local p = {}

local notblank = function(v) return (v or '') ~= '' end
local ifblank = function (v, alt) if notblank(v) then return v else return alt end end
local getArgs = require('Module:Arguments').getArgs

function p._chart(args)
	local values = {}
	local chartArgs = {}
	local templateArgs = {
		right = 1, left = 1, center = 1, none = 1,
		thumb = 1, thumbnail = 1, border = 1
	}
	local alignClasses = {center = 'none', none = 'none', left = 'left', right = 'right'}
	
	for k, v in pairs(args) do --ipairs fails with blank positional arguments
		if tonumber(k) then
			local lv = mw.ustring.lower(v)
			if v:sub(1,4) == 'arg:' then
				chartArgs.insert(v)
			elseif mw.ustring.match(lv, "%d+%s*px%s*$") then
				values.width = lv
			elseif templateArgs[lv] then
				values[lv] = lv
			elseif v ~= '' then
				values.caption = v
			end
		end
	end
	local opts = {
		align = ifblank(args.align, values.right or values.left or values.center or values.none),
		thumb = notblank(args.thumb) or values.thumb or values.thumbnail,
		width = ifblank(args.width, values.width),
		border = notblank(args.border) or values.border,
		chart = ifblank(args.chart, args.definition)
	}
	assert(notblank(opts.chart), 'Must specify chart= or definition=')

	local caption = ifblank(args.caption, ifblank(
		values.caption, notblank(args.title) and (args.title .. ".") or ""
	))
	if not notblank(args.hideSource) then
		caption = caption .. ' See or edit [[c:Data:'
		if notblank(ifblank(args.source, args.data)) then
			caption = caption .. ifblank(args.source, args.data) .. '|source data]].'
		else
			caption = caption .. opts.chart .. '|chart definition]].'
		end
	end

	local html = mw.html.create('div'):addClass((opts.align == 'center') and 'center' or nil)
	if opts.thumb then
		html = html:tag('div'):addClass('thumb'):addClass('t' .. (alignClasses[opts.align] or 'right'))
			:css('width', (not opts.width) and '100%' or nil)
			:tag('div'):addClass('thumbinner')
				:css('width', opts.width and 'fit-content' or nil)
	end
	html = html:tag('div'):addClass('enwiki-chart')
		:addClass(opts.thumb and 'thumbimage' or ('float' .. (alignClasses[opts.align] or 'none')))
		:css('width', opts.width)
		:css('border-style', opts.border and '1' or nil)
		:cssText(ifblank(args.style))
		:tag('div'):addClass('enwiki-chart-content')
			:wikitext(mw.getCurrentFrame():preprocess(
				"{{#chart:" .. 
				opts.chart ..
				(notblank(args.data) and ("|data=" .. args.data) or "") ..
				((#chartArgs > 0) and ("|" .. table.concat(chartArgs, '|')) or "") ..
				"}}"
			))
			:done()
	if opts.thumb then
		html = html:done():tag('div'):addClass('thumbcaption')
	else
		html = html:tag('div'):addClass('center')
		:tag('small')
	end

	return tostring(html:wikitext(caption):allDone()) ..
		(opts.thumb and '' or '<div style="clear:both;"></div>')
end
function p.chart(frame)
	return p._chart(getArgs(frame))
end

return p