-- 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 select = select;

local t_insert = table.insert;

local pairs, next, type = pairs, next, type;

local unpack = table.unpack or unpack; --luacheck: ignore 113

local _ENV = nil;

-- luacheck: std none

local function get(self, ...)

	local t = self.data;

	for n = 1,select('#', ...) do

		t = t[select(n, ...)];

		if not t then break; end

	end

	return t;

end

local function add(self, ...)

	local t = self.data;

	local count = select('#', ...);

	for n = 1,count-1 do

		local key = select(n, ...);

		local tab = t[key];

		if not tab then tab = {}; t[key] = tab; end

		t = tab;

	end

	t_insert(t, (select(count, ...)));

end

local function set(self, ...)

	local t = self.data;

	local count = select('#', ...);

	for n = 1,count-2 do

		local key = select(n, ...);

		local tab = t[key];

		if not tab then tab = {}; t[key] = tab; end

		t = tab;

	end

	t[(select(count-1, ...))] = (select(count, ...));

end

local function r(t, n, _end, ...)

	if t == nil then return; end

	local k = select(n, ...);

	if n == _end then

		t[k] = nil;

		return;

	end

	if k then

		local v = t[k];

		if v then

			r(v, n+1, _end, ...);

			if not next(v) then

				t[k] = nil;

			end

		end

	else

		for _,b in pairs(t) do

			r(b, n+1, _end, ...);

			if not next(b) then

				t[_] = nil;

			end

		end

	end

end

local function remove(self, ...)

	local _end = select('#', ...);

	for n = _end,1 do

		if select(n, ...) then _end = n; break; end

	end

	r(self.data, 1, _end, ...);

end

local function s(t, n, results, _end, ...)

	if t == nil then return; end

	local k = select(n, ...);

	if n == _end then

		if k == nil then

			for _, v in pairs(t) do

				t_insert(results, v);

			end

		else

			t_insert(results, t[k]);

		end

		return;

	end

	if k then

		local v = t[k];

		if v then

			s(v, n+1, results, _end, ...);

		end

	else

		for _,b in pairs(t) do

			s(b, n+1, results, _end, ...);

		end

	end

end

-- Search for keys, nil == wildcard

local function search(self, ...)

	local _end = select('#', ...);

	for n = _end,1 do

		if select(n, ...) then _end = n; break; end

	end

	local results = {};

	s(self.data, 1, results, _end, ...);

	return results;

end

-- Append results to an existing list

local function search_add(self, results, ...)

	if not results then results = {}; end

	local _end = select('#', ...);

	for n = _end,1 do

		if select(n, ...) then _end = n; break; end

	end

	s(self.data, 1, results, _end, ...);

	return results;

end

local function iter(self, ...)

	local query = { ... };

	local maxdepth = select("#", ...);

	local stack = { self.data };

	local keys = { };

	local function it(self) -- luacheck: ignore 432/self

		local depth = #stack;

		local key = next(stack[depth], keys[depth]);

		if key == nil then -- Go up the stack

			stack[depth], keys[depth] = nil, nil;

			if depth > 1 then

				return it(self);

			end

			return; -- The end

		else

			keys[depth] = key;

		end

		local value = stack[depth][key];

		if query[depth] == nil or key == query[depth] then

			if depth == maxdepth then -- Result

				local result = {}; -- Collect keys forming path to result

				for i = 1, depth do

					result[i] = keys[i];

				end

				result[depth+1] = value;

				return unpack(result, 1, depth+1);

			elseif type(value) == "table" then

				t_insert(stack, value); -- Descend

			end

		end

		return it(self);

	end;

	return it, self;

end

local function new()

	return {

		data = {};

		get = get;

		add = add;

		set = set;

		remove = remove;

		search = search;

		search_add = search_add;

		iter = iter;

	};

end

return {

	iter = iter;

	new = new;

};