-- This module stores functions that are shared between [[Module:UserLinks]]

-- and [[Module:UserLinks/extra]].



-- Load data and define often-used variables

local cfg = mw.loadData('Module:UserLinks/config')

local namespaces = mw.site.namespaces



-- Lazily initialise modules that we may or may not need

local mCategoryHandler



-- Define namespaces for which links need to be escaped with the colon trick.

-- See [[w:en:Help:Colon trick]].

local colonNamespaces = {

	6 = true, -- File

	14 = true, -- Category

}



local p = {}



function p.maybeLoadModule(s)

	-- Attempts to load the module s. If it succeeds, returns the module;

	-- otherwise, returns false.

	local success, mdl = pcall(require, s)

	if success then

		return mdl

	else

		return false

	end

end



function p.raiseError(message, section, level)

	-- Raises an error using the Lua error function. The error message is

	-- designed to be caught with pcall and then passed to p.makeWikitextError.

	-- The section, if specified, is the section name on a help page that gives

	-- help to users about that particular error.

	if section then

		message = message .. '|' .. section

	end

	if not level or level == 0 then

		level = 0

	else

		level = level + 1

	end

	error(message, level)

end



local localBlacklist = {

	'/[sS]andbox$', -- Don't categorise sandboxes

	'/[tT]est ?cases$', -- Don't categorise test case pages

}



local function currentTitleMatchesLocalBlacklist()

	-- Return true if the current title matches any of the patterns in the

	-- local blacklist table. Otherwise return false.

	local title = mw.title.getCurrentTitle().prefixedText

	for i, pattern in ipairs(localBlacklist) do

		if title:find(pattern) then

			return true

		end

	end

	return false

end



function p.makeWikitextError(encodedMessage, demo)

	local errorMessage, section = mw.ustring.match(encodedMessage, '^(.-)|(.*)$')

	errorMessage = errorMessage or encodedMessage

	

	-- If not a demo, get the error category link and pass it through

	-- [[Module:Category handler]]'s blacklist.

	local category

	if not demo then

		category = string.format(

			'[[%s:%s]]',

			namespaces14].name,

			p.message('error-config-category')

		)

		mCategoryHandler = p.maybeLoadModule('Module:Category handler')

		if mCategoryHandler then

			-- Categorise all namespaces, but not blacklisted pages.

			category = mCategoryHandler.main{all = category}

		end

		if category and currentTitleMatchesLocalBlacklist() then

			category = nil

		end

	end

	category = category or ''

	

	-- Format the error message and the section link.

	local formattedError

	if section then

		formattedError = p.message(

			'error-config-message-help',

			errorMessage,

			section

		)

	else

		formattedError = p.message(

			'error-config-message-nohelp',

			errorMessage

		)

	end



	-- Return the error message and the category inside html error tags.

	return string.format(

		'<strong class="error">%s</strong>%s',

		formattedError,

		category

	)

end



local function formatPage(interwiki, namespace, page)

	-- Formats an interwiki, a namespace and a page into a wikilink-ready

	-- string. The interwiki and namespace are optional. If a namespace is

	-- specified, it should be a valid key to mw.site.namespaces. The page

	-- parameter is required.

	local ret = {}

	interwiki = interwiki or ''

	if interwiki ~= '' or colonNamespacesnamespace then

		ret#ret + 1 = ':'

	end

	ret#ret + 1 = interwiki

	if interwiki ~= '' then

		ret#ret + 1 = ':'

	end

	if namespace then

		local nsTable = namespacesnamespace

		if not nsTable then

			error('"' .. tostring(namespace) .. '" is not a valid namespace key', 2)

		end

		ret#ret + 1 = nsTable.name

		if namespace ~= 0 then

			ret#ret + 1 = ':'

		end

	end

	ret#ret + 1 = page

	return table.concat(ret)

end



local function formatDisplay(s)

	-- Replaces spaces in a string with "&nbsp;" to make sure they don't wrap.

	-- Don't replace anything if we are substing, as we generally don't want

	-- to use "&nbsp;" in that case.

	if mw.isSubsting() then

		return s

	else

		return s:gsub(' ', '&nbsp;')

	end

end



function p.makeWikilink(interwiki, namespace, page, display)

	-- Creates a wikilink. The interwiki, namespace and display parameters are

	-- optional. If a namespace parameter is specified it must be a valid key

	-- to mw.site.namespaces.

	local formattedPage = formatPage(interwiki, namespace, page)

	if display then

		display = formatDisplay(display)

		return string.format('[[%s|%s]]', formattedPage, display)

	else

		return string.format('[[%s]]', formattedPage)

	end

end



local function formatUrlLink(url, display)

	-- Formats a URL link with an optional display parameter.

	if display then

		display = formatDisplay(display)

		return string.format('[%s %s]', url, display)

	else

		return string.format('[%s]', url)

	end

end



function p.makeUrlLink(s, display)

	-- Makes a URL link with an optional display parameter. The first input

	-- may be any valid input to mw.uri.new.

	local url = mw.uri.new(s)

	url = tostring(url)

	return formatUrlLink(url, display)

end



function p.makeFullUrlLink(interwiki, namespace, page, query, display)

	-- Makes a link to the full URL of a page. The interwiki, namespace, query

	-- and display parameters are optional. If a namespace parameter is

	-- specified it must be a valid key to mw.site.namespaces. The query

	-- parameter can be a string or a table as specified in the mw.uri library.

	local formattedPage = formatPage(interwiki, namespace, page)

	local url = mw.uri.fullUrl(formattedPage, query)

	url = tostring(url)

	return formatUrlLink(url, display)

end



function p.message(key, ...)

	-- Returns the message with the given key from [[Module:UserLinks/config]].

	-- Extra parameters are substituted in the message for keys $1, $2, $3, etc.

	local msg = cfgkey

	if not msg then

		p.raiseError(

			'No message found with key "' .. tostring(key) .. '"',

			'No message found',

			2

		)

	end

	local noArgs = select('#', ...)

	if noArgs < 1 then

		return msg

	else

		local msg = mw.message.newRawMessage(msg, ...)

		return msg:plain()

	end

end



return p