Module:etymology/templates/doublet

local export = {}

local require_when_needed = require("Module:require when needed")

local concat = table.concat
local format_categories = require_when_needed("Module:utilities", "format_categories")
local insert = table.insert
local process_params = require_when_needed("Module:parameters", "process")
local serial_comma_join = require_when_needed("Module:table", "serialCommaJoin")

local rsplit = mw.text.split
local rsubn = mw.ustring.gsub
local ulower = string.ulower

-- version of rsubn() that discards all but the first return value
local function rsub(term, foo, bar)
	return (rsubn(term, foo, bar))
end


local function get_parsed_part(template, lang, args, terms, i)
	local term = terms
	local alt = args
	local id = args
	local sc = args
	local tr = args
	local ts = args
	local gloss = args
	local pos = args
	local lit = args
	local g = args

	if not (term or alt or tr or ts) then
		require("Module:debug/track")(template .. "/no term or alt or tr")
		return nil
	else
		return require("Module:links").full_link(
			{ term = term, alt = alt, id = id, lang = lang, sc = sc, tr = tr,
			ts = ts, gloss = gloss, pos = pos, lit = lit,
			genders = g and rsplit(g, ",") or {}
		}, "term", true)
	end
end


local function get_parsed_parts(template, lang, args, terms)
	local parts = {}

	-- Find the maximum index among any of the list parameters.
	local maxmaxindex = 0
	for _, v in pairs(args) do
		if type(v) == "table" and v.maxindex and v.maxindex > maxmaxindex then
			maxmaxindex = v.maxindex
		end
	end

	for index = 1, maxmaxindex do
		insert(parts, get_parsed_part(template, lang, args, terms, index))
	end
	
	return parts
end

local function get_args(frame)
	local boolean = {type = "boolean"}
	local list = {list = true, allow_holes = true, require_index = true}
	return process_params(frame:getParent().args, {
		 = {
			required = true,
			type = "language",
			default = "und"
		},
		 = {list = true, allow_holes = true},
		 = list,
		 = {
			list = true,
			allow_holes = true,
			require_index = true,
			alias_of = "t"
		},
		 = list,
		 = list,
		 = list,
		 = list,
		 = list,
		 = list,
		 = list,
		 = {
			type = "script",
			list = true,
			allow_holes = true,
			require_index = true
		},
		 = boolean, -- should be processed in the template itself
		 = boolean,
		 = boolean,
		 = {},
	})
end

-- Implementation of miscellaneous templates such as {{doublet}} that can take
-- multiple terms. Doesn't handle {{blend}} or {{univerbation}}, which display
-- + signs between elements and use compound_like in ].
function export.misc_variant_multiple_terms(frame)
	local args = get_args(frame)
	local lang = args

	local parts = {}
	if not args then
		insert(parts, frame.args)
	end
	if #args > 0 or #args > 0 then
		if not args then
			insert(parts, " ")
			insert(parts, frame.args or "of")
			insert(parts, " ")
		end
		local formatted_terms = get_parsed_parts(ulower(
			-- Remove link and convert uppercase to lowercase to get an
			-- approximation of the original template name.
			rsub(rsub(frame.args, "^%%]$", "")),
			lang, args, args)
		insert(parts, serial_comma_join(formatted_terms))
	end
	if not args and frame.args then
		local categories = {}
		insert(categories, lang:getFullName() .. " " .. frame.args)
		insert(parts, format_categories(categories, lang, args))
	end

	return concat(parts)
end

return export