-- Low-overhead version of {{Subatomic particle|...}} to avoid exceeding

-- template include size at [[List of baryons]].



local particleTable, supsub



local function stripToNil(text)

	-- If text is a string, return its trimmed content, or nil if empty.

	-- Otherwise return text (which may, for example, be nil).

	if type(text) == 'string' then

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

	end

	return text

end



local BREAK = "__BR__"



-- A group is a list of one or more particles with optional separating text.

-- Some items are defined with special meanings:

--   Parameter       Output

--    /               " / "

--    +               " + "

--    or              " or "

--    seen            " (seen) "

--    _word1_word2    " word1 word2" (wordN is any text)

--    (text)          "(text)" (text is any text)

--    br              "<br />" (and separates the group into logical lines)

-- Each logical line in the final text is in a nowrap span.

local Group

Group = {

	add = function (self, item)

		if item ~= nil then

			if item == BREAK then

				self:purgeCurrent()

			else

				self.nrCurrent = self.nrCurrent + 1

				self.currentself.nrCurrent = item

			end

		end

	end,

	new = function ()

		return setmetatable({

			nrCurrent = 0,

			current = {},

			nrLines = 0,

			lines = {},

		}, Group)

	end,

	purgeCurrent = function (self)

		if self.nrCurrent > 0 then

			self.nrLines = self.nrLines + 1

			self.linesself.nrLines =

				'<span style="white-space:nowrap;">' ..

				table.concat(self.current) ..

				'</span>'

			self.nrCurrent = 0

			self.current = {}

		end

	end,

	text = function (self)

		self:purgeCurrent()

		return table.concat(self.lines, '<br />')

	end,

}

Group.__index = Group



local keyitems = {

	'/'    = " / ",

	'+'    = " + ",

	'or'   = " or ",

	'seen' = " (seen) ",

	'br'   = BREAK,

}



local function expand(item, wantLink)

	-- Return text after expanding given item.

	-- Throw an error if item is not recognized.

	local function quit(reason)

		reason = reason or 'has an invalid definition'

		error('Particle "' .. item .. '" ' .. reason, 0)

	end

	local function su(sup, sub, align)

		local options = {

			align = align,

			lineHeight = '1.0em',

		}

		return supsub(sup, sub, options)

	end

	local kw = keyitemsitem

	if kw then

		return kw

	end

	if item:sub(1, 1) == '_' then

		return item:gsub('_', ' ')

	end

	if item:sub(1, 1) == '(' and item:sub(-1) == ')' then

		return item  -- no space wanted

	end

	local particle = particleTableitem:lower()] or quit('is not defined')

	local prefix, suffix

	if wantLink then

		prefix = '[[' .. (particle.link or quit('has no link defined')) .. '|'

		suffix = ']]'

	else

		prefix = ''

		suffix = ''

	end

	local symbol = particle1 or quit('has no symbol defined')

	if particle.anti then

		symbol = '<span style="text-decoration:overline;">' .. symbol .. '</span>'

	end

	return

		prefix ..

		su(particle.TL, particle.BL, 'r') ..

		symbol ..

		su(particle.TR, particle.BR, 'l') ..

		suffix

end



local function main(frame, wantLink)

	-- Arguments are passed using #invoke in an article to avoid double-expansion.

	local sandbox = frame:getTitle():find('sandbox', 1, true) and '/sandbox' or ''

	particleTable = mw.loadData('Module:Particles/data' .. sandbox).particles

	supsub = require('Module:Su')._main

	local group = Group.new()

	for _, arg in ipairs(frame.args) do

		arg = stripToNil(arg)

		if arg then

			group:add(expand(arg, wantLink))

		end

	end

	return group:text()

end



local function link(frame)

	return main(frame, true)

end



local function nolink(frame)

	return main(frame, false)

end



return {

	link = link,

	nolink = nolink,

}