-- This module implements {{requested move}}.



-- Load necessary modules

local getArgs = require('Module:Arguments').getArgs

local tableTools = require('Module:TableTools')

local yesno = require('Module:Yesno')

local mRedirect = require('Module:Redirect')



-- Set static values

local defaultNewPagename = '?' -- Name of new pages that haven't been specified



local p = {}



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

-- Helper functions

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

 

local function err(msg, numargs, reason, count)

	-- Generates a wikitext error message

	local commented = '<!-- {{subst:requested move|'

	if count ~= 1 then

	   commented = commented .. 'new1='

	end

	commented = commented .. numargs1]['new'

	for i = 2,count do

		commented = commented .. string.format('|current%i=%s', i, (numargsi]['current' or ''))

		commented = commented .. string.format('|new%i=%s', i, (numargsi]['new' or ''))

	end

	if reason then 

	    commented = commented .. '|reason=' .. reason

	end

	commented = commented .. '}} -->'

	return string.format('{{error|%s}}', msg) .. commented

end



local function validateTitle(page, paramName, paramNum) 

	-- Validates a page name, and if it is valid, returns true and the title

	-- object for that page. If it is not valid, returns false and the

	-- appropriate error message.



	-- Check for a small subset of characters that cannot be used in MediaWiki

	-- titles. For the full set of restrictions, see

	-- [[Wikipedia:Page name#Technical restrictions and limitations]]. This is

	-- also covered by the invalid title check, but with this check we can give

	-- a more specific error message.

	local invalidChar = page:match('[#<>%[%]|{}]')

	if invalidChar then

		local msg = 'Invalid character "'

			.. invalidChar

			.. '" found in the "'

			.. paramName

			.. paramNum

			.. '" parameter'

		return false, msg

	end



	-- Get the title object. This also checks for invalid titles that aren't

	-- covered by the previous check.

	local titleObj = mw.title.new(page)

	if not titleObj then

		local msg = 'Invalid title detected in parameter "'

			.. paramName

			.. paramNum 

			.. '"; check for [[Wikipedia:Page name#'

			.. 'Technical restrictions and limitations|invalid characters]]'

		return false, msg

	end



	-- Check for interwiki links. Titles with interwikis make valid title

	-- objects, but cannot be created on the local wiki.

	local interwiki = titleObj.interwiki

	if interwiki and interwiki ~= '' then

		local msg = 'Invalid title detected in parameter "'

			.. paramName

			.. paramNum 

			.. '"; has [[Help:Interwiki linking|interwiki prefix]] "'

			.. titleObj.interwiki

			.. ':"'

		return false, msg

	end



	return true, titleObj

end



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

-- Validate title entry point (used at [[Template:RMassist/core]])

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

function p.validateTitle(frame)

	local value = frame.args1

	local validTitle, currentTitle = validateTitle(value or '', '1', '')

	if not validTitle then

		-- If invalid, the second parameter is the error message.

		local msg = currentTitle

		return msg

	end

	return 'yes'

end



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

-- Confirm protection levels (used at [[Template:Requested move/dated]])

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



function p.protected(frame)

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

	if args.protected then

		local levels = mw.title.new(args.protected).protectionLevels

		local levelMove = levels'move' and levels'move'][1

		local levelEdit = levels'edit' and levels'edit'][1

		local levelCreate = levels'create' and levels'create'][1

		if levelMove == 'sysop' 

		or levelEdit == 'sysop' 

		or levelEdit == 'editprotected' 

		or levelCreate == 'sysop' then

			return 'sysop'

		elseif levelMove == 'templateeditor' 

		or levelEdit == 'templateeditor' 

		or levelCreate == 'templateeditor' then

			return 'templateeditor'

		end

	end

end



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

-- Main function

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



function p.main(frame)

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

	-- Initialise variables and preprocess the arguments

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

	

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

	local title = mw.title.getCurrentTitle()



	--[[

	-- To iterate over the current1, new1, current2, new2, ... arguments

	-- we get an array of tables sorted by number and compressed so that

	-- it can be traversed with ipairs.	The table format looks like this:

	-- {

	--  {current = x, new = y, num = 1},

	--  {current = z, new = q, num = 2},

	--  ...

	-- }

	-- The "num" field is used to correctly preserve the number of the parameter

	-- that was used, in case users skip any numbers in the invocation.

	--

	-- The current1 parameter is a special case, as it does not need to be

	-- specified. To avoid clashes with later current parameters, we need to

	-- add it to the args table manually.

	--

	-- Also, we allow the first positional parameter to be an alias for the

	-- new1 parameter, so that the syntax for the old templates

	-- {{requested move}} and {{move-multi}} will both be supported.

	--

	-- The "multi" variable tracks whether we are using the syntax previously

	-- produced by {{requested move}}, or the syntax previously produced by

	-- {{move-multi}}. For the former, multi is false, and for the latter it is

	-- true.

	--]]

	if not args.current1 then

		args.current1 = title.subjectPageTitle.prefixedText

	end



	-- Find the first new page title, if specified, and keep a record of the

	-- prefix used to make it; the prefix will be used later to make error

	-- messages.

	local firstNewParam

	if args.new1 then

		firstNewParamPrefix = 'new'

	elseif args1 then

		args.new1 = args1

		firstNewParamPrefix = ''

	else

		firstNewParamPrefix = ''

	end



	-- Build the sorted argument table.

	local argsByNum = {}

	for k, v in pairs(args) do

		k = tostring(k)

		local prefix, num = k:match('^(%l*)([1-9][0-9]*)$')

		if prefix == 'current' or prefix == 'new' then

			num = tonumber(num)

			local subtable = argsByNumnum or {}

			subtableprefix = v

			subtable.num = num

			argsByNumnum = subtable

		end

	end

	argsByNum = tableTools.compressSparseArray(argsByNum)



	-- Calculate the number of arguments and whether we are dealing with a

	-- multiple nomination.

	local argsByNumCount = #argsByNum

	local multi

	if argsByNumCount >= 2 then

		multi = true

	else

		multi = false

	end

	

	--[[

	-- Validate new params.

	-- This check ensures we don't have any absent new parameters, and that

	-- users haven't simply copied in the values from the documentation page.

	--]]

	if multi then

		for i, t in ipairs(argsByNum) do

			local new = t.new

			local num = t.num

			if not new or new == 'New title for page ' .. tostring(num) then

				argsByNumi].new = defaultNewPagename

			end

		end

	else

		local new = argsByNum1].new

		if not new or new == 'NewName' then

			argsByNum1].new = defaultNewPagename

		end

	end



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

	-- Error checks

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

	

	-- Subst check

	if not mw.isSubsting() then

		local lb = mw.text.nowiki('{{')

		local rb = mw.text.nowiki('}}')

		local msg = '<strong class="error">'

			.. 'This template must be [[Wikipedia:Template substitution|substituted]];'

			.. ' replace %srequested move%s with %ssubst:requested move%s'

			.. '</strong>'

		msg = string.format(msg, lb, rb, lb, rb)

		return msg

	end

	

	-- Check we are on a talk page

	if not title.isTalkPage then

		local msg = '[[Template:Requested move]] must be used in a TALKSPACE, e.g., [[%s:%s]]'

		msg = string.format(msg, mw.site.namespacestitle.namespace].talk.name, title.text)

		return err(msg, argsByNum, args.reason, argsByNumCount)

	end

	

	-- Check the arguments

	local currentDupes, newDupes = {}, {}

	for i, t in ipairs(argsByNum) do

		local current = t.current

		local new = t.new

		local num = t.num

		local validCurrent

		local currentTitle

		local subjectSpace



		-- Check for invalid or missing currentn parameters

		-- This check must come first, as mw.title.new will give an error if

		-- it is given invalid input.

		if not current then

			local msg = '"current%d" parameter missing;'

				.. ' please add it or remove the "new%d" parameter'

			msg = string.format(msg, num, num)

			return err(msg, argsByNum, args.reason, argsByNumCount)

		end



		-- Get the currentn title object, and check for invalid titles. This check

		-- must come before the namespace and existence checks, as they will

		-- produce script errors if the title object doesn't exist.

		validCurrent, currentTitle = validateTitle(current, 'current', num)

		if not validCurrent then

			-- If invalid, the second parameter is the error message.

			local msg = currentTitle 

			return err(msg, argsByNum, args.reason, argsByNumCount)

		end



		-- Category namespace check

		subjectSpace = mw.site.namespacescurrentTitle.namespace].subject.id

		if subjectSpace == 14 then

			local msg = '[[Template:Requested move]] is not for categories,'

				.. ' see [[Wikipedia:Categories for discussion]]'

			return err(msg, argsByNum, args.reason, argsByNumCount)

		

		-- File namespace check

		elseif subjectSpace == 6 then

			local msg = '[[Template:Requested move]] is not for files;'

				.. ' see [[Wikipedia:Moving a page#Moving a file page]]'

				.. ' (use [[Template:Rename media]] instead)'

			return err(msg, argsByNum, args.reason, argsByNumCount)



		-- Draft and User namespace check

		elseif subjectSpace == 2 or subjectSpace == 118 then

			local msg = '[[Template:Requested move]] is not for moves from draft or user space.'

				.. '<br>If you would like to submit your draft for review, add <code>{{tlf|subst:submit}}</code>'

				    .. 'to the top of the page.'

				.. '<br>Otherwise, see [[Help:How to move a page]] for instructions.'

				.. '<br>If you cannot move it yourself, see [[Wikipedia:Requested moves#Requesting technical moves|Requesting technical moves]].'

			return err(msg, argsByNum, args.reason, argsByNumCount)

		end



		-- Request to move a single page must be placed on that page's talk, or the page it redirects to

		if not multi and args.current1 ~= title.subjectPageTitle.prefixedText then

			local idealpage = mw.title.new(args.current1).talkPageTitle

			local rtarget = mRedirect.getTarget(idealpage)

			if rtarget == title.prefixedText then

				multi = true

			else

				local msg = 'Request to move a single page must be placed on that page\'s talk or the page its talk redirects to'

				return err(msg, argsByNum, args.reason, argsByNumCount)

			end

		end



		-- Check for non-existent titles.

		if not currentTitle.exists then

			local msg = 'Must create [[:%s]] before requesting that it be moved'

			msg = string.format(msg, current)

			return err(msg, argsByNum, args.reason, argsByNumCount)

		end



		-- Check for duplicate current titles

		-- We know the id isn't zero because we have already checked for

		-- existence.

		local currentId = currentTitle.id

		if currentDupescurrentId then

			local msg = 'Duplicate title detected ("'

				.. currentTitle.prefixedText

				.. '"); cannot move the same page to two different places'

			return err(msg, argsByNum, args.reason, argsByNumCount)

		else

			currentDupescurrentId = true

		end



		-- Check for invalid new titles. This check must come before the

		-- duplicate title check for new titles, as it will produce a script

		-- error if the title object doesn't exist.

		local validNew, newTitle = validateTitle(

			new,

			multi and 'new' or firstNewParamPrefix,

			num

		)

		if not validNew then

			-- If invalid, the second parameter is the error message.

			local msg = newTitle

			return err(msg, argsByNum, args.reason, argsByNumCount)

		end



		-- Check for duplicate new titles.

		-- We can't use the page_id, as new pages might not exist, and therefore

		-- multiple pages may have an id of 0. Use the prefixedText as a

		-- reasonable fallback. We also need to check that we aren't using the

		-- default new page name, as we don't want it to be treated as a duplicate

		-- page if more than one new page name has been omitted.

		local newPrefixedText = newTitle.prefixedText

		if newPrefixedText ~= defaultNewPagename then

			if newDupesnewPrefixedText then

				local msg = 'Duplicate title detected ("'

					.. newTitle.prefixedText

					.. '"); cannot move two different pages to the same place'

				return err(msg, argsByNum, args.reason, argsByNumCount)

			else

				newDupesnewPrefixedText = true

			end

		end

	end

	

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

	-- Check for page protection

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

	

	local highestProtection = ''

	local protectedTitle = ''

	

	-- Checking page protection requires use of .protectionLevels(), one of the 

	-- "expensive" parser functions, which stop working after 500 uses total.

	-- Without some limit set, this starts breaking near 250 distinct titles.

	local titleLimit = 80

	local titlesChecked = 0

	local titles = {}

	-- Consolidate duplicate titles (i.e., when moving A to B and B to C)

	for i = 1,argsByNumCount do

		titlesmw.title.new(argsByNumi]['current'])] = true

		titlesmw.title.new(argsByNumi]['new'])] = true

	end

	-- Check each title t, while ignoring the "true" value

	for t, _ in pairs(titles) do

		if titlesChecked < titleLimit then

			local levels = t.protectionLevels

			titlesChecked = titlesChecked + 1

			local levelMove = levels'move' and levels'move'][1

			local levelEdit = levels'edit' and levels'edit'][1

			local levelCreate = levels'create' and levels'create'][1

			if levelMove == 'sysop' 

			or levelEdit == 'sysop' 

			or levelEdit == 'editprotected' 

			or levelCreate == 'sysop' then

				highestProtection = 'sysop'

				protectedTitle = tostring(t)

				break

			elseif levelMove == 'templateeditor' 

			or levelEdit == 'templateeditor' 

			or levelCreate == 'templateeditor' then

				highestProtection = 'templateeditor'

				protectedTitle = tostring(t)

			end

		else

		-- End the "for" loop if the titleLimit is reached

			break

		end

	end



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

	-- Generate the heading

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



	-- For custom values of |heading=, use those.

	-- For |heading=no, |heading=n, etc., don't include a heading.

	-- Otherwise use the current date as a heading.

	local heading = args.heading or args.header

	local useHeading = yesno(heading, heading)

	if heading and useHeading == heading then

		heading = '== ' .. heading .. ' ==\n\n'

	elseif useHeading == false then

		heading = ''

	else

		local lang = mw.language.getContentLanguage()

		local headingDate = lang:formatDate('j F Y')

		heading = '== Requested move ' .. headingDate .. ' ==\n\n'

	end

	

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

	-- Build the {{requested move/dated}} invocation

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



	local rmd = {}

	rmd#rmd + 1 = '{{requested move/dated/sandbox'



	if multi then

		rmd#rmd + 1 = '|multiple=yes'

		rmd#rmd + 1 = '\n|current1=' .. argsByNum1].current

	end



	--[[

	-- The first new title. This is used both by single and by multi; for single

	-- it is the only parameter used. For single the parameter name is the first

	-- positional parameter, and for multi the parameter name is "new1".

	--]]

	local new1param = multi and 'new1=' or ''

	rmd#rmd + 1 = '|' .. new1param .. argsByNum1].new



	-- Add more arguments for multi.

	if multi then

		for i = 2, argsByNumCount do

			local t = argsByNumi

			local numString = tostring(i)

			local current = t.current

			local new = t.new

			rmd#rmd + 1 = '|current' .. numString .. '=' .. current

			rmd#rmd + 1 = '|new' .. numString .. '=' .. new

		end

	end 

	

	-- Highest page protection (if admin or template-editor)

	if highestProtection == 'sysop' or highestProtection == 'templateeditor' then

		rmd#rmd + 1 = '|protected=' .. protectedTitle

	end

	

	-- Pass through demo=yes to the 

	if args.demo ~= nil then

		rmd#rmd + 1 = '|demo='

		rmd#rmd + 1 = args.demo

	end

	

	-- The old multi template always has a bar before the closing curly

	-- braces, so we will do that too.

	if multi then

		rmd#rmd + 1 = '|'

	end

	

	rmd#rmd + 1 = '}}'

	rmd = table.concat(rmd)



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

	-- Generate the list of links to the pages to be moved

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



	local linkList = {}

	for i, t in ipairs(argsByNum) do

		local current = t.current

		local new = t.new

		local msg = '\n%s[[:%s]] → '

		if new ~= defaultNewPagename then

			msg = msg .. '{{no redirect|%s}}'

		else

			msg = msg .. '%s'

		end

		local item = string.format(

			msg,

			multi and '* ' or '', -- Don't make a list for single page moves.

			current,

			new

		)

		linkList#linkList + 1 = item

	end

	linkList = table.concat(linkList)



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

	-- Reason and talk blurb

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



	-- Reason

	local reason = args.reason or args2 or 'Please place your rationale for the proposed move here.'

	reason = '– ' .. reason

	if yesno(args.sign or args.sig or args.signature or 'unspecified', not reason:match("~~~$")) then

		reason = reason .. ' ~~~~'

	end



	-- Talk blurb

	local talk

	if yesno(args.talk, true) then

		talk = frame:expandTemplate{title = 'Requested move/talk'}

	else

		talk = ''

	end



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

	-- Assemble the output

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



	-- The old templates start with a line break, so we will do that too.

	local ret = string.format(

		'\n%s%s\n%s%s%s%s',

		heading,

		rmd,

		linkList,

		multi and '\n' or ' ',

		reason,

		talk

	)

	return ret

end



return p