);

end

local function destroy_session(session, err)

	if session.destroyed then return; end

	-- Remove session/resource from user's session list

	if session.full_jid then

		local host_session = hosts[session.host];

		-- Allow plugins to prevent session destruction

		if host_session.events.fire_event("pre-resource-unbind", {session=session, error=err}) then

			(session.log or log)("debug", "Resource unbind prevented by module");

			return;

		end

		(session.log or log)("debug", "Unbinding resource for %s (%s@%s)%s",

			session.full_jid or "(unknown)", session.username or "(unknown)",

			session.host or "(unknown)", err and (": "..err) or "");

		session.destroyed = true; -- Past this point the session is DOOMED!

		host_session.sessions[session.username].sessions[session.resource] = nil;

		full_sessions[session.full_jid] = nil;

		if not next(host_session.sessions[session.username].sessions) then

			log("debug", "All resources of %s are now offline", session.username);

			host_session.sessions[session.username] = nil;

			bare_sessions[session.username..'@'..session.host] = nil;

		end

		host_session.events.fire_event("resource-unbind", {session=session, error=err});

	else

		(session.log or log)("debug", "Destroying unbound session for <%s@%s>%s",

			session.username or "(unknown)", session.host or "(unknown)",

			err and (": "..err) or "");

	end

	retire_session(session);

end

local function make_authenticated(session, username, role_name)

	username = nodeprep(username);

	if not username or #username == 0 then return nil, "Invalid username"; end

	session.username = username;

	if session.type == "c2s_unauthed" then

		session.type = "c2s_unbound";

	end

	local role;

	if role_name then

		role = hosts[session.host].authz.get_role_by_name(role_name);

	else

		role = hosts[session.host].authz.get_user_role(username);

	end

	if role then

		sessionlib.set_role(session, role);

	end

	session.log("info", "Authenticated as %s@%s [%s]", username, session.host or "(unknown)", role and role.name or "no role");

	return true;

end

-- returns true, nil on success

-- returns nil, err_type, err, err_message on failure

local function bind_resource(session, resource)

	if not session.username then return nil, "auth", "not-authorized", "Cannot bind resource before authentication"; end

	if session.resource then return nil, "cancel", "not-allowed", "Cannot bind multiple resources on a single connection"; end

	-- We don't support binding multiple resources

	local event_payload = { session = session, resource = resource };

	if hosts[session.host].events.fire_event("pre-resource-bind", event_payload) == false then

		local err = event_payload.error;

		if err then return nil, err.type, err.condition, err.text; end

		return nil, "cancel", "not-allowed";

	else

		-- In case a plugin wants to poke at it

		resource = event_payload.resource;

	end

	resource = resourceprep(resource or "", true);

	resource = resource ~= "" and resource or generate_identifier();

	--FIXME: Randomly-generated resources must be unique per-user, and never conflict with existing

	if not hosts[session.host].sessions[session.username] then

		local sessions = { sessions = {} };

		hosts[session.host].sessions[session.username] = sessions;

		bare_sessions[session.username..'@'..session.host] = sessions;

	else

		local sessions = hosts[session.host].sessions[session.username].sessions;

		if sessions[resource] then

			-- Resource conflict

			local policy = config_get(session.host, "conflict_resolve");

			local increment;

			if policy == "random" then

				resource = generate_identifier();

				increment = true;

			elseif policy == "increment" then

				increment = true; -- TODO ping old resource

			elseif policy == "kick_new" then

				return nil, "cancel", "conflict", "Resource already exists";

			else -- if policy == "kick_old" then

				sessions[resource]:close {

					condition = "conflict";

					text = "Replaced by new connection";

				};

				if not next(sessions) then

					hosts[session.host].sessions[session.username] = { sessions = sessions };

					bare_sessions[session.username.."@"..session.host] = hosts[session.host].sessions[session.username];

				end

			end

			if increment and sessions[resource] then

				local count = 1;

				while sessions[resource.."#"..count] do

					count = count + 1;

				end

				resource = resource.."#"..count;

			end

		end

	end

	session.resource = resource;

	session.full_jid = session.username .. '@' .. session.host .. '/' .. resource;

	hosts[session.host].sessions[session.username].sessions[resource] = session;

	full_sessions[session.full_jid] = session;

	if session.type == "c2s_unbound" then

		session.type = "c2s";

	end

	local err;

	session.roster, err = rm_load_roster(session.username, session.host);

	if err then

		-- FIXME: Why is all this rollback down here, instead of just doing the roster test up above?

		full_sessions[session.full_jid] = nil;

		hosts[session.host].sessions[session.username].sessions[resource] = nil;

		session.full_jid = nil;

		session.resource = nil;

		if session.type == "c2s" then

			session.type = "c2s_unbound";

		end

		if next(bare_sessions[session.username..'@'..session.host].sessions) == nil then

			bare_sessions[session.username..'@'..session.host] = nil;

			hosts[session.host].sessions[session.username] = nil;

		end

		session.log("error", "Roster loading failed: %s", err);

		return nil, "cancel", "internal-server-error", "Error loading roster";

	end

	hosts[session.host].events.fire_event("resource-bind", {session=session});

	return true;

end

local function send_to_available_resources(username, host, stanza)

	local jid = username.."@"..host;

	local count = 0;

	local user = bare_sessions[jid];

	if user then

		for _, session in pairs(user.sessions) do

			if session.presence then

				session.send(stanza);

				count = count + 1;

			end

		end

	end

	return count;

end

local function send_to_interested_resources(username, host, stanza)

	local jid = username.."@"..host;

	local count = 0;

	local user = bare_sessions[jid];

	if user then

		for _, session in pairs(user.sessions) do

			if session.interested then

				session.send(stanza);

				count = count + 1;

			end

		end

	end

	return count;

end

return {

	new_session = new_session;

	retire_session = retire_session;

	update_session = update_session;

	destroy_session = destroy_session;

	make_authenticated = make_authenticated;

	bind_resource = bind_resource;

	send_to_available_resources = send_to_available_resources;

	send_to_interested_resources = send_to_interested_resources;

};