module:set_global();

local config = require "core.configmanager";

local argparse = require "util.argparse";

local dns = require"net.adns".resolver();

local async = require "util.async";

local set = require "util.set";

local nameprep = require"util.encodings".stringprep.nameprep;

local idna_to_ascii = require"util.encodings".idna.to_ascii;

local services = { "xmpp-client"; "xmpps-client"; "xmpp-server"; "xmpps-server" }

local function validate_dnsname_option(options, option_name, default)

	local host = options[option_name];

	if host == nil then return default end

	local normalized = nameprep(host);

	if not normalized then

		module:log("error", "--%s %q fails normalization");

		return;

	end

	local alabel = idna_to_ascii(normalized);

	if not alabel then

		module:log("error", "--%s %q fails IDNA");

		return;

	end

	return alabel;

end

function module.command(arg)

	local opts = argparse.parse(arg, {

		short_params = { d = "domain"; p = "primary"; t = "target"; l = "ttl"; h = "help"; ["?"] = "help" };

		value_params = { domain = true; primary = true; target = true; ttl = true };

	});

	if not arg[1] or arg[2] or not opts or opts.help or not opts.domain then

		local out = opts.help and io.stdout or io.stderr;

		out:write("prosodyctl mod_dnsupdate [options] virtualhost\n");

		out:write("\t-d --domain\tbase domain name *required*\n");

		out:write("\t-p --primary\tprimary DNS name server\n");

		out:write("\t-t --target\ttarget hostname for SRV\n");

		out:write("\t-l --ttl\tTTL to use\n");

		out:write("\t--each\tremove and replace individual SRV records\n");

		out:write("\t--reset\tremove and replace all SRV records\n");

		return opts and opts.help and 0 or 1;

	end

	local vhost = nameprep(arg[1]); -- TODO loop over arg[]?

	if not vhost then

		module:log("error", "Host %q fails normalization", arg[1]);

		return 1;

	end

	local ihost = idna_to_ascii(vhost);

	if not ihost then

		module:log("error", "Host %q falis IDNA", vhost);

		return 1;

	end

	if not config.get(vhost, "defined") then

		module:log("error", "Host %q is not defined in the config", vhost);

		return 1;

	end

	local domain = validate_dnsname_option(opts, "domain");

	if not domain then

		module:log("error", "--domain is required");

		return 1;

	end

	local primary = validate_dnsname_option(opts, "primary")

		or async.wait_for(dns:lookup_promise(domain, "SOA"):next(function(ret) return ret[1].soa.mname; end));

	if not primary then

		module:log("error", "Could not discover primary name server, specify it with --primary");

		return 1;

	end

	local target = validate_dnsname_option(opts, "target", module:context(vhost):get_option_string("xmpp_host", ihost));

	-- TODO validate that target has A/AAAA

	local configured_ports = {

		["xmpp-client"] = module:get_option_array("c2s_ports", { 5222 });

		["xmpps-client"] = module:get_option_array("c2s_direct_tls_ports", {});

	};

	if opts.multiplex then

		for opt, ports in pairs(configured_ports) do

			ports:append(module:get_option_array(opt:sub(1, 5) == "xmpps" and "ssl_ports" or "ports", {}));

		end

	end

	local existing_srv = {};

	for _, service in ipairs(services) do

		existing_srv[service] = dns:lookup_promise(("_%s._tcp.%s"):format(service, ihost), "SRV");

	end

	print("zone", domain);

	print("server", primary);

	print("ttl " .. tostring(opts.ttl or 60 * 60));

	for _, service in ipairs(services) do

		local ports = set.new(configured_ports[service]);

		local records = (async.wait_for(existing_srv[service]));

		local replace = opts.reset;

		for _, rr in ipairs(records) do

			if not ports:contains(rr.srv.port) or target ~= nameprep(rr.srv.target):gsub("%.$", "") then

				if not opts.each then

					replace = true;

					break

				end

				print(("del _%s._tcp.%s IN SRV %s"):format(service, ihost, rr));

			end

		end

		if replace then

			print(("del _%s._tcp.%s IN SRV"):format(service, ihost));

			for port in ports do print(("add _%s._tcp.%s IN SRV 1 1 %d %s"):format(service, ihost, port, target)); end

		end

	end

	print("show");

	print("send");

	print("answer");

end