local p = {}

local lang = 'en-GB' -- local default language

--	Below these comments: Internationalization table
--	How to translate this module (for languages without variants):
--	• Characters inside single and double quotation marks are called strings.
--	 The strings in this i18n table are used as output.
--	• Strings within square brackets are keys.
--	• Strings are concatenated (joined) with two dots.
--	• Set the string after «local lang =» to your language's code.
--	 Change the first key after "i18n" (usually "en-GB") to the same thing.
--	• For each string which is not inside a function, translate it directly.
--	• Strings with keys named "format" are Lua regular expressions.
--	 «» is a match; «.+» means all characters; «%s+» means all spaces.
--	• For each string which is concatenated to the variable «var»,
--	 translate the phrase assuming that «var» will be a noun.
--	• Remove any unnecessary translations.

local i18n = require("Module:Adjacent stations/i18n")
local function getData
	if verify then
		local title = mw.title.new('Module:Adjacent stations/' .. system -- .. '/sandbox'
			)
		if not (title and title.exists) then return nil end
	end
	return require('Module:Adjacent stations/' .. system -- .. '/sandbox'
		)
end

local function getLine
	if lineN then
		if data['aliases'] then
			lineN = data['aliases'][mw.ustring.lower(lineN)] or lineN
		end
		local default = data['lines']['_default'] or {}
		local line = data['lines'][lineN] or {}
		for k, v in pairs(default) do
			if v then line[k] = line[k] or v end
		end
		line['title'] = line['title'] and mw.ustring.gsub
		return line, lineN
	end
end

local function getColor
	if system then
		if line then return frame:expandTemplate{ title = system .. ' color', args = {line, ['branch'] = Type} } end
		return frame:expandTemplate{ title = system .. ' color' }
	else
		line = (getLine)
		local default = data['lines']['_default']
		if line or default then
			default = default or {}
			if not line then line = mw.clone(default) end
			local color = line['color'] or line['background color'] or default['color'] or default['background color'] or data['system color']
			local Type_value = Type and line['types'] and (line['types'][Type] and line['types'][Type]['color'])
			if Type_value then color = Type_value end
			return color
		end
		return (default and (default['color'] or default['background color']) or data['system color'] or '')
	end
end

local lineN, typeN

local function somethingMissing
	local formatKeys = {}
	for k in pairs(formats) do
		table.insert
	end
	return name .. ' was "' .. key .. '" but neither an entry for it nor a default was found. Choices were: ' .. table.concat
end

local function getStation
	if type(_Format) == 'table' then
		local lineNformats = _Format
		_Format = lineNformats[lineN] or lineNformats[1]
		if not _Format then
			error(somethingMissing)
		elseif type(_Format) == 'table' then
			local typeNformats = _Format
			_Format = typeNformats[typeN] or typeNformats[1]
			if not _Format then
				error(somethingMissing)
			end
		end
	end
	if typeN then _Format = mw.ustring.gsub end
	if lineN then _Format = mw.ustring.gsub end
	return (mw.ustring.match) and (mw.ustring.gsub) or table.concat
end

local function getTerminusText
	local function subst
		-- var1 is the terminus or table of termini; var2 is the key for the table of termini
		return type(var1) == 'string' and getStation(var1, (Format[var1] or Format[1]))
		or type(var1) == 'table' and #var1 > 0 and getStation(var1[var2], (Format[var1[var2]] or Format[1]))
		or ''
	end

	if Format then
		if type(var) == 'string' then
			return subst(var)
		elseif type(var) == 'table' and #var > 0 then
			local t = {subst}

			for i = 2, #var - 1 do
				t[i] = i18n[lang]['comma'](subst)
			end

			if #var > 1 then t[#var] = i18n[lang]['or'](subst) end
			if var['via'] then
				if i18n[lang]['via-first'] then
					table.insert(t, 1, i18n[lang]['via'](subst))
				else
					table.insert(t, i18n[lang]['via'](subst))
				end
			end

			return table.concat(t)
		else
			return ''
		end
	else
		return var or ''
	end
end

function p._main(_args) -- Arguments are processed here instead of the main function

	local yesno = require('Module:Yesno')
	local trimq = require('Module:Trim quotes')._trim

	local boolean = {
		['oneway-left'] = true,
		['oneway-right'] = true,
		['reverse'] = true,
		['reverse-left'] = true,
		['reverse-right'] = true

	local args = {} -- Processed arguments
	local index = {} -- A list of addresses corresponding to number suffixes in the arguments

	for k, v in pairs(_args) do -- Maps each raw argument to processed arguments by string matching
		_args[k] = v:match('^%s*(.-)%s*$')
		if _args[k] and _args[k] ~= '' then
			local a = mw.ustring.match(k, '^(.*%D)%d+$') or k -- The parameter; address 1 can be omitted
			local b = tonumber(mw.ustring.match(k, '^.*%D(%d+)$')) or 1 -- The address for a given argument; address 1 can be omitted

			if boolean[a] then
				v = yesno(v)
			end

			if not args[b] then
				args[b] = {[a] = v}
				table.insert
			elseif args[b][a] then
				return error(i18n[lang]['error_duplicate'](a .. b))
			else
				args[b][a] = v
			end
		end
	end
	table.sort(index)

	local function small
		return italic and ''
			or ''
	end

	local style = { -- Style for each cell type
		['header cell'] = 'class="hcA"|',
		['header midcell'] = 'colspan="3" class="hmA"|',
		['body cell'] = 'class="bcA"|',
		['body banner'] = 'class="bbA" style="background-color:#',

	local function rgb(var)
		if var:len == 3 then
			return {tonumber(var:sub, 16) * 17, tonumber(var:sub, 16) * 17, tonumber(var:sub, 16) * 17}
		elseif var:len == 6 then
			return {tonumber(var:sub, 16), tonumber(var:sub, 16), tonumber(var:sub, 16)}
		end
		return {}
	end

	local data = {} -- A table of data modules for each address
	local noclearclass = (((_args.noclear or '') ~= '') and ' adjacent-stations-noclear' or '')
	local wikitable = {'{| class="wikitable adjacent-stations' .. noclearclass .. '"'}

	for i, v in ipairs(index) do
		-- If an address has a system argument, indexes the data module
		data[v] = args[v]['system'] and getData(args[v]['system'])
		-- If an address has no system, the row uses data from the previous address
			or data[index[i - 1]]
			or (args[v]['header'] and getData(args[index[i+1]]['system']))
			or error(i18n[lang]['error_unknown'](args[v]['system']))

		local lang = data[v]['lang'] or lang

		if args[v]['system'] and not args[v]['hide-system'] then -- Header row
			local stop_noun = data[v]['header stop noun'] or i18n[lang]['stop_noun']
			table.insert(wikitable, table.concat({'\n|-',
				'\n! scope="col" ', style['header cell'], i18n[lang]['preceding'](stop_noun),
				'\n! scope="col" ', style['header midcell'], (data[v]['system icon'] and data[v]['system icon'] .. ' ' or ''), (data[v]['system title'] or ('[['.. args[v]['system'] ..']]')),
				'\n! scope="col" ', style['header cell'], i18n[lang]['following'](stop_noun)
			table.insert
			table.insert
			table.insert
		end

		if args[v]['header'] then -- Subheader
			table.insert
			table.insert
			table.insert
			table.insert
		end

		if args[v]['line'] or args[v]['left'] or args[v]['right'] or args[v]['nonstop'] then
			if not args[v]['line'] and i > 1 and not args[v]['system'] then
				args[v]['line'] = args[index[i - 1]]['line']
			end

			lineN = args[v]['line'] or '_default'
			typeN = args[v]['type']
			if data[v]['aliases'] then
				lineN = data[v]['aliases'][mw.ustring.lower(lineN)] or lineN
				if typeN then typeN = data[v]['aliases'][mw.ustring.lower(typeN)] or typeN end
			end

			-- get the line table
			local line = data[v]['lines'] and (mw.clone(data[v]['lines'][lineN]) or error(i18n[lang]['error_unknown'](args[v]['line']))) or error(i18n[lang]['error_line'])
			local default = data[v]['lines']['_default'] or {}
			line['title'] = line['title'] or default['title']
			line['title'] = mw.ustring.gsub

			-- cell across row for non-stop service
			if args[v]['nonstop'] then
				table.insert(wikitable,
					table.concat({'\n|-\n|colspan="5" ',
						style['body cell'],
						((args[v]['nonstop'] == 'former') and i18n[lang]['nonstop_past'] or i18n[lang]['nonstop_present'])(p._box)
				)
				table.insert
				table.insert
				table.insert
			else
				local Format = data[v]['station format'] or i18n[lang]['error_format']

				local color, color_2, background_color, circular
				local Type = line['types'] and line['types'][typeN] -- get the line type table

				if Type then
					if Type['color'] then
						-- line color is used as background if there is no background color in the line type table
						background_color = Type['background color'] or line['color']
						color = Type['color']
						color_2 = Type['color2'] or color
					else
						background_color = Type['background color'] or line['background color']
						color = line['color'] or default['color'] or ''
						color_2 = line['color2'] or color
					end
					if Type['circular'] then
						-- Type may override the circular status of the line
						circular = Type['circular']
					end
				else
					background_color = line['background color']
					color = line['color'] or default['color'] or ''
					color_2 = line['color2'] or color
					circular = line['circular']
				end

				-- Alternate termini can be specified based on type
				local sideCell = {true, true}
				for i, b in ipairs do
					if not args[v][b] then -- If no station is given on one side, the station is assumed to be the terminus on that side
						local _through = args[v]['through-' .. b] or args[v]['through']
						local _through_data = getLine
						if _through_data then _through = _through_data['title'] or _through end
						sideCell[i] = _through and "''" .. i18n[lang]['through'](trimq(_through)) .. "''"
							or "''" .. trimq((args[v]['reverse-' .. b]
							or args[v]['reverse']) and i18n[lang]['reverse']
							or i18n[lang]['terminus']) .. "''"
					else
						local terminusT
						local terminusN = Type and Type[b .. ' terminus'] or line[b .. ' terminus']

						-- If the terminus table has more than one numbered key or has the via key then the table shows only the default termini, since terminusN[2] cannot be used and terminusN[via] is reserved
						if type(terminusN) == 'string' or (type(terminusN) == 'table' and (terminusN[2] or terminusN['via'])) then
							if args[v]['to-' .. b] then
								terminusT = args[v]['to-' .. b]
								local _or = mw.ustring.match
								if _or then
									terminusT = mw.ustring.gsub
									terminusT = mw.ustring.gsub
								end
								local _via = (mw.ustring.match)
								if _via then
									terminusT = mw.ustring.gsub
									terminusT = mw.text.split
									terminusT['via'] = _via
								elseif _or then
									terminusT = mw.text.split
								end
							else
								terminusT = terminusN
							end
						elseif type(terminusN) == 'table' then
							terminusT = terminusN[args[v]['to-' .. b]] or terminusN[args[v]['to']] or terminusN[1]
						end

						local mainText = args[v]['note-' .. b] and getTerminusText .. small(args[v]['note-' .. b]) or getTerminusText

						local subText = (args[v]['oneway-' .. b] or line['oneway-' .. b]) and i18n[lang]['oneway']
							or args[v][b] == terminusT and i18n[lang]['terminus']
							or circular and terminusT
							or i18n[lang]['towards'](getTerminusText)
						subText = small

						sideCell[i] = mainText .. subText
					end
				end

				table.insert
				table.insert
				table.insert(wikitable, table.concat({'\n|', style['body banner'], color, '"|',
					'\n|', (background_color and 'class="bcA" style="background-color:rgba(' .. table.concat(rgb(background_color), ',') .. ',.2)"|' or style['body cell']), line['title'],

					-- Type; table key 'types' in subpages . If table does not exist then the input is displayed as the text
					(typeN and '' or ''),

					-- Note-mid; table key 'note-mid' in subpages. Overridden by user input
					((args[v]['note-mid'] and small(args[v]['note-mid'])) or (Type and Type['note-mid'] and small(Type['note-mid'])) or (line['note-mid'] and small(line['note-mid'])) or ''),

					-- Transfer; uses system's station link table
					(args[v]['transfer'] and small('transfer at ' .. getTerminusText, true) or ''),

					'\n|', style['body banner'], color_2, '"|'}))
				table.insert
			end
		end

		if args[v]['note-row'] then -- Note
			if args[v]['note-row']:match('^%s*<tr') or args[v]['note-row']:match('^%s*%|%-') then
				table.insert
			else
				table.insert
			end
			table.insert
			table.insert
			table.insert
		end
	end

	local function combine
		if t[n + 4] ~= '' and t[n + 4] == t[n] then
			t[n + 4] = '' -- The cell in the next row is deleted
			local rowspan = 2
			while t[n + rowspan * 4] == t[n] do
				t[n + rowspan * 4] = ''
				rowspan = rowspan + 1
			end
			t[n] = mw.ustring.gsub
		end
	end

	local M = #wikitable
	for i = 3, M, 4 do combine end
	for i = 4, M, 4 do combine end
	for i = 5, M, 4 do combine end

	table.insert

	return table.concat(wikitable)
end

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

local function makeInvokeFunction(funcName)
	-- makes a function that can be returned from #invoke, using
	-- Module:Arguments
	return function (frame)
		local args = getArgs
		return p[funcName]
	end
end

p.main = makeInvokeFunction('_main')

function p._color
	local data = args.data
	if args[1] or data then
		data = data or getData
		if not data then return getColor end
		return getColor
	end
end

p.color = makeInvokeFunction('_color')

function p._box
	local system = args[1] or args.system
	lineN = args[2] or args.line
	if not (system or lineN) then return '' end
	local line, Type, line_data
	local inline = args[3] or args.inline
	typeN = args.type
	local data = args.data
	if system or data then
		data = data or getData
		local color
		if data then
			local default = data['lines']['_default'] or {}
			line, lineN = getLine
			if typeN then
				typeN = data['aliases'] and data['aliases'][mw.ustring.lower(typeN)] or typeN
				Type = line['types'] and line['types'][typeN] and line['types'][typeN]['title'] or typeN
			end
			color = getColor
			if inline ~= 'box' then
				line_data = line or error(i18n[lang]['error_unknown'](lineN))
				line = line_data['title'] or default['title'] or error(i18n[lang]['error_missing']('title'))
				line = mw.ustring.gsub
			end
		else
			color = getColor
			if inline ~= 'box' then
				line = frame:expandTemplate{ title = system .. ' lines', args = {lineN, ['branch'] = typeN} }
				if mw.text.trim(line) == '' then return error(i18n[lang]['error_unknown'](lineN)) end
			end
			Type = typeN
		end

		local result

		if Type and Type ~= '' and inline ~= 'box' then
			if line == '' then
				line = Type
			else
				result = ' – ' .. Type
			end
		end
		if args.note then result = (result or '') .. ' ' .. args.note end
		result = result or ''

		if not inline then -- Template:Legend
			result = ''
		elseif inline == 'yes' then
			result = '&nbsp;' .. line .. result
		elseif inline == 'box' then
			result = '' .. result
		elseif inline == 'link' then
			local link = args.link or mw.ustring.match(line, '%[%[([^%[:|%]]+)[|%]]')
			if link then
				result = '' .. result
			else
				result = '' .. result
			end
		elseif inline == 'square' then
			result = '&nbsp;' .. line .. result
		elseif inline == 'lsquare' then
			local link = args.link or mw.ustring.match(line, '%[%[([^%[:|%]]+)[|%]]')
			if link then
				result = ''
			else
				result = ''
			end
		elseif inline == 'dot' then
			result = ' ' .. line .. result
		elseif inline == 'ldot' then
			local link = args.link or mw.ustring.match(line, '%[%[([^%[:|%]]+)[|%]]')
			if link then
				result = ''
			else
				result = ''
			end
		elseif inline == 'small' then
			result = '' .. ' ' .. line .. result
		else
			local yesno = require("Module:Yesno")
			local link = args.link or mw.ustring.match(line, '%[%[([^%[:|%]]+)[|%]]')
			local border_color, text_color
			local color_box = data['color box format'] or data['rail box format'] or {}
			if line_data then
				if line_data['types'] and line_data['types'][typeN] then
					local Type_data = line_data['types'][typeN]
					border_color = Type_data['border color'] or line_data['border color'] or color
					text_color = Type_data['text color'] or line_data['text color']
					if color_box == 'title' and not args[4] then
						lineN = Type_data['short name'] or line_data['short name'] or require('Module:Delink')._delink{line}
					else
						lineN = Type_data['short name'] or line_data['short name'] or lineN
					end
				else
					border_color = line_data['border color'] or color
					text_color = line_data['text color']
					if color_box == 'title' and not args[4] then
						lineN = line_data['short name'] or require('Module:Delink')._delink{line}
					else
						lineN = line_data['short name'] or lineN
					end
				end
			else
				border_color = color
			end
			text_color = text_color and '#' .. text_color or require('Module:Color contrast')._greatercontrast{color}
			local bold = ';font-weight:bold'
			if (yesno(args.bold) == false) then bold = '' end
			if inline == 'route' then -- Template:RouteBox
				if link then
					result = ''
				else
					result = ''
				end
			elseif inline == 'croute' then -- Template:Bahnlinie
				if link then
					result = ''
				else
					result = ''
				end
			elseif inline == 'xroute' then -- Template:Bahnlinie
				if link then
					result = ''
				else
					result = ''
				end
			elseif inline == 'broute' then
				if link then
					result = ''
				else
					result = ''
				end
			else -- Template:Legend (fallback; duplication to simplify logic)
				result = ''
			end
		end

		result = mw.ustring.gsub

		return result
	end
end

p.box = makeInvokeFunction('_box')

function p._icon
	local system = args[1] or args.system
	local data = args.data

	if not system and not data then
		return
	end

	data = data or getData(system)

	local line, line_name = getLine

	local icon
	local icon_format

	if line then
		local line_type = args[3] or args.type
		if line_type then
			line_type = data.aliases and data.aliases[mw.ustring.lower(line_type)] or line_type
			line_type = line.types and line.types[line_type] -- If there's no type table or entry for this type, then it can't have its own icon
			icon_format = line_type['icon format'] or data['type icon format']

			if line_type.icon then
				icon = line_type.icon
			end
		end

		if not icon then
			icon = line.icon
		end

		-- Only if there is no icon use the icon_format.
		if not icon and not icon_format then
			icon_format = line['icon format'] or data['line icon format']
		end

		local default = data.lines._default or {}
		if icon and string.find and default and default.icon then
			icon = mw.ustring.gsub
		end

	end

	if not icon then
		icon = data['system icon']
	end

	if not icon_format then
		icon_format = data['system icon format']
	end

	if icon_format then
		if icon_format ~= 'image' then
			icon = p._box({data = data, [2] = (args[2] or args.line), [3] = icon_format, type = (args[3] or args.type), bold = args.bold, link = args.link}, frame)

			if args.name then
				if line and line.title then
					return icon .. " " .. line.title
				end
				return icon .. " " .. data["system title"]
			end
		end
	end

	local size = args.size
	if size then
		if mw.ustring.match then
			size = '|' .. size .. 'px'
		else
			size = '|' .. size
		end
		-- Upright values are to be disabled until there is use of upright scaling in subpages; doesn't seem to work anyway as of 2018-08-10
		local regex = {
			'|%s*%d*x?%d+px%s*([%]|])', -- '|%s*upright=%d+%.?%d*%s*([%]|])', '|%s*upright%s*([%]|])'
		if mw.ustring.match then
			icon = mw.ustring.gsub
	--	elseif mw.ustring.match then
	--		icon = gsub
	--	elseif mw.ustring.match then
	--		icon = gsub
		else
			icon = mw.ustring.gsub(icon, '(%[%[[^%]|]+)([%]|])', '%1' .. size .. '%2')
		end
	end

	local link = args.link
	if link then
		if mw.ustring.match then
			icon = mw.ustring.gsub(icon, '|%s*link=[^%]|]*([%]|])', '|link=' .. link .. '%1')
		else
			icon = mw.ustring.gsub(icon, '(%[%[[^%]|]+)([%]|])', '%1|link=' .. link .. '%2')
		end
	end

	local alt = args.alt or link
	if alt then
		if mw.ustring.match then
			icon = mw.ustring.gsub(icon, '|%s*alt=[^%]|]*([%]|])', '|alt=' .. alt .. '%1')
		else
			icon = mw.ustring.gsub(icon, '(%[%[[^%]|]+)([%]|])', '%1|alt=' .. alt .. '%2')
		end
	end

	if args.name then
		if line and line.title then
			return icon .. " " .. line.title
		end
		return icon .. " " .. data["system title"]
	end
	return icon
end

p.icon = makeInvokeFunction('_icon')

function p._line
	local system = args[1] or args.system
	local line = args[2] or args.line
	if not line then return '' end
	local Type = args[3] or args.type
	local data = args.data
	if system or data then
		data = data or getData
		if data then
			line = (getLine) or error(i18n[lang]['error_unknown'](line))
			if Type then
				Type = data['aliases'] and data['aliases'][mw.ustring.lower(Type)] or Type
				Type = line['types'] and line['types'][Type] and line['types'][Type]['title'] or Type
			end
			line = line['title'] or error(i18n[lang]['error_missing']('title'))
		else
			line = frame:expandTemplate{ title = system .. ' lines', args = {line, ['branch'] = Type} }
			if mw.text.trim(line) == '' then return error(i18n[lang]['error_unknown'](lineN)) end
		end

		if Type and Type ~= '' then
			if line == '' then
				line = Type
			else
				line = line .. ' – ' .. Type
			end
		end
		return line
	end
end

p.line = makeInvokeFunction('_line')

function p._shortline
	local system = args[1] or args.system
	lineN = args[2] or args.line
	if not (system or lineN) then return '' end
	local line, Type, line_data
	typeN = args.type
	local data = args.data
	if system or data then
		data = data or getData
		if data then
			local default = data['lines']['_default'] or {}
			line, lineN = getLine
			if typeN then
				typeN = data['aliases'] and data['aliases'][mw.ustring.lower(typeN)] or typeN
				Type = line['types'] and line['types'][typeN] and line['types'][typeN]['title'] or typeN
			end
			line_data = line or error(i18n[lang]['error_unknown'](lineN))
			line = line_data['title'] or default['title'] or error(i18n[lang]['error_missing']('title'))
			line = mw.ustring.gsub
		else
			line = frame:expandTemplate{ title = system .. ' lines', args = {lineN, ['branch'] = typeN} }
			if mw.text.trim(line) == '' then return error(i18n[lang]['error_unknown'](lineN)) end
			Type = typeN
		end

		local result

		if Type and Type ~= '' then
			if line == '' then
				line = Type
			else
				result = ' – ' .. Type
			end
		end
		if args.note then result = (result or '') .. ' ' .. args.note end
		result = result or ''

		local link = args.link or mw.ustring.match(line, '%[%[([^%[:|%]]+)[|%]]')
		if line_data then
			if line_data['types'] and line_data['types'][typeN] then
				local Type_data = line_data['types'][typeN]
				lineN = Type_data['short name'] or line_data['short name'] or lineN
			else
				lineN = line_data['short name'] or lineN
			end
		end
			
		if link then
			result = '' .. lineN .. ''
		else
			result = lineN
		end
	
		result = mw.ustring.gsub

		return result
	end
end

p.shortline = makeInvokeFunction('_shortline')

function p._station
	local system = args[1] or args.system
	local station = args[2] or args.station
	if not station then return '' end
	lineN = args[3] or args.line
	typeN = args[4] or args.type
	local data = args.data
	if system or data then
		data = data or getData
		if data then
			local _Format = data['station format'][station] or data['station format'][1]
			if _Format then
				if data['aliases'] then
					if lineN then
						lineN = data['aliases'][mw.ustring.lower(lineN)] or lineN
					end
					if typeN then
						typeN = data['aliases'][mw.ustring.lower(typeN)] or typeN
					end
				end
				station = getStation
			else
				station = station or ''
			end
		else
			station = frame:expandTemplate{ title = system .. ' stations', args = {['station'] = station, ['line'] = lineN, ['branch'] = typeN} }
		end

		return station
	end
end

p.station = makeInvokeFunction('_station')

function p._terminusTable
	local system = args[1] or args.system
	lineN = args[2] or args.line
	local side = mw.ustring.sub(mw.ustring.lower(args[3] or args.side or ''), 1, 1)
	typeN = args.type
	local prefix = (side == 'r') and 'right' or 'left'
	local data = args.data

	if system or data then
		data = data or getData
	end
	if data then
		local line = getLine or error(i18n[lang]['error_unknown'](lineN))
		if typeN and data and data['aliases'] then typeN = data['aliases'][mw.ustring.lower(typeN)] or typeN end
		local Type = line['types'] and line['types'][typeN]

		local circular
		if Type then
			if Type['circular'] then
				-- Type may override the circular status of the line
				circular = Type['circular']
			end
		else
			circular = line['circular']
		end

		return Type and Type[prefix .. ' terminus'] or line[prefix .. ' terminus'], data['station format'] or i18n[lang]['error_format'], circular
	else
		local terminus = frame:expandTemplate{ title = 'S-line/' .. system .. ' ' .. prefix .. '/' .. lineN }
		return mw.ustring.gsub
	end
end

function p._terminus
	local var, Format, circular = p._terminusTable

	return circular and var or getTerminusText
end

p.terminus = makeInvokeFunction('_terminus')

function p._style
	local style = args[1] or args.style
	local system = args[2] or args.system
	local line = args[3] or args.line
	local station = args[4] or args.station
	local result = {}
	local data = args.data
	local default = 'background-color:#efefef' -- Default background color for 
	if system or data then
		data = data or getData
	end
	if data then
		local function getValue(var)
			if type(var) == 'table' then
				var = var[line] or var[1]
				if type(var) == 'table' then
					var = var[station] or var[1]
				end
			end
			if var ~= '' then return var end
		end

		if style == 'header' then
			local tmp = data['name format'] and getValue(data['name format'])
			if tmp then table.insert end
		elseif style == 'subheader' then
			local tmp = data['header background color'] and getValue(data['header background color'])
			if tmp then
				table.insert
				local color = data['header text color'] and getValue(data['header text color'])
				if color then
					table.insert
				else
					local greatercontrast = require('Module:Color contrast')._greatercontrast
					if greatercontrast{tmp} == '#FFFFFF' then table.insert end
				end
			else
				table.insert
				local color = data['header text color'] and getValue(data['header text color'])
				if color then table.insert end
			end
		end
		result = table.concat
	elseif system then
		local title = 'Template:' .. system .. ' style'
		local titleObj = mw.title.new(title)
		if titleObj and titleObj.exists then
			local tmp
			if style == 'header' then
				tmp = frame:expandTemplate{ title = title, args = {'name_format', line, station} }
				if tmp ~= '' then table.insert end
			elseif style == 'subheader' then
				tmp = frame:expandTemplate{ title = title, args = {'thbgcolor', line, station} }
				if tmp ~= '' then
					table.insert
					local color = frame:expandTemplate{ title = title, args = {'thcolor', line, station} }
					if color ~= '' then
						table.insert
					else
						local ratio = require('Module:Color contrast')._ratio
						if ratio{tmp, '222222'} < 4.5 then table.insert end -- 222222 is the default text color in Vector
					end
				else
					table.insert
					tmp = frame:expandTemplate{ title = title, args = {'thcolor', line, station} }
					if tmp ~= '' then
						table.insert
					end
				end
			end
			result = table.concat
		else
			if style == 'subheader' then
				result = default
			else
				result = ''
			end
		end
	else
		if style == 'subheader' then
			result = default
		else
			result = ''
		end
	end

	return result
end

function p.style(frame)
	local args = getArgs
	return p._style
end

function p.convert(frame)
	local args = frame.args
	local code = mw.text.split(mw.ustring.gsub, '%s*}}%s*{{%s*')
	local system
	local group = tonumber(args.offset or 0) or 0
	local firstgroup = group + 1
	local delete = {
		['s-rail'] = true,
		['s-rail-next'] = true,
		['s-rail-national'] = true,
		['s-start'] = true,
		['s-rail-start'] = true,
		['start'] = true,
		['s-end'] = true,
		['end'] = true
	local order = {
		'line', 'left', 'right', 'to-left', 'to-right',
		'oneway-left', 'oneway-right', 'through-left', 'through-right',
		'reverse', 'reverse-left', 'reverse-right',
		'note-left', 'note-mid', 'note-right', 'transfer'
		-- circular: use module subpage
		-- state: not implemented
	local replace = {
		['previous'] = 'left',
		['next'] = 'right',
		['type'] = 'to-left',
		['type2'] = 'to-right',
		['branch'] = 'type',
		['note'] = 'note-left',
		['notemid'] = 'note-mid',
		['note2'] = 'note-right',
		['oneway1'] = 'oneway-left',
		['oneway2'] = 'oneway-right',
		['through1'] = 'through-left',
		['through2'] = 'through-right'
	local remove_rows = {}
	local data = {}
	local noclear = false
	for i, v in ipairs(code) do
		code[i] = mw.ustring.gsub
		local template = mw.ustring.lower(mw.text.trim(mw.ustring.match))
		code[i] = mw.ustring.match(code[i], '(|.+)$')
		if (mw.ustring.match) then
			noclear = true
		end
		if template == 's-line' then
			data[i] = {}
			local this_system = mw.text.trim(mw.ustring.match(code[i], '|%s*system%s*=([^|]+)'))
			code[i] = mw.text.split
			for m, n in ipairs(code[i]) do
				local tmp = mw.text.split
				if tmp[3] then
					tmp[2] = mw.ustring.gsub
				end
				tmp[1] = replace[tmp[1]] or tmp[1]
				if tmp[2] then
					-- checks for matching brackets
					local curly = select(2, mw.ustring.gsub)-select(2, mw.ustring.gsub)
					local square = select(2, mw.ustring.gsub)-select(2, mw.ustring.gsub)
					if not (curly == 0 and square == 0) then
						local count = mw.clone(m)+1
						while not (curly == 0 and square == 0) do
							tmp[2] = tmp[2]..'|'..code[i][count]
							curly = curly+select(2, mw.ustring.gsub)-select(2, mw.ustring.gsub)
							square = square+select(2, mw.ustring.gsub)-select(2, mw.ustring.gsub)
							code[i][count] = ''
							count = count+1
						end
					end
					data[i][tmp[1]] = tmp[2]
				end
			end
			if (this_system ~= system) or (not system) then
				system = this_system
				data[i]['system'] = system
			else
				data[i]['system'] = nil
			end
			local last = data[i-1] or data[i-2] or data[i-3]
			if last then
				for r, s in pairs({
					['hide1'] = {'left', 'to-left', 'note-left', 'oneway-left'},
					['hide2'] = {'right', 'to-right', 'note-right', 'oneway-right'},
					['hidemid'] = {'type', 'note-mid'}
					if data[i][r] then
						for m, n in ipairs(s) do
							if not data[i][n] then
								data[i][n] = last[n]
							end
						end
					end
				end
			end
			code[i] = {}
			local X = '|'
			local Y = (i+group)..'='
			if data[i]['system'] then
				table.insert
				table.insert
				table.insert
				table.insert
			end
			for m, n in ipairs(order) do
				if data[i][n] then
					table.insert
					table.insert
					table.insert
					table.insert
				end
			end
			code[i] = table.concat(code[i])
		elseif template == 's-note' then
			code[i] = mw.ustring.gsub
			code[i] = mw.ustring.gsub
		elseif template == 's-text' then
			code[i] = mw.ustring.gsub
		elseif delete[template] then
			code[i] = ''
			table.insert -- at the start, so that the rows are deleted in reverse order
			group = group-1
		end
	end
	for i, v in ipairs(remove_rows) do
		table.remove
	end
	code = table.concat
	local t = {''}
	system = mw.ustring.match(code, '|system(%d*)=')
	code = mw.ustring.gsub
	if tonumber(system) > firstgroup then
		-- If s-line isn't the first template then the system will have to be moved to the top
		system = mw.ustring.match(code, '|system%d*=([^|]*[^|\n])')
		code = mw.ustring.gsub
		code = '\n|system'..firstgroup..'='..system..code
	elseif not mw.ustring.match then
		-- If there's only one parameter group then there's no need to have line breaks
		code = mw.ustring.gsub
		code = mw.ustring.gsub(code, '(|[^=|]+)1=', '%1=')
		t[2] = '}}'
		if not mw.ustring.match then
			code = mw.ustring.gsub
			code = mw.ustring.gsub
		end
	end
	if not mw.ustring.match then
		code = mw.ustring.gsub
		code = mw.ustring.gsub
		code = mw.ustring.gsub
		code = mw.ustring.gsub
	end
	return t[1]..code..t[2]
end