--[[

-- This module produces a "redirect" hatnote. It looks like this:

-- '"X" redirects here. For other uses, see Y.'

-- It implements the {{redirect}} template.

--]]



local mHatnote = require('Module:Hatnote')

local mHatList = require('Module:Hatnote list')

local mArguments --lazily initialize

local libraryUtil = require('libraryUtil')

local checkType = libraryUtil.checkType

local checkTypeMulti = libraryUtil.checkTypeMulti



local p = {}



--------------------------------------------------------------------------------

-- Helper functions

--------------------------------------------------------------------------------



local function getTitle(...)

	--Calls mw.title.new and returns either a title object, or nil on error

	local success, titleObj = pcall(mw.title.new, ...)

	return success and titleObj or nil

end



--------------------------------------------------------------------------------

-- Main functions

--------------------------------------------------------------------------------



function p.redirect(frame)

	mArguments = require('Module:Arguments')

	local args = mArguments.getArgs(frame, {parentOnly=true})

	--Get number of redirects

	local numRedirects = tonumber(frame.args1]) or 1

	-- Create the options table.

	local options = {}

	options.selfref = args.selfref

	return p._redirect(args, numRedirects, options)

end



function p._redirect(args, numRedirects, options, currentTitle, redirectTitle, targetTitle)

	-- Validate the input. Don't bother checking currentTitle, redirectTitle or

	-- targetTitle, as they are only used in testing.

	checkType('_redirect', 1, args, 'table')

	checkType('_redirect', 2, numRedirects, 'number', true)

	numRedirects = numRedirects or 1

	checkType('_redirect', 3, options, 'table', true)

	options = options or {}

	currentTitle = currentTitle or mw.title.getCurrentTitle()

	-- Get the table of redirects

	local redirect = {}

	for i = 1, numRedirects do

		-- Return an error if a redirect parameter is missing.

		if not argsi then

			return mHatnote.makeWikitextError(

				'missing redirect parameter',

				'Template:Redirect#Errors',

				args.category

			)

		end

		redirecti = argsi

	end

	-- Generate the text.

	local formattedRedirect = {}

	for k,v in pairs(redirect) do

		formattedRedirectk = mHatnote.quote(v)

	end

	local text = {

		mHatList.andList(formattedRedirect) .. ' ' .. (#redirect == 1 and 'redirects' or 'redirect') .. ' here.',

		mHatList._forSee(args, #redirect + 1, {title = redirect1], extratext = args.text})

	}

	text = table.concat(text, ' ')

	-- Functionality for adding categories	

	local categoryTable = {}

	local function addCategory(cat)

		if cat and cat ~= '' then

			-- Add by index to avoid duplicates

			categoryTablestring.format('[[Category:%s]]', cat)] = true

		end

	end

	--Generate tracking categories

	local mhOptions = {}

	local redirTitle

	for k,v in pairs(redirect) do

		-- We don't need a tracking category if the template invocation has been

		-- copied directly from the docs, or if we aren't in main- or category-space.

		if not v:find('^REDIRECT%d*$') and v ~= 'TERM' -- 

			and currentTitle.namespace == 0 or currentTitle.namespace == 14

		then

			redirTitle = redirectTitle or getTitle(v)

			if not redirTitle or not redirTitle.exists then

				addCategory('Missing redirects')

			elseif not redirTitle.isRedirect then

				if string.find(redirTitle:getContent(), '#invoke:RfD') then

					addCategory('Articles with redirect hatnotes impacted by RfD')

				else

					addCategory('Articles with redirect hatnotes needing review')

				end

			else

				local target = targetTitle or redirTitle.redirectTarget

				if target and target ~= currentTitle then

					addCategory('Articles with redirect hatnotes needing review')

				end

			end

		end



		-- Generate the options to pass to [[Module:Hatnote]].

		if currentTitle.namespace == 0 and not mhOptions.selfref

			and redirTitle and redirTitle.namespace ~= 0

		then

			-- We are on a mainspace page, and the hatnote starts with something

			-- like "Wikipedia:Foo redirects here", so automatically label it as

			-- a self-reference.

			mhOptions.selfref = true

		else

			mhOptions.selfref = options.selfref

		end

	end

	--concatenate all the categories

	local category = ''

	for k,v in pairs(categoryTable) do

		category = category .. k

	end



	return mHatnote._hatnote(text, mhOptions) .. category

end

 

return p