Module:Infobox/dates/sandbox

This is the module sandbox page for Module:Infobox/dates (diff).
See also the companion subpage for test cases (run).
local getArgs = require('Module:Arguments').getArgs

local default_error_category = "[[Category:Pages using infobox television with nonstandard dates]]"

local p = {}

function p.start_end_date_template_validation(frame)
	local args = getArgs(frame)
	local error_category = args.error_category or default_error_category

	local start_date = args.first_aired or args.released or args.airdate or args.release_date or args.airdate_overall
	if start_date then
		if not start_date:find("dtstart") then
			return error_category
		end
	end

	local end_date = args.last_aired
	if end_date then
		if not end_date:find("dtend") and end_date ~= "present" then
			return error_category
		end
	end
end

local function replace_space(value)
	if value then
		return value:gsub("&nbsp;", " ")
	end
	return value
end

function p.dates(frame)
	local args = getArgs(frame)
	
	-- Handle missing arguments cases
	if table.getn(args) < 2 then
		if args['1'] == nil and args['2'] == nil then
			return ''
		elseif args['1'] == nil then
			return args['2']
		elseif args['2'] == nil then
			return args['1']
		end
	end
	
	-- Extract the hidden span portion if it exists
	local function extract_span(text)
		local span_start = string.find(text, "<span")
		if span_start then
			return string.sub(text, span_start)
		end
		return ""
	end
	
	-- Extract visible part (before any span)
	local function extract_visible(text)
		return text:match("^(.-)<span") or text
	end

	-- Get spans from original inputs
	local span1 = extract_span(args['1'])
	local span2 = extract_span(args['2'])

	-- Get visible parts only
	local visible1 = extract_visible(args['1'])
	local visible2 = extract_visible(args['2'])

	-- Clean up spaces
	visible1 = replace_space(visible1)
	visible2 = replace_space(visible2)

	-- Try to parse dates from visible text
	local pr1, m1, d1, y1, su1, pr2, m2, d2, y2, su2
	local dmy = false

	-- Try MDY format first
	pr1, m1, d1, y1, su1 = string.match(visible1, '(.-)(%u%a+)%s(%d+),%s(%d+)(.*)')
	pr2, m2, d2, y2, su2 = string.match(visible2, '(.-)(%u%a+)%s(%d+),%s(%d+)(.*)')
	
	-- If MDY failed, try DMY format
	if y1 == nil then
		dmy = true
		pr1, d1, m1, y1, su1 = string.match(visible1, '(.-)(%d%d?) %a+ %d+ (.*)')
		pr2, d2, m2, y2, su2 = string.match(visible2, '(.-)(%d%d?) %a+ %d+ (.*)')
	end

	-- NEW: If month and year (e.g., "April 2015"), extract correctly
	if y1 == nil then
		m1, y1 = visible1:match('(%a+) (%d%d%d%d)')
		pr1, su1 = "", "" -- Ensure placeholders remain valid
	end

	if y2 == nil then
		m2, y2 = visible2:match('(%a+) (%d%d%d%d)')
		pr2, su2 = "", ""
	end

	-- If both MDY and DMY fail, check for a 4-digit year format
	if y1 == nil then
		y1 = visible1:match('(%d%d%d%d)')
		pr1, su1 = "", "" -- Set placeholders for consistency
	end

	if y2 == nil then
		y2 = visible2:match('(%d%d%d%d)')
		pr2, su2 = "", ""
	end

	-- Set default empty strings for suffixes
	su1, su2 = su1 or '', su2 or ''
	pr1, pr2 = pr1 or '', pr2 or ''
	
	local dash_break = '&nbsp;–<br />'
	local dash = '–'

	-- Handle unparsable dates or fallback
	if y1 == nil or y2 == nil then
		return args['1'] .. dash .. args['2']
	end
	
	-- Validate date range
	local MONTHS = {January=1, February=2, March=3, April=4, May=5, June=6, 
	                July=7, August=8, September=9, October=10, November=11, December=12}
	
	-- Check if both dates have valid months
	if not MONTHS[m1] or not MONTHS[m2] then
		return args['1'] .. dash .. args['2']
	end
	
	local diff = os.time({year=y2, month=MONTHS[m2], day=d2 or 1, hour=0, min=0, sec=0}) - 
	            os.time({year=y1, month=MONTHS[m1], day=d1 or 1, hour=0, min=0, sec=0})
	
	if diff < 0 then
		return 'Invalid date range'
	end
	
	-- Format based on the rules at [[MOS:DATERANGE]], but use special handling for same year cases
	if y1 == y2 then
		-- Same year
		if d1 == nil and d2 == nil then
			-- Foramt: m1–m2 y1 (May–July 1940)
			return pr1 .. m1 .. span1 .. dash .. m2 .. ' ' .. y1 .. span2			
		end

		if m1 == m2 then
			-- Same month and year
			if dmy then
				-- Foramt: d1–d2 m1 y1 (5–7 January 1979)
				return pr1 .. d1 .. span1 .. dash .. d2 .. ' ' .. m1 .. ' ' .. y1 .. span2
			else
				-- Foramt: m1 d1–d2, y1 (January 5–7, 1979)
				return pr1 .. m1 .. ' ' .. d1 .. span1 .. dash .. d2 .. ', ' .. y1 .. span2
			end
		else
			-- Different months, same year
			if dmy then
				-- Format: d1 m1 – d2 m2 y1 (3 June –<br/> 18 August 1952)
				return pr1 .. d1 .. ' ' .. m1 .. span1 .. dash_break .. d2 .. ' ' .. m2 .. ' ' .. y1 .. span2
			else
				-- Format: m1 d1 – m2 d2, y1 (June 3 –<br/> August 18, 1952)
				return pr1 .. m1 .. ' ' .. d1 .. span1 .. dash_break .. m2 .. ' ' .. d2 .. ', ' .. y1 .. span2
			end
		end
	else
		-- Different years - use the full original inputs with a dash and a line break
		 return visible1 .. span1 .. dash_break .. visible2 .. span2
	end
end

return p
Usage
