View source for Module:Infobox television episode

--- @module
local p = {}

local maintenance_categories = {
	incorrectly_formatted = "[[Category:Pages using infobox television episode with incorrectly formatted values|%s]]",
	unlinked_values = "[[Category:Pages using infobox television episode with unlinked values|%s]]",
	image_values_without_an_image = "[[Category:Pages using infobox television episode with image-related values without an image]]",
	unnecessary_title_parameter = "[[Category:Pages using infobox television episode with unnecessary title parameter]]",
	non_matching_title = "[[Category:Pages using infobox television episode with non-matching title]]",
	flag_icon = "[[Category:Pages using infobox television with flag icon]]",
	dates_incorrectly_formatted = "[[Category:Pages using infobox television episode with nonstandard dates]]",
	manual_display_title = "[[Category:Pages using infobox television episode with unnecessary manual displaytitle]]",
	list_markup = "[[Category:Pages using infobox television episode with unnecessary list markup]]",
}

--- Returns the text after removing line breaks (<br> tags) and additional spaces as a result.
---
--- @param text string
--- @return string
local function get_name_with_br_fixes(text)
	local title, _ = string.gsub(text, "<br%s?/?>", "")
	title, _ = string.gsub(title, "  ", " ")
	return title
end

--- Returns the page name after replacing quotation marks for single quotes and fixing it to use the
--- "Space+single" and "Single+space" templates if a leading or trailing apostrophe or quotation mark is used.
---
--- Note: per [[MOS:QWQ]] an episode title with quotation marks should be replaced with single quotes.
---
--- @param frame table
--- @param article_title string
--- @return string
local function get_page_name_with_apostrophe_quotation_fixes(frame, article_title)
	local page_name, _ = string.gsub(article_title, '"', "'")

	local left_side_template = frame:expandTemplate{title = "Space+single"}
	local right_side_template = frame:expandTemplate{title = "Single+space"}
	page_name, _ = string.gsub(string.gsub(page_name, "^'", left_side_template), "'$", right_side_template)

	return page_name
end

--- Returns the series link.
---
--- @param series string
--- @return string
local function get_series_link(series)
	local delink = require("Module:Delink")._delink
	return delink({series, wikilinks = "target"})
end

--- Returns two strings:
---- The series name after de-linking it and escaping "-".
---- The series name after de-linking it.
---
--- @param series string
--- @return string, string
local function get_series_name(series)
	local delink = require("Module:Delink")._delink
	local series_name = delink({series})

	-- Escape the character "-" as it is needed for string.find() to work.
	local _
	local series_name_escaped, _ = string.gsub(series_name, "-", "%%-")
	return series_name_escaped, series_name
end

--- Returns a table consisting of the episode's title parts.
---
--- The return table's properties:
--- - title - The episode's title.
--- - disambiguation - the disambiguation text without parentheses.
---
--- Note: could potentially be moved to an outside module for other template and module uses.
---
--- @param text string
--- @return table<string, string | nil>
local function get_title_parts(text)
	local title, disambiguation = string.match(text, "^(.+) (%b())$")

	local titleString = title -- TODO: needed until https://github.com/Benjamin-Dobell/IntelliJ-Luanalysis/issues/63 is resolved.
	if not title or type(title) ~= "string" then
		titleString = text
	end

	---@type table<string, string | nil>
	local title_parts = {title = --[[---@not number | nil]] titleString, disambiguation = nil}

	if not disambiguation or type(disambiguation) ~= "string" then
		return title_parts
	end

	-- Remove outside parentheses from names which use parentheses as part of the name such as "episode (Randall and Hopkirk (Deceased))".
	disambiguation = string.sub(--[[---@not number | nil]] disambiguation, 2, -2)
	title_parts.disambiguation = --[[---@not number]] disambiguation
	return title_parts
end

--- Returns the title used in the {{Lowercase title}} template and an optional maintenance category.
---
--- @param page_text string
--- @param args table
--- @param title_parts table
--- @return string | nil
local function get_lowercase_template_status(page_text, args, title_parts)
	local lowercase_template =  string.match(page_text, "{{[Ll]owercase title.-}}")
	if lowercase_template then
		local lowercase_title, _ = string.gsub(title_parts.title,"^%u", string.lower)
		if args.title then
			if args.title == lowercase_title then
				return maintenance_categories.unnecessary_title_parameter
			else
				return maintenance_categories.non_matching_title
			end
			return ""
		end
		return lowercase_title
	end

	return nil
end

--- Returns the title used in the {{Correct title}} template and an optional maintenance category.
---
--- @param page_text string
--- @param args table
--- @param return_category boolean
--- @return string | nil
local function get_correct_title_value(page_text, args, return_category)
	local correct_title_template_pattern = "{{[Cc]orrect title|title=(.*)|reason=.-}}"

	local correct_title = string.match(page_text, correct_title_template_pattern)

	if not correct_title then
		correct_title_template_pattern = "{{[Cc]orrect title|(.*)|reason=.-}}"
		correct_title = string.match(page_text, correct_title_template_pattern)
	end

	if not correct_title and type(correct_title) ~= "string" then
		return nil
	end

	local correct_title_title_parts = get_title_parts(correct_title)

	if not correct_title_title_parts.disambiguation then
		-- If the correct title value has no disambiguation, check if the title used in the infobox is the same as the title used for the correct title value.
		if return_category and args.title then
			if args.title == correct_title_title_parts.title then
				return maintenance_categories.unnecessary_title_parameter
			else
				return maintenance_categories.non_matching_title
			end
		end
		return correct_title_title_parts.title
	end

	local series_name_escaped, _ = get_series_name(args.series)

	if series_name_escaped ~= "" and (correct_title_title_parts.disambiguation == series_name_escaped or string.find(correct_title_title_parts.disambiguation, series_name_escaped)) then
		if return_category and args.title then
			if args.title == correct_title_title_parts.title then
				return maintenance_categories.unnecessary_title_parameter
			else
				return maintenance_categories.non_matching_title
			end
		end
		return correct_title_title_parts.title
	end

	-- Can't determine if the text in parentheses is disambiguation or part of the title since |series= isn't used.
	if return_category then
		return ""
	end

	return correct_title
end

--- Returns the display title text used in either the {{DISPLAYTITLE}} or {{Italic title}} templates.
---
--- @param page_text string
--- @param article_title string
--- @return string | nil
local function get_display_title_text(page_text, article_title)
	local title_modification = string.match(page_text, "{{DISPLAYTITLE:(.-)}}")
	if title_modification and type(title_modification) == "string" then
		return --[[---@not number | nil]] title_modification
	end

	title_modification = string.match(page_text, "{{Italic title|string=(.-)}}")
	if title_modification and type(title_modification) == "string" then
		local italic_title_text, _ = string.gsub(article_title, --[[---@not number | nil]] title_modification, "''" .. title_modification .. "''")
		return italic_title_text
	end

	return nil
end

--- Returns a maintenance category if the italic_title value is not "no".
---
--- Infobox parameters checked:
--- - |italic_title=
---
--- @param args table
--- @return string
local function is_italic_title_valid_value(args)
	if args.italic_title and args.italic_title ~= "no" then
		return string.format(maintenance_categories.incorrectly_formatted, "italic_title")
	end
	return ""
end

--- Returns a maintenance category if the date is not formatted correctly with a {{Start date}} template.
--- Allow "Unaired" as a valid value for unaired television episodes.
---
--- Infobox parameters checked:
--- - |airdate=
--- - |released=
--- - |airdate_overall=
---
--- @param start_date string
--- @return string
local function are_dates_formatted_correctly(start_date)
	if start_date and (string.find(start_date, "film%-date") or not string.find(start_date, "itvstart") and start_date ~= "Unaired") then
		return maintenance_categories.dates_incorrectly_formatted
	end
	return ""
end

--- Returns a maintenance category if list markup is used. The infobox can handle list markup correctly.
---
--- Note: the code here is temporarily checking only the parameters which have been converted
--- to use the plainlist class directly. Once current uses will be converted, the function will check all parameters
--- for incorrect usage.
---
--- Infobox parameters checked:
---	- Parameters listed below.
---
--- Currently checks for the following list markup:
--- - <br> tags - per [[MOS:NOBR]].
--- - <li> tags.
--- - "plainlist" class.
--- - "hlist" class.
---
--- @param args table
--- @return string
local function uses_list_markup(args)
	local invalid_tags = {
		["br"] = "<[bB][rR]%s?/?>",
		["li"] = "<li>",
		["plainlist"] = "plainlist",
		["hlist"] = "hlist",
	}

	---@type table<string, boolean>
	local parameters = {
		director = true,
		writer = true,
		story = true,
		teleplay = true,
		narrator = true,
		presenter = true,
		producer = true,
		music = true,
		photographer = true,
		editor = true,
		production = true,
		airdate = true,
		guests = true,
		commentary = true,
	}

	for parameter_name, _ in pairs(parameters) do
		for _, list_pattern in pairs(invalid_tags) do
			local parameter_value = args[parameter_name]
			if parameter_value and string.find(parameter_value, list_pattern) then
				return maintenance_categories.list_markup
			end
		end
	end
	return ""
end

--- Returns a maintenance category if a flag icon is used.
---
--- All of the infobox values are checked.
---
--- @param args table
--- @return string
local function has_flag_icon(args)
	for _, value in pairs(args) do
		if string.find(value, "flagicon") then
			return maintenance_categories.flag_icon
		end
	end
	return ""
end

--- Returns a maintenance category if the values are linked.
---
--- Infobox parameters checked:
--- - |episode=
--- - |season=
--- - |series_no=
--- - |episode_list=
---
--- The function currently checks if the following values are present:
--- - ]] - links.
---
--- @param args table
--- @return string
local function are_values_linked(args)
	local parameters = {
		episode = args.episode,
		season = args.season,
		series_no = args.series_no,
		episode_list = args.episode_list,
	}

	for key, value in pairs(parameters) do
		if string.find(value, "]]", 1, true) then
			return string.format(maintenance_categories.incorrectly_formatted, key)
		end
	end
	return ""
end

--- Returns a maintenance category if the values are formatted.
---
--- Most of the infobox values are checked. Not included are:
--- - |title= - is handled in is_infobox_title_equal_to_article_title()
--- - |series= - is handled in are_values_links_only()
--- - |next= - is handled in are_values_links_only()
--- - |prev= is handled in are_values_links_only()
--- - |rtitle=
--- - |rprev=
--- - |rnext=
--- - |image_alt=
--- - |alt=
--- - |caption=
--- - |based_on=
--- - |music=
--- - |guests=
--- - |module=
---
--- The function currently checks if the following values are present:
--- - '' - italics or bold.
---
--- Note:
--- If the series is American Horror Story then the season_article value is allowed to be formatted.
--- If in the future more series need this exception then the hardcoded value in the function should be taken out into a list.
---
--- @param args table
--- @return string
local function are_values_formatted(args)
	---@type table<string, boolean>
	local ignore_parameters = {
		title = true,
		series = true,
		prev = true,
		next = true,
		rtitle = true,
		rprev = true,
		rnext = true,
		image_alt = true,
		alt = true,
		caption = true,
		based_on = true,
		music = true,
		guests = true,
		module = true,
	}

	for key, value in pairs(args) do
		if not ignore_parameters[key] and string.find(value, "''", 1, true) then
			if key == "season_article" and args.series == "[[American Horror Story]]" then --TODO: This is hardcoded for now.
				-- Do nothing.
			else
				return string.format(maintenance_categories.incorrectly_formatted, key)
			end
		end
	end
	return ""
end

--- Returns a maintenance category if the values use additional overall numbering.
---
--- Infobox parameters checked:
--- - |episode=
--- - |season=
--- - |series_no=
---
--- The function currently checks if the following values are present:
--- - overall - unsupported series overall numbering.
---
--- @param args table
--- @return string
local function are_values_using_overall(args)
	local parameters = {
		episode = args.episode,
		season = args.season,
		series_no = args.series_no,
	}

	for key, value in pairs(parameters) do
		if string.find(value, "overall") then
			return string.format(maintenance_categories.incorrectly_formatted, key)
		end
	end

	return ""
end

--- Returns a maintenance category if the values are unlinked and if additional characters are found in the text.
---
--- Infobox parameters checked:
--- - |series=
--- - |prev=
--- - |next=
---
--- The function currently checks if a value is unlinked or if there is any additional character
--- before or after the linked text.
---
--- @param args table
--- @return string
local function are_values_links_only(args)
	local parameters = {
		series = args.series,
		prev = args.prev,
		next = args.next,
	}

	for key, value in pairs(parameters) do
		-- Check whether the values are linked.
		if not string.find(value, "%[%[.*%]%]") then
			return string.format(maintenance_categories.unlinked_values, key)
		end

		-- Check whether the values have anything before or after link brackets.
		if string.gsub(value, "(%[%[.*%]%])", "") ~= "" then
			return string.format(maintenance_categories.incorrectly_formatted, key)
		end
	end

	return ""
end

--- Returns a maintenance category if the |image= value includes the "File:" or "Image:" prefix.
---
--- Infobox parameters checked:
--- - |image=
---
--- @param image string
--- @return string
local function is_image_using_incorrect_syntax(image)
	if not image then
		return ""
	end

	if string.find(image, "[Ff]ile:") or string.find(image, "[Ii]mage:") then
		return string.format(maintenance_categories.incorrectly_formatted, "image")
	end

	return ""
end

--- Returns a maintenance category if the |image_size= value includes "px".
---
--- Infobox parameters checked:
--- - |image_size=
---
--- @param image_size string
--- @return string
local function is_image_size_using_px(image_size)
	if image_size and string.find(image_size, "px") then
		return string.format(maintenance_categories.incorrectly_formatted, "image_size")
	end
	return ""
end

--- Returns a maintenance category if there is no image file while image auxiliary values are present.
---
--- Infobox parameters checked:
--- - |image=
--- - |image_size=
--- - |image_upright=
--- - |image_alt=
--- - |alt=
--- - |caption=
---
--- @param args table
--- @return string
local function are_image_auxiliary_values_used_for_no_image(args)
	if args.image then
		return ""
	end

	if args.image_size or args.image_upright or args.image_alt or args.alt or args.caption then
		return maintenance_categories.image_values_without_an_image
	end

	return ""
end

--- Returns a maintenance category if the infobox title is equal to the article title.
---
--- Infobox parameters checked:
--- - |title=
--- - |series=
--- - |italic_title
---
--- The function currently checks if the infobox title is equal to the article title while ignoring styling such as:
--- - Nowrap spans.
--- - Line breaks.
--- - Leading and trailing apostrophe spaces.
---
--- A return value can be one of three options:
--- - The value of maintenance_categories.non_matching_title - when the args.title does not match the article title.
--- - The value of maintenance_categories.unnecessary_title_parameter - when the args.title matches the article title.
--- - An empty string - when args.title isn't used or the args.title uses an allowed modification
--- (such as a nowrap template) while the rest of the args.title matchs the article title.
---
--- Testing parameters:
--- - |page_test= - a real Wikipedia page to read the content of the page.
--- - |page_title_test= - the title of the page being checked.
---
--- @param frame table
--- @param args table
--- @return string
local function is_infobox_title_equal_to_article_title(frame, args)
	if not args.title then
		return ""
	end

	local page_text
	if args.page_test then
		page_text = mw.title.new(args.page_test):getContent()
	else
		page_text = mw.title.getCurrentTitle():getContent()
	end

	-- Check if the article is using a {{Correct title}} template.
	local correct_title = get_correct_title_value(page_text, args, true)
	if correct_title then
		return correct_title
	end

	local article_title = args.page_title_test
	if not args.page_title_test then
		article_title = mw.title.getCurrentTitle().text
	end

	local title_parts = get_title_parts(article_title)

	-- Check if the article is using a {{Lowercase title}} template.
	local lowercase_title = get_lowercase_template_status(page_text, args, title_parts)
	if lowercase_title then
		return lowercase_title
	end

	if title_parts.disambiguation then
		local series_name_escaped, _ = get_series_name(args.series)
		series_name_escaped = get_name_with_br_fixes(series_name_escaped)
		if series_name_escaped ~= "" and (title_parts.disambiguation == series_name_escaped or string.find(title_parts.disambiguation, series_name_escaped)) then
			-- Remove disambiguation.
			article_title = title_parts.title
		end
	end

	if args.italic_title then
		-- Check if the article is using a {{DISPLAYTITLE}} or {{Italic title}} template.
		local title_modification = get_display_title_text(page_text, article_title)
		if title_modification then
			if title_modification == args.title then
				return maintenance_categories.unnecessary_title_parameter
			else
				return maintenance_categories.non_matching_title
			end
		end
	end

	local page_name = get_page_name_with_apostrophe_quotation_fixes(frame, article_title)

	-- Remove nowrap span.
	if string.find(args.title, "nowrap") then
		local title = frame:expandTemplate{title = "Strip tags", args = {args.title}}
		if title == page_name then
			return ""
		end
		return maintenance_categories.non_matching_title
	end

	-- Remove line breaks and additional spaces as a result.
	if string.find(args.title, "<br%s?/?>") then
		local title = get_name_with_br_fixes(args.title)
		if title == page_name then
			return ""
		end
		return maintenance_categories.non_matching_title
	end

	if args.title == page_name then
		return maintenance_categories.unnecessary_title_parameter
	end

	-- Article and infobox titles do not match.
	return maintenance_categories.non_matching_title
end

--- Returns the relevant maintenance categories based on the {{Infobox television episode}} values validated.
---
--- @param frame table
--- @return string
function p.validate_values(frame)
	local getArgs = require("Module:Arguments").getArgs
	local args = getArgs(frame)

	---@type string[]
	local categories = {}
	table.insert(categories, is_infobox_title_equal_to_article_title(frame, args))
	table.insert(categories, are_image_auxiliary_values_used_for_no_image(args))
	table.insert(categories, is_image_using_incorrect_syntax(args.image))
	table.insert(categories, is_image_size_using_px(args.image_size))
	table.insert(categories, are_values_links_only(args))
	table.insert(categories, are_values_using_overall(args))
	table.insert(categories, are_values_formatted(args))
	table.insert(categories, are_values_linked(args))
	table.insert(categories, has_flag_icon(args))
	table.insert(categories, uses_list_markup(args))
	table.insert(categories, are_dates_formatted_correctly(args.airdate or args.released))
	table.insert(categories, is_italic_title_valid_value(args))

	return table.concat(categories)
end

--- Returns an {{Italic dab2}} instance if title qualifies. Also returns a maintenance category if conditions are met.
---
--- The article's title is italicized if the series name is included in the article's title disambiguation.
--- No italicization happens if one of the following conditions is met:
---
--- - |italic_title= is set to "no".
--- - The article's title does not use disambiguation.
--- - No |series= value is set.
--- - The article's disambiguation is not equal or does not include the series name.
---
--- The page is added to a maintenance category if the title is italicized and there is already an
--- {{Italic dab}}, {{Italic title}} or {{DISPLAYTITLE}} template.
---
--- Infobox parameters checked:
--- - |series=
--- - |italic_title=
---
--- Testing parameters:
--- - |page_test= - a real Wikipedia page to read the content of the page.
--- - |page_title_test= - the title of the page being checked.
---
--- @param frame table
--- @return string, string
function p.italic_title(frame)
	local getArgs = require("Module:Arguments").getArgs
	local args = getArgs(frame)

	local page_text
	if args.page_test then
		page_text = mw.title.new(args.page_test):getContent()
	else
		page_text = mw.title.getCurrentTitle():getContent()
	end

	local maintenance_category = ""
	-- In case the page does not need to be italicized or can't be automatically done, a "no" value will disable both
	-- the italicization and the error handling.
	if args.italic_title == "no" then
		return "", maintenance_category
	end

	local article_title = args.page_title_test
	if not args.page_title_test then
		article_title = mw.title.getCurrentTitle().text
	end

	-- Check if the page already has an {{Italic dab}}, {{Italic title}} or {{DISPLAYTITLE}} template.
	local has_italic_dab, _ = string.find(page_text, "{{[Ii]talic dab")
	local has_italic_title, _ = string.find(page_text, "{{[Ii]talic title")
	local has_display_title, _ = string.find(page_text, "{{DISPLAYTITLE")

	if has_italic_dab or has_italic_title or has_display_title then
		maintenance_category = maintenance_categories.manual_display_title
	end

	local title_parts = get_title_parts(article_title)

	-- The title is not italicized if the title does not use disambiguation or if the series parameter isn't used.
	if not title_parts.disambiguation or not args.series then
		return "", maintenance_category
	end

	local series_name_escaped, series_name = get_series_name(args.series)
	series_name_escaped = get_name_with_br_fixes(series_name_escaped)
	series_name = get_name_with_br_fixes(series_name)

	-- Check if the disambiguation equals the series name or if the series name can be found in the disambiguation.
	local italic_dab
	if title_parts.disambiguation == series_name then
		italic_dab = frame:expandTemplate{title = "Italic dab2"}
	elseif string.find(title_parts.disambiguation, series_name_escaped) then
		italic_dab = frame:expandTemplate{title = "Italic dab2", args = {string = series_name}}
	else
		return "", maintenance_category
	end

	if args.page_title_test and italic_dab then
		italic_dab = "italic_dab"
	end
	return italic_dab, maintenance_category

end

--- Returns a formatted title string.
---
--- @param rtitle string
--- @return string
local function create_title_with_rtitle_value(rtitle)
	local title_pattern = '"(.*)" and "(.*)"'
	if string.find(rtitle, title_pattern) then
		local episode1, episode2 = string.match(rtitle, title_pattern)
		local title_format = "\"'''%s'''\" and \"'''%s'''\""
		return string.format(title_format, episode1, episode2)
	end

	local title_pattern_br = '"(.*)" and%s?<br%s?/?>%s?"(.*)"'
	if string.find(rtitle, title_pattern_br) then
		local episode1, episode2 = string.match(rtitle, title_pattern_br)
		local title_format = "\"'''%s'''\" and<br/> \"'''%s'''\""
		return string.format(title_format, episode1, episode2)
	end

	return string.format("'''%s'''", rtitle)
end

--- Returns the text used for the |above= field of the infobox.
---
--- Infobox parameters checked:
--- - |rtitle=
--- - |title=
--- - |series=
---
--- Testing parameters:
--- - |page_test= - a real Wikipedia page to read the content of the page.
--- - |page_title_test= - the title of the page being checked.
---
--- @param frame table
--- @return string
local function _above_title(frame, args)
	if args.rtitle then
		return create_title_with_rtitle_value(args.rtitle)
	end

	local page
	if args.page_test then
		page = mw.title.new(args.page_test)
	else
		page = mw.title.getCurrentTitle()
	end

	local page_text = page:getContent()

	local article_title = args.page_title_test
	if not args.page_title_test then
		article_title = page.text
	end

	local title_format = "\"'''%s'''\""

	local correct_title = get_correct_title_value(page_text, args, false)
	if correct_title then
		return string.format(title_format, correct_title)
	end

	local title_parts = get_title_parts(article_title)

	local lowercase_title = get_lowercase_template_status(page_text, args, title_parts)
	if lowercase_title then
		return string.format(title_format, lowercase_title)
	end

	local series_name_escaped, _ = get_series_name(args.series)

	-- args.no_bold is used from IMDb episode so it requires this correction here also.
	if (args.italic_title and not args.rtitle) or args.no_bold then
		local title_modification = get_display_title_text(page_text, article_title)

		if title_modification then
			if title_parts.disambiguation == series_name_escaped then
				local correct_title_title_parts = get_title_parts(title_modification)
				title_modification = correct_title_title_parts.title
			end
			return string.format(title_format, title_modification)
		end
	end

	if args.title then
		return string.format(title_format, args.title)
	end

	if not title_parts.disambiguation or (series_name_escaped ~= "" and (title_parts.disambiguation == series_name_escaped or string.find(title_parts.disambiguation, series_name_escaped))) or args.no_bold then
		return string.format(title_format, get_page_name_with_apostrophe_quotation_fixes(frame, title_parts.title))
	end

	return string.format(title_format, get_page_name_with_apostrophe_quotation_fixes(frame, article_title))
end

--- Returns the episode title from the article title, with textual fixes if needed.
---
--- Used by {{Infobox television episode}} and {{IMDb episode}} to automatically style the title without needing manual input.
---
--- @param frame table
--- @return string
function p.above_title(frame)
	local getArgs = require("Module:Arguments").getArgs
	local args = getArgs(frame)
	local title = _above_title(frame, args)
	
	-- The title used by {{IMDb episode}} should not be in bold.
	if args.no_bold then
		title = string.gsub(title, "'''", "")
	end
	return title
end

--- Returns a list of episodes link if not formatted, otherwise returns the text used for args.episode_list.
---
--- Infobox parameters checked:
--- - |episode_list=
--- - |series=
---
--- @param frame table
--- @return string
function p.episode_list(frame)
	local getArgs = require("Module:Arguments").getArgs
	---@type table<string, string>
	local args = getArgs(frame)

	if args.episode_list then
		for _, v in pairs({"]]", "''"}) do
			if string.find(args.episode_list, v) then
				return args.episode_list
			end
		end

		if string.find(args.episode_list, "[Ss]toryline") then
			return "[[" .. args.episode_list .. "|Storylines]]"
		end

		return "[[" .. args.episode_list .. "|List of episodes]]"
	end

	if args.series then
		local series_name = get_series_link(args.series)
		local list_of_episodes = "List of " .. series_name .. " episodes"

		if mw.title.new(list_of_episodes):getContent() then
			return "[[" .. list_of_episodes .. "|List of episodes]]"
		end
	end
end

--- Returns the relevant maintenance categories based on the {{Infobox television crossover episode}} values validated.
---
--- @param frame table
--- @return string
function p.validate_values_crossover(frame)
	local getArgs = require("Module:Arguments").getArgs
	local args = getArgs(frame)

	---@type string[]
	local categories = {}
	table.insert(categories, are_image_auxiliary_values_used_for_no_image(args))
	table.insert(categories, is_image_using_incorrect_syntax(args.image))
	table.insert(categories, is_image_size_using_px(args.image_size))
	table.insert(categories, has_flag_icon(args))
	table.insert(categories, are_dates_formatted_correctly(args.airdate_overall))

	for i = 1, 5 do
		if not args["series" .. i] then
			break
		end

		local nested_args = {
			series = args["series" .. i],
			episode = args["episode_no" .. i],
			season = args["season" .. i],
			airdate = args["airdate" .. i],
			prev = args["prev" .. i],
			next = args["next" .. i],
			episode_list = args["episode_list" .. i],
		}

		table.insert(categories, are_values_links_only(nested_args))
		table.insert(categories, are_values_using_overall(nested_args))
		table.insert(categories, are_values_formatted(nested_args))
		table.insert(categories, are_values_linked(nested_args))
		table.insert(categories, are_dates_formatted_correctly(nested_args.airdate))
	end

	return table.concat(categories, "")
end

return p
Description	What you type	What you get
Italic	''Italic text''	Italic text
Bold	'''Bold text'''	Bold text
Bold & italic	'''''Bold & italic text'''''	*Bold & italic text*