require('strict')
local p = {}
local navbar = require('Module:Navbar')._navbar
local cfg = mw.loadData('Module:Navbox/configuration')
local getArgs -- lazily initialized
local args
local format = string.format

local function striped(wikitext, border)
	-- Return wikitext with markers replaced for odd/even striping.
	-- Child (subgroup) navboxes are flagged with a category that is removed
	-- by parent navboxes. The result is that the category shows all pages
	-- where a child navbox is not contained in a parent navbox.
	local orphanCat = cfg.category.orphan
	if border == cfg.keyword.border_subgroup and args[cfg.arg.orphan] ~= cfg.keyword.orphan_yes then
		-- No change; striping occurs in outermost navbox.
		return wikitext .. orphanCat
	end
	local first, second = cfg.class.navbox_odd_part, cfg.class.navbox_even_part
	if args[cfg.arg.evenodd] then
		if args[cfg.arg.evenodd] == cfg.keyword.evenodd_swap then
			first, second = second, first
		else
			first = args[cfg.arg.evenodd]
			second = first
		end
	end
	local changer
	if first == second then
		changer = first
	else
		local index = 0
		changer = function (code)
			if code == '0' then
				-- Current occurrence is for a group before a nested table.
				-- Set it to first as a valid although pointless class.
				-- The next occurrence will be the first row after a title
				-- in a subgroup and will also be first.
				index = 0
				return first
			end
			index = index + 1
			return index % 2 == 1 and first or second
		end
	end
	local regex = orphanCat:gsub('([%[%]])', '%%%1')
	return (wikitext:gsub(regex, ''):gsub(cfg.marker.regex, changer)) -- () omits gsub count
end

local function processItem(item, nowrapitems)
	if item:sub(1, 2) == '{|' then
		-- Applying nowrap to lines in a table does not make sense.
		-- Add newlines to compensate for trim of x in |parm=x in a template.
		return '\n' .. item ..'\n'
	end
	if nowrapitems == cfg.keyword.nowrapitems_yes then
		local lines = {}
		for line in (item .. '\n'):gmatch('([^\n]*)\n') do
			local prefix, content = line:match('^([*:;#]+)%s*(.*)')
			if prefix and not content:match(cfg.pattern.nowrap) then
				line = format(cfg.nowrap_item, prefix, content)
			end
			table.insert(lines, line)
		end
		item = table.concat(lines, '\n')
	end
	if item:match('^[*:;#]') then
		return '\n' .. item ..'\n'
	end
	return item
end

local function has_navbar()
	return args[cfg.arg.navbar] ~= cfg.keyword.navbar_off
		and args[cfg.arg.navbar] ~= cfg.keyword.navbar_plain
		and (
			args[cfg.arg.name]
			or mw.getCurrentFrame():getParent():getTitle():gsub(cfg.pattern.sandbox, '')
				~= cfg.pattern.navbox
		)
end

local function renderNavBar(titleCell)
	if has_navbar() then
		titleCell:wikitext(navbar{
			[cfg.navbar.name] = args[cfg.arg.name],
			[cfg.navbar.mini] = 1,
			[cfg.navbar.fontstyle] = (args[cfg.arg.basestyle] or '') .. ';' ..
				(args[cfg.arg.titlestyle] or '') ..
				';background:none transparent;border:none;box-shadow:none;padding:0;'
		})
	end

end

local function renderTitleRow(tbl)
	if not args[cfg.arg.title] then return end

	local titleRow = tbl:tag('tr')

	local titleCell = titleRow:tag('th'):attr('scope', 'col')

	local titleColspan = 2
	if args[cfg.arg.imageleft] then titleColspan = titleColspan + 1 end
	if args[cfg.arg.image] then titleColspan = titleColspan + 1 end

	titleCell
		:cssText(args[cfg.arg.basestyle])
		:cssText(args[cfg.arg.titlestyle])
		:addClass(cfg.class.navbox_title)
		:attr('colspan', titleColspan)

	renderNavBar(titleCell)

	titleCell
		:tag('div')
			-- id for aria-labelledby attribute
			:attr('id', mw.uri.anchorEncode(args[cfg.arg.title]))
			:addClass(args[cfg.arg.titleclass])
			:css('font-size', '114%')
			:css('margin', '0 4em')
			:wikitext(processItem(args[cfg.arg.title]))
end

local function getAboveBelowColspan()
	local ret = 2
	if args[cfg.arg.imageleft] then ret = ret + 1 end
	if args[cfg.arg.image] then ret = ret + 1 end
	return ret
end

local function renderAboveRow(tbl)
	if not args[cfg.arg.above] then return end

	tbl:tag('tr')
		:tag('td')
			:addClass(cfg.class.navbox_abovebelow)
			:addClass(args[cfg.arg.aboveclass])
			:cssText(args[cfg.arg.basestyle])
			:cssText(args[cfg.arg.abovestyle])
			:attr('colspan', getAboveBelowColspan())
			:tag('div')
				-- id for aria-labelledby attribute, if no title
				:attr('id', (not args[cfg.arg.title]) and mw.uri.anchorEncode(args[cfg.arg.above]) or nil)
				:wikitext(processItem(args[cfg.arg.above], args[cfg.arg.nowrapitems]))
end

local function renderBelowRow(tbl)
	if not args[cfg.arg.below] then return end

	tbl:tag('tr')
		:tag('td')
			:addClass(cfg.class.navbox_abovebelow)
			:addClass(args[cfg.arg.belowclass])
			:cssText(args[cfg.arg.basestyle])
			:cssText(args[cfg.arg.belowstyle])
			:attr('colspan', getAboveBelowColspan())
			:tag('div')
				:wikitext(processItem(args[cfg.arg.below], args[cfg.arg.nowrapitems]))
end

local function renderListRow(tbl, index, listnum, listnums_size)
	local row = tbl:tag('tr')

	if index == 1 and args[cfg.arg.imageleft] then
		row
			:tag('td')
				:addClass(cfg.class.noviewer)
				:addClass(cfg.class.navbox_image)
				:addClass(args[cfg.arg.imageclass])
				:css('width', '1px')               -- Minimize width
				:css('padding', '0 2px 0 0')
				:cssText(args[cfg.arg.imageleftstyle])
				:attr('rowspan', listnums_size)
				:tag('div')
					:wikitext(processItem(args[cfg.arg.imageleft]))
	end

	local group_and_num = format(cfg.arg.group_and_num, listnum)
	local groupstyle_and_num = format(cfg.arg.groupstyle_and_num, listnum)
	if args[group_and_num] then
		local groupCell = row:tag('th')

		-- id for aria-labelledby attribute, if lone group with no title or above
		if listnum == 1 and not (args[cfg.arg.title] or args[cfg.arg.above] or args[cfg.arg.group2]) then
			groupCell
				:attr('id', mw.uri.anchorEncode(args[cfg.arg.group1]))
		end

		groupCell
			:attr('scope', 'row')
			:addClass(cfg.class.navbox_group)
			:addClass(args[cfg.arg.groupclass])
			:cssText(args[cfg.arg.basestyle])
			-- If groupwidth not specified, minimize width
			:css('width', args[cfg.arg.groupwidth] or '1%')

		groupCell
			:cssText(args[cfg.arg.groupstyle])
			:cssText(args[groupstyle_and_num])
			:wikitext(args[group_and_num])
	end

	local listCell = row:tag('td')

	if args[group_and_num] then
		listCell
			:addClass(cfg.class.navbox_list_with_group)
	else
		listCell:attr('colspan', 2)
	end

	if not args[cfg.arg.groupwidth] then
		listCell:css('width', '100%')
	end

	local rowstyle  -- usually nil so cssText(rowstyle) usually adds nothing
	if index % 2 == 1 then
		rowstyle = args[cfg.arg.oddstyle]
	else
		rowstyle = args[cfg.arg.evenstyle]
	end

	local list_and_num = format(cfg.arg.list_and_num, listnum)
	local listText = args[list_and_num]
	local oddEven = cfg.marker.oddeven
	if listText:sub(1, 12) == '</div><table' then
		-- Assume list text is for a subgroup navbox so no automatic striping for this row.
		oddEven = listText:find(cfg.pattern.navbox_title) and cfg.marker.restart or cfg.class.navbox_odd_part
	end

	local liststyle_and_num = format(cfg.arg.liststyle_and_num, listnum)
	local listclass_and_num = format(cfg.arg.listclass_and_num, listnum)
	listCell
		:css('padding', '0')
		:cssText(args[cfg.arg.liststyle])
		:cssText(rowstyle)
		:cssText(args[liststyle_and_num])
		:addClass(cfg.class.navbox_list)
		:addClass(cfg.class.navbox_part .. oddEven)
		:addClass(args[cfg.arg.listclass])
		:addClass(args[listclass_and_num])
		:tag('div')
			:css('padding',
				(index == 1 and args[cfg.arg.list1padding]) or args[cfg.arg.listpadding] or '0 0.25em'
			)
			:wikitext(processItem(listText, args[cfg.arg.nowrapitems]))

	if index == 1 and args[cfg.arg.image] then
		row
			:tag('td')
				:addClass(cfg.class.noviewer)
				:addClass(cfg.class.navbox_image)
				:addClass(args[cfg.arg.imageclass])
				:css('width', '1px')               -- Minimize width
				:css('padding', '0 0 0 2px')
				:cssText(args[cfg.arg.imagestyle])
				:attr('rowspan', listnums_size)
				:tag('div')
					:wikitext(processItem(args[cfg.arg.image]))
	end
end

local function has_list_class(htmlclass)
	local patterns = {
		'^' .. htmlclass .. '$',
		'%s' .. htmlclass .. '$',
		'^' .. htmlclass .. '%s',
		'%s' .. htmlclass .. '%s'
	}
	
	for arg, _ in pairs(args) do
		if type(arg) == 'string' and mw.ustring.find(arg, cfg.pattern.class) then
			for _, pattern in ipairs(patterns) do
				if mw.ustring.find(args[arg] or '', pattern) then
					return true
				end
			end
		end
	end
	return false
end

-- there are a lot of list classes in the wild, so we add their TemplateStyles
local function add_list_styles()
	local frame = mw.getCurrentFrame()
	local function add_list_templatestyles(htmlclass, templatestyles)
		if has_list_class(htmlclass) then
			return frame:extensionTag{
				name = 'templatestyles', args = { src = templatestyles }
			}
		else
			return ''
		end
	end
	
	local hlist_styles = add_list_templatestyles('hlist', cfg.hlist_templatestyles)
	local plainlist_styles = add_list_templatestyles('plainlist', cfg.plainlist_templatestyles)
	
	-- a second workaround for [[phab:T303378]]
	-- when that issue is fixed, we can actually use has_navbar not to emit the
	-- tag here if we want
	if has_navbar() and hlist_styles == '' then
		hlist_styles = frame:extensionTag{
			name = 'templatestyles', args = { src = cfg.hlist_templatestyles }
		}
	end
	
	-- hlist -> plainlist is best-effort to preserve old Common.css ordering.
	-- this ordering is not a guarantee because most navboxes will emit only
	-- one of these classes [hlist_note]
	return hlist_styles .. plainlist_styles
end

local function needsHorizontalLists(border)
	if border == cfg.keyword.border_subgroup or args[cfg.arg.tracking] == cfg.keyword.tracking_no then
		return false
	end
	return not has_list_class(cfg.pattern.hlist) and not has_list_class(cfg.pattern.plainlist)
end

local function hasBackgroundColors()
	for _, key in ipairs({cfg.arg.titlestyle, cfg.arg.groupstyle,
		cfg.arg.basestyle, cfg.arg.abovestyle, cfg.arg.belowstyle}) do
		if tostring(args[key]):find('background', 1, true) then
			return true
		end
	end
	return false
end

local function hasBorders()
	for _, key in ipairs({cfg.arg.groupstyle, cfg.arg.basestyle,
		cfg.arg.abovestyle, cfg.arg.belowstyle}) do
		if tostring(args[key]):find('border', 1, true) then
			return true
		end
	end
	return false
end

local function isIllegible()
	local styleratio = require('Module:Color contrast')._styleratio
	for key, style in pairs(args) do
		if tostring(key):match(cfg.pattern.style) then
			if styleratio{mw.text.unstripNoWiki(style)} < 4.5 then
				return true
			end
		end
	end
	return false
end

local function getTrackingCategories(border)
	local cats = {}
	if needsHorizontalLists(border) then table.insert(cats, cfg.category.horizontal_lists) end
	if hasBackgroundColors() then table.insert(cats, cfg.category.background_colors) end
	if isIllegible() then table.insert(cats, cfg.category.illegible) end
	if hasBorders() then table.insert(cats, cfg.category.borders) end
	return cats
end

local function renderTrackingCategories(builder, border)
	local title = mw.title.getCurrentTitle()
	if title.namespace ~= 10 then return end -- not in template space
	local subpage = title.subpageText
	if subpage == cfg.keyword.subpage_doc or subpage == cfg.keyword.subpage_sandbox
		or subpage == cfg.keyword.subpage_testcases then return end

	for _, cat in ipairs(getTrackingCategories(border)) do
		builder:wikitext('[[Category:' .. cat .. ']]')
	end
end

local function renderMainTable(border, listnums)
	local tbl = mw.html.create('table')
		:addClass(cfg.class.nowraplinks)
		:addClass(args[cfg.arg.bodyclass])

	local state = args[cfg.arg.state]
	if args[cfg.arg.title] and state ~= cfg.keyword.state_plain and state ~= cfg.keyword.state_off then
		if state == cfg.keyword.state_collapsed then
			state = cfg.class.collapsed
		end
		tbl
			:addClass(cfg.class.collapsible)
			:addClass(state or cfg.class.autocollapse)
	end

	tbl:css('border-spacing', 0)
	if border == cfg.keyword.border_subgroup or border == cfg.keyword.border_none then
		tbl
			:addClass(cfg.class.navbox_subgroup)
			:cssText(args[cfg.arg.bodystyle])
			:cssText(args[cfg.arg.style])
	else  -- regular navbox - bodystyle and style will be applied to the wrapper table
		tbl
			:addClass(cfg.class.navbox_inner)
			:css('background', 'transparent')
			:css('color', 'inherit')
	end
	tbl:cssText(args[cfg.arg.innerstyle])

	renderTitleRow(tbl)
	renderAboveRow(tbl)
	local listnums_size = #listnums
	for i, listnum in ipairs(listnums) do
		renderListRow(tbl, i, listnum, listnums_size)
	end
	renderBelowRow(tbl)

	return tbl
end

local function add_navbox_styles(hiding_templatestyles)
	local frame = mw.getCurrentFrame()
	-- This is a lambda so that it doesn't need the frame as a parameter
	local function add_user_styles(templatestyles)
		if templatestyles and templatestyles ~= '' then
			return frame:extensionTag{
				name = 'templatestyles', args = { src = templatestyles }
			}
		end
		return ''
	end

	-- get templatestyles. load base from config so that Lua only needs to do
	-- the work once of parser tag expansion
	local base_templatestyles = cfg.templatestyles
	local templatestyles = add_user_styles(args[cfg.arg.templatestyles])
	local child_templatestyles = add_user_styles(args[cfg.arg.child_templatestyles])

	-- The 'navbox-styles' div exists to wrap the styles to work around T200206
	-- more elegantly. Instead of combinatorial rules, this ends up being linear
	-- number of CSS rules.
	return mw.html.create('div')
		:addClass(cfg.class.navbox_styles)
		:wikitext(
			add_list_styles() .. -- see [hlist_note] applied to 'before base_templatestyles'
			base_templatestyles ..
			templatestyles ..
			child_templatestyles ..
			table.concat(hiding_templatestyles)
		)
		:done()
end

-- work around [[phab:T303378]]
-- for each arg: find all the templatestyles strip markers, insert them into a
-- table. then remove all templatestyles markers from the arg
local function move_hiding_templatestyles(args)
	local gfind = string.gfind
	local gsub = string.gsub
	local templatestyles_markers = {}
	local strip_marker_pattern = '(\127[^\127]*UNIQ%-%-templatestyles%-%x+%-QINU[^\127]*\127)'
	for k, arg in pairs(args) do
		for marker in gfind(arg, strip_marker_pattern) do
			table.insert(templatestyles_markers, marker)
		end
		args[k] = gsub(arg, strip_marker_pattern, '')
	end
	return templatestyles_markers
end

function p._navbox(navboxArgs)
	args = navboxArgs
	local hiding_templatestyles = move_hiding_templatestyles(args)
	local listnums = {}

	for k, _ in pairs(args) do
		if type(k) == 'string' then
			local listnum = k:match(cfg.pattern.listnum)
			if listnum then table.insert(listnums, tonumber(listnum)) end
		end
	end
	table.sort(listnums)

	local border = mw.text.trim(args[cfg.arg.border] or args[1] or '')
	if border == cfg.keyword.border_child then
		border = cfg.keyword.border_subgroup
	end

	-- render the main body of the navbox
	local tbl = renderMainTable(border, listnums)

	local res = mw.html.create()
	-- render the appropriate wrapper for the navbox, based on the border param

	if border == cfg.keyword.border_none then
		res:node(add_navbox_styles(hiding_templatestyles))
		local nav = res:tag('div')
			:attr('role', 'navigation')
			:node(tbl)
		-- aria-labelledby title, otherwise above, otherwise lone group
		if args[cfg.arg.title] or args[cfg.arg.above] or (args[cfg.arg.group1]
			and not args[cfg.arg.group2]) then
			nav:attr(
				'aria-labelledby',
				mw.uri.anchorEncode(
					args[cfg.arg.title] or args[cfg.arg.above] or args[cfg.arg.group1]
				)
			)
		else
			nav:attr('aria-label', cfg.aria_label)
		end
	elseif border == cfg.keyword.border_subgroup then
		-- We assume that this navbox is being rendered in a list cell of a
		-- parent navbox, and is therefore inside a div with padding:0em 0.25em.
		-- We start with a </div> to avoid the padding being applied, and at the
		-- end add a <div> to balance out the parent's </div>
		res
			:wikitext('</div>')
			:node(tbl)
			:wikitext('<div>')
	else
		res:node(add_navbox_styles(hiding_templatestyles))
		local nav = res:tag('div')
			:attr('role', 'navigation')
			:addClass(cfg.class.navbox)
			:addClass(args[cfg.arg.navboxclass])
			:cssText(args[cfg.arg.bodystyle])
			:cssText(args[cfg.arg.style])
			:css('padding', '3px')
			:node(tbl)
		-- aria-labelledby title, otherwise above, otherwise lone group
		if args[cfg.arg.title] or args[cfg.arg.above]
			or (args[cfg.arg.group1] and not args[cfg.arg.group2]) then
			nav:attr(
				'aria-labelledby',
				mw.uri.anchorEncode(args[cfg.arg.title] or args[cfg.arg.above] or args[cfg.arg.group1])
			)
		else
			nav:attr('aria-label', cfg.aria_label)
		end
	end

	if (args[cfg.arg.nocat] or cfg.keyword.nocat_false):lower() == cfg.keyword.nocat_false then
		renderTrackingCategories(res, border)
	end
	return striped(tostring(res), border)
end

function p.navbox(frame)
	if not getArgs then
		getArgs = require('Module:Arguments').getArgs
	end
	args = getArgs(frame, {wrappers = {cfg.pattern.navbox)))

	-- Read the arguments in the order they'll be output in, to make references
	-- number in the right order.
	local _
	_ = args[cfg.arg.title]
	_ = args[cfg.arg.above]
	-- Limit this to 20 as covering 'most' cases (that's a SWAG) and because
	-- iterator approach won't work here
	for i = 1, 20 do
		_ = args[format(cfg.arg.group_and_num, i)]
		_ = args[format(cfg.arg.list_and_num, i)]
	end
	_ = args[cfg.arg.below]

	return p._navbox(args)
end

return p