Editing Module:Protection banner

-- This module implements {{pp-meta}} and its daughter templates such as
-- {{pp-dispute}}, {{pp-vandalism}} and {{pp-sock}}.

-- Initialise necessary modules.
require('Module:No globals')
local newFileLink = require('Module:File link').new
local effectiveProtectionLevel = require('Module:Effective protection level')._main
local yesno = require('Module:Yesno')

-- Lazily initialise modules and objects we don't always need.
local getArgs, makeMessageBox, lang

-- Set constants.
local CONFIG_MODULE = 'Module:Protection banner/config'

--------------------------------------------------------------------------------
-- Helper functions
--------------------------------------------------------------------------------

local function makeCategoryLink(cat, sort)
	local nsText = mw.site.namespaces[14].name
	if cat and sort then
		return string.format(
			'[[%s:%s|%s]]',
			nsText,
			cat,
			sort
		)
	elseif cat then
		return string.format(
			'[[%s:%s]]',
			nsText,
			cat
		)
	else
		return ''
	end
end

-- Validation function for the expiry and the protection date
local function validateDate(dateString, dateType)
	lang = lang or mw.language.getContentLanguage()
	local success, result = pcall(lang.formatDate, lang, 'U', dateString)
	if success then
		result = tonumber(result)
		if result then
			return result
		end
	end
	error(string.format(
		'invalid %s ("%s")',
		dateType,
		tostring(dateString)
	), 0)
end

local function makeFullUrl(page, query, display)
	return string.format(
		'[%s %s]',
		tostring(mw.uri.fullUrl(page, query)),
		display
	)
end

local function toTableEnd(t, pos)
	-- Sends the value at position pos to the end of array t, and shifts the
	-- other items down accordingly.
	return table.insert(t, table.remove(t, pos))
end

local function walkHierarchy(hierarchy, start)
	local toWalk, retval = {[start] = true}, {}
	while true do
		-- Can't use pairs() since we're adding and removing things as we're iterating
		local k = next(toWalk)
		if k == nil then break end
		toWalk[k] = nil
		retval[k] = true
		for _,v in ipairs(hierarchy[k]) do
			if not retval[v] then
				toWalk[v] = true
			end
		end
	end
	return retval
end

--------------------------------------------------------------------------------
-- Protection class
--------------------------------------------------------------------------------

local Protection = {}
Protection.__index = Protection

Protection.supportedActions = {
	edit = true,
	move = true,
	autoreview = true
}

Protection.bannerConfigFields = {
	'text',
	'explanation',
	'tooltip',
	'alt',
	'link',
	'image'
}

function Protection.new(args, cfg, title)
	local obj = {}
	obj._cfg = cfg
	obj.title = title or mw.title.getCurrentTitle()

	-- Set action
	if not args.action then
		obj.action = 'edit'
	elseif Protection.supportedActions[args.action] then
		obj.action = args.action
	else
		error(string.format(
			'invalid action ("%s")',
			tostring(args.action)
		), 0)
	end

	-- Set level
	obj.level = effectiveProtectionLevel(obj.action, obj.title)
	if obj.level == 'accountcreator' then
		-- Lump titleblacklisted pages in with template-protected pages,
		-- since templateeditors can do both.
		obj.level = 'templateeditor'
	elseif not obj.level or (obj.action == 'move' and obj.level == 'autoconfirmed') then
		-- Users need to be autoconfirmed to move pages anyway, so treat
		-- semi-move-protected pages as unprotected.
		obj.level = '*'
	end

	-- Set expiry
	if args.expiry then
		if cfg.indefStrings[args.expiry] then
			obj.expiry = 'indef'
		elseif type(args.expiry) == 'number' then
			obj.expiry = args.expiry
		else
			obj.expiry = validateDate(args.expiry, 'expiry date')
		end
	end

	-- Set reason
	if args[1] then
		obj.reason = mw.ustring.lower(args[1])
		if obj.reason:find('|') then
			error('reasons cannot contain the pipe character ("|")', 0)
		end
	end

	-- Set protection date
	if args.date then
		obj.protectionDate = validateDate(args.date, 'protection date')
	end
	
	-- Set banner config
	do
		obj.bannerConfig = {}
		local configTables = {}
		if cfg.banners[obj.action] then
			configTables[#configTables + 1] = cfg.banners[obj.action][obj.reason]
		end
		if cfg.defaultBanners[obj.action] then
			configTables[#configTables + 1] = cfg.defaultBanners[obj.action][obj.level]
			configTables[#configTables + 1] = cfg.defaultBanners[obj.action].default
		end
		configTables[#configTables + 1] = cfg.masterBanner
		for i, field in ipairs(Protection.bannerConfigFields) do
			for j, t in ipairs(configTables) do
				if t[field] then
					obj.bannerConfig[field] = t[field]
					break
				end
			end
		end
	end
	return setmetatable(obj, Protection)
end

function Protection:isProtected()
	return self.level ~= '*'
end

function Protection:isTemporary()
	return type(self.expiry) == 'number'
end

function Protection:makeProtectionCategory()
	local cfg = self._cfg
	local title = self.title
	
	-- Exit if the page is not protected.
	if not self:isProtected() then
		return ''
	end
	
	-- Get the expiry key fragment.
	local expiryFragment
	if self.expiry == 'indef' then
		expiryFragment = self.expiry
	elseif type(self.expiry) == 'number' then
		expiryFragment = 'temp'
	end

	-- Get the namespace key fragment.
	local namespaceFragment
	do
		namespaceFragment = cfg.categoryNamespaceKeys[title.namespace]
		if not namespaceFragment and title.namespace % 2 == 1 then
				namespaceFragment = 'talk'
		end
	end
 
	-- Define the order that key fragments are tested in. This is done with an
	-- array of tables containing the value to be tested, along with its
	-- position in the cfg.protectionCategories table.
	local order = {
		{val = expiryFragment,    keypos = 1},
		{val = namespaceFragment, keypos = 2},
		{val = self.reason,       keypos = 3},
		{val = self.level,        keypos = 4},
		{val = self.action,       keypos = 5}
	}

	--[[
	-- The old protection templates used an ad-hoc protection category system,
	-- with some templates prioritising namespaces in their categories, and
	-- others prioritising the protection reason. To emulate this in this module
	-- we use the config table cfg.reasonsWithNamespacePriority to set the
	-- reasons for which namespaces have priority over protection reason.
	-- If we are dealing with one of those reasons, move the namespace table to
	-- the end of the order table, i.e. give it highest priority. If not, the
	-- reason should have highest priority, so move that to the end of the table
	-- instead.
	--]]
	if self.reason and cfg.reasonsWithNamespacePriority[self.reason] then
		-- table.insert(order, 3, table.remove(order, 2))
		toTableEnd(order, 2)
	else
		toTableEnd(order, 3)
	end
 
	--[[
	-- Define the attempt order. Inactive subtables (subtables with nil "value"
	-- fields) are moved to the end, where they will later be given the key
	-- "all". This is to cut down on the number of table lookups in
	-- cfg.protectionCategories, which grows exponentially with the number of
	-- non-nil keys. We keep track of the number of active subtables with the
	-- noActive parameter.
	--]]
	local noActive, attemptOrder
	do
		local active, inactive = {}, {}
		for i, t in ipairs(order) do
			if t.val then
				active[#active + 1] = t
			else
				inactive[#inactive + 1] = t
			end
		end
		noActive = #active
		attemptOrder = active
		for i, t in ipairs(inactive) do
			attemptOrder[#attemptOrder + 1] = t
		end
	end
 
	--[[
	-- Check increasingly generic key combinations until we find a match. If a
	-- specific category exists for the combination of key fragments we are
	-- given, that match will be found first. If not, we keep trying different
	-- key fragment combinations until we match using the key
	-- "all-all-all-all-all".
	--
	-- To generate the keys, we index the key subtables using a binary matrix
	-- with indexes i and j. j is only calculated up to the number of active
	-- subtables. For example, if there were three active subtables, the matrix
	-- would look like this, with 0 corresponding to the key fragment "all", and
	-- 1 corresponding to other key fragments.
	-- 
	--   j 1  2  3
	-- i  
	-- 1   1  1  1
	-- 2   0  1  1
	-- 3   1  0  1
	-- 4   0  0  1
	-- 5   1  1  0
	-- 6   0  1  0
	-- 7   1  0  0
	-- 8   0  0  0
	-- 
	-- Values of j higher than the number of active subtables are set
	-- to the string "all".
	--
	-- A key for cfg.protectionCategories is constructed for each value of i.
	-- The position of the value in the key is determined by the keypos field in
	-- each subtable.
	--]]
	local cats = cfg.protectionCategories
	for i = 1, 2^noActive do
		local key = {}
		for j, t in ipairs(attemptOrder) do
			if j > noActive then
				key[t.keypos] = 'all'
			else
				local quotient = i / 2 ^ (j - 1)
				quotient = math.ceil(quotient)
				if quotient % 2 == 1 then
					key[t.keypos] = t.val
				else
					key[t.keypos] = 'all'
				end
			end
		end
		key = table.concat(key, '|')
		local attempt = cats[key]
		if attempt then
			return makeCategoryLink(attempt, title.text)
		end
	end
	return ''
end

function Protection:needsExpiry()
	local cfg = self._cfg
	local actionNeedsCheck = cfg.expiryCheckActions[self.action]
	return not self.expiry and (
		actionNeedsCheck or (
			actionNeedsCheck == nil
			and self.reason -- the old {{pp-protected}} didn't check for expiry
			and not cfg.reasonsWithoutExpiryCheck[self.reason]
		)
	)
end

function Protection:isIncorrect()
	local expiry = self.expiry
	return not self:isProtected()
		or type(expiry) == 'number' and expiry < os.time()
end

function Protection:isTemplateProtectedNonTemplate()
	local action, namespace = self.action, self.title.namespace
	return self.level == 'templateeditor'
		and (
			(action ~= 'edit' and action ~= 'move')
			or (namespace ~= 10 and namespace ~= 828)
		)
end

function Protection:makeCategoryLinks()
	local msg = self._cfg.msg
	local ret = { self:makeProtectionCategory() }
	if self:needsExpiry() then
		ret[#ret + 1] = makeCategoryLink(
			msg['tracking-category-expiry'],
			self.title.text
		)
	end
	if self:isIncorrect() then
		ret[#ret + 1] = makeCategoryLink(
			msg['tracking-category-incorrect'],
			self.title.text
		)
	end
	if self:isTemplateProtectedNonTemplate() then
		ret[#ret + 1] = makeCategoryLink(
			msg['tracking-category-template'],
			self.title.text
		)
	end
	return table.concat(ret)
end

--------------------------------------------------------------------------------
-- Blurb class
--------------------------------------------------------------------------------

local Blurb = {}
Blurb.__index = Blurb

Blurb.bannerTextFields = {
	text = true,
	explanation = true,
	tooltip = true,
	alt = true,
	link = true
}

function Blurb.new(protectionObj, args, cfg)
	return setmetatable({
		_cfg = cfg,
		_protectionObj = protectionObj,
		_args = args
	}, Blurb)
end

-- Private methods --

function Blurb:_formatDate(num)
	-- Formats a Unix timestamp into dd Month, YYYY format.
	lang = lang or mw.language.getContentLanguage()
	local success, date = pcall(
		lang.formatDate,
		lang,
		self._cfg.msg['expiry-date-format'] or 'j F Y',
		'@' .. tostring(num)
	)
	if success then
		return date
	end
end

function Blurb:_getExpandedMessage(msgKey)
	return self:_substituteParameters(self._cfg.msg[msgKey])
end

function Blurb:_substituteParameters(msg)
	if not self._params then
		local parameterFuncs = {}

		parameterFuncs.CURRENTVERSION     = self._makeCurrentVersionParameter
		parameterFuncs.EDITREQUEST        = self._makeEditRequestParameter
		parameterFuncs.EXPIRY             = self._makeExpiryParameter
		parameterFuncs.EXPLANATIONBLURB   = self._makeExplanationBlurbParameter
		parameterFuncs.IMAGELINK          = self._makeImageLinkParameter
		parameterFuncs.INTROBLURB         = self._makeIntroBlurbParameter
		parameterFuncs.INTROFRAGMENT      = self._makeIntroFragmentParameter
		parameterFuncs.PAGETYPE           = self._makePagetypeParameter
		parameterFuncs.PROTECTIONBLURB    = self._makeProtectionBlurbParameter
		parameterFuncs.PROTECTIONDATE     = self._makeProtectionDateParameter
		parameterFuncs.PROTECTIONLEVEL    = self._makeProtectionLevelParameter
		parameterFuncs.PROTECTIONLOG      = self._makeProtectionLogParameter
		parameterFuncs.TALKPAGE           = self._makeTalkPageParameter
		parameterFuncs.TOOLTIPBLURB       = self._makeTooltipBlurbParameter
		parameterFuncs.TOOLTIPFRAGMENT    = self._makeTooltipFragmentParameter
		parameterFuncs.VANDAL             = self._makeVandalTemplateParameter
		
		self._params = setmetatable({}, {
			__index = function (t, k)
				local param
				if parameterFuncs[k] then
					param = parameterFuncs[k](self)
				end
				param = param or ''
				t[k] = param
				return param
			end
		})
	end
	
	msg = msg:gsub('${(%u+)}', self._params)
	return msg
end

function Blurb:_makeCurrentVersionParameter()
	-- A link to the page history or the move log, depending on the kind of
	-- protection.
	local pagename = self._protectionObj.title.prefixedText
	if self._protectionObj.action == 'move' then
		-- We need the move log link.
		return makeFullUrl(
			'Special:Log',
			{type = 'move', page = pagename},
			self:_getExpandedMessage('current-version-move-display')
		)
	else
		-- We need the history link.
		return makeFullUrl(
			pagename,
			{action = 'history'},
			self:_getExpandedMessage('current-version-edit-display')
		)
	end
end

function Blurb:_makeEditRequestParameter()
	local mEditRequest = require('Module:Submit an edit request')
	local action = self._protectionObj.action
	local level = self._protectionObj.level
	
	-- Get the edit request type.
	local requestType
	if action == 'edit' then
		if level == 'autoconfirmed' then
			requestType = 'semi'
		elseif level == 'templateeditor' then
			requestType = 'template'
		end
	end
	requestType = requestType or 'full'
	
	-- Get the display value.
	local display = self:_getExpandedMessage('edit-request-display')

	return mEditRequest._link{type = requestType, display = display}
end

function Blurb:_makeExpiryParameter()
	local expiry = self._protectionObj.expiry
	if type(expiry) == 'number' then
		return self:_formatDate(expiry)
	else
		return expiry
	end
end

function Blurb:_makeExplanationBlurbParameter()
	-- Cover special cases first.
	if self._protectionObj.title.namespace == 8 then
		-- MediaWiki namespace
		return self:_getExpandedMessage('explanation-blurb-nounprotect')
	end

	-- Get explanation blurb table keys
	local action = self._protectionObj.action
	local level = self._protectionObj.level
	local talkKey = self._protectionObj.title.isTalkPage and 'talk' or 'subject'

	-- Find the message in the explanation blurb table and substitute any
	-- parameters.
	local explanations = self._cfg.explanationBlurbs
	local msg
	if explanations[action][level] and explanations[action][level][talkKey] then
		msg = explanations[action][level][talkKey]
	elseif explanations[action][level] and explanations[action][level].default then
		msg = explanations[action][level].default
	elseif explanations[action].default and explanations[action].default[talkKey] then
		msg = explanations[action].default[talkKey]
	elseif explanations[action].default and explanations[action].default.default then
		msg = explanations[action].default.default
	else
		error(string.format(
			'could not find explanation blurb for action "%s", level "%s" and talk key "%s"',
			action,
			level,
			talkKey
		))
	end
	return self:_substituteParameters(msg)
end

function Blurb:_makeImageLinkParameter()
	local imageLinks = self._cfg.imageLinks
	local action = self._protectionObj.action
	local level = self._protectionObj.level
	local msg
	if imageLinks[action][level] then
		msg = imageLinks[action][level]
	elseif imageLinks[action].default then
		msg = imageLinks[action].default
	else
		msg = imageLinks.edit.default
	end
	return self:_substituteParameters(msg)
end

function Blurb:_makeIntroBlurbParameter()
	if self._protectionObj:isTemporary() then
		return self:_getExpandedMessage('intro-blurb-expiry')
	else
		return self:_getExpandedMessage('intro-blurb-noexpiry')
	end
end

function Blurb:_makeIntroFragmentParameter()
	if self._protectionObj:isTemporary() then
		return self:_getExpandedMessage('intro-fragment-expiry')
	else
		return self:_getExpandedMessage('intro-fragment-noexpiry')
	end
end

function Blurb:_makePagetypeParameter()
	local pagetypes = self._cfg.pagetypes
	return pagetypes[self._protectionObj.title.namespace]
		or pagetypes.default
		or error('no default pagetype defined')
end

function Blurb:_makeProtectionBlurbParameter()
	local protectionBlurbs = self._cfg.protectionBlurbs
	local action = self._protectionObj.action
	local level = self._protectionObj.level
	local msg
	if protectionBlurbs[action][level] then
		msg = protectionBlurbs[action][level]
	elseif protectionBlurbs[action].default then
		msg = protectionBlurbs[action].default
	elseif protectionBlurbs.edit.default then
		msg = protectionBlurbs.edit.default
	else
		error('no protection blurb defined for protectionBlurbs.edit.default')
	end
	return self:_substituteParameters(msg)
end

function Blurb:_makeProtectionDateParameter()
	local protectionDate = self._protectionObj.protectionDate
	if type(protectionDate) == 'number' then
		return self:_formatDate(protectionDate)
	else
		return protectionDate
	end
end

function Blurb:_makeProtectionLevelParameter()
	local protectionLevels = self._cfg.protectionLevels
	local action = self._protectionObj.action
	local level = self._protectionObj.level
	local msg
	if protectionLevels[action][level] then
		msg = protectionLevels[action][level]
	elseif protectionLevels[action].default then
		msg = protectionLevels[action].default
	elseif protectionLevels.edit.default then
		msg = protectionLevels.edit.default
	else
		error('no protection level defined for protectionLevels.edit.default')
	end
	return self:_substituteParameters(msg)
end

function Blurb:_makeProtectionLogParameter()
	local pagename = self._protectionObj.title.prefixedText
	if self._protectionObj.action == 'autoreview' then
		-- We need the pending changes log.
		return makeFullUrl(
			'Special:Log',
			{type = 'stable', page = pagename},
			self:_getExpandedMessage('pc-log-display')
		)
	else
		-- We need the protection log.
		return makeFullUrl(
			'Special:Log',
			{type = 'protect', page = pagename},
			self:_getExpandedMessage('protection-log-display')
		)
	end
end

function Blurb:_makeTalkPageParameter()
	return string.format(
		'[[%s:%s#%s|%s]]',
		mw.site.namespaces[self._protectionObj.title.namespace].talk.name,
		self._protectionObj.title.text,
		self._args.section or 'top',
		self:_getExpandedMessage('talk-page-link-display')
	)
end

function Blurb:_makeTooltipBlurbParameter()
	if self._protectionObj:isTemporary() then
		return self:_getExpandedMessage('tooltip-blurb-expiry')
	else
		return self:_getExpandedMessage('tooltip-blurb-noexpiry')
	end
end

function Blurb:_makeTooltipFragmentParameter()
	if self._protectionObj:isTemporary() then
		return self:_getExpandedMessage('tooltip-fragment-expiry')
	else
		return self:_getExpandedMessage('tooltip-fragment-noexpiry')
	end
end

function Blurb:_makeVandalTemplateParameter()
	return require('Module:Vandal-m')._main{
		self._args.user or self._protectionObj.title.baseText
	}
end

-- Public methods --

function Blurb:makeBannerText(key)
	-- Validate input.
	if not key or not Blurb.bannerTextFields[key] then
		error(string.format(
			'"%s" is not a valid banner config field',
			tostring(key)
		), 2)
	end

	-- Generate the text.
	local msg = self._protectionObj.bannerConfig[key]
	if type(msg) == 'string' then
		return self:_substituteParameters(msg)
	elseif type(msg) == 'function' then
		msg = msg(self._protectionObj, self._args)
		if type(msg) ~= 'string' then
			error(string.format(
				'bad output from banner config function with key "%s"'
					.. ' (expected string, got %s)',
				tostring(key),
				type(msg)
			))
		end
		return self:_substituteParameters(msg)
	end
end

--------------------------------------------------------------------------------
-- BannerTemplate class
--------------------------------------------------------------------------------

local BannerTemplate = {}
BannerTemplate.__index = BannerTemplate

function BannerTemplate.new(protectionObj, cfg)
	local obj = {}
	obj._cfg = cfg

	-- Set the image filename.
	local imageFilename = protectionObj.bannerConfig.image
	if imageFilename then
		obj._imageFilename = imageFilename
	else
		-- If an image filename isn't specified explicitly in the banner config,
		-- generate it from the protection status and the namespace.
		local action = protectionObj.action
		local level = protectionObj.level
		local namespace = protectionObj.title.namespace
		local reason = protectionObj.reason
		
		-- Deal with special cases first.
		if (
			namespace == 10
			or namespace == 828
			or reason and obj._cfg.indefImageReasons[reason]
			)
			and action == 'edit'
			and level == 'sysop'
			and not protectionObj:isTemporary()
		then
			-- Fully protected modules and templates get the special red "indef"
			-- padlock.
			obj._imageFilename = obj._cfg.msg['image-filename-indef']
		else
			-- Deal with regular protection types.
			local images = obj._cfg.images
			if images[action] then
				if images[action][level] then
					obj._imageFilename = images[action][level]
				elseif images[action].default then
					obj._imageFilename = images[action].default
				end
			end
		end
	end
	return setmetatable(obj, BannerTemplate)
end

function BannerTemplate:setImageWidth(width)
	self._imageWidth = width
end

function BannerTemplate:setImageTooltip(tooltip)
	self._imageCaption = tooltip
end

function BannerTemplate:renderImage()
	local filename = self._imageFilename
		or self._cfg.msg['image-filename-default']
		or 'Transparent.gif'
	return newFileLink(filename)
		:width(self._imageWidth or 20)
		:alt(self._imageAlt)
		:link(self._imageLink)
		:caption(self._imageCaption)
		:render()
end

--------------------------------------------------------------------------------
-- Banner class
--------------------------------------------------------------------------------

local Banner = setmetatable({}, BannerTemplate)
Banner.__index = Banner

function Banner.new(protectionObj, blurbObj, cfg)
	local obj = BannerTemplate.new(protectionObj, cfg) -- This doesn't need the blurb.
	obj:setImageWidth(40)
	obj:setImageTooltip(blurbObj:makeBannerText('alt')) -- Large banners use the alt text for the tooltip.
	obj._reasonText = blurbObj:makeBannerText('text')
	obj._explanationText = blurbObj:makeBannerText('explanation')
	obj._page = protectionObj.title.prefixedText -- Only makes a difference in testing.
	return setmetatable(obj, Banner)
end

function Banner:__tostring()
	-- Renders the banner.
	makeMessageBox = makeMessageBox or require('Module:Message box').main
	local reasonText = self._reasonText or error('no reason text set')
	local explanationText = self._explanationText
	local mbargs = {
		page = self._page,
		type = 'protection',
		image = self:renderImage(),
		text = string.format(
			"'''%s'''%s",
			reasonText,
			explanationText and '<br />' .. explanationText or ''
		)
	}
	return makeMessageBox('mbox', mbargs)
end

--------------------------------------------------------------------------------
-- Padlock class
--------------------------------------------------------------------------------

local Padlock = setmetatable({}, BannerTemplate)
Padlock.__index = Padlock

function Padlock.new(protectionObj, blurbObj, cfg)
	local obj = BannerTemplate.new(protectionObj, cfg) -- This doesn't need the blurb.
	obj:setImageWidth(20)
	obj:setImageTooltip(blurbObj:makeBannerText('tooltip'))
	obj._imageAlt = blurbObj:makeBannerText('alt')
	obj._imageLink = blurbObj:makeBannerText('link')
	obj._right = cfg.padlockPositions[protectionObj.action]
		or cfg.padlockPositions.default
		or '55px'
	return setmetatable(obj, Padlock)
end

function Padlock:__tostring()
	local root = mw.html.create('div')
	root
		:addClass('metadata topicon nopopups')
		:attr('id', 'protected-icon')
		:css{display = 'none', right = self._right}
		:wikitext(self:renderImage())
	return tostring(root)
end

--------------------------------------------------------------------------------
-- Exports
--------------------------------------------------------------------------------

local p = {}

function p._exportClasses()
	-- This is used for testing purposes.
	return {
		Protection = Protection,
		Blurb = Blurb,
		BannerTemplate = BannerTemplate,
		Banner = Banner,
		Padlock = Padlock,
	}
end

function p._main(args, cfg, title)
	args = args or {}
	cfg = cfg or require(CONFIG_MODULE)

	-- Initialise the protection object and check for errors
	local protectionObjCreated, protectionObj = pcall(
		Protection.new,
		args,
		cfg,
		title
	)
	if not protectionObjCreated then
		local errorBlurb = cfg.msg['error-message-blurb'] or 'Error: $1.'
		local errorText = mw.message.newRawMessage(errorBlurb)
			:params(protectionObj) -- protectionObj is the error message
			:plain()
		return string.format(
			'<strong class="error">%s</strong>%s',
			errorText,
			makeCategoryLink(
				cfg.msg['tracking-category-incorrect'],
				title and title.text or mw.title.getCurrentTitle().text
			)
		)
	end

	local ret = {}

	-- If a page's edit protection is equally or more restrictive than its protection from some other action,
	-- then don't bother displaying anything for the other action (except categories).
	if protectionObj.action == 'edit' or not walkHierarchy(cfg.hierarchy, protectionObj.level)[effectiveProtectionLevel('edit', protectionObj.title)] then
		-- Initialise the blurb object
		local blurbObj = Blurb.new(protectionObj, args, cfg)
	
		-- Render the banner
		if protectionObj:isProtected() then
			ret[#ret + 1] = tostring(
				(yesno(args.small) and Padlock or Banner)
				.new(protectionObj, blurbObj, cfg)
			)
		end
	end

	-- Render the categories
	if yesno(args.category) ~= false then
		ret[#ret + 1] = protectionObj:makeCategoryLinks()
	end
	
	return table.concat(ret)	
end

function p.main(frame, cfg)
	cfg = cfg or require(CONFIG_MODULE)

	-- Find default args, if any.
	local parent = frame.getParent and frame:getParent()
	local defaultArgs = parent and cfg.wrappers[parent:getTitle():gsub('/sandbox$', '')] or {}

	-- Find user args, and use the parent frame if we are being called from a
	-- wrapper template.
	getArgs = getArgs or require('Module:Arguments').getArgs
	local userArgs = getArgs(frame, {
		parentOnly = defaultArgs,
		frameOnly = not defaultArgs
	})

	-- Build the args table. User-specified args overwrite default args.
	local args = {}
	for k, v in pairs(defaultArgs) do
		args[k] = v
	end
	for k, v in pairs(userArgs) do
		args[k] = v
	end
	return p._main(args, cfg)
end

return p