-- This module implements {{shortcut}}.

-- Set constants
local CONFIG_MODULE = 'Module:Shortcut/config'

-- Load required modules
local checkType = require('libraryUtil').checkType
local yesno = require('Module:Yesno')

local p = {}

local function message(msg, ...)
	return mw.message.newRawMessage(msg, ...):plain()
end

local function makeCategoryLink(cat)
	return string.format('[[%s:%s]]', mw.site.namespaces[14].name, cat)
end

function p._main(shortcuts, options, frame, cfg)
	checkType('_main', 1, shortcuts, 'table')
	checkType('_main', 2, options, 'table', true)
	options = options or {}
	frame = frame or mw.getCurrentFrame()
	cfg = cfg or mw.loadData(CONFIG_MODULE)
	local isCategorized = yesno(options.category) ~= false

	-- Validate shortcuts
	for i, shortcut in ipairs(shortcuts) do
		if type(shortcut) ~= 'string' or #shortcut < 1 then
			error(message(cfg['invalid-shortcut-error'], i), 2)
		end
	end

	-- Make the list items. These are the shortcuts plus any extra lines such
	-- as options.msg.
	local listItems = {}
	for i, shortcut in ipairs(shortcuts) do
		listItems[i] = string.format('[[%s]]', shortcut)
	end
	table.insert(listItems, options.msg)

	-- Return an error if we have nothing to display
	if #listItems < 1 then
		local msg = cfg['no-content-error']
		msg = string.format('<strong class="error">%s</strong>', msg)
		if isCategorized and cfg['no-content-error-category'] then
			msg = msg .. makeCategoryLink(cfg['no-content-error-category'])
		end
		return msg
	end

	local root = mw.html.create()

	-- Anchors
	local anchorDiv = root
		:tag('div')
			:css('position', 'relative')
			:css('top', '-3em')
	for i, shortcut in ipairs(shortcuts) do
		local anchor = mw.uri.anchorEncode(shortcut)
		anchorDiv:tag('span'):attr('id', anchor)
	end

	root:newline() -- To match the old [[Template:Shortcut]]

	-- Shortcut heading
	local shortcutHeading
	do
		local nShortcuts = #shortcuts
		if nShortcuts > 0 then
			shortcutHeading = message(cfg['shortcut-heading'], nShortcuts)
			shortcutHeading = frame:preprocess(shortcutHeading)
			shortcutHeading = shortcutHeading .. '\n'
		end
	end

	-- Shortcut box
	local shortcutList = root
		:tag('table')
			:addClass('shortcutbox noprint')
			:css('float', 'right')
			:css('border', '1px solid #aaa')
			:css('background', '#fff')
			:css('margin', '.3em .3em .3em 1em')
			:css('padding', '3px')
			:css('text-align', 'center')
				:tag('tr')
					:tag('th')
						:addClass('plainlist')
						:css('border', 'none')
						:css('background', 'transparent')
						:tag('small')
							:wikitext(shortcutHeading)
							:tag('ul')
	for i, item in ipairs(listItems) do
		shortcutList:tag('li'):wikitext(item)
	end

	-- Output an error category if the first shortcut doesn't exist
	if isCategorized
		and shortcuts[1]
		and cfg['first-parameter-error-category']
	then
		local title = mw.title.new(shortcuts[1])
		if not title or not title.exists then
			root:wikitext(makeCategoryLink(cfg['first-parameter-error-category']))
		end
	end

	return tostring(root)
end

function p.main(frame)
	local args = require('Module:Arguments').getArgs(frame, {
		wrappers = 'Template:Shortcut'
	})

	-- Separate shortcuts from options
	local shortcuts, options = {}, {}
	for k, v in pairs(args) do
		if type(k) == 'number' then
			shortcuts[k] = v
		else
			options[k] = v
		end
	end

	-- Compress the shortcut array, which may contain nils.
	local function compressArray(t)
		local nums, ret = {}, {}
		for k in pairs(t) do
			nums[#nums + 1] = k
		end
		table.sort(nums)
		for i, num in ipairs(nums) do
			ret[i] = t[num]
		end
		return ret
	end
	shortcuts = compressArray(shortcuts)

	return p._main(shortcuts, options, frame)
end

return p