local export = {}

local m_links = require("Module:links")
local m_languages = require("Module:languages")


local function format_list_items(items, lang)
	local result = {}
	
	for i, item in ipairs(items) do
		if lang and not string.find(item, "<span") then
			item = m_links.full_link({lang = lang, term = item})
		end
		
		result[i] = '\n* ' .. item
	end
	
	return table.concat(result)
end

local collapse_header =
	[[<div class="test-list-switcher" data-toggle-category="{{{toggle_category}}}">]]
local column_header = [[<div class="{{{class}}} term-list ul-column-count" ]]
	.. [[data-column-count="{{{column_count}}}" ]]
	.. [[style="background-color: {{{background_color}}};">]]
local button = [[<div class="list-switcher-element" ]]
	.. [[data-showtext="&nbsp;show more ▼&nbsp;" ]]
	.. [[data-hidetext="&nbsp;show less ▲&nbsp;" style="display: none;">&nbsp;</div>]]

function export.create_list(args)
	-- Fields in args that are used:
	-- args.column_count, args.content, args.alphabetize, args.background_color,
	-- args.collapse, args.toggle_category, args.class, args.lang
	-- Check for required fields?
	if type(args) ~= "table" then
		error("expected table, got " .. type(args))
	end
	
	args.class = args.class or "derivedterms"
	args.column_count = args.column_count or 1
	args.toggle_category = args.toggle_category or "derived terms"
	
	local output = {}
	
	if args.header then
		table.insert(output, args.header)
	end
	if args.collapse then
		table.insert(output, (collapse_header:gsub('{{{(.-)}}}', args)))
		table.insert(output, button)
	end
	table.insert(output, (column_header:gsub('{{{(.-)}}}', args)))
	
    if args.alphabetize then
		require("Module:collation").sort(args.content, args.lang)
	end
	table.insert(output, format_list_items(args.content, args.lang))
	
	table.insert(output, '</div>')
	if args.collapse then
		table.insert(output, '</div>')
	end
	
	return table.concat(output)
end


-- This function is for compatibility with earlier version of [[Module:columns]]
-- (now found in [[Module:columns/old]]).
function export.create_table(...)
	-- Earlier arguments to create_table:
	-- n_columns, content, alphabetize, bg, collapse, class, title, column_width, line_start, lang
	local args = {}
	args.column_count, args.content, args.alphabetize, args.background_color,
		args.collapse, args.class, args.title, args.column_width,
		args.line_start, args.lang = ...
	
	return export.create_list(args)
end


function export.display(frame)
	local params = {
		["class"] = {},
		["collapse"] = {type = "boolean"},
		["columns"] = {type = "number"},
		["lang"] = {},
		["sort"] = {type = "boolean"},
		["title"] = {default = ""},
		["toggle_category"] = {},
	}
	
	local frame_args = require("Module:parameters").process(frame.args, params)
	
	params = {
		[1] = {list = true},
		
		["title"] = {},
		["lang"] = not frame_args["lang"] and {required = true, default = "und"} or nil,
		["collapse"] = {},
	}
	
	local args = require("Module:parameters").process(frame:getParent().args, params)
	
	local lang = frame_args["lang"] or args["lang"]
	lang = m_languages.getByCode(lang) or m_languages.err(lang, "lang")
	
	local header
	if args["title"] then
		header = '<div class="term-list-header">' .. args["title"] .. "</div>"
	end
	
	return export.create_list { column_count = frame_args["columns"],
		content = args[1], alphabetize = frame_args["sort"],
		header = header, background_color = "#F8F8FF",
		collapse = frame_args["collapse"],
		toggle_category = frame_args["toggle_category"],
		class = frame_args["class"], lang = lang, }
end


return export
"https://si.wiktionary.org/w/index.php?title=Module:columns/sandbox&oldid=44044" වෙතින් සම්ප්‍රවේශනය කෙරිණි