/*
	This file is part of cpp-ethereum.

	cpp-ethereum 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 3 of the License, or
	(at your option) any later version.

	cpp-ethereum 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 cpp-ethereum.  If not, see <http://www.gnu.org/licenses/>.
*/
/** @file Common.cpp
 * @author Gav Wood <i@gavwood.com>
 * @date 2014
 */

#include "Common.h"
using namespace std;
using namespace dev;
using namespace dev::p2p;

const unsigned dev::p2p::c_protocolVersion = 3;
const unsigned dev::p2p::c_defaultIPPort = 30303;

bool p2p::isPublicAddress(std::string const& _addressToCheck)
{
	return _addressToCheck.empty() ? false : isPublicAddress(bi::address::from_string(_addressToCheck));
}

bool p2p::isPublicAddress(bi::address const& _addressToCheck)
{
	return !(isPrivateAddress(_addressToCheck) || isLocalHostAddress(_addressToCheck));
}

// Helper function to determine if an address falls within one of the reserved ranges
// For V4:
// Class A "10.*", Class B "172.[16->31].*", Class C "192.168.*"
bool p2p::isPrivateAddress(bi::address const& _addressToCheck)
{
	if (_addressToCheck.is_v4())
	{
		bi::address_v4 v4Address = _addressToCheck.to_v4();
		bi::address_v4::bytes_type bytesToCheck = v4Address.to_bytes();
		if (bytesToCheck[0] == 10 || bytesToCheck[0] == 127)
			return true;
		if (bytesToCheck[0] == 172 && (bytesToCheck[1] >= 16 && bytesToCheck[1] <= 31))
			return true;
		if (bytesToCheck[0] == 192 && bytesToCheck[1] == 168)
			return true;
	}
	else if (_addressToCheck.is_v6())
	{
		bi::address_v6 v6Address = _addressToCheck.to_v6();
		bi::address_v6::bytes_type bytesToCheck = v6Address.to_bytes();
		if (bytesToCheck[0] == 0xfd && bytesToCheck[1] == 0)
			return true;
		if (!bytesToCheck[0] && !bytesToCheck[1] && !bytesToCheck[2] && !bytesToCheck[3] && !bytesToCheck[4] && !bytesToCheck[5] && !bytesToCheck[6] && !bytesToCheck[7]
				 && !bytesToCheck[8] && !bytesToCheck[9] && !bytesToCheck[10] && !bytesToCheck[11] && !bytesToCheck[12] && !bytesToCheck[13] && !bytesToCheck[14] && (bytesToCheck[15] == 0 || bytesToCheck[15] == 1))
			return true;
	}
	return false;
}

bool p2p::isPrivateAddress(std::string const& _addressToCheck)
{
	return _addressToCheck.empty() ? false : isPrivateAddress(bi::address::from_string(_addressToCheck));
}

// Helper function to determine if an address is localhost
bool p2p::isLocalHostAddress(bi::address const& _addressToCheck)
{
	// @todo: ivp6 link-local adresses (macos), ex: fe80::1%lo0
	static const set<bi::address> c_rejectAddresses = {
		{bi::address_v4::from_string("127.0.0.1")},
		{bi::address_v4::from_string("0.0.0.0")},
		{bi::address_v6::from_string("::1")},
		{bi::address_v6::from_string("::")}
	};
	
	return find(c_rejectAddresses.begin(), c_rejectAddresses.end(), _addressToCheck) != c_rejectAddresses.end();
}

bool p2p::isLocalHostAddress(std::string const& _addressToCheck)
{
	return _addressToCheck.empty() ? false : isLocalHostAddress(bi::address::from_string(_addressToCheck));
}

std::string p2p::reasonOf(DisconnectReason _r)
{
	switch (_r)
	{
	case DisconnectRequested: return "Disconnect was requested.";
	case TCPError: return "Low-level TCP communication error.";
	case BadProtocol: return "Data format error.";
	case UselessPeer: return "Peer had no use for this node.";
	case TooManyPeers: return "Peer had too many connections.";
	case DuplicatePeer: return "Peer was already connected.";
	case IncompatibleProtocol: return "Peer protocol versions are incompatible.";
	case NullIdentity: return "Null identity given.";
	case ClientQuit: return "Peer is exiting.";
	case UnexpectedIdentity: return "Unexpected identity given.";
	case LocalIdentity: return "Connected to ourselves.";
	case UserReason: return "Subprotocol reason.";
	case NoDisconnect: return "(No disconnect has happened.)";
	default: return "Unknown reason.";
	}
}

void Node::cullEndpoint()
{
	if (!isPublicAddress(endpoint.tcp.address()) && isPublicAddress(endpoint.udp.address()))
		endpoint.tcp.address(endpoint.udp.address());
}