-- Prosody IM v0.1

-- Copyright (C) 2008 Matthew Wild

-- Copyright (C) 2008 Waqas Hussain

-- 

-- This program is free software; you can redistribute it and/or

-- modify it under the terms of the GNU General Public License

-- as published by the Free Software Foundation; either version 2

-- of the License, or (at your option) any later version.

-- 

-- This program is distributed in the hope that it will be useful,

-- but WITHOUT ANY WARRANTY; without even the implied warranty of

-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

-- GNU General Public License for more details.

-- 

-- You should have received a copy of the GNU General Public License

-- along with this program; if not, write to the Free Software

-- Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

--

local tonumber, tostring = tonumber, tostring;

local ipairs, pairs, print, next= ipairs, pairs, print, next;

local collectgarbage = collectgarbage;

local m_random = import("math", "random");

local format = import("string", "format");

local hosts = hosts;

local sessions = sessions;

local modulemanager = require "core.modulemanager";

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

local error = error;

local uuid_generate = require "util.uuid".generate;

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

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

local fire_event = require "core.eventmanager".fire_event;

local gettime = require "socket".gettime;

local st = require "util.stanza";

local newproxy = newproxy;

local getmetatable = getmetatable;

module "sessionmanager"

local open_sessions = 0;

function new_session(conn)

	local session = { conn = conn,  priority = 0, type = "c2s_unauthed", conntime = gettime() };

	if true then

		session.trace = newproxy(true);

		getmetatable(session.trace).__gc = function () open_sessions = open_sessions - 1; end;

	end

	open_sessions = open_sessions + 1;

	log("info", "open sessions now: ".. open_sessions);

	local w = conn.write;

	session.send = function (t) w(tostring(t)); end

	return session;

end

function destroy_session(session, err)

	(session.log or log)("info", "Destroying session");

	-- Send unavailable presence

	if session.presence then

		local pres = st.presence{ type = "unavailable" };

		if (not err) or err == "closed" then err = "connection closed"; end

		pres:tag("status"):text("Disconnected: "..err);

		session:dispatch_stanza(pres);

	end

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

	if session.host and session.username then

		-- FIXME: How can the below ever be nil? (but they sometimes are...)

		if hosts[session.host] and hosts[session.host].sessions[session.username] then

			if session.resource then

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

			end

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

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

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

			end

		else

			log("error", "host or session table didn't exist, please report this! Host: %s [%s] Sessions: %s [%s]", 

					tostring(hosts[session.host]), tostring(session.host),

					tostring(hosts[session.host].sessions[session.username] ), tostring(session.username));

		end

	end

	for k in pairs(session) do

		if k ~= "trace" then

			session[k] = nil;

		end

	end

end

function make_authenticated(session, username)

	session.username = username;

	if session.type == "c2s_unauthed" then

		session.type = "c2s";

	end

	return true;

end

-- returns true, nil on success

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

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", "already-bound", "Cannot bind multiple resources on a single connection"; end

	-- We don't support binding multiple resources

	session.conntimetotal = gettime()-session.conntime;

	resource = resource or uuid_generate();

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

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

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

	else

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

		local limit = config_get(session.host, "core", "max_resources") or 10;

		if #sessions >= limit then

			return nil, "cancel", "conflict", "Resource limit reached; only "..limit.." resources allowed";

		end

		if sessions[resource] then

			-- Resource conflict

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

			local increment;

			if policy == "random" then

				resource = uuid_generate();

				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

				hosts[session.host].sessions[session.username].sessions[resource]:close {

					condition = "conflict";

					text = "Replaced by new connection";

				};

			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;

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

	return true;

end

function streamopened(session, attr)

						local send = session.send;

						session.host = attr.to or error("Client failed to specify destination hostname");

			                        session.version = tonumber(attr.version) or 0;

			                        session.streamid = m_random(1000000, 99999999);

			                        (session.log or session)("debug", "Client sent opening <stream:stream> to %s", session.host);

						send("<?xml version='1.0'?>");

			                        send(format("<stream:stream xmlns='jabber:client' xmlns:stream='http://etherx.jabber.org/streams' id='%s' from='%s' version='1.0'>", session.streamid, session.host));

						if not hosts[session.host] then

							-- We don't serve this host...

							session:close{ condition = "host-unknown", text = "This server does not serve "..tostring(session.host)};

							return;

						end

						local features = st.stanza("stream:features");

						fire_event("stream-features", session, features);

						send(features);

						(session.log or log)("info", "Sent reply <stream:stream> to client");

						session.notopen = nil;

end

function send_to_available_resources(user, host, stanza)

	local count = 0;

	local to = stanza.attr.to;

	stanza.attr.to = nil;

	local h = hosts[host];

	if h and h.type == "local" then

		local u = h.sessions[user];

		if u then

			for k, session in pairs(u.sessions) do

				if session.presence then

					session.send(stanza);

					count = count + 1;

				end

			end

		end

	end

	stanza.attr.to = to;

	return count;

end