/*
 *  charybdis: an advanced ircd.
 *  client.c: Controls clients.
 *
 *  Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
 *  Copyright (C) 1996-2002 Hybrid Development Team
 *  Copyright (C) 2002-2005 ircd-ratbox development team
 *  Copyright (C) 2007 William Pitcock
 *  Copyright (C) 2016 Charybdis Development Team
 *  Copyright (C) 2016 Jason Volk <jason@zemos.net>
 *
 *  This program 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; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  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, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 *  USA
 */

#include <ircd/socket.h>
#include <ircd/lex_cast.h>

namespace ircd {

ctx::pool request
{
	"request", 1_MiB
};

client::list client::clients
{};

bool handle_ec_timeout(client &);
bool handle_ec_eof(client &);
bool handle_ec_success(client &);
bool handle_ec(client &, const error_code &);

void async_recv_next(std::shared_ptr<client>, const milliseconds &timeout);
void async_recv_next(std::shared_ptr<client>);

void disconnect(client &, const socket::dc & = socket::dc::FIN);
void disconnect_all();

template<class... args> std::shared_ptr<client> make_client(args&&...);

} // namespace ircd

ircd::client::init::init()
{
	request.add(1);
}

ircd::client::init::~init()
noexcept
{
	request.interrupt();
	disconnect_all();
}

bool
ircd::http::client::handle()
try
{
	char buffer[2048];
	parse::buffer pb{buffer, buffer + sizeof(buffer)};
	parse::context pc{pb, [this](char *&read, char *const &stop)
	{
		const mutable_buffers buffers{{read, stop}};
		read += sock->read_some(buffers);
	}};

	const http::request::head head{pc}; try
	{
		log::debug("client[%s] requesting resource \"%s\"",
		           string(remote_address(*this)).c_str(),
		           std::string(head.resource).c_str());

		const auto &resource(*resource::resources.at(head.resource));
		resource(*this, pc, head);
	}
	catch(const std::out_of_range &e)
	{
		throw http::error(http::code::NOT_FOUND);
	}

	return true;
}
catch(const http::error &e)
{
	char content_len[64]; const auto content_len_len
	{
		snprintf(content_len, sizeof(content_len), "Content-Length: %zu\r\n", e.content.size())
	};

	const const_buffers iov
	{
		{ "HTTP/1.1 ", 9                       },
		{ e.what(), strlen(e.what())           },
		{ "\r\n", 2                            },
		{ string_view(content_len)             },
		{ "\r\n", 2                            },
		{ e.content.data(), e.content.size()   }
	};

	sock->write(iov);
	log::debug("client[%s] http::error(%d): %s",
	           string(remote_address(*this)).c_str(),
	           int(e.code),
	           e.what());

	switch(e.code)
	{
		case http::BAD_REQUEST:               return false;
		case http::INTERNAL_SERVER_ERROR:     return false;
		default:                              return true;
	}

	return true;
}

ircd::host_port
ircd::local_address(const client &client)
{
	if(!client.sock)
		return { "0.0.0.0"s, 0 };

	const auto &sock(*client.sock);
	return { local_ip(sock), local_port(sock) };
}

ircd::host_port
ircd::remote_address(const client &client)
{
	if(!client.sock)
		return { "0.0.0.0"s, 0 };

	const auto &sock(*client.sock);
	return { remote_ip(sock), remote_port(sock) };
}

ircd::client::client()
:client{std::shared_ptr<socket>{}}
{
}

ircd::client::client(const host_port &host_port,
                     const seconds &timeout)
:client
{
	std::make_shared<socket>(host_port.first, host_port.second, timeout)
}
{
}

ircd::client::client(std::shared_ptr<socket> sock)
:type{type}
,clit{clients.emplace(end(clients), this)}
,sock{std::move(sock)}
{
}

ircd::client::~client()
noexcept
{
	clients.erase(clit);
}

bool
ircd::client::main()
noexcept try
{
	return handle();
}
catch(const boost::system::system_error &e)
{
	log::error("system_error: %s", e.what());
	return false;
}
catch(const std::exception &e)
{
	log::error("exception: %s", e.what());
	return false;
}

std::shared_ptr<ircd::client>
ircd::add_client(std::shared_ptr<socket> s)
{
	const auto client(std::make_shared<http::client>(std::move(s)));
	log::info("New client[%s] on local[%s]",
	          string(remote_address(*client)).c_str(),
	          string(local_address(*client)).c_str());

	async_recv_next(client, 30s);
	return client;
}

bool
ircd::client::handle()
{
	return false;
}

template<class... args>
std::shared_ptr<ircd::client>
ircd::make_client(args&&... a)
{
	return std::make_shared<client>(std::forward<args>(a)...);
}

void
ircd::disconnect_all()
{
	for(auto &client : client::clients) try
	{
		disconnect(*client, socket::dc::RST);
	}
	catch(...)
	{
	}
}

void
ircd::disconnect(client &client,
                 const socket::dc &type)
{
	auto &sock(*client.sock);
	sock.disconnect(type);
}

void
ircd::async_recv_next(std::shared_ptr<client> client)
{
	async_recv_next(std::move(client), milliseconds(-1));
}

void
ircd::async_recv_next(std::shared_ptr<client> client,
                      const milliseconds &timeout)
{
	auto &sock(*client->sock);
	sock(timeout, [client, timeout]
	(const error_code &ec)
	noexcept
	{
		if(!handle_ec(*client, ec))
			return;

		request([client, timeout]
		{
			if(client->main())
				async_recv_next(client, timeout);
		});
	});
}

bool
ircd::handle_ec(client &client,
                const error_code &ec)
{
	using namespace boost::system::errc;
	using boost::asio::error::eof;

	switch(ec.value())
	{
		case success:                return handle_ec_success(client);
		case eof:                    return handle_ec_eof(client);
		case operation_canceled:     return handle_ec_timeout(client);
		default:                     throw boost::system::system_error(ec);
	}
}

bool
ircd::handle_ec_success(client &client)
{
	return true;
}

bool
ircd::handle_ec_eof(client &client)
{
	return false;
}

bool
ircd::handle_ec_timeout(client &client)
{
	auto &sock(*client.sock);
	log::debug("client[%s]: disconnecting after inactivity timeout",
	          string(remote_address(client)).c_str());

	sock.disconnect();
	return false;
}

std::string
ircd::string(const host_port &pair)
{
	std::string ret(64, '\0');
	ret.resize(snprintf(&ret.front(), ret.size(), "%s:%u",
	                    pair.first.c_str(),
	                    pair.second));
	return ret;
}