local p = {}

local SUFFIX = ""
-- Change to main module upon deployment
local parserModuleName = "Module:Road data/parser" .. SUFFIX
local cityModuleName = "Module:Jct/city" .. SUFFIX

local concat = table.concat
local insert = table.insert
local format = mw.ustring.format
local roadDataModule = require("Module:Road data" .. SUFFIX)

local rdt

-- Links/abbreviations
local function routeText(route, jctname, frame)
	local link
	local type = route.type
	if not type or type == '' then
		link = route.route
	else
		link = roadDataModule.link(route)
	end

	local dir = route.dir and ' ' .. string.lower(route.dir) or ''
	local routeText = link .. dir

	local name = route.name
	if name and name ~= '' then
		local mainText = jctname and name or routeText
		local parenText = jctname and routeText or name

		if route.rdt then
			return frame:expandTemplate{ title = 'BSsplit', args = {mainText, parenText, align = 'left', valign = 'middle'} }
		else
			return format('%s (%s)', mainText, parenText)
		end
	else
		return routeText
	end
end

local function extra(args)
	local extraTypes = mw.loadData('Module:Road data/extra')
	local extraIcon = extraTypes[string.lower(args.extra or '')]
	if not extraIcon then return '' end
	local size = require("Module:Road data/size").size({style = 'jct'})
	local countryIcon = extraIcon[args.country] or extraIcon.default
	if type(countryIcon) == 'table' then
		local localIcon = countryIcon[args.state] or countryIcon.default
		return string.format("[[File:%s|%s|alt=|link=]]", localIcon, size)
	else
		return string.format("[[File:%s|%s|alt=|link=]]", countryIcon, size)
	end
end

local function parseArgs(args)
	local state = args.state or args.province or ''
	args.state = state
	local country
	if args.country and args.country ~= '' then
		country = string.upper(args.country)
	else
		local countryModule = mw.loadData("Module:Road data/countrymask")
		country = countryModule[state] or 'UNK'
	end
	args.country = country

	local params = {'denom', 'county', 'township', 'dab', 'nolink', 'noshield', 'to', 'dir', 'name'}
	local routes = {}
	local routeCount = 1
	local seenTo = false
	while true do
		local routeType = args[routeCount * 2 - 1]
		if not routeType then break end
		local route = {type = routeType, route = args[routeCount * 2]}
		for _,v in pairs(params) do
			route[v] = args[v .. routeCount]
		end
		route.country = country
		route.state = state

		-- Set the first .to to true.
		-- Set all following .to to ''.
		if seenTo then
			if route.to then
				-- Report duplicate to flag.
				route.toerror = true
			end
			route.to = ''
		elseif route.to then
			route.to = true
			seenTo = true
		end

		route.rdt = args.rdt
		insert(routes, route)
		routeCount = routeCount + 1
	end
	return routes
end

local function prefix(to, num)
	if to and to ~= '' then
		return num == 1 and 'To ' or ' to '
	end
	return num == 1 and '' or ' / '
end

local function addErrorMsg(catCode, msg, errorMsg)
	errorMsg.code = errorMsg.code or catCode
	insert(errorMsg, format('<span style="display: none;">Module:Jct %s</span>', msg))
end

function p._jct(args, frame)
	rdt = args.rdt
	local routes = parseArgs(args)
	local shields = {}
	local links = {}
	local allMissingShields = {}
	local typeErr = false
	local toErr = false
	frame = frame or mw.getCurrentFrame()
	for num,route in ipairs(routes) do
		if not (args.noshield or route.noshield) then
			local shield, missingShields = roadDataModule.shield(route)
			insert(shields, shield)
			if missingShields[1] then
				insert(allMissingShields, concat(missingShields, ' / '))
			end
		end
		local prefix = prefix(route.to, num)
		if prefix ~= '' then insert(links, prefix) end
		insert(links, routeText(route, args.jctname, frame))
		typeErr = typeErr or route.typeerror or false
		toErr = toErr or route.toerror or false
	end
	local graphics = concat(shields) .. extra(args) .. ' '
	local linkText = concat(links)
	local cities = ''
	if args.city1 or args.location1 then
		local citiesPrefix
		if args.citiesprefix then
			citiesPrefix = args.citiesprefix ~= '' and format(" %s ", args.citiesprefix) or ''
		else
			citiesPrefix = '&nbsp;'
		end
		local cityModule = require(cityModuleName)
		cities = citiesPrefix .. cityModule.city(args)
	end

	local errorMsg = {}
	-- Errors must be reported by the level of severity, most severe first.
	if typeErr then
		-- Report invalid type errors.
		addErrorMsg("§", 'error: Invalid route type', errorMsg)
	end
	if #allMissingShields > 0 then
		-- Report missing shield error.
		-- shieldExists() would have populated missingShields if shields are missing.
		addErrorMsg("¶", 'error: Missing route marker graphics: ' .. concat(allMissingShields, ' / '), errorMsg)
	end
	if toErr then
		-- Report invalid to errors.
		addErrorMsg("&", 'error: Invalid "to" argument', errorMsg)
	end
	if args.road then
		-- Report deprecated "road" warning.
		addErrorMsg("∆", 'warning: "road" parameter is deprecated', errorMsg)
	end
	if rdt and rdt ~= 'y' then
		-- Report invalid type errors.
		addErrorMsg("R", 'error: Invalid rdt value', errorMsg)
	end
	if #errorMsg > 0 then
		local page = mw.title.getCurrentTitle().prefixedText -- Get transcluding page's title
		-- Add a category for the first, most severe error.
		insert(errorMsg, format('[[Category:Jct template errors|%s %s]]', errorMsg.code, page))
		errorMsg = concat(errorMsg)
	else
		errorMsg = ''
	end

	return graphics .. linkText .. cities .. errorMsg
end

function p.jct(frame)
	-- Import module function to work with passed arguments
	local getArgs = require('Module:Arguments').getArgs
	local args = getArgs(frame, {removeBlanks = false})
	return p._jct(args, frame)
end

function p._roadlink(args, frame)
	local routes = parseArgs(args)
	local links = {}
	local typeErr = false
	local toErr = false
	frame = frame or mw.getCurrentFrame()
	for num,route in ipairs(routes) do
		local prefix = prefix(route.to, num)
		if prefix ~= '' then insert(links, prefix) end
		insert(links, routeText(route, args.jctname, frame))
		typeErr = typeErr or route.typeerror or false
		toErr = toErr or route.toerror or false
	end
	local linkText = concat(links)
	local cities = ''
	if args.city1 or args.location1 then
		local citiesPrefix
		if args.citiesprefix then
			citiesPrefix = args.citiesprefix ~= '' and format(" %s ", args.citiesprefix) or ''
		else
			citiesPrefix = '&nbsp;'
		end
		local cityModule = require(cityModuleName)
		cities = citiesPrefix .. cityModule.city(args)
	end

	local errorMsg = {}
	-- Errors must be reported by the level of severity, most severe first.
	if typeErr then
		-- Report invalid type errors.
		addErrorMsg("2", 'error: Invalid route type', errorMsg)
	end
	if toErr then
		-- Report invalid to errors.
		addErrorMsg("3", 'error: Invalid "to" argument', errorMsg)
	end
	if args.road then
		-- Report deprecated "road" warning.
		addErrorMsg("W", 'warning: "road" parameter is deprecated', errorMsg)
	end
	if rdt and rdt ~= 'y' then
		-- Report invalid type errors.
		addErrorMsg("R", 'error: Invalid rdt value', errorMsg)
	end
	if #errorMsg > 0 then
		local page = mw.title.getCurrentTitle().prefixedText -- Get transcluding page's title
		-- Add a category for the first, most severe error.
		insert(errorMsg, format('[[Category:Jct template errors|%s %s]]', errorMsg.code, page))
		errorMsg = concat(errorMsg)
	else
		errorMsg = ''
	end

	return linkText .. cities
end

function p.roadlink(frame)
	-- Import module function to work with passed arguments
	local getArgs = require('Module:Arguments').getArgs
	local args = getArgs(frame, {removeBlanks = true})
	return p._roadlink(args, frame)
end

return p