-- This module provides some functions to help avoid problems with templates

-- that might exceed expand size or time and which might put the page in

-- [[:Category:Pages where template include size is exceeded]] or

-- [[:Category:Pages with script errors]] (time exceeding 10 seconds).



local function collection()

	-- Return a table to hold items.

	return {

		n = 0,

		add = function (self, item)

			self.n = self.n + 1

			selfself.n = item

		end,

		join = function (self, sep)

			return table.concat(self, sep)

		end,

	}

end



local function strip_to_nil(text)

	-- If text is a non-empty string, return its trimmed content,

	-- otherwise return nothing (empty string or not a string).

	if type(text) == 'string' then

		return text:match('(%S.-)%s*$')

	end

end



local function message(msg, nocat)

	-- Return formatted message text for an error.

	-- Can append "#FormattingError" to URL of a page with a problem to find it.

	-- This should not be called because there is no validity checking.

	local anchor = '<span id="FormattingError"></span>'

	local category = nocat and '' or '[[Category:Biglist errors]]'

	return anchor ..

		'<strong class="error">Error: ' ..

		msg ..

		'</strong>' ..

		category .. '\n'

end



local function urlencode(text)

	-- Return equivalent of {{urlencode:text}}.

	local function byte(char)

		return string.format('%%%02X', string.byte(char))

	end

	return text:gsub('[^ %w%-._]', byte):gsub(' ', '+')

end



local function replace2(text, template)

	-- Return template after substituting text and urlencoded text.

	local plain = text:gsub('%%', '%%%%')  -- for gsub, '%' has a special meaning in replacement

	local plainp = plain:gsub(' ', '+')    -- plain and space replaced with plus

	local encoded = urlencode(text):gsub('%%', '%%%%')

	return template:gsub('<TXT>', plain):gsub('<TXTP>', plainp):gsub('<UENC>', encoded)

end



local function clean(text, default)

	-- Return text, if not empty, after trimming leading/trailing whitespace.

	-- Otherwise return default which may be nil.

	if text then

		text = text:match("^%s*(.-)%s*$")

		if text ~= '' then

			return text

		end

	end

	return default

end



local function make_list(args, formatter, template)

	-- Return a list of formatted items.

	-- Input is a string of multiple lines, one item per line.

	local text = args.list or args1 or ''

	local prefix = clean(args.prefix) or ''

	local comment = clean(args.comment)

	local results = collection()

	for line in string.gmatch(text .. '\n', '[\t ]*(.-)[\t\r ]*\n') do

		-- Skip line if empty or a comment.

		if line ~= '' then

			if not (comment and line:sub(1, #comment) == comment) then

				results:add(prefix .. formatter(line, template))

			end

		end

	end

	return results:join('\n')

end



local templates = {

	-- Equivalent of {{userlinks|text}}.

	userlinks = [=[

<span class="plainlinks userlinks">[[User:<TXT>|<TXT>]] <span class="plainlinks">([[User talk:<TXT>|talk]] '''·''' [[Special:Contributions/<TXT>|contribs]]<span class="sysop-show"> '''·''' [[Special:DeletedContributions/<TXT>|deleted contribs]]</span> '''·''' [https://en.wikipedia.org/?title=Special:Log&user=<UENC> logs] '''·''' [https://en.wikipedia.org/?title=Special:AbuseLog&wpSearchUser=<UENC> edit filter log]<span class="sysop-show"> '''·''' [[Special:Block/<TXT>|block user]]</span> '''·''' [https://en.wikipedia.org/?title=Special:Log&type=block&page=User:<UENC> block log])</span></span>]=],

	-- Equivalent of how {{search|topic}} is used.

	topicsearch = [=[

[[<TXT>]] – <span class="plainlinks">([https://en.wikipedia.org/?title=Special:Search&search=<UENC> wp] [https://www.google.com/search?q=site%3Awikipedia.org+<TXTP> gwp] [https://www.google.com/search?q=<TXTP> g] [https://www.bing.com/search?q=site%3Awikipedia.org+<TXTP> bwp] [https://www.bing.com/search?q=<TXTP> b] | [https://www.britannica.com/search?nop&query=<TXTP> eb] [https://www.google.com/custom?sitesearch=1911encyclopedia.org&q=<TXTP> 1911] [https://www.bartleby.com/cgi-bin/texis/webinator/65search?query=<TXTP> co] [https://www.google.com/search?q=site%3Ahttp%3A%2F%2Fwww.pcmag.com%2Fencyclopedia_term%2F+<TXTP> gct] [https://scienceworld.wolfram.com/search/index.cgi?as_q=<TXTP> sw] [https://archive.org/search.php?query=<UENC> arc] [https://babel.hathitrust.org/cgi/ls?field1=ocr;q1=<UENC>;a=srchls;lmt=ft ht])</span>]=],

}



local function main(formatter, tname)

	local template = templatestname

	if template then

		return function (frame)

			local args = frame.args

			local success, result = pcall(make_list, args, formatter, template)

			if success then

				return result

			end

			return message(result, clean(args.nocat))

		end

	else

		return function (frame)

			local args = frame.args

			return message('Unknown template name "' .. tname .. '"', clean(args.nocat))

		end

	end

end



local function coltit(frame)

	-- [[List of RAL colors]] has "node-count limit exceeded" problem.

	-- Following are equivalent:

	--   {{coltit|xxx}}

	--   {{#invoke:biglist|coltit|xxx}}

	-- or

	--   {{coltit|rgb=xxx}}

	--   {{#invoke:biglist|coltit|rgb=xxx}}

	-- Output is an empty cell for a table; the cell has the given background color.

	-- This does not emulate other features of the template.

	local args = frame.args

	local hex = strip_to_nil(args1])  -- should be hex color code such as 'AABBCC'

	if hex then

		return string.format('title="color %s" style="background:#%s;"| ', hex, hex)

	end

	local rgb = strip_to_nil(args.rgb)  -- should be decimal triple such as '123,123,123'

	if rgb then

		return string.format('title="color %s" style="background:rgb(%s);"| ', rgb, rgb)

	end

	error('biglist coltit: need parameter 1 or rgb', 0)

end



local function columnslist(frame)

	-- [[List of least concern fishes]] has problem exceeding template expansion size.

	-- Will possibly be other articles with similar problems.

	-- Following are equivalent:

	--   {{columns-list|colwidth=30em|xxx}}

	--   {{#invoke:biglist|columns-list|colwidth=30em|xxx}}

	-- Output is:

	--   <div ...>xxx</div>

	-- This assumes colwidth is wanted and does not emulate other features of the template.

	local args = frame.args

	local content = strip_to_nil(args1]) or ''

	local colwidth = strip_to_nil(args.colwidth) or ''

	if colwidth ~= '' then

		colwidth = ' style="column-width: ' .. colwidth .. '"'

	end

	return frame:extensionTag{

		name = 'templatestyles', args = { src = 'Div col/styles.css' }

	} .. '<div class="div-col"' .. colwidth .. '>\n' .. content .. '</div>'

end



local function storm(frame)

	-- [[Wikipedia:What Wikipedia is not]] has an example at [[WP:CRYSTAL]]

	-- where the name of a "virtually certain" future storm is needed.

	-- This function returns the next such name (unlinked) depending on the current date.

	-- Names are from [[Tropical cyclone naming#North Atlantic Ocean]].

	-- Usage:

	--   {{#invoke:biglist|storm}}

	-- Output example:

	--   Tropical Storm Alex (2022)

	local storms = {

		2017 = 'Tropical Storm Alberto (2018)',

		2018 = 'Tropical Storm Andrea (2019)',

		2019 = 'Tropical Storm Arthur (2020)',

		2020 = 'Tropical Storm Ana (2021)',

		2021 = 'Tropical Storm Alex (2022)',

		2022 = 'Tropical Storm Arlene (2023)',

		2023 = 'Tropical Storm Alberto (2024)',

		2024 = 'Tropical Storm Andrea (2025)',

		2025 = 'Tropical Storm Arthur (2026)',

		default = 'Tropical Storm Alberto (2030)',

	}

	local date = os.date('!*t')  -- today's UTC date

	local y, m = date.year, date.month  -- full year, month (1-12)

	if m >= 11 then

		y = y + 1

	end

	return stormsy or storms.default

end



local function weatherboxcols(frame)

	-- [[List of cities by sunshine duration]] has problem exceeding time available.

	-- Examples:

	--   {{#invoke:biglist|weatherboxcols|123.4}}         → style="background:#B9B94C; font-size:85%;"|123.4

	--   {{#invoke:biglist|weatherboxcols|123.4|1,823.0}} → style="background:#B9B94C; font-size:85%;"|1,823.0

	local args = frame.args

	local display = strip_to_nil(args1]) or ''

	local value = tonumber((display:gsub(',', '')))

	local function show(bg, fg)

		local text = strip_to_nil(args2]) or display

		if not fg and (value and value < 62) then

			fg = 'FFFFFF'

		end

		if fg then

			fg = 'color:#' .. fg .. ';'

		else

			fg = ''

		end

		return 'style="background:#' .. bg .. ';' .. fg .. ' font-size:85%;"' .. '|' .. text

	end

	if not value then

		return show('FFFFFF', '000000')

	end

	local redgreen, blue

	if value <= 0 then

		redgreen = 0

	elseif value <= 90 then

		redgreen = 1.889 * value

	elseif value <= 180 then

		redgreen = 0.472 * (270.169 + value)

	elseif value < 360 then

		redgreen = 0.236 * (720.424 + value)

	else

		redgreen = 255

	end

	if value <= 0 then

		blue = 0

	elseif value <= 90 then

		blue = 1.889 * value

	elseif value < 150 then

		blue = 2.883 * (150 - value)

	elseif value <= 270 then

		blue = 0

	elseif value < 719.735 then

		blue = 0.567 * (value - 270)

	else

		blue = 255

	end

	return show(string.format('%02X%02X%02X', redgreen, redgreen, blue))

end



return {

	coltit = coltit,

	'columns-list' = columnslist,

	storm = storm,

	topicsearch = main(replace2, 'topicsearch'),

	userlinks = main(replace2, 'userlinks'),

	weatherboxcols = weatherboxcols,

}