Editing Module:Sandbox/Szqecs/Adjacent stations

--
-- This module implements {{Adjacent stations}}
--

local p = {}

local args = {}
local origArgs
local root
local data = {}

local function union(t1, t2, t3, t4)
	-- Returns the union of the values of four tables, as a sequence.
	local vals = {}
	for k, v in pairs(t1) do
		vals[v] = true
	end
	for k, v in pairs(t2) do
		vals[v] = true
	end
	for k, v in pairs(t3) do
		vals[v] = true
	end
	for k, v in pairs(t4) do
		vals[v] = true
	end
	local ret = {}
	for k, v in pairs(vals) do
		table.insert(ret, k)
	end
	return ret
end

local function getArgNums(prefix)
	-- Returns a table containing the numbers of the arguments that exist
	-- for the specified prefix. For example, if the prefix was 'data', and
	-- 'line1', 'line2', and 'line5' exist, it would return {1, 2, 5}.
	local nums = {}
	for k, v in pairs(args) do
		local num = tostring(k):match('^' .. prefix .. '([1-9]%d*)$')
		if num then table.insert(nums, tonumber(num)) end
	end
	table.sort(nums)
	return nums
end

local function addRow(rowArgs)
	-- Adds a row to the infobox, with either a header cell
	-- or a label/data cell combination.
	
end

local function renderHeader()
	root
		:tag('tr')
			:tag('th')
				:addClass('hcA')
				:wikitext('Previous station')
			:tag('th')
				:attr('colspan', 3)
				:addClass('hmA')
				:wikitext('Title')
			:tag('th')
				:addClass('hcA')
				:wikitext('Following station')
end

local function renderRows()
	-- Gets the union of the header, line, type and note-row argument numbers,
	-- and renders them all in order using addRow.
	local rownums = union(getArgNums('header'), getArgNums('line'), getArgNums('type'), getArgNums('note-row'))
	table.sort(rownums)
	for i, num in ipairs(rownums) do
		local typeName = args['type' .. tostring(num)] or args['line' .. tostring(num)]
		local data
		if typeName and ((args['system'] .. tostring(num)) or (arg['system'] .. tostring(rownums[i - 1]))) then
		end
		addRow({

		})
	end
end

local function _main()
	-- Specify the overall layout of the succession box, with special settings
		root = mw.html.create('table')
		root:addClass('wikitable adjacent-stations')
			
		renderHeader()
		renderRows()
 
	return tostring(root)
end

local function preprocessSingleArg(argName)
	-- If the argument exists and isn't blank, add it to the argument table.
	-- Blank arguments are treated as nil to match the behaviour of ParserFunctions.
	if not args[argName] and origArgs[argName] and origArgs[argName] ~= '' then
		args[argName] = origArgs[argName]
	end
end

local function preprocessArgs(prefixTable, step)
	-- Assign the parameters with the given prefixes to the args table, in order, in batches
	-- of the step size specified. This is to prevent references etc. from appearing in the
	-- wrong order. The prefixTable should be an array containing tables, each of which has
	-- two possible fields, a "prefix" string and a "depend" table. The function always parses
	-- parameters containing the "prefix" string, but only parses parameters in the "depend"
	-- table if the prefix parameter is present and non-blank.
	if type(prefixTable) ~= 'table' then
		error("Non-table value detected for the prefix table", 2)
	end
	if type(step) ~= 'number' then
		error("Invalid step value detected", 2)
	end
	
	-- Get arguments without a number suffix, and check for bad input.
	for i, v in ipairs(prefixTable) do
		if type(v) ~= 'table' or type(v.prefix) ~= "string" or (v.depend and type(v.depend) ~= 'table') then
			error('Invalid input detected to preprocessArgs prefix table', 2)
		end
		preprocessSingleArg(v.prefix)
		-- Only parse the depend parameter if the prefix parameter is present and not blank.
		if args[v.prefix] and v.depend then
			for j, dependValue in ipairs(v.depend) do
				if type(dependValue) ~= 'string' then
					error('Invalid "depend" parameter value detected in preprocessArgs')
				end
				preprocessSingleArg(dependValue)
			end
		end
	end

	-- Get arguments with number suffixes.
	local a = 1 -- Counter variable.
	local moreArgumentsExist = true
	while moreArgumentsExist == true do
		moreArgumentsExist = false
		for i = a, a + step - 1 do
			for j, v in ipairs(prefixTable) do
				local prefixArgName = v.prefix .. tostring(i)
				if origArgs[prefixArgName] then
					moreArgumentsExist = true -- Do another loop if any arguments are found, even blank ones.
					preprocessSingleArg(prefixArgName)
				end
				-- Process the depend table if the prefix argument is present and not blank, or
				-- we are processing "prefix1" and "prefix" is present and not blank, and
				-- if the depend table is present.
				if v.depend and (args[prefixArgName] or (i == 1 and args[v.prefix])) then
					for j, dependValue in ipairs(v.depend) do
						local dependArgName = dependValue .. tostring(i)
						preprocessSingleArg(dependArgName)
					end
				end
			end
		end
		a = a + step
	end
end
 
function p.main(frame)
	-- If called via #invoke, use the args passed into the invoking template.
	-- Otherwise, for testing purposes, assume args are being passed directly in.
	if frame == mw.getCurrentFrame() then
		origArgs = frame:getParent().args
	else
		origArgs = frame
	end
	local dependants = {
		'left', 'right', 'to-left', 'to-right', 'to', 'transfer',
		'oneway-left', 'oneway-right', 'non-stop', 'through',
		'through-left', 'through-right', 'reverse', 'reverse-left', 'reverse-right'
	}
	preprocessArgs({
		{prefix = 'system'},
		{prefix = 'line', depend = dependants},
		{prefix = 'type', depend = dependants}
	})
	return _main()
end
 
return p