Module:Time ago

-- Replacement for [[Template:Time ago]]
local HtmlBuilder = require('Module:HtmlBuilder')

local p = {}

function p.timeAgo( frame )
	-- Initialize variables
	local lang = mw.language.getContentLanguage()
	local auto_magnitude_num
	local min_magnitude_num
	local result
	local magnitude = frame.args.magnitude
	local min_magnitude = frame.args.min_magnitude
	if frame.args.ago then ago = frame.args.ago else ago = 'ago' end
	local purge = ''

	-- Add a purge link if something (usually "yes") is entered into the purge parameter
	if ( frame.args.purge ) then
		local builder = HtmlBuilder.create()
		builder
			.wikitext(' ')
			.tag('span')
				.addClass('plainlinks')
				.wikitext('([' .. mw.title.getCurrentTitle():fullUrl('action=purge') .. ' purge])')
				.done()

		purge = tostring(builder)
	end

	-- Check that the entered timestamp is valid. If it isn't, then give an error message.
	local noError, inputTime = pcall( lang.formatDate, lang, 'U', frame.args[1] )
	if not noError then
		local builder = HtmlBuilder.create()
		builder
			.tag('strong')
				.addClass('error')
				.wikitext('Error: first parameter cannot be parsed as a date or time.')
				.done()

		return tostring(builder) .. purge
	end

	-- Store the difference between the current time and the inputted time, as well as its absolute value.
	local timeDiff = lang:formatDate( 'U' ) - inputTime
	local absTimeDiff = math.abs( timeDiff )

	if magnitude then
		auto_magnitude_num = 0
		min_magnitude_num = timeText[magnitude]
	else
		if ( math.floor( absTimeDiff / 120 ) > 0 ) then auto_magnitude_num = 60 else auto_magnitude_num = 1 end
		if ( math.floor( absTimeDiff / 7200 ) > 0 ) then auto_magnitude_num = 3600 end
		if ( math.floor( absTimeDiff / 172800 ) > 0 ) then auto_magnitude_num = 86400 end
		if ( math.floor( absTimeDiff / 5356800 ) > 0 ) then auto_magnitude_num = 2678400 end
		if ( math.floor( absTimeDiff / 63115200 ) > 0 ) then auto_magnitude_num = 31557600 end
		if min_magnitude then min_magnitude_num = timeText[min_magnitude] else min_magnitude_num = -1 end
	end

	if not min_magnitude_num then min_magnitude_num = 1 end -- Default to seconds if an invalid magnitude is entered.

	local magnitude_num = math.max( min_magnitude_num, auto_magnitude_num )
	local result_num = math.floor ( absTimeDiff / magnitude_num )
	local result_unit

	if ( timeDiff >= 0 ) then -- Past
		if result_num == 1 then result_unit = timeUnits[ magnitude_num ][1] else result_unit = timeUnits[ magnitude_num ][2] end
		result = result_num .. ' ' .. result_unit .. ' ' .. ago
	else -- Future
		if result_num == 1 then result_unit = timeUnits[ magnitude_num ][3] else result_unit = timeUnits[ magnitude_num ][4] end
		result = result_num .. ' ' .. result_unit .. ' time'
	end

	return result .. purge
end

-- Table to convert entered text values to numeric values.
timeText = {
	['seconds'] = 1,
	['minutes'] = 60,
	['hours'] = 3600,
	['days'] = 86400,
	['weeks'] = 604800,
	['months'] = 2678400,
	['years'] = 31557600
}

-- Table containing tables of possible units to use in output.
timeUnits = {
	[1] = { 'second', 'seconds', 'second\'s', 'seconds\'' },
	[60] = { 'minute', 'minutes', 'minute\'s', 'minutes\'' },
	[3600] = { 'hour', 'hours', 'hour\'s', 'hours\'' },
	[86400] = { 'day', 'days', 'day\'s', 'days\'' },
	[604800] = { 'week', 'weeks', 'week\'s', 'weeks\'' },
	[2678400] = { 'month', 'months', 'month\'s', 'months\'' },
	[31557600] = { 'year', 'years', 'year\'s', 'years\'' }
}

return p