Editing Module:Episode short description

--- @module
local television = {}

-- Unique suffix list.
local uniqueSuffix = {
	[1] = "st",
	[2] = "nd",
	[3] = "rd",
}

-- Common suffix.
local commonSuffix = "th"

-- Test validation.
local test = false

local descriptions = {
	no_series = {
		type = 1,
		text = "Red Letter Media episode",
		category = "",
	},
	only_series_name = {
		type = 2,
		text = "Episode of %s",
		category = "",
	},
	season_and_series_name = {
		type = 3,
		text = "Episode of %s",
		category = "",
	},
	single_episode = {
		type = 4,
		text = "%s episode of %s",
		category = "",
	},
	multi_episodes = {
		type = 5,
		text = "%s episodes of %s",
		category = "",
	},
	limited_series = {
		type = 6,
		text = {
			single_episode = "%s episode of %s",
			multi_episodes = "%s episodes of %s",
		},
		category = "", -- None
	},
	special_episode = {
		type = 7,
		text = "%s episode of %s",
		category = "", -- None
	},
}

-- Tracking category list.
local trackingCategories = {
	disambiguated = "[[Category:Episode articles with short description and disambiguated page names|%s]]"
}

--- Returns a tracking category from a list by its name and adds a sort key.
--- @param typeName string The name of the category type.
--- @param useTrackingList boolean Whether to return a category from the trackingCategories list.
--- @param sortKey string The key by which to sort the page in the category.
local function getTrackingCategoryFromList(typeName, useTrackingList, sortKey)
	local category
	if useTrackingList then
		category = trackingCategories[typeName]
	else
		category = descriptions[typeName].category
	end
	return string.format(category, sortKey)
end

--- Returns true if the article name is disambiguated.
---
--- This is usually in the format of "Episode name (<TV series name>)" or "Episode name (<TV series name> episode)".
--- @param articleTitle string The name of the page.
--- @param tvSeriesName string The TV series name.
local function isDisambiguated(articleTitle, tvSeriesName)
	local disambiguation = string.match(tostring(articleTitle), "%s%((.-)%)")

	if not (disambiguation and tvSeriesName) then
		return false
	end

	-- Search for the TV series name in the article name disambiguation.
	if (string.find(disambiguation, tvSeriesName)) then
		return true
	end

	return false
end

--- Returns the sort key for the current page.
local function getSortKey()
	local sortTitleModule = require("Module:Sort title")
	return sortTitleModule._getSortKey()
end

--- Returns a tracking category depending on the type of short description created.
--- @param tvSeriesName string The TV series name.
--- @param descriptionName string
local function getTrackingCategory(tvSeriesName, descriptionName)
	local articleTitle = mw.title.getCurrentTitle()
	local namespace = articleTitle.nsText

	-- Check if the invoking page is from the allowed namespace.
	if (not (namespace == "" or namespace == "Draft" or test)) then
		return ""
	end

	local sortKey = getSortKey()
	if (isDisambiguated(articleTitle, tvSeriesName) == true) then
		local category1 = getTrackingCategoryFromList(descriptionName, false, sortKey)
		local category2 = getTrackingCategoryFromList("disambiguated", true, sortKey)
		return category1 .. category2
	end

	return getTrackingCategoryFromList(descriptionName, false, sortKey)
end


--- Returns a short description in the style of: "Television episode" and a maintenance category:
--- "Category:Television episode articles with short description with no series name".
local function getShortDescriptionNoSeries()
	local shortDescription = descriptions.no_series.text
	local category = getTrackingCategory(nil, "no_series")
	return shortDescription, category
end

--- Returns a short description in the style of: "Episode of Lost".
--- @param tvSeriesName string The TV series name.
local function getShortDescriptionOnlySeriesName(tvSeriesName)
	local text = descriptions.only_series_name.text
	local shortDescription = string.format(text, tvSeriesName)
	local category = getTrackingCategory(tvSeriesName, "only_series_name")
	return shortDescription, category
end

--- Returns a short description in the style of: "5th episode of Lost".
--- @param tvSeriesName string The TV series name.
--- @param episodeOrdinalNumber string The episode's ordinal number.
local function getShortDescriptionSingleEpisode(tvSeriesName, episodeOrdinalNumber)
	local text = descriptions.single_episode.text
	local shortDescription =  string.format(text, episodeOrdinalNumber, tvSeriesName)
	local category = getTrackingCategory(tvSeriesName, "single_episode")
	return shortDescription, category
end

--- Returns a short description for a multi-part episode in the style of:
--- "23rd and 24th episodes of Lost".
--- @param tvSeriesName string The TV series name.
--- @param episodeOrdinalNumbers table A list of episode ordinal numbers.
local function getShortDescriptionMultiEpisode(tvSeriesName, episodeOrdinalNumbers)
	local episodeText = mw.text.listToText(episodeOrdinalNumbers)

	local text = descriptions.multi_episodes.text
	local shortDescription = string.format(text, episodeText, tvSeriesName)
	local category = getTrackingCategory(tvSeriesName, "multi_episodes")
	return shortDescription, category
end

--- Returns a short description for a special episode in the style of:
--- "Special episode of Lost" or "<value> episode of Lost".
--- @param tvSeriesName string The TV series name.
--- @param special string The type of special episode. A "yes" value defaults to "Special".
local function getShortDescriptionSpecialEpisode(tvSeriesName, special)
	if (special == "yes" or special == "y") then
		special = "Special"
	end
	local text = descriptions.special_episode.text
	local shortDescription = string.format(text, special, tvSeriesName)
	local category = getTrackingCategory(tvSeriesName, "single_episode")
	return shortDescription, category
end

--- Returns a short description based on the description type passed.
--- @param descriptionType number A description type number.
--- @param tvSeriesName string The series name.
--- @param episodeOrdinalNumbers table A list of episode ordinal numbers.
--- @param specialEpisode string The type of special episode.
local function getShortDescriptionByType(
		descriptionType, tvSeriesName, episodeOrdinalNumbers, specialEpisode)
	if descriptionType == descriptions.no_series.type then
		return getShortDescriptionNoSeries()
	elseif descriptionType == descriptions.only_series_name.type then
		return getShortDescriptionOnlySeriesName(tvSeriesName)
	--- elseif descriptionType == descriptions.season_and_series_name.type then
	--- 	return getShortDescriptionSeasonAndSeriesName(tvSeriesName, seasonOrdinalNumber, seasonTextStyle)
	elseif descriptionType == descriptions.single_episode.type then
		return getShortDescriptionSingleEpisode(
                tvSeriesName, episodeOrdinalNumbers[1])
	elseif descriptionType == descriptions.multi_episodes.type then
		return getShortDescriptionMultiEpisode(
				tvSeriesName, episodeOrdinalNumbers)
	elseif descriptionType == descriptions.special_episode.type then
		return getShortDescriptionSpecialEpisode(tvSeriesName, specialEpisode)
	else
		return ""
	end
end

--- Returns the type of the description to use.
--- @param tvSeriesName string The TV series name.
--- @param episodeOrdinalNumbers table A list of episode ordinal numbers.
--- @param specialEpisode string The type of special episode.
local function getDescriptionType(tvSeriesName, episodeOrdinalNumbers, specialEpisode)
	if (not tvSeriesName) then
		return descriptions.no_series.type
	end

	if (specialEpisode) then
		return descriptions.special_episode.type
	end

	if (#episodeOrdinalNumbers < 1) then
		return descriptions.only_series_name.type
	end

	if (#episodeOrdinalNumbers == 1) then
		return descriptions.single_episode.type
	end

	if (#episodeOrdinalNumbers > 1) then
		return descriptions.multi_episodes.type
	end

	return descriptions.only_series_name.type
end

--- Returns the ordinal indicator for an integer between 0 and 100.
---
--- Numbers "1", "2" and "3" have unique suffixes.
--- Numbers between 4 and 20 have the same common suffix - "th".
--- Numbers ending with 0 have the same common suffix - "th".
--- @param number number A number value.
local function getOrdinalIndicatorLessThan100(number)
	local suffix
	while (not suffix) do
		-- Check if the number equals 0; This should never be a valid entry. Assign suffix as an empty string.
		if (number == 0) then
			suffix = ""
		-- Check if the number is less than 4; Numbers "1", "2" and "3" have unique suffixes.
		elseif (number < 4) then
			suffix = uniqueSuffix[number]
		-- Check if the number is more than 4 AND less than 20; These numbers all have the same common suffix.
		elseif (number < 20) then
			suffix = commonSuffix
		-- Check if the remainder after division of the number by 10 equals 0.
		elseif (number % 10 == 0) then
			suffix = commonSuffix
		else
			-- Numbers that are above 20 and which their remainder doesn't equal 0 (such as 45).
			-- Remainder after division of the number by 10; So if the current number is 45, the new number is 5.
			number = number % 10
		end
	end
	return suffix
end

--- Returns the ordinal indicator for an integer between 0 and 1000.
--- @param number number A number value.
local function getOrdinalIndicatorLessThan1000(number)
	if (number < 100) then
		return getOrdinalIndicatorLessThan100(number)
	elseif (number % 100 == 0) then
		return commonSuffix
	else
		-- Numbers that are above 100 and which their remainder doesn't equal 0 (such as 345).
		-- Pass the remainder after division of the number by 100 (So for 345, it would pass 45) as the parameter.
		return getOrdinalIndicatorLessThan100(number % 100)
	end
end

--- Returns a table of episode numbers.
---
--- Episode values may be of multipart episodes, in such situations, an episode may be seperated by one of the following:
--- ",", "/", "&", "-", "–", "and".
--- Decimal values and episode overall values sometimes erroneously used are removed.
--- @param number string A number value in string format.
local function cleanEpisodeNumber(number)
	if (not number) then
		return {}
	end

	number = string.gsub(number, "%(.*%)", " ")
	number = string.gsub(number, "%.%d+", " ")

	local numbers = {}
	for digits in string.gmatch(number, "%d+") do
		table.insert(numbers, tonumber(digits))
	end
	return numbers
end

--- Returns a table of episode ordinal numbers.
---
--- In most situations there will be only one episode, but this can support more.
--- @param episodeNumber number The episode's number.
local function getEpisodeOrdinalNumbers(episodeNumber)
	local episodeNumbers = cleanEpisodeNumber(episodeNumber)

	if (#episodeNumbers < 1) then
		return episodeNumbers
	end

	local episodeOrdinals = {}
	for _, cleanedEpisodeNumber in pairs(episodeNumbers) do
		local ordinalIndicator = getOrdinalIndicatorLessThan1000(cleanedEpisodeNumber)
		table.insert(episodeOrdinals, cleanedEpisodeNumber .. ordinalIndicator)
	end

	return episodeOrdinals
end

--- Returns the TV series title without disambiguation, and the disambiguation, or nil if no TV series name was set.
--- @param tvSeriesName string The TV series name.
--- @param notDab string If set, the parenthesis in the title is not disambiguation.
local function getTVSeriesName(tvSeriesName, notDab)
	if (tvSeriesName) then
		if (not notDab) then
			local title, disambiguation = string.match(tvSeriesName, "^(.+) %((.*)%)$")
			if not title then
				title = tvSeriesName
			end
			return title, disambiguation
		end
		return tvSeriesName, nil
	end
	return nil, nil
end

--- Returns the initial values after removing unwanted characters.
--- @param args table The values that should be processed.
local function cleanValues(args)
	for i, v in ipairs({"episode_num", "series_name"}) do
		if (args[v]) then
			args[v] = args[v]:gsub("\127[^\127]*UNIQ%-%-(%a+)%-%x+%-QINU[^\127]*\127", "")	-- Remove all strip-markers.
			args[v] = args[v]:gsub("</? *br */?>", " ")					-- Replace <br /> (and variants) with space character.
			args[v] = args[v]:gsub("%b<>[^<]+%b<>", "")					-- Remove html markup.
			args[v] = args[v]:gsub("%b<>", "")							-- Remove self-closed html tags.
			if i ~= 4 then
				args[v] = args[v]:gsub("%[%[[^|]+|([^%]]+)%]%]", "%1")	-- Remove wiki-link retain label.
			else
				args[v] = args[v]:gsub("%[%[([^|]+)|.*%]%]", "%1")		-- Remove wiki-link retain article.
			end
			args[v] = args[v]:gsub("%[%[([^%]]+)%]%]", "%1")			-- Remove wiki-link retain article.
			args[v] = args[v]:gsub("%[%S+ +([^%]]-)%]", "%1")			-- Remove URLs retain label.
			args[v] = args[v]:gsub("%[[^%]]-%]", "")					-- Remove all remaining URLs.

			if (args[v] == "") then										-- Check if the value is an empty string.
				args[v] = nil											-- The value is an empty string; Set it to nil.
			end
		end
	end
	return args
end

--- Public function - main process.
--- @param frame table The frame invoking the module.
--- @param args table The key-value parameters passed to the module.
function television._getShortDescription(frame, args)
	args = cleanValues(args)
	local tvSeriesName, tvSeriesNameDab = getTVSeriesName(args.series_name, args.not_dab)
	--- RLMWiki doesn't need seasons
	--- local seasonNumber, seasonTextStyle = getSeasonNumberAndTextStyle(args.season_num, args.season_num_uk)
	--- local seasonOrdinalNumber = getSeasonOrdinalNumber(seasonNumber)
	local episodeOrdinalNumbers = getEpisodeOrdinalNumbers(args.episode_num)
	--- local limitedSeries = isLimitedSeries(args.limited, tvSeriesNameDab)
	
	local descriptionType = getDescriptionType(
			tvSeriesName,
			episodeOrdinalNumbers,
			args.special
	)

	local shortDescription, trackingCat = getShortDescriptionByType(
			descriptionType,
			tvSeriesName,
			episodeOrdinalNumbers,
			args.special
	)

	-- Check if the invoking page is from /testcases or /doc pages.
	if (args.test) then
		return shortDescription, trackingCat
	elseif (args.doc) then
		return shortDescription
	else
		local tableData = {shortDescription, "noreplace"}
		return frame:expandTemplate({title = "short description", args = tableData}) .. trackingCat
	end
end

--- Public function which is used to create a television episode's short description
--- from the data available in [Template:Infobox television episode].
--- A suitable description will be generated depending on the values of the various parameters.
--- See documentation for examples.
---
--- Parameters:
--- |episode_num=		— optional; The episode's number.
--- |series_name=		— optional; The TV series name.
--- |not_dab=			— optional; Set if the TV series name has parentheses as part of its name.
--- |special=			— optional; Setting to "yes" will set the description as a "special episode".
---							Any other value will replace the word "special" with the one entered.
---							For example "special=recap" will create "recap episode".
--- @param frame table The frame invoking the module.
function television.getShortDescription(frame)
	local getArgs = require("Module:Arguments").getArgs
	local args = getArgs(frame)
	return television._getShortDescription(frame, args)
end


--- Public function which is used for testing output only.
--- @param frame table The frame invoking the module.
function television.test(frame)
	local getArgs = require("Module:Arguments").getArgs
	local args = getArgs(frame)

	test = args.test
	local shortDescription, categories = television._getShortDescription(frame, args)

	if (test == "cat") then
		return categories
	else
		return shortDescription
	end
end

return television