local p={}
local lib_arg={};
local yesno = {}

function p.isPreview()
	local frame = mw.getCurrentFrame()
	local check_str = '{{REVISIONID}}'
	if mw.isSubsting() then check_str = "{{safesubst:REVISIONID}}" end
	local Preview_mode = frame:preprocess(check_str);						-- use magic word to get revision id
	return (Preview_mode == nil or mw.text.trim(Preview_mode or '') == '')	-- if there is a value then this is not a preiview
end

function p.previewNotice(frame)
	if mw.isSubsting() then return '' end
	local text = ''
	if type(frame) == type('string') then --type('string') avoid version change
		text = mw.text.trim(frame)
	else
		if type((frame or {}).args) ~= type({}) then frame.args = {} end
		text = mw.text.trim(frame.args['1'] or frame.args[1] or frame.args.text or
			frame['1'] or frame[1] or frame.text or '')
	end
	text = mw.text.trim(text)
	if text ~= '' then
		mw.addWarning(text)
	end
	return ''
end

function p.isCreating()
	local frame = mw.getCurrentFrame()
	local check_str = '{{PAGEID}}'
	if mw.isSubsting() then check_str = "{{safesubst:PAGEID}}" end
	local Preview_mode = frame:preprocess(check_str);
	return (Preview_mode == nil or mw.text.trim(Preview_mode or '') == '')
end

function p.hasParent(layer)
	local frame = mw.getCurrentFrame()
	local times = tonumber(layer or '') or 0
	local Parent = frame:getParent();
	for i=2,tonumber(times) do
		Parent = Parent:getParent()
		if Parent == nil then break end
	end
	return not (Parent == nil or Parent == '')
end

function p.getTitle(layer)
	local frame = mw.getCurrentFrame()
	local times = tonumber(layer or '') or 0
	if times <= 0 then return frame:getTitle()end
	local Parent = frame:getParent();
	for i=2,tonumber(times) do
		Parent = Parent:getParent()
		if Parent == nil then return '' end
	end
	return Parent:getTitle();
end

function p.nextSubst(frame)
	local args, working_frame
    if frame == mw.getCurrentFrame() then
        -- We're being called via #invoke. The args are passed through to the module
        -- from the template page, so use the args that were passed into the template.
        if lib_arg.getArgs == nil then lib_arg = require('Module:Arguments') end
        args = lib_arg.getArgs(frame, {
        	parentFirst=true,
        	trim = false,
			removeBlanks = false
        })
        working_frame = frame
    else
        -- We're being called from another module or from the debug console, so assume
        -- the args are passed in directly.
        args = frame
        working_frame = mw.getCurrentFrame()
        if type(args) ~= type({}) then args = {frame} end
    end
    local input_data = args[1] or args['1']
    if mw.text.trim(input_data or '') == '' then return '' end
    local num_args = {}
	for key,value in pairs(args) do
		local num = tonumber(key) or 0
		local stored = false
		if num then
			if num > 1 then
				num_args[key - 1] = value
				stored = true
			end
			if num == 1 then stored = true end
		end
		if stored ~= true then num_args[key] = value end
	end
	local str_args = mw.ustring.sub(require('Module:Template invocation').invocation(input_data, num_args),3,-3)
	if(mw.isSubsting())then 
		return "{{subst:" .. str_args .. "}}" ;
	end
	return working_frame:preprocess("{{safesubst:" .. str_args .. "}}")
end

return p