-- This module implements {{newDYKnomination}}.

local lang = mw.language.getContentLanguage()

-------------------------------------------------------------------------------
-- Output template
-------------------------------------------------------------------------------

-- This template contains the final output of the module. Parameters like
-- ${PARAMETER_NAME} are substituted with the results of the output template
-- parameter functions below.

local OUTPUT_TEMPLATE = [=[
{{DYKsubpage
|monthyear=${MONTH_AND_YEAR} 
|passed=<!--When closing discussion, enter yes, no, or withdrawn -->
|2=${INPUT_ERRORS}
<noinclude>
{{DYK tools|nominator=${NOMINATOR}}}
</noinclude>
{{DYK header|${HEADING}}}
{{DYK nompage links|nompage=${NOM_SUBPAGE}|${NOMPAGE_LINK_ARGS}}}
${IMAGE}${DYK_LISTEN}${DYK_WATCH}<!--

                   Please do not edit above this line unless you are a DYK volunteer who is closing the discussion.

-->
* ${HOOK}${ALT_HOOKS}${REVIEWED}${COMMENT}
<small>${STATUS} by ${AUTHORS}. ${NOMINATED} at ~~~~~.${BACKLOG} Post-promotion hook changes for this nom [[User:GalliumBot#darn|will be logged]] at [[Template talk:Did you know nominations/${NOM_SUBPAGE}]]; consider [[Help:Watchlist|watching]] this nomination, if it is successful, until the hook appears on the Main Page.</small>
<!--${CHECK_CREDITS_WARNING}
${CREDITS}
-->
* <!-- REPLACE THIS LINE TO WRITE FIRST COMMENT, KEEPING THE ASTERISK  *   -->

${FILE_BREAK}}}<!--Please do not write below this line or remove this line. Place comments above this line.-->]=]

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

-- Creates a formatted error message that can be used with substitution.
local function formatError(msg)
	return string.format('{{DYK error|1=%s}}', msg)
end

-- Creates a boilerplate error message for invalid titles.
local function formatInvalidTitleError(page, pageType)
	local msg = string.format(
		'"%s" is not a valid %s; check for bad characters',
		page, pageType
	)
	return formatError(msg)
end

-- Make a title object from the given page name. Return nil if the title is
-- invalid.
local function makeTitle(page)
	local title = mw.title.new(page)
	if title and title.text ~= "" then
		return title
	end
end

-- Same as {{ROOTPAGENAME}}. If the page is an invalid title, returns nil.
local function getRootPageText(page)
	local title = makeTitle(page)
	if title and title.rootPageTitle then
		return title.rootPageTitle.text
	end
end

-- Makes template invocations for templates like {{DYK listen}} and
-- {{DYK watch}}.
local function makeFileTemplateInvocation(name, first, second)
	if not first then
		return nil
	end
	local ret = {}
	ret[#ret + 1] = '{{'
	ret[#ret + 1] = name
	ret[#ret + 1] = '|'
	ret[#ret + 1] = first
	if second then
		ret[#ret + 1] = '|'
		ret[#ret + 1] = second
	end
	ret[#ret + 1] = '}}'
	return table.concat(ret)
end

-- Normalize positional parameters for a template invocation. If any of the
-- parameters contain equals signs, the parameters are all prefixed with
-- numbers.
local function normalizeTemplateParameters(params)
	local ret = {}
	local hasEquals = false
	for i, param in ipairs(params) do
		if param:find('=') then
			hasEquals = true
			break
		end
	end
	if hasEquals then
		for i, param in ipairs(params) do
			ret[i] = string.format('%d=%s', i, param)
		end
	else
		for i, param in ipairs(params) do
			ret[i] = param
		end
	end
	return ret
end

-- Makes a link to a user's user page and talk page, like found in a standard
-- signature.
local function makeUserLinks(user)
	return string.format(
		'{{user0|%s}}',
		user
	)
end

-- Returns an array of authors. If the user didn't specify any authors, the
-- first one is the result of {{REVISIONUSER}}.
local function getNormalisedAuthors(data)
	local authors = {}
	for i, author in ipairs(data.authors) do
		authors[i] = author
	end
	authors[1] = authors[1] or data.revisionUser
	return authors
end

-- Removes gaps from sparse arrays. This is used to process numbered arguments
-- like author2 and ALT4.
local compressSparseArray = require("Module:TableTools").compressSparseArray

-- Splits numbered arguments by their prefixes. A table of arguments like this:
--    {foo1 = "foo1", foo2 = "foo2", bar3 = "bar3"}
-- Would be turned into this:
--    {foo = {[1] = "foo1", [2] = "foo2"}, bar = {[3] = "bar3"}}
-- Note that the subtables of the returned tables are not normal arrays, but
-- sparse arrays (there can be gaps between values).
local function splitByPrefix(args)
	local ret = {}
	for key, val in pairs(args) do
		if type(key) == 'string' then
			local prefix, num = key:match('^(.-)([1-9][0-9]*)$')
			if prefix then
				num = tonumber(num)
				ret[prefix] = ret[prefix] or {}
				ret[prefix][num] = val
			end
		end
	end
	return ret
end

-- Returns an array of numbered arguments with the given prefixes. Earlier
-- prefixes have precedence, and args[prefix] will overwrite args[prefix .. 1].
-- For example, for this arguments table:
--   {
--      author = "author",
--      author1 = "author1",
--      author2 = "author2,
--      creator2 = "creator2"
--   }
-- The function call getPrefixedArgs(args, splitArgs, {'creator', 'author'})
-- will produce:
--   {"author", "creator2"}
--
-- Parameters:
-- args - the table of arguments specified by the user
-- splitArgs - the table of arguments as processed by splitByPrefix
-- prefixes - an array of prefixes
local function getPrefixedArgs(args, splitArgs, prefixes)
	local ret = {}
	for i, prefix in ipairs(prefixes) do
		if splitArgs[prefix] then
			for num, val in pairs(splitArgs[prefix]) do
				if not ret[num] then
					ret[num] = val
				end
			end
		end
	end
	-- Allow prefix to overwrite prefix1.
	for _, prefix in ipairs(prefixes) do
		local val = args[prefix]
		if val then
			ret[1] = val
			break
		end
	end
	return compressSparseArray(ret)
end

-------------------------------------------------------------------------------
-- Output template parameter functions
-------------------------------------------------------------------------------

-- The results of these functions are substituted into parameters in the
-- output template. The parameters look like ${PARAMETER_NAME}. Trying to use
-- a parameter that doesn't have a function defined here will result in an
-- error.
--
-- The functions take a data table as a single argument. This table contains
-- the following fields:
-- * errors - a table of formatted error messages that were found when
--     processing the input.
-- * args - the table of arguments supplied by the user.
-- * articles - an array of the article names found in the arguments.
-- * authors - an array of the expanders/creators/writers/authors found in the
--     arguments.
-- * revisionUser - the user that last edited the page. As this module is only
--     substituted, this is always the current user.
-- * alts - an array of the ALT hooks found in the arguments.
-- * title - the mw.title object for the current page.
--
-- Template parameter functions should return a string, false, or nil.
-- Functions returning false or nil will be treated as outputting the empty
-- string "".

local params = {}

-- Renders any errors that were found when processing the input.
function params.INPUT_ERRORS(data)
	local nErrors = #data.errors
	if nErrors > 1 then
		return '\n* ' .. table.concat(data.errors, '\n* ')
	elseif nErrors == 1 then
		return '\n' .. data.errors[1]
	end
end

-- The current month and year, e.g. "March 2015".
function params.MONTH_AND_YEAR()
	return lang:formatDate('F Y')
end

-- The contents of the heading.
function params.HEADING(data)
	return table.concat(data.articles, ', ')
end

function params.NOMINATOR(data)
	return data.revisionUser
end

-- The current subpage name.
function params.NOM_SUBPAGE(data)
	if string.match(data.title.text,"/") then
		return string.gsub(data.title.text,data.title.rootText .. "/","")
	else
		return data.title.text
	end
end

-- Other arguments for the nompage link template, separated by pipes.
function params.NOMPAGE_LINK_ARGS(data)
	local vals = normalizeTemplateParameters(data.articles)
	return table.concat(vals, '|')
end

-- All of the image display code.
function params.IMAGE(data)
	local args = data.args
	if not args.image then
		return nil
	end
	local image = getRootPageText(args.image)
	if not image then
		image = formatInvalidTitleError(args.image, 'image name')
	end
	local caption = args.caption or args.rollover
	local template = [=[
{{main page image/DYK|image=%s|caption=%s}}<!--See [[Template:Main page image/DYK]] for other parameters-->
]=]
	return string.format(
		template,
		image,
		caption or 'CAPTION TEXT GOES HERE'
	)
end

-- The {{DYK listen}} template.
function params.DYK_LISTEN(data)
	local args = data.args
	return makeFileTemplateInvocation(
		'DYK Listen',
		args.sound,
		args.soundcaption
	)
end

-- The {{DYK watch}} template.
function params.DYK_WATCH(data)
	local args = data.args
	return makeFileTemplateInvocation(
		'DYK Watch',
		args.video,
		args.videocaption
	)
end

-- The hook text.
function params.HOOK(data)
	return data.args.hook or "... that ....?"
end

-- All of the ALT hooks that were specified with the ALT1, ALT2, ... etc.
-- parameters.
function params.ALT_HOOKS(data)
	local ret = {}
	for i, alt in ipairs(data.alts) do
		ret[i] = string.format("\n** '''ALT%d''': %s", i, alt)
	end
	return table.concat(ret)
end

-- A note saying which nomination the submitter reviewed.
function params.REVIEWED(data)
	local args = data.args
	local ret = "\n** ''Reviewed'': "
	if args.reviewed then
		local reviewedTitle = makeTitle(
			'Template:Did you know nominations/' .. args.reviewed
		)
		if reviewedTitle and reviewedTitle.exists then
			ret = ret .. string.format(
				'[[%s|%s]]',
				reviewedTitle.prefixedText,
				reviewedTitle.subpageText
			)
		else
			local reviewedTitle = makeTitle(
				'Wikipedia:Did you know nominations/' .. args.reviewed	
			)
			if reviewedTitle and reviewedTitle.exists then
				ret = ret .. string.format(
					'[[%s|%s]]',
					reviewedTitle.prefixedText,
					reviewedTitle.subpageText
				)
			else
				ret = ret .. args.reviewed
			end
		end
	end
	return ret
end

-- A comment.
function params.COMMENT(data)
	if data.args.comment then
		return "\n** ''Comment'': " .. data.args.comment
	end
end

-- The status of the article when it was nominated for DYK.
function params.STATUS(data)
	local status = data.args.status
	status = status and status:lower()

	-- Created
	if status == 'new' then
		return 'Created'
	-- Expanded
	elseif status == 'expanded' or status == 'expansion' then
		return '5x expanded'
	
	-- Moved to mainspace
	elseif status == 'mainspace' or status == 'moved' then
		return 'Moved to mainspace'
	
	-- Converted from a redirect
	elseif status == 'convert'
                or status == 'converted'
                or status == 'redirect'
        then
		return 'Converted from a redirect'

	-- Improved to GA
	elseif status == 'ga' then
		return 'Improved to Good Article status'

	-- Default
	else
		return 'Created/expanded'
	end
end	

-- A list of the authors, with user and user talk links.
function params.AUTHORS(data)
	local authors = getNormalisedAuthors(data)
	for i, author in ipairs(authors) do
		authors[i] = makeUserLinks(author)
	end
	local separator = ', '
	local conjunction
	if #authors > 2 then
		conjunction = ', and '
	else
		conjunction = ' and '
	end
	return mw.text.listToText(authors, separator, conjunction)
end

-- Blurb for who the article was nominated by.
function params.NOMINATED(data)
	local authors = data.authors
	if #authors > 1 or authors[1] and authors[1] ~= data.revisionUser then
		return 'Nominated by ' .. makeUserLinks(data.revisionUser)
	else
		return 'Self-nominated'
	end
end

function params.BACKLOG(data)
	local togglePageText = mw.title.new('Template:Did you know/Backlog mode?'):getContent()
	if togglePageText ~= nil and togglePageText:find('^true') ~= nil then
		return " '''Note''': at the time of this nomination, DYK is currently in unreviewed backlog mode. All nominations made by editors with 20 or more prior nominations during this time will require '''two''' QPQs for every article nominated."
	end
end

-- Warning to check that the credits are correct.
function params.CHECK_CREDITS_WARNING(data)
	if #data.articles > 1 then
		return 'Please check to make sure these auto-generated credits are correct.'
	end
end

-- DYK credits. These are used by the bot to credit people on their talk pages
-- and to tag articles.
function params.CREDITS(data)
	local authors = getNormalisedAuthors(data)
	local articles = data.articles
	local nompage = params.NOM_SUBPAGE(data)
	local nominator = data.revisionUser
	local nominatorIsAuthor = false
	for i, author in ipairs(data.authors) do
		if author == nominator then
			nominatorIsAuthor = true
			break
		end
	end

	local ret = {}

	local function addTemplate(template, article, user, subpage)
		local params = normalizeTemplateParameters{article, user}
		if subpage then
			table.insert(params, 'subpage=' .. subpage)
		end
		ret[#ret + 1] = string.format(
			'* {{%s|%s}}',
			template,
			table.concat(params, '|')
		)
	end

	-- First article, a special case
	do
		local article = articles[1]
		addTemplate(
			'DYKmake',
			article,
			authors[1],
			nompage
		)
		for i = 2, #authors do
			addTemplate('DYKmake', article, authors[i], nompage)
		end
		if not nominatorIsAuthor then
			addTemplate('DYKnom', article, nominator)
		end
	end

	-- Second article and up
	for i = 2, #articles do
		local article = articles[i]
		for j, author in ipairs(authors) do
			addTemplate('DYKmake', article, author, nompage)
		end
		if not nominatorIsAuthor then
			addTemplate('DYKnom', article, nominator)
		end
	end

	return table.concat(ret, '\n')
end

-- If a file was displayed, use the {{-}} template so that it doesn't spill
-- over into the next nomination.
function params.FILE_BREAK(data)
	local args = data.args
	if args.image or args.sound or args.video then
		return '{{-}}'
	end
end

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

local p = {}

function p._main(args, frame, title)
	-- Subst check.
	-- Check for the frame object as well to make debugging easier from the
	-- debug console.
	if frame and not mw.isSubsting() then
		return '<strong class="error">' ..
			'This template must be [[Wikipedia:Substitution|substituted]]. ' ..
			'Replace <code>{{NewDYKnomination}}</code> with ' ..
			'<code>{{subst:NewDYKnomination}}</code>.</strong>'
	end

	-- Set default arguments.
	frame = frame or mw.getCurrentFrame()
	title = title or mw.title.getCurrentTitle()

	-- Process data from the arguments.
	local splitArgs = splitByPrefix(args)
	local articles = getPrefixedArgs(args, splitArgs, {'article'})
	local authors = getPrefixedArgs(
		args,
		splitArgs,
		{'expander', 'creator', 'writer', 'author'}
	)
	local alts = getPrefixedArgs(args, splitArgs, {'ALT'})

	-- Input sanity checks.
	local errors = {}
	for i, article in ipairs(articles) do
		local articleTitle = makeTitle(article)
		if not articleTitle then
			table.insert(errors, formatInvalidTitleError(
				article,
				'article name'
			))
			articles[i] = ''
		end
	end
	if #articles < 1 then
		articles[1] = title.subpageText
	end
	for i, author in ipairs(authors) do
		authors[i] = getRootPageText(author)
		if not authors[i] then
			table.insert(errors, formatInvalidTitleError(author, 'user name'))
			authors[i] = ''
		end
	end

	-- Substitute the parameters in the output template.
	local data = {
		errors = errors,
		args = args,
		articles = articles,
		authors = authors,
		revisionUser = frame:preprocess('{{safesubst:REVISIONUSER}}'),
		alts = alts,
		title = title,
	}
	local ret = OUTPUT_TEMPLATE:gsub('${([%u_]+)}', function (funcName)
		local func = params[funcName]
		if not func then
			error(string.format(
				"invalid parameter '${%s}' " ..
				"(no corresponding parameter function found)",
				funcName
			))
		end
		return func(data) or ''
	end)
	return ret
end

function p.main(frame)
	local args = require('Module:Arguments').getArgs(frame, {
		wrappers = 'Template:NewDYKnomination'
	})
	return p._main(args, frame)
end

return p