-- This implements {{change}}

local p = {}



local function ntsh(outvalue)

	local sortkey = '0000000000000000000'

	if outvalue == nil then

		return '<span style="display:none" data-sort-value="' .. sortkey .. '♠"></span>'

	end

	

	-- This code was copied from [[Template:Convert]]	

	if outvalue == 0 then

		sortkey = '5000000000000000000'

	else

		local mag = math.floor(math.log10(math.abs(outvalue)) + 1e-14)

		local prefix

		if outvalue > 0 then

			prefix = 7000 + mag

		else

			prefix = 2999 - mag

			outvalue = outvalue + 10^(mag+1)

		end

		sortkey = string.format('%d', prefix) .. string.format('%015.0f', math.floor(outvalue * 10^(14-mag)))

	end

	return '<span style="display:none" data-sort-value="' .. sortkey .. '♠"></span>'

end



local function trim(s)

	return s:match('^%s*(.-)%s*$')

end



local function isnotempty(s)

	return s and trim(s) ~= ''

end



function change(args)

	local rnd = require('Module:Math')._round

	local prec_format = require('Module:Math')._precision_format

	local lang = mw.getContentLanguage()

	local function formatnum(num)

		return lang:parseFormattedNumber(num) and lang:formatNum(lang:parseFormattedNumber(num)) or num

	end

	

	local errorflag = nil

	

	local dsp = args'disp' or 'row'

	local inv = args'invert' or 'off'

	local srt = args'sort' or ((isnotempty(args'pre']) or isnotempty(args'sort'])) and 'on' or 'off')

	local n1 = (inv == 'on') and tonumber(lang:parseFormattedNumber(args'2'])) or tonumber(lang:parseFormattedNumber(args'1']))

	local n2 = (inv == 'on') and tonumber(lang:parseFormattedNumber(args'1'])) or tonumber(lang:parseFormattedNumber(args'2']))

	local dec = args'dec' or '2'

	local s = ((args'italics' or 'off') == 'on' and "''" or "")

			.. ((args'bold' or 'off') == 'on' and "'''" or "")

	

	local pc, pcr, pcrf = 'NA', 'NA'

	

	if n1 and n2 and n1 ~= 0 then

		pc = 100*(n2/n1 - 1)

		pcr = rnd(pc, dec)

		if pcr > 0 then

			pcrf = '<span style="color:green">' ..

				s .. '+' .. prec_format(pc, dec) .. '%' .. s .. '</span>'

		elseif pcr < 0 then

			pcrf = '<span style="color:red">' ..

				s .. prec_format(pc, dec) .. '%' .. s .. '</span>'

		else

			pcrf = s .. prec_format(0, dec) .. '%' .. s

		end

		pcrf = ntsh(pcr) .. pcrf

	else

		pcrf = ntsh(nil) .. s .. 'NA' .. s

		if n1 == nil or n2 == nil then

			errorflag = 1

		end

	end

	

	if dsp == 'out' then

		return pcrf, errorflag

	else

		local pre1 = args'pre1' or args'pre' or ''

		local pre2 = args'pre2' or args'pre' or ''

		local suf1 = args'suf1' or args'suf' or ''

		local suf2 = args'suf2' or args'suf' or ''



		local rspn = 'rowspan=' .. (args'rowspan' or '1') .. ' '

		local algn = 'text-align:' .. (args'align' or 'right') .. ';'

		local bg = 'background-color:' .. (args'bgcolour' or args'bgcolor' or 'inherit') .. ';'



		if rspn == 'rowspan=1 ' then rspn = '' end

		if bg == 'background-color:inherit;' then bg = '' end

		local style = rspn .. 'style="' .. algn .. bg .. '"'

		

		local sk1, sk2 = '', ''

		

		if srt == 'on' then

			sk1 = ntsh(n1)

			sk2 = ntsh(n2)

		end

		

		if n1 ~= nil then

			if n1 < 0 then

				n1 = '−' .. formatnum(-1*n1)

			else

				n1 = formatnum(n1)

			end

		else

			n1 = (inv == 'on') and (args'2' or '') or (args'1' or '')

		end

		

		if n2 ~= nil then

			if n2 < 0 then

				n2 = '−' .. formatnum(-1*n2)

			else

				n2 = formatnum(n2)

			end

		else

			n2 = (inv == 'on') and (args'1' or '') or (args'2' or '')

		end

		

		if dsp == 'row2' then

			return style .. '|' .. s .. pre2 .. n2 .. suf2 .. s

				.. '\n|' .. style .. '|' .. pcrf, errorflag

		elseif inv == 'off' then

			return style .. '|' .. s .. pre1 .. n1 .. suf1 .. s

				.. '\n|' .. style .. '|' .. s .. pre2 .. n2 .. suf2 .. s

				.. '\n|' .. style .. '|' .. pcrf, errorflag

		else

			return style .. '|' .. s .. pre1 .. n2 .. suf1 .. s

				.. '\n|' .. style .. '|' .. s .. pre2 .. n1 .. suf2 .. s

				.. '\n|' .. style .. '|' .. pcrf, errorflag

		end

	end

end



function p.main(frame)

	local res, eflag = change((frame.args1 or frame.args2]) and frame.args or frame:getParent().args)

	if eflag then

		res = res .. frame:expandTemplate{title = 'change/error'}

	end

	return res

end



return p