-- This module implements {{portal bar}}.

require('Module:No globals')

-- determine whether we're being called from a sandbox
local isSandbox = mw.getCurrentFrame():getTitle():find('sandbox', 1, true)
local sandbox = isSandbox and '/sandbox' or ''

local portalModule = require('Module:Portal'..sandbox)
local getImageName = portalModule._image
local yesno = require( 'Module:Yesno' )
local p = {}

local function sandboxVersion(s)
	return isSandbox and s.."-sand" or s
end

-- Builds the portal bar used by {{portal bar}}.
function p._main( portals, args )
	if #portals < 1 then return '' end -- Don't display a blank navbox if no portals were specified.

	if args.border == nil then args.border = true end
	args.border = yesno(args.border, true)
	
	local nav = mw.html.create( 'div' )
		:addClass(sandboxVersion('portal-bar'))
		:addClass( 'noprint metadata noviewer' )
		:attr( 'role', 'navigation' )
		:attr( 'aria-label' , 'Portals' )
		:addClass(sandboxVersion(args.border and 'portal-bar-bordered' or 'portal-bar-unbordered'))

	local container = nav:tag('ul')
	container:addClass(sandboxVersion('portal-bar-content'))

	local size = '24x21px'
	for _, portal in ipairs( portals ) do
		container
			:tag( 'li' )
			:addClass(sandboxVersion('portal-bar-item'))
			:wikitext( string.format('<span class="nowrap">[[File:%s|%s]] </span>[[Portal:%s|%s主題]]',
					getImageName{ portal }, size, portal, portal))
	end
	
	local styleFile = 'Module:Portal bar'..sandbox..'/styles.css'
	return mw.getCurrentFrame():extensionTag{
		name = 'templatestyles', args = { src = styleFile }
	} .. tostring( nav ) 
end

-- Processes external arguments and sends them to the other functions.
function p.main( frame )
	-- If called via #invoke, use the args passed into the invoking
	-- template, or the args passed to #invoke if any exist. Otherwise
	-- assume args are being passed directly in from the debug console
	-- or from another Lua module.
	local origArgs
	if type( frame.getParent ) == 'function' then
		origArgs = frame:getParent().args
		for k, v in pairs( frame.args ) do
			origArgs = frame.args
			break
		end
	else
		origArgs = frame
	end
	-- Process the args to make an array of portal names that can be used with ipairs. We need to use ipairs because we want to list
	-- all the portals in the order they were passed to the template, but we also want to be able to deal with positional arguments
	-- passed explicitly, for example {{portal|2=Politics}}. The behaviour of ipairs is undefined if nil values are present, so we
	-- need to make sure they are all removed.
	local portals, args = {}, {}
	for k, v in pairs( origArgs ) do
		if type( k ) == 'number' and type( v ) == 'string' then -- Make sure we have no non-string portal names.
			if mw.ustring.find( v, '%S' ) then -- Remove blank values.
				table.insert( portals, k )
			end
		elseif type( k ) ~= 'number' then -- Separate named arguments from portals.
			if type( v ) == 'string' then
				v = mw.text.trim( v )
			end
			args[ k ] = v
		end
	end
	table.sort( portals )
	for i, v in ipairs( portals ) do
		portals[ i ] = mw.text.trim( origArgs[ v ] ) -- Swap keys with values, trimming whitespace.
	end
	return p._main( portals, args )
end

return p