/*
 * InspIRCd -- Internet Relay Chat Daemon
 *
 *   Copyright (C) 2020 Matt Schatz <genius3000@g3k.solutions>
 *   Copyright (C) 2019 Robby <robby@chatbelgie.be>
 *   Copyright (C) 2018 Sadie Powell <sadie@witchery.services>
 *   Copyright (C) 2014 Adam <Adam@anope.org>
 *   Copyright (C) 2013, 2015-2016 Attila Molnar <attilamolnar@hush.com>
 *
 * This file is part of InspIRCd.  InspIRCd is free software: you can
 * redistribute it and/or modify it under the terms of the GNU General Public
 * License as published by the Free Software Foundation, version 2.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
 * FOR A PARTICULAR PURPOSE.  See the GNU General Public License for more
 * details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */


#include "inspircd.h"
#include "modules/ssl.h"
#include "modules/cap.h"

// From IRCv3 tls-3.1
enum
{
	RPL_STARTTLS = 670,
	ERR_STARTTLS = 691
};

class CommandStartTLS final
	: public SplitCommand
{
	dynamic_reference_nocheck<IOHookProvider>& ssl;

 public:
	CommandStartTLS(Module* mod, dynamic_reference_nocheck<IOHookProvider>& s)
		: SplitCommand(mod, "STARTTLS")
		, ssl(s)
	{
		works_before_reg = true;
	}

	CmdResult HandleLocal(LocalUser* user, const Params& parameters) override
	{
		if (!ssl)
		{
			user->WriteNumeric(ERR_STARTTLS, "STARTTLS is not enabled");
			return CmdResult::FAILURE;
		}

		if (user->registered == REG_ALL)
		{
			user->WriteNumeric(ERR_STARTTLS, "STARTTLS is not permitted after client registration is complete");
			return CmdResult::FAILURE;
		}

		if (user->eh.GetIOHook())
		{
			user->WriteNumeric(ERR_STARTTLS, "STARTTLS failure");
			return CmdResult::FAILURE;
		}

		user->WriteNumeric(RPL_STARTTLS, "STARTTLS successful, go ahead with TLS handshake");
		/* We need to flush the write buffer prior to adding the IOHook,
		 * otherwise we'll be sending this line inside the TLS session - which
		 * won't start its handshake until the client gets this line. Currently,
		 * we assume the write will not block here; this is usually safe, as
		 * STARTTLS is sent very early on in the registration phase, where the
		 * user hasn't built up much sendq. Handling a blocked write here would
		 * be very annoying.
		 */
		user->eh.DoWrite();

		ssl->OnAccept(&user->eh, NULL, NULL);

		return CmdResult::SUCCESS;
	}
};

class TLSCap final
	: public Cap::Capability
{
 private:
	dynamic_reference_nocheck<IOHookProvider>& sslref;

	bool OnList(LocalUser* user) override
	{
		return sslref;
	}

	bool OnRequest(LocalUser* user, bool adding) override
	{
		return sslref;
	}

 public:
	TLSCap(Module* mod, dynamic_reference_nocheck<IOHookProvider>& ssl)
		: Cap::Capability(mod, "tls")
		, sslref(ssl)
	{
	}
};

class ModuleStartTLS final
	: public Module
{
 private:
	CommandStartTLS starttls;
	TLSCap tls;
	dynamic_reference_nocheck<IOHookProvider> ssl;

 public:
	ModuleStartTLS()
		: Module(VF_VENDOR, "Provides the IRCv3 tls client capability.")
		, starttls(this, ssl)
		, tls(this, ssl)
		, ssl(this, "ssl")
	{
	}

	void ReadConfig(ConfigStatus& status) override
	{
		auto conf = ServerInstance->Config->ConfValue("starttls");

		std::string newprovider = conf->getString("provider");
		if (newprovider.empty())
			ssl.SetProvider("ssl");
		else
			ssl.SetProvider("ssl/" + newprovider);
	}
};

MODULE_INIT(ModuleStartTLS)