local lang = require("Module:languages").getByCode("zgh")

local list_to_set = require("Module:table").listToSet

local export = {}
local pos_functions = {}

-----------------------
-- Utility functions --
-----------------------

-- If Not Empty
local function ine(arg)
	if arg == "" then
		return nil
	else
		return arg
	end
end

-- version of mw.ustring.gsub() that discards all but the first return value
function rsub(term, foo, bar)
	local retval = mw.ustring.gsub(term, foo, bar)
	return retval
end

local rfind = mw.ustring.find

local function append_cat(data, pos)
	table.insert(data.categories, lang:getCanonicalName()  .. pos)
end

function remove_links(text)
	text = rsub(text, "%[%[[^|%]]*|", "")
	text = rsub(text, "%[%[", "")
	text = rsub(text, "%]%]", "")
	return text
end

-- The main entry point.
function export.show(frame)

	local PAGENAME = mw.title.getCurrentTitle().text

	local poscat = frame.args[1] or error("Part of speech has not been specified. Please pass parameter 1 to the module invocation.")
	
	local params = {
		[1] = {list = "head", allow_holes = true, default = ""},
		["head"] = {default = ""},
		["tr"] = {list = true, allow_holes = true},
	}
	
	local args = frame:getParent().args  -- TODO: Use [[Module:parameters]] here
	
	-- Gather parameters
	local data = {lang = lang, pos_category = poscat, categories = {}, heads = {}, translits = {}, genders = {}, inflections = { enable_auto_translit = true }}
	
	local head = args["head"] or args[1] or PAGENAME or ""
	local translit = ine(args["tr"])
	local i = 1
	
	while head do
		table.insert(data.heads, head)
		data.translits[#data.heads] = translit
		i = i + 1
		head = ine(args["head" .. i])
		translit = ine(args["tr" .. i])
	end
	
	if pos_functions[poscat] then
		pos_functions[poscat].func(args, data)
	end
	
	return require("Module:headword").full_headword(data)
end

local function getargs(args, argpref, defgender)
	-- Gather parameters
	local forms = {}
	
	local form = ine(args[argpref])
	local translit = ine(args[argpref .. "tr"])
	local gender = ine(args[argpref .. "g"])
	local gender2 = ine(args[argpref .. "g2"])
	local i = 1
	
	while form do
		local genderlist = (gender or gender2) and {gender, gender2} or defgender and {defgender} or nil
		table.insert(forms, {term = form, translit = translit, gender = genderlist})

		i = i + 1
		form = ine(args[argpref .. i])
		translit = ine(args[argpref .. i .. "tr"])
		gender = ine(args[argpref .. i .. "g"])
		gender2 = ine(args[argpref .. i .. "g2"])
	end

	return forms
end

local function handle_infl(args, data, argpref, label, defgender)
	local newinfls = getargs(args, argpref, defgender)
	newinfls.label = label

	if #newinfls > 0 then
		table.insert(data.inflections, newinfls)
	end
end

local function handle_all_infl(args, data, argpref, label, nobase)
	if not nobase and argpref ~= "" then
		handle_infl(args, data, argpref, label)
	end
	
	local labelsp = label == "" and "" or label .. " "
	handle_infl(args, data, argpref .. "cons", labelsp .. "建構形")
end

-- Handle the case where pl=-, indicating an uncountable noun.
local function handle_noun_plural(args, data)
	if args["pl"] == "-" then
		table.insert(data.inflections, {label = "usually [[Appendix:Glossary#uncountable|uncountable]]"})
        append_cat(data, "不可數名詞")
	else
		handle_infl(args, data, "pl", "複數")
	end
end

local valid_genders = list_to_set(
	{"m", "f", "m-p", "f-p", "p"})

local function is_masc_sg(g)
	return g == "m" 
end
local function is_fem_sg(g)
	return g == "f"
end

local function handle_gender(args, data, default, nonlemma)
	local g = ine(args["g"]) or default
	local g2 = ine(args["g2"])

	local function process_gender(g)
		if not g then
			table.insert(data.genders, "?")
		elseif valid_genders[g] then
			table.insert(data.genders, g)
		else
			error("Unrecognized gender: " .. g)
		end
	end

	process_gender(g)
	if g2 then
		process_gender(g2)
	end

	if nonlemma then
		return
	end
	
	if g and g2 then
		append_cat(data, "有多種性別的詞")
	end
end

-- Part-of-speech functions
	
pos_functions["形容詞"] = {
	func = function(args, data)
		handle_all_infl(args, data, "", "")
		handle_all_infl(args, data, "f", "陰性")
		handle_all_infl(args, data, "pl", "陽性複數")
		handle_all_infl(args, data, "fpl", "陰性複數")
	end
}

function handle_noun_infls(args, data, singonly)
	handle_all_infl(args, data, "", "") 

	if not singonly then
		handle_noun_plural(args, data)
		handle_all_infl(args, data, "pl", "複數", "nobase")
	end
	
	handle_all_infl(args, data, "f", "陰性")
	handle_all_infl(args, data, "m", "陽性")
end

pos_functions["名詞"] = {
	func = function(args, data)
		handle_gender(args, data)
		handle_noun_infls(args, data)
	end
}

pos_functions["數詞"] = {
	func = function(args, data)
		append_cat(data, "基數詞")
		handle_gender(args, data)
		handle_noun_infls(args, data)
	end
}

pos_functions["專有名詞"] = {
	func = function(args, data)
		handle_gender(args, data)
		handle_noun_infls(args, data, "僅用單數")
	end
}


pos_functions["代詞"] = {
	params = {["g"] = {}},
	func = function(args, data)
		handle_gender(args, data)
		handle_all_infl(args, data, "f", "陰性")
		handle_all_infl(args, data, "pl", "陽性複數")
		handle_all_infl(args, data, "fpl", "陰性複數")
	end
}

return export