-- 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.
--



require "util.stanza"

local st = stanza;
local tostring = tostring;
local pairs = pairs;
local ipairs = ipairs;
local t_insert = table.insert;
local t_concat = table.concat;

local default_log = require "util.logger".init("xmlhandlers");

-- COMPAT: w/LuaExpat 1.1.0
local lxp_supports_doctype = pcall(lxp.new, { StartDoctypeDecl = false });

if not lxp_supports_doctype then
	default_log("warn", "The version of LuaExpat on your system leaves Prosody "
		.."vulnerable to denial-of-service attacks. You should upgrade to "
		.."LuaExpat 1.1.1 or higher as soon as possible. See "
		.."http://prosody.im/doc/depends#luaexpat for more information.");
end

local error = error;

module "xmlhandlers"

local ns_prefixes = {
						["http://www.w3.org/XML/1998/namespace"] = "xml";
				}

function init_xmlhandlers(session, stream_callbacks)
		local ns_stack = { "" };
		local curr_tag;
		local chardata = {};
		local xml_handlers = {};
		local log = session.log or default_log;
		
		local cb_streamopened = stream_callbacks.streamopened;
		local cb_streamclosed = stream_callbacks.streamclosed;
		local cb_error = stream_callbacks.error or function (session, e) error("XML stream error: "..tostring(e)); end;
		local cb_handlestanza = stream_callbacks.handlestanza;
		
		local stream_tag = stream_callbacks.stream_tag;
		local stream_default_ns = stream_callbacks.default_ns;
		
		local stanza
		function xml_handlers:StartElement(tagname, attr)
			if stanza and #chardata > 0 then
				-- We have some character data in the buffer
				stanza:text(t_concat(chardata));
				chardata = {};
			end
			local curr_ns,name = tagname:match("^([^\1]*)\1?(.*)$");
			if name == "" then
				curr_ns, name = "", curr_ns;
			end

			if curr_ns ~= stream_default_ns then
				attr.xmlns = curr_ns;
			end
			
			-- FIXME !!!!!
			for i=1,#attr do
				local k = attr[i];
				attr[i] = nil;
				local ns, nm = k:match("^([^\1]*)\1?(.*)$");
				if nm ~= "" then
					ns = ns_prefixes[ns]; 
					if ns then 
						attr[ns..":"..nm] = attr[k];
						attr[k] = nil;
					end
				end
			end
			
			if not stanza then --if we are not currently inside a stanza
				if session.notopen then
					if tagname == stream_tag then
						if cb_streamopened then
							cb_streamopened(session, attr);
						end
					else
						-- Garbage before stream?
						cb_error(session, "no-stream");
					end
					return;
				end
				if curr_ns == "jabber:client" and name ~= "iq" and name ~= "presence" and name ~= "message" then
					cb_error(session, "invalid-top-level-element");
				end
				
				stanza = st.stanza(name, attr);
				curr_tag = stanza;
			else -- we are inside a stanza, so add a tag
				attr.xmlns = nil;
				if curr_ns ~= stream_default_ns then
					attr.xmlns = curr_ns;
				end
				stanza:tag(name, attr);
			end
		end
		function xml_handlers:CharacterData(data)
			if stanza then
				t_insert(chardata, data);
			end
		end
		function xml_handlers:EndElement(tagname)
			local curr_ns,name = tagname:match("^([^\1]*)\1?(.*)$");
			if name == "" then
				curr_ns, name = "", curr_ns;
			end
			if (not stanza) or (#stanza.last_add > 0 and name ~= stanza.last_add[#stanza.last_add].name) then 
				if tagname == stream_tag then
					if cb_streamclosed then
						cb_streamclosed(session);
					end
				elseif name == "error" then
					cb_error(session, "stream-error", stanza);
				else
					cb_error(session, "parse-error", "unexpected-element-close", name);
				end
				stanza, chardata = nil, {};
				return;
			end
			if #chardata > 0 then
				-- We have some character data in the buffer
				stanza:text(t_concat(chardata));
				chardata = {};
			end
			-- Complete stanza
			if #stanza.last_add == 0 then
				cb_handlestanza(session, stanza);
				stanza = nil;
			else
				stanza:up();
			end
		end

		local function restricted_handler()
			cb_error(session, "parse-error", "restricted-xml", "Restricted XML, see RFC 6120 section 11.1.");
		end
		
		if lxp_supports_doctype then
			xml_handlers.StartDoctypeDecl = restricted_handler;
		end
		xml_handlers.Comment = restricted_handler;
		xml_handlers.ProcessingInstruction = restricted_handler;
	
	return xml_handlers;
end

return init_xmlhandlers;