-- 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 error         =         error;

local t_insert      =  table.insert;

local t_remove      =  table.remove;

local t_concat      =  table.concat;

local s_match       =  string.match;

local tostring      =      tostring;

local setmetatable  =  setmetatable;

local getmetatable  =  getmetatable;

local pairs         =         pairs;

local ipairs        =        ipairs;

local type          =          type;

local s_gsub        =   string.gsub;

local s_sub         =    string.sub;

local s_find        =   string.find;

local valid_utf8 = require "util.encodings".utf8.valid;

local do_pretty_printing, termcolours = pcall(require, "util.termcolours");

local xmlns_stanzas = "urn:ietf:params:xml:ns:xmpp-stanzas";

local _ENV = nil;

-- luacheck: std none

local stanza_mt = { __name = "stanza" };

stanza_mt.__index = stanza_mt;

-- Basic check for valid XML character data.

-- Disallow control characters.

-- Tab U+09 and newline U+0A are allowed.

-- For attributes, allow the \1 separator between namespace and name.

local function valid_xml_cdata(str, attr)

	return not s_find(str, attr and "[^\1\9\10\13\20-\255]" or "[^\9\10\13\20-\255]");

end

local function check_name(name, name_type)

	if type(name) ~= "string" then

		error("invalid "..name_type.." name: expected string, got "..type(name));

	elseif #name == 0 then

		error("invalid "..name_type.." name: empty string");

	elseif s_find(name, "[<>& '\"]") then

		error("invalid "..name_type.." name: contains invalid characters");

	elseif not valid_xml_cdata(name, name_type == "attribute") then

		error("invalid "..name_type.." name: contains control characters");

	elseif not valid_utf8(name) then

		error("invalid "..name_type.." name: contains invalid utf8");

	end

end

local function check_text(text, text_type)

	if type(text) ~= "string" then

		error("invalid "..text_type.." value: expected string, got "..type(text));

	elseif not valid_xml_cdata(text, false) then

		error("invalid "..text_type.." value: contains control characters");

	elseif not valid_utf8(text) then

		error("invalid "..text_type.." value: contains invalid utf8");

	end

end

local function check_attr(attr)

	if attr ~= nil then

		if type(attr) ~= "table" then

			error("invalid attributes: expected table, got "..type(attr));

		end

		for k, v in pairs(attr) do

			check_name(k, "attribute");

			check_text(v, "attribute");

		end

	end

end

local function new_stanza(name, attr, namespaces)

	check_name(name, "tag");

	check_attr(attr);

	local stanza = { name = name, attr = attr or {}, namespaces = namespaces, tags = {} };

	return setmetatable(stanza, stanza_mt);

end

local function is_stanza(s)

	return getmetatable(s) == stanza_mt;

end

function stanza_mt:query(xmlns)

	return self:tag("query", { xmlns = xmlns });

end

function stanza_mt:body(text, attr)

	return self:text_tag("body", text, attr);

end

function stanza_mt:text_tag(name, text, attr, namespaces)

	return self:tag(name, attr, namespaces):text(text):up();

end

function stanza_mt:tag(name, attr, namespaces)

	local s = new_stanza(name, attr, namespaces);

	local last_add = self.last_add;

	if not last_add then last_add = {}; self.last_add = last_add; end

	(last_add[#last_add] or self):add_direct_child(s);

	t_insert(last_add, s);

	return self;

end

function stanza_mt:text(text)

	if text ~= nil and text ~= "" then

		local last_add = self.last_add;

		(last_add and last_add[#last_add] or self):add_direct_child(text);

	end

	return self;

end

function stanza_mt:up()

	local last_add = self.last_add;

	if last_add then t_remove(last_add); end

	return self;

end

function stanza_mt:at_top()

	return self.last_add == nil or #self.last_add == 0

end

function stanza_mt:reset()

	self.last_add = nil;

	return self;

end

function stanza_mt:add_direct_child(child)

	if is_stanza(child) then

		t_insert(self.tags, child);

		t_insert(self, child);

	else

		check_text(child, "text");

		t_insert(self, child);

	end

end

function stanza_mt:add_child(child)

	local last_add = self.last_add;

	(last_add and last_add[#last_add] or self):add_direct_child(child);

	return self;

end

function stanza_mt:remove_children(name, xmlns)

	xmlns = xmlns or self.attr.xmlns;

	return self:maptags(function (tag)

		if (not name or tag.name == name) and tag.attr.xmlns == xmlns then

			return nil;

		end

		return tag;

	end);

end

function stanza_mt:get_child(name, xmlns)

	for _, child in ipairs(self.tags) do

		if (not name or child.name == name)

			and ((not xmlns and self.attr.xmlns == child.attr.xmlns)

				or child.attr.xmlns == xmlns) then

			return child;

		end

	end

	return nil;

end

function stanza_mt:get_child_text(name, xmlns)

	local tag = self:get_child(name, xmlns);

	if tag then

		return tag:get_text();

	end

	return nil;

end

function stanza_mt:child_with_name(name)

	for _, child in ipairs(self.tags) do

		if child.name == name then return child; end

	end

	return nil;

end

function stanza_mt:child_with_ns(ns)

	for _, child in ipairs(self.tags) do

		if child.attr.xmlns == ns then return child; end

	end

	return nil;

end

function stanza_mt:get_child_with_attr(name, xmlns, attr_name, attr_value, normalize)

	for tag in self:childtags(name, xmlns) do

		if (normalize and normalize(tag.attr[attr_name]) or tag.attr[attr_name]) == attr_value then

			return tag;

		end

	end

	return nil;

end

function stanza_mt:children()

	local i = 0;

	return function (a)

			i = i + 1

			return a[i];

		end, self, i;

end

function stanza_mt:childtags(name, xmlns)

	local tags = self.tags;

	local start_i, max_i = 1, #tags;

	return function ()

		for i = start_i, max_i do

			local v = tags[i];

			if (not name or v.name == name)

			and ((not xmlns and self.attr.xmlns == v.attr.xmlns)

				or v.attr.xmlns == xmlns) then

				start_i = i+1;

				return v;

			end

		end

	end;

end

function stanza_mt:maptags(callback)

	local tags, curr_tag = self.tags, 1;

	local n_children, n_tags = #self, #tags;

	local max_iterations = n_children + 1;

	local i = 1;

	while curr_tag <= n_tags and n_tags > 0 do

		if self[i] == tags[curr_tag] then

			local ret = callback(self[i]);

			if ret == nil then

				t_remove(self, i);

				t_remove(tags, curr_tag);

				n_children = n_children - 1;

				n_tags = n_tags - 1;

				i = i - 1;

				curr_tag = curr_tag - 1;

			else

				self[i] = ret;

				tags[curr_tag] = ret;

			end

			curr_tag = curr_tag + 1;

		end

		i = i + 1;

		if i > max_iterations then

			-- COMPAT: Hopefully temporary guard against #981 while we

			-- figure out the root cause

			error("Invalid stanza state! Please report this error.");

		end

	end

	return self;

end

function stanza_mt:find(path)

	local pos = 1;

	local len = #path + 1;

	repeat

		local xmlns, name, text;

		local char = s_sub(path, pos, pos);

		if char == "@" then

			return self.attr[s_sub(path, pos + 1)];

		elseif char == "{" then

			xmlns, pos = s_match(path, "^([^}]+)}()", pos + 1);

		end

		name, text, pos = s_match(path, "^([^@/#]*)([/#]?)()", pos);

		name = name ~= "" and name or nil;

		if pos == len then

			if text == "#" then

				return self:get_child_text(name, xmlns);

			end

			return self:get_child(name, xmlns);

		end

		self = self:get_child(name, xmlns);

	until not self

end

local function _clone(stanza, only_top)

	local attr, tags = {}, {};

	for k,v in pairs(stanza.attr) do attr[k] = v; end

	local old_namespaces, namespaces = stanza.namespaces;

	if old_namespaces then

		namespaces = {};

		for k,v in pairs(old_namespaces) do namespaces[k] = v; end

	end

	local new = { name = stanza.name, attr = attr, namespaces = namespaces, tags = tags };

	if not only_top then

		for i=1,#stanza do

			local child = stanza[i];

			if child.name then

				child = _clone(child);

				t_insert(tags, child);

			end

			t_insert(new, child);

		end

	end

	return setmetatable(new, stanza_mt);

end

local function clone(stanza, only_top)

	if not is_stanza(stanza) then

		error("bad argument to clone: expected stanza, got "..type(stanza));

	end

	return _clone(stanza, only_top);

end

local escape_table = { ["'"] = "&apos;", ["\""] = "&quot;", ["<"] = "&lt;", [">"] = "&gt;", ["&"] = "&amp;" };

local function xml_escape(str) return (s_gsub(str, "['&<>\"]", escape_table)); end

local function _dostring(t, buf, self, _xml_escape, parentns)

	local nsid = 0;

	local name = t.name

	t_insert(buf, "<"..name);

	for k, v in pairs(t.attr) do

		if s_find(k, "\1", 1, true) then

			local ns, attrk = s_match(k, "^([^\1]*)\1?(.*)$");

			nsid = nsid + 1;

			t_insert(buf, " xmlns:ns"..nsid.."='".._xml_escape(ns).."' ".."ns"..nsid..":"..attrk.."='".._xml_escape(v).."'");

		elseif not(k == "xmlns" and v == parentns) then

			t_insert(buf, " "..k.."='".._xml_escape(v).."'");

		end

	end

	local len = #t;

	if len == 0 then

		t_insert(buf, "/>");

	else

		t_insert(buf, ">");

		for n=1,len do

			local child = t[n];

			if child.name then

				self(child, buf, self, _xml_escape, t.attr.xmlns);

			else

				t_insert(buf, _xml_escape(child));

			end

		end

		t_insert(buf, "</"..name..">");

	end

end

function stanza_mt.__tostring(t)

	local buf = {};

	_dostring(t, buf, _dostring, xml_escape, nil);

	return t_concat(buf);

end

function stanza_mt.top_tag(t)

	local top_tag_clone = clone(t, true);

	return tostring(top_tag_clone):sub(1,-3)..">";

end

function stanza_mt.get_text(t)

	if #t.tags == 0 then

		return t_concat(t);

	end

	return nil;

end