local messageBox = require('Module:Message box')
local navbarModule = require('Module:Navbar')
local horizontal = require('Module:List').horizontal

local p = {}

-- Get constants.
local lang = mw.language.getContentLanguage()
local currentUnixDate = tonumber(lang:formatDate('U'))

local function err(msg)
	return mw.ustring.format('<strong class="error">%s</strong>', msg)
end

local function getUnixDate(date)
	local success, unixDate = pcall(lang.formatDate, lang, 'U', date)
	if success then
		return tonumber(unixDate)
	end
end

local function unixDateError(date)
	return err(tostring(date) .. ' is not a valid date.')
end

local function makeOmbox(oargs)
	return messageBox.main('ombox', oargs)
end

local function makeNavbar(name)
	return navbarModule.navbar{name, mini = '1'}
end

local function randomizeArray(t)
	-- Iterate through the array backwards, each time swapping the entry "i" with a random entry.
	-- Courtesy of Xinhuan at http://forums.wowace.com/showthread.php?p=279756
	math.randomseed(mw.site.stats.edits)
	for i = #t, 2, -1 do
		local r = math.random(i)
		t[i], t[r] = t[r], t[i]
	end
	return t
end

local function getArgNums(args, prefix)
	-- Returns a table containing the numbers of the arguments that exist for the specified prefix. For example, if the prefix
	-- was 'data', and 'data1', 'data2', and 'data5' exist, it would return {1, 2, 5}.
	local nums = {}
	for k, v in pairs(args) do
		k = tostring(k)
		local num = mw.ustring.match(k, '^' .. prefix .. '([1-9]%d*)$')
		if num then
			table.insert(nums, tonumber(num))
		end
	end
	table.sort(nums)
	return nums
end

local function showBeforeDate(datePairs)
	-- Shows a value if it is before a given date.
	for i, datePair in ipairs(datePairs) do
		local date = datePair.date
		local val = datePair.val
		if not date then -- No date specified, so assume we have no more dates to process.
			return val
		end
		local unixDate = getUnixDate(date)
		if not unixDate then return unixDateError(date) end
		if currentUnixDate < unixDate then -- The specified date is in the future.
			return val
		end
	end
end

local function countdown(date, event)
	if type(event) ~= 'string' then return err('No event name provided.') end
	-- Get the current date unix timestamp.
	local unixDate = getUnixDate(date)
	if not unixDate then return unixDateError(date) end
	unixDate = tonumber(unixDate)
	-- Subtract the timestamp from the current unix timestamp to find the time left, and output that in a readable way.
	local secondsLeft = unixDate - currentUnixDate
	if secondsLeft <= 0 then return end
	local timeLeft = lang:formatDuration(secondsLeft, {'weeks', 'days', 'hours'})
	-- Find whether we are plural or not.
	local isOrAre
	if mw.ustring.match(timeLeft, '^%d+') == '1' then
		isOrAre = 'is'
	else
		isOrAre = 'are'
	end
	local timeLeft = mw.ustring.gsub(timeLeft, '(%d+)', '<span class="ace-banner-timeleft">%1</span>')
	-- Make the refresh link, and join it all together.
	local refreshLink = mw.title.getCurrentTitle():fullUrl{action = 'purge'}
	refreshLink = mw.ustring.format('<span class="ace-banner-refresh plainlinks">([%s refresh])</span>', refreshLink)
	return mw.ustring.format('There %s %s until %s. %s', isOrAre, timeLeft, event, refreshLink)
end

local function format_guides(args, year)
	local guideNums = getArgNums(args, 'guide')
	local guides = {}
	for _, num in ipairs(guideNums) do
		table.insert(guides, args['guide' .. tostring(num)])
	end
	local guide_text = mw.ustring.format(
		'\nThese [[:Category:Wikipedia Arbitration Committee Elections %s voter guides|guides]] '
		.. 'represent the thoughts of their authors. All individually written '
		.. 'voter guides are eligible for inclusion.\n',
		year
	)
	guides = randomizeArray(guides)
	guides = horizontal(guides)
	
	local ret = [=[
<div class="mw-collapsible mw-collapsed">
<div class="ace-banner-guides-title"><div>Personal voter guides</div></div>
<div class="mw-collapsible-content">%s%s</div>
</div>]=]
	return mw.ustring.format(ret, guide_text, guides)
end

local function getElectionInfo(year, key)
	local frame = mw.getCurrentFrame()
	local result = frame:expandTemplate{title = 'Arbitration Committee candidate/data', args = {year, key}}
	if result ~= '' then
		return result
	else
		return nil
	end
end

local function getStartDate(year, key)
	local date = getElectionInfo(year, key)
	if not date then
		return nil
	else
		return '00:00, ' .. lang:formatDate('d F Y', date)
	end
end

local function getEndDate(year, key)
	local date = getElectionInfo(year, key)
	if not date then
		return nil
	else
		return '23:59, ' .. lang:formatDate('d F Y', date .. ' -1 day')
	end
end

local function getVotePage(year)
	local pollId = getElectionInfo(year, 'poll')
	if pollId then
		return string.format('[https://en.wikipedia.org/key/Special:SecurePoll/vote/%s Vote]', pollId)
	else
		return '<span style="color:gray">Vote</span>'
	end
end

local function getVoteLog(year)
	local voteWikiId = getElectionInfo(year, 'votewikiid')
	if voteWikiId then
		return string.format('[https://vote.wikimedia.org/key/Special:SecurePoll/list/%s Voter log]', voteWikiId)
	else
		return '<span style="color:gray">Voter log</span>'
	end
end

function p._main(args)
	-- Get data for the box, plus the box title.
	local year = args.year or lang:formatDate('Y')
	local name = args.name or 'ACE' .. year
	local navbar = makeNavbar(name)
	local electionpage = args.electionpage or mw.ustring.format(
		'[[Wikipedia:Arbitration Committee Elections December %s|%s Arbitration Committee Elections]]',
		year, year
	)
	-- Get nomination or voting link, depending on the date.
	local beforenomlink = args.beforenomlink or mw.ustring.format('[[Wikipedia:Requests for comment/Arbitration Committee Elections December %s/Electoral Commission|Electoral Commission RFC]]', year)
	local nomstart = args.nomstart or getStartDate(year, 'nombegin') or error('No nomstart date supplied')
	local nomlink = args.nomlink or mw.ustring.format('[[Wikipedia:Arbitration Committee Elections December %s/Candidates|Nominate]]', year)
	local nomend = args.nomend or getEndDate(year, 'nomend') or error('No nomend date supplied')
	local votestart = args.votestart or getStartDate(year, 'begin') or error('No votestart date supplied')
	local votepage = args.votepage or getVotePage(year)
	local votelink = args.votelink or mw.ustring.format('<span class="ace-banner-votelink">%s</span>', votepage)
	local votelog = args.votelog or getVoteLog(year)
	local voteend = args.voteend or getEndDate(year, 'end') or error('No voteend date supplied')
	local voteendlink = args.voteendlink or votelog
	local scheduleText = showBeforeDate{
		{val = beforenomlink, date = nomstart},
		{val = nomlink, date = nomend},
		{val = countdown(votestart, 'voting begins'), date = votestart},
		{val = votelink, date = voteend},
		{val = voteendlink}
	}
	-- support votelog as its own element. must be done after we have scheduleText
	if scheduleText ~= votelink then
		votelog = nil
	end
	
	-- Get other links.
	local contact = args.contact or mw.ustring.format('[[Wikipedia talk:Arbitration Committee Elections December %s/Coordination|Contact the coordinators]]', year)
	local discuss = args.discuss or mw.ustring.format('[[Wikipedia talk:Arbitration Committee Elections December %s|Discuss the elections]]', year)
	local cguide = args.cguide or mw.ustring.format('[[Wikipedia:Arbitration Committee Elections December %s/Candidates/Guide|Candidate guide]]', year)
	local cstatements = args.cstatements or mw.ustring.format('[[Wikipedia:Arbitration Committee Elections December %s/Candidates|Candidate statements]]', year)
	local cquestions = args.cquestions or mw.ustring.format('[[Wikipedia:Arbitration Committee Elections December %s/Questions|Questions for the candidates]]', year)
	local cdiscuss = args.cdiscuss or mw.ustring.format('[[Wikipedia:Arbitration Committee Elections December %s/Candidates/Discussion|Discuss the candidates]]', year)
	local guidecat = args.guidecat or mw.ustring.format('')
	local guides = format_guides(args, year)
	
	-- Get the text field of ombox.
	local lead_links = horizontal({
		class = 'ace-banner-lead-links',
		'<span class="ace-banner-mainpage">' .. electionpage .. '</span>',
		scheduleText,
		votelog,
		contact,
		discuss,
		'[[Wikipedia:5-minute guide to ArbCom elections|Quick guide]]'
	})

	local candidate_links = horizontal({
		class = 'ace-banner-candidates-links inline',
		cguide,
		cstatements,
		cquestions,
		cdiscuss,
	})

	return makeOmbox({
		image = args.image or '[[File:Judges cupola.svg|50px|ArbCom|link=]]',
		style = args.style or nil,
		text = mw.ustring.format(
			'<div class="ace-banner-navbar">%s</div>%s<span class="ace-banner-candidates">Candidates: </span>%s%s',
			navbar,
			lead_links,
			candidate_links,
			guides
		),
		templatestyles = 'Module:Arbcom election banner/styles.css',
		class = 'ace-banner'
	})		
end
 
function p.main(frame)
	-- If called via #invoke, use the args passed into the invoking template, or the args passed to #invoke if any exist.
	-- Otherwise assume args are being passed directly in from the debug console or from another Lua module.
	local origArgs
	if frame == mw.getCurrentFrame() then
		origArgs = frame:getParent().args
		for k, v in pairs(frame.args) do
			origArgs = frame.args
			break
		end
	else
		origArgs = frame
	end
	-- Trim whitespace and remove blank arguments.
	local args = {}
	for k, v in pairs(origArgs) do
		if type(v) == 'string' then
			v = mw.text.trim(v)
		end
		if v ~= '' then
			args[k] = v
		end
	end
	return p._main(args)
end
 
return p