-- 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.

--

local t_insert, t_remove = table.insert, table.remove;

module "filters"

local function initialize_session(session)

	local filters = {};

	session.filters = filters;

	function session.filter(type, data)

		local filter_list = filters[type];

		for i = 1, #filter_list do

			data = filter_list[i](data);

		end

		return data;

	end

end

function add_filter(session, type, callback, priority)

	if not session.filters then

		initialize_session(session);

	end

	local filter_list = session.filters[type];

	if not filter_list then

		filter_list = {};

		session.filters[type] = filter_list;

	end

	priority = priority or 0;

	local i = 0;

	repeat

		i = i + 1;

	until not filter_list[i] or filter_list[filter_list[i]] >= priority;

	t_insert(filter_list, i, callback);

	filter_list[callback] = priority;

end

function remove_filter(session, type, callback)

	local filter_list = session.filters[type];

	if filter_list and filter_list[callback] then

		for i=1, #filter_list do

			if filter_list[i] == callback then

				t_remove(filter_list, i);

				filter_list[callback] = nil;

				return true;

			end

		end

	end

end

return _M;