local p = {}

local concat = table.concat
local insert = table.insert
local format = mw.ustring.format
local trim = mw.text.trim

local parserModule = require("Module:Road data/parser")
local parser = parserModule.parser
local util = require("Module:Road data/util")
local sizeModuleName = 'Module:Road data/size/sandbox' -- REMOVE SANDBOX

-- Shields
local function addContextBanner(route, name, suffix, bannerSpec, size)
	local bannerModule = 'Module:Road data/banners/' .. string.upper(route.country)
	local shieldField = name .. 'shield'
	local shield = parser(route, shieldField)

	if shield == nil then
		-- This route type does not define shield.
		-- Find shield in the default banner table.
		shield = parser(route, 'shield', name, bannerModule)
		if shield and shield ~= '' then
			if suffix == nil then
				suffix = parser(route, 'shield', 'suffix', bannerModule)
			end

			if suffix and suffix ~= '' then
				shield = shield .. " " .. suffix
			end

			shield = shield .. ".svg"
		end
	end

	if shield and shield ~= '' then
		-- Add banner plate
		insert(bannerSpec, {shield, size})
	end
end

local function bannerSpec(banner, bannerSize, bannerSuffix, route, size)
	local banners = {}

	if type(banner) == "table" then
		local bannerSizeIsNotTable = type(bannerSize) ~= "table"

		for i, filename in ipairs(banner) do
			local singleBannerSize = bannerSizeIsNotTable and bannerSize or bannerSize[i]
			insert(banners, {filename, singleBannerSize})
		end
	elseif banner ~= '' then
		insert(banners, {banner, bannerSize})
	end

	if route.dir then
		addContextBanner(route, 'dir', bannerSuffix, banners, size)
	end

	if route.to then
		addContextBanner(route, 'to', bannerSuffix, banners, size)
	end

	return banners
end

local function shieldSpec(route, shieldType, size, ignoreUpright)
	local shieldSpec = {}

	local shield
	if route.to and shieldType == 'main' then shield = parser(route, 'shieldtomain') end
	if not shield and route.to then shield = parser(route, 'shieldto') end
	if not shield and shieldType == 'main' then shield = parser(route, 'shieldmain') end
	if not shield and shieldType == 'list' then shield = parser(route, 'shieldlist') end
	if not shield then shield = parser(route, 'shield') or '' end
	if shield == '' then return shieldSpec end

	local orientation = parser(route, 'orientation')
	local shieldSize
	local shieldSizeIsNotTable

	if type(orientation) == "table" then
		shieldSize = {}
		shieldSizeIsNotTable = false

		for i, shieldOrientation in ipairs(orientation) do
			insert(shieldSize, (shieldOrientation ~= 'upright' or ignoreUpright) and 'x' .. size or size)
		end
	else
		shieldSize = (orientation ~= 'upright' or ignoreUpright) and 'x' .. size or size
		shieldSizeIsNotTable = true
	end
	
	local banner = parser(route, 'banner') or {}
	local bannerSize = size
	local bannerSuffix = parser(route, 'bannersuffix')
	
	local bannerIsNotTable = type(banner) ~= "table"
	local bannerSuffixIsNotTable = type(bannerSuffix) ~= "table"

	if type(shield) == "table" then
		for i, filename in ipairs(shield) do
			-- Fallback to default size for the size style
			local singleShieldSize = shieldSizeIsNotTable and shieldSize or shieldSize[i] or size

			-- banner.all describes banners that apply to all multiple shields
			local shieldBanner = bannerIsNotTable and banner or (banner[i] or banner.all or {})
			local shieldBannerSuffix = bannerSuffix and (bannerSuffixIsNotTable and bannerSuffix or bannerSuffix[i])

			insert(shieldSpec, {
				shield = {filename, singleShieldSize},
				banners = bannerSpec(shieldBanner, bannerSize, shieldBannerSuffix, route, size),
				route = route
			})
		end
	elseif shield ~= '' then
		insert(shieldSpec, {
			shield = {shield, shieldSize},
			banners = bannerSpec(banner, bannerSize, bannerSuffix, route, size),
			route = route
		})
	end

	return shieldSpec
end

local missingShields
local shieldExistsCache = {}

local function shieldExists(shield)
	local exists = shieldExistsCache[shield]

	if exists == nil then
		local file = mw.title.new(shield, 'Media').file
		exists = file.exists
		-- Cache result
		shieldExistsCache[shield] = exists
	end

	if exists then return true end

	insert(missingShields, shield)
	return false
end

local function render(shieldEntry, nonDecorative)
	local shield = shieldEntry.shield
	local banners = shieldEntry.banners
	local exists = shieldExists(shield[1])
	if not exists then return '' end
	
	local alt = ''
	if nonDecorative then
		alt = (parser(shieldEntry.route, 'abbr') or '') .. ' marker'
	end
	
	local shieldCode = format("[[File:%s|%s|link=|alt=%s]]", shield[1], shield[2], alt)
	if not banners[1] then return shieldCode end

	for _, banner in ipairs(banners) do
		shieldCode = format(
			"[[File:%s|%s|link=|alt=%s]]<br>%s",
			banner[1],
			banner[2],
			alt,
			shieldCode
		)
	end

	return '<span style="display: inline-block; vertical-align: baseline; line-height: 0; text-align: center;">'
		.. shieldCode
		.. '</span>'
end

function p.shield(route, shieldType, sizeOrStyle, nonDecorative)
	missingShields = {}
	
	local size
	local ignoreUpright
	
	if sizeOrStyle and sizeOrStyle:match('^%d+px$') then
		size = sizeOrStyle
		ignoreUpright = false
	else
		local sizeModule = require(sizeModuleName) -- REMOVE SANDBOX
		size = sizeModule._size({ style = sizeOrStyle })
		ignoreUpright = sizeModule._ignoreUpright(sizeOrStyle)
	end
	
	local rendered = {}
	for _, entry in ipairs(shieldSpec(route, shieldType, size, ignoreUpright)) do
		insert(rendered, render(entry, nonDecorative))
	end
	
	return concat(rendered, '&thinsp;'), missingShields
end

-- Links
function p.link(route, useName)
	local abbr, errMsg = parser(route, useName and 'name' or 'abbr')

	if not abbr then
		route.typeerror = true
		return util.err(errMsg or format("Invalid type: %s", route.type or "(nil)"))
	end

	if route.nolink then return abbr, abbr end

	local link = parser(route, 'link') or ''
	if link == '' then return abbr, abbr end

	return format("[[%s|%s]]", link, abbr), abbr
end

return p