/**
 * EQEmulator: Everquest Server Emulator
 * Copyright (C) 2001-2019 EQEmulator Development Team (https://github.com/EQEmu/Server)
 *
 * 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; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY except by those people which sell it, which
 * are required to give you total support for your newly bought product;
 * 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 "client.h"
#include "login_server.h"
#include "../common/misc_functions.h"
#include "../common/eqemu_logsys.h"
#include "../common/string_util.h"
#include "encryption.h"
#include "../common/eqemu_logsys_fmt.h"

extern LoginServer server;

/**
 * @param c
 * @param v
 */
Client::Client(std::shared_ptr<EQStreamInterface> c, LSClientVersion v)
{
	connection       = c;
	version          = v;
	status           = cs_not_sent_session_ready;
	account_id       = 0;
	play_server_id   = 0;
	play_sequence_id = 0;
}

bool Client::Process()
{
	EQApplicationPacket *app = connection->PopPacket();
	while (app) {
		if (server.options.IsTraceOn()) {
			Log(Logs::General, Logs::Login_Server, "Application packet received from client (size %u)", app->Size());
		}

		if (server.options.IsDumpInPacketsOn()) {
			DumpPacket(app);
		}

		if (status == cs_failed_to_login) {
			delete app;
			app = connection->PopPacket();
			continue;
		}

		switch (app->GetOpcode()) {
			case OP_SessionReady: {
				if (server.options.IsTraceOn()) {
					Log(Logs::General, Logs::Login_Server, "Session ready received from client.");
				}
				Handle_SessionReady((const char *) app->pBuffer, app->Size());
				break;
			}
			case OP_Login: {
				if (app->Size() < 20) {
					Log(Logs::General, Logs::Error, "Login received but it is too small, discarding.");
					break;
				}

				if (server.options.IsTraceOn()) {
					Log(Logs::General, Logs::Login_Server, "Login received from client.");
				}

				Handle_Login((const char *) app->pBuffer, app->Size());
				break;
			}
			case OP_ServerListRequest: {
				if (app->Size() < 4) {
					Log(Logs::General, Logs::Error, "Server List Request received but it is too small, discarding.");
					break;
				}

				if (server.options.IsTraceOn()) {
					Log(Logs::General, Logs::Login_Server, "Server list request received from client.");
				}

				SendServerListPacket(*(uint32_t *) app->pBuffer);
				break;
			}
			case OP_PlayEverquestRequest: {
				if (app->Size() < sizeof(PlayEverquestRequest_Struct)) {
					Log(Logs::General, Logs::Error, "Play received but it is too small, discarding.");
					break;
				}

				Handle_Play((const char *) app->pBuffer);
				break;
			}
			default: {
				if (LogSys.log_settings[Logs::Client_Server_Packet_Unhandled].is_category_enabled == 1) {
					char dump[64];
					app->build_header_dump(dump);
					Log(Logs::General, Logs::Error, "Recieved unhandled application packet from the client: %s.", dump);
				}
			}
		}

		delete app;
		app = connection->PopPacket();
	}

	return true;
}

/**
 * Sends our reply to session ready packet
 *
 * @param data
 * @param size
 */
void Client::Handle_SessionReady(const char *data, unsigned int size)
{
	if (status != cs_not_sent_session_ready) {
		Log(Logs::General, Logs::Error, "Session ready received again after already being received.");
		return;
	}

	if (size < sizeof(unsigned int)) {
		Log(Logs::General, Logs::Error, "Session ready was too small.");
		return;
	}

	status = cs_waiting_for_login;

	/**
	* The packets are mostly the same but slightly different between the two versions.
	*/
	if (version == cv_sod) {
		EQApplicationPacket *outapp = new EQApplicationPacket(OP_ChatMessage, 17);
		outapp->pBuffer[0]  = 0x02;
		outapp->pBuffer[10] = 0x01;
		outapp->pBuffer[11] = 0x65;

		if (server.options.IsDumpOutPacketsOn()) {
			DumpPacket(outapp);
		}

		connection->QueuePacket(outapp);
		delete outapp;
	}
	else {
		const char          *msg    = "ChatMessage";
		EQApplicationPacket *outapp = new EQApplicationPacket(OP_ChatMessage, 16 + strlen(msg));
		outapp->pBuffer[0]  = 0x02;
		outapp->pBuffer[10] = 0x01;
		outapp->pBuffer[11] = 0x65;
		strcpy((char *) (outapp->pBuffer + 15), msg);

		if (server.options.IsDumpOutPacketsOn()) {
			DumpPacket(outapp);
		}

		connection->QueuePacket(outapp);
		delete outapp;
	}
}

/**
 * Verifies login and send a reply
 *
 * @param data
 * @param size
 */
void Client::Handle_Login(const char *data, unsigned int size)
{
	if (status != cs_waiting_for_login) {
		LogF(
			Logs::General,
			Logs::Error,
			"{0} Login received after already having logged in",
			__func__
		);
		return;
	}

	if ((size - 12) % 8 != 0) {
		LogF(
			Logs::General,
			Logs::Error,
			"{0} Login received packet of size: {1}, this would cause a block corruption, discarding.",
			__func__,
			size
		);
		return;
	}

	if (size < sizeof(LoginLoginRequest_Struct)) {
		LogF(
			Logs::General,
			Logs::Error,
			"{0} Login received packet of size: %u, this would cause a buffer overflow, discarding.",
			__func__,
			size
		);

		return;
	}

	char *login_packet_buffer = nullptr;

	unsigned int db_account_id  = 0;
	std::string  db_loginserver = "eqemu";
	std::string  db_account_password_hash;

	std::string outbuffer;
	outbuffer.resize(size - 12);
	if (outbuffer.length() == 0) {
		LogF(Logs::General, Logs::Debug, "Corrupt buffer sent to server, no length.");
		return;
	}

	auto r = eqcrypt_block(data + 10, size - 12, &outbuffer[0], 0);
	if (r == nullptr) {
		LogF(Logs::General, Logs::Debug, "Failed to decrypt eqcrypt block");
		return;
	}

	std::string cred;

	std::string user(&outbuffer[0]);
	if (user.length() >= outbuffer.length()) {
		LogF(
			Logs::General,
			Logs::Debug,
			"{0} Corrupt buffer sent to server, preventing buffer overflow.",
			__func__
		);
		return;
	}

	memcpy(&llrs, data, sizeof(LoginLoginRequest_Struct));

	bool result = false;
	if (outbuffer[0] == 0 && outbuffer[1] == 0) {
		if (server.options.IsTokenLoginAllowed()) {
			cred   = (&outbuffer[2 + user.length()]);
			result = server.db->GetLoginTokenDataFromToken(
				cred,
				connection->GetRemoteAddr(),
				db_account_id,
				db_loginserver,
				user
			);
		}
	}
	else {
		if (server.options.IsPasswordLoginAllowed()) {
			cred            = (&outbuffer[1 + user.length()]);
			auto components = SplitString(user, '.');
			if (components.size() == 2) {
				db_loginserver = components[0];
				user           = components[1];
			}

			LogF(
				Logs::General,
				Logs::Login_Server,
				"{0} Attempting password based login [{1}] login [{2}] user [{3}]",
				__func__,
				user,
				db_loginserver,
				user
			);

			ParseAccountString(user, user, db_loginserver);

			if (server.db->GetLoginDataFromAccountInfo(user, db_loginserver, db_account_password_hash, db_account_id)) {
				result = VerifyLoginHash(user, db_loginserver, cred, db_account_password_hash);

				LogF(
					Logs::Detail,
					Logs::Login_Server,
					"{0} [VerifyLoginHash] Success [{1}]",
					__func__,
					(result ? "true" : "false")
				);
			}
			else {
				status = cs_creating_account;
				AttemptLoginAccountCreation(user, cred, db_loginserver);

				return;
			}
		}
	}

	/**
	 * Login accepted
	 */
	if (result) {
		LogF(
			Logs::Detail, Logs::Login_Server, "{0} [{1}] login [{2}] user [{3}] Login succeeded",
			__func__,
			user,
			db_loginserver,
			user
		);

		DoSuccessfulLogin(user, db_account_id, db_loginserver);
	}
	else {
		LogF(
			Logs::Detail, Logs::Login_Server, "{0} [{1}] login [{2}] user [{3}] Login failed",
			__func__,
			user,
			db_loginserver,
			user
		);

		DoFailedLogin();
	}
}

/**
 * Sends a packet to the requested server to see if the client is allowed or not
 *
 * @param data
 */
void Client::Handle_Play(const char *data)
{
	if (status != cs_logged_in) {
		Log(Logs::General, Logs::Error, "Client sent a play request when they were not logged in, discarding.");
		return;
	}

	const PlayEverquestRequest_Struct *play        = (const PlayEverquestRequest_Struct *) data;
	unsigned int                      server_id_in = (unsigned int) play->ServerNumber;
	unsigned int                      sequence_in  = (unsigned int) play->Sequence;

	if (server.options.IsTraceOn()) {
		Log(Logs::General,
			Logs::Login_Server,
			"Play received from client, server number %u sequence %u.",
			server_id_in,
			sequence_in);
	}

	this->play_server_id = (unsigned int) play->ServerNumber;
	play_sequence_id = sequence_in;
	play_server_id   = server_id_in;
	server.server_manager->SendUserToWorldRequest(server_id_in, account_id, loginserver_name);
}

/**
 * @param seq
 */
void Client::SendServerListPacket(uint32 seq)
{
	EQApplicationPacket *outapp = server.server_manager->CreateServerListPacket(this, seq);

	if (server.options.IsDumpOutPacketsOn()) {
		DumpPacket(outapp);
	}

	connection->QueuePacket(outapp);
	delete outapp;
}

void Client::SendPlayResponse(EQApplicationPacket *outapp)
{
	if (server.options.IsTraceOn()) {
		Log(Logs::General, Logs::Netcode, "Sending play response for %s.", GetAccountName().c_str());
		// server_log->LogPacket(log_network_trace, (const char*)outapp->pBuffer, outapp->size);
	}
	connection->QueuePacket(outapp);
}

void Client::GenerateKey()
{
	key.clear();
	int count = 0;
	while (count < 10) {
		static const char key_selection[] =
							  {
								  'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H',
								  'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P',
								  'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X',
								  'Y', 'Z', '0', '1', '2', '3', '4', '5',
								  '6', '7', '8', '9'
							  };

		key.append((const char *) &key_selection[random.Int(0, 35)], 1);
		count++;
	}
}

/**
 * @param user
 * @param pass
 * @param loginserver
 */
void Client::AttemptLoginAccountCreation(
	const std::string &user,
	const std::string &pass,
	const std::string &loginserver
)
{
	if (loginserver == "eqemu") {

		LogF(Logs::General, Logs::Login_Server, "Attempting login account creation via '{0}'", loginserver);

		if (!server.options.CanAutoLinkAccounts()) {
			LogF(Logs::General, Logs::Login_Server, "CanAutoLinkAccounts disabled - sending failed login");
			DoFailedLogin();
			return;
		}

		if (server.options.GetEQEmuLoginServerAddress().length() == 0) {
			DoFailedLogin();
			return;
		}

		auto addr_components = SplitString(server.options.GetEQEmuLoginServerAddress(), ':');
		if (addr_components.size() != 2) {
			DoFailedLogin();
			return;
		}

		stored_user = user;
		stored_pass = pass;

		auto address = addr_components[0];
		auto port    = std::stoi(addr_components[1]);
		EQ::Net::DNSLookup(
			address, port, false, [=](const std::string &addr) {
				if (addr.empty()) {
					DoFailedLogin();
					return;
				}

				login_connection_manager.reset(new EQ::Net::DaybreakConnectionManager());
				login_connection_manager->OnNewConnection(
					std::bind(
						&Client::LoginOnNewConnection,
						this,
						std::placeholders::_1
					)
				);
				login_connection_manager->OnConnectionStateChange(
					std::bind(
						&Client::LoginOnStatusChange,
						this,
						std::placeholders::_1,
						std::placeholders::_2,
						std::placeholders::_3
					)
				);
				login_connection_manager->OnPacketRecv(
					std::bind(
						&Client::LoginOnPacketRecv,
						this,
						std::placeholders::_1,
						std::placeholders::_2
					)
				);

				login_connection_manager->Connect(addr, port);
			}
		);
	}
	else {

		if (!server.options.CanAutoCreateAccounts()) {
			DoFailedLogin();
			return;
		}

		CreateLocalAccount(user, pass);
	}
}

void Client::DoFailedLogin()
{
	stored_user.clear();
	stored_pass.clear();

	EQApplicationPacket     outapp(OP_LoginAccepted, sizeof(LoginLoginFailed_Struct));
	LoginLoginFailed_Struct *llas = (LoginLoginFailed_Struct *) outapp.pBuffer;
	llas->unknown1 = llrs.unknown1;
	llas->unknown2 = llrs.unknown2;
	llas->unknown3 = llrs.unknown3;
	llas->unknown4 = llrs.unknown4;
	llas->unknown5 = llrs.unknown5;
	memcpy(llas->unknown6, FailedLoginResponseData, sizeof(FailedLoginResponseData));

	if (server.options.IsDumpOutPacketsOn()) {
		DumpPacket(&outapp);
	}

	connection->QueuePacket(&outapp);
	status = cs_failed_to_login;
}

/**
 * Verifies a login hash, will also attempt to update a login hash if needed
 *
 * @param user
 * @param loginserver
 * @param cred
 * @param hash
 * @return
 */
bool Client::VerifyLoginHash(
	const std::string &user,
	const std::string &loginserver,
	const std::string &cred,
	const std::string &hash
)
{
	auto mode = server.options.GetEncryptionMode();
	if (eqcrypt_verify_hash(user, cred, hash, mode)) {
		return true;
	}
	else {
		if (server.options.IsUpdatingInsecurePasswords()) {
			if (mode < EncryptionModeArgon2) {
				mode = EncryptionModeArgon2;
			}

			if (hash.length() == 32) { //md5 is insecure
				for (int i = EncryptionModeMD5; i <= EncryptionModeMD5Triple; ++i) {
					if (i != mode && eqcrypt_verify_hash(user, cred, hash, i)) {
						server.db->UpdateLoginHash(user, loginserver, eqcrypt_hash(user, cred, mode));
						return true;
					}
				}
			}
			else if (hash.length() == 40) { //sha1 is insecure
				for (int i = EncryptionModeSHA; i <= EncryptionModeSHATriple; ++i) {
					if (i != mode && eqcrypt_verify_hash(user, cred, hash, i)) {
						server.db->UpdateLoginHash(user, loginserver, eqcrypt_hash(user, cred, mode));
						return true;
					}
				}
			}
			else if (hash.length() == 128) { //sha2-512 is insecure
				for (int i = EncryptionModeSHA512; i <= EncryptionModeSHA512Triple; ++i) {
					if (i != mode && eqcrypt_verify_hash(user, cred, hash, i)) {
						server.db->UpdateLoginHash(user, loginserver, eqcrypt_hash(user, cred, mode));
						return true;
					}
				}
			}
			//argon2 is still secure
			//scrypt is still secure
		}
	}

	return false;
}

/**
 * @param user
 * @param db_account_id
 * @param db_loginserver
 */
void Client::DoSuccessfulLogin(const std::string &user, int db_account_id, const std::string &db_loginserver)
{
	stored_user.clear();
	stored_pass.clear();

	server.client_manager->RemoveExistingClient(db_account_id, db_loginserver);

	in_addr in;
	in.s_addr = connection->GetRemoteIP();

	server.db->UpdateLSAccountData(db_account_id, std::string(inet_ntoa(in)));
	GenerateKey();

	account_id       = db_account_id;
	account_name     = user;
	loginserver_name = db_loginserver;

	EQApplicationPacket  *outapp         = new EQApplicationPacket(OP_LoginAccepted, 10 + 80);
	LoginAccepted_Struct *login_accepted = (LoginAccepted_Struct *) outapp->pBuffer;
	login_accepted->unknown1 = llrs.unknown1;
	login_accepted->unknown2 = llrs.unknown2;
	login_accepted->unknown3 = llrs.unknown3;
	login_accepted->unknown4 = llrs.unknown4;
	login_accepted->unknown5 = llrs.unknown5;

	LoginFailedAttempts_Struct *login_failed_attempts = new LoginFailedAttempts_Struct;
	memset(login_failed_attempts, 0, sizeof(LoginFailedAttempts_Struct));

	login_failed_attempts->failed_attempts = 0;
	login_failed_attempts->message         = 0x01;
	login_failed_attempts->lsid            = db_account_id;
	login_failed_attempts->unknown3[3]  = 0x03;
	login_failed_attempts->unknown4[3]  = 0x02;
	login_failed_attempts->unknown5[0]  = 0xe7;
	login_failed_attempts->unknown5[1]  = 0x03;
	login_failed_attempts->unknown6[0]  = 0xff;
	login_failed_attempts->unknown6[1]  = 0xff;
	login_failed_attempts->unknown6[2]  = 0xff;
	login_failed_attempts->unknown6[3]  = 0xff;
	login_failed_attempts->unknown7[0]  = 0xa0;
	login_failed_attempts->unknown7[1]  = 0x05;
	login_failed_attempts->unknown8[3]  = 0x02;
	login_failed_attempts->unknown9[0]  = 0xff;
	login_failed_attempts->unknown9[1]  = 0x03;
	login_failed_attempts->unknown11[0] = 0x63;
	login_failed_attempts->unknown12[0] = 0x01;
	memcpy(login_failed_attempts->key, key.c_str(), key.size());

	char encrypted_buffer[80] = {0};
	auto rc                   = eqcrypt_block((const char *) login_failed_attempts, 75, encrypted_buffer, 1);
	if (rc == nullptr) {
		LogF(Logs::General, Logs::Debug, "Failed to encrypt eqcrypt block");
	}

	memcpy(login_accepted->encrypt, encrypted_buffer, 80);

	if (server.options.IsDumpOutPacketsOn()) {
		DumpPacket(outapp);
	}

	connection->QueuePacket(outapp);
	delete outapp;

	status = cs_logged_in;
}

/**
 * @param user
 * @param pass
 */
void Client::CreateLocalAccount(const std::string &user, const std::string &pass)
{
	auto mode = server.options.GetEncryptionMode();
	auto hash = eqcrypt_hash(user, pass, mode);

	unsigned int db_id    = 0;
	std::string  db_login = server.options.GetDefaultLoginServerName();
	if (!server.db->CreateLoginData(user, hash, db_login, db_id)) {
		DoFailedLogin();
	}
	else {
		DoSuccessfulLogin(user, db_id, db_login);
	}
}

/**
 * @param user
 * @param pass
 * @param id
 */
void Client::CreateEQEmuAccount(const std::string &user, const std::string &pass, unsigned int id)
{
	auto mode = server.options.GetEncryptionMode();
	auto hash = eqcrypt_hash(user, pass, mode);

	if (!server.db->CreateLoginDataWithID(user, hash, "eqemu", id)) {
		DoFailedLogin();
	}
	else {
		DoSuccessfulLogin(user, id, "eqemu");
	}
}

/**
 * @param connection
 */
void Client::LoginOnNewConnection(std::shared_ptr<EQ::Net::DaybreakConnection> connection)
{
	login_connection = connection;
}

/**
 * @param conn
 * @param from
 * @param to
 */
void Client::LoginOnStatusChange(
	std::shared_ptr<EQ::Net::DaybreakConnection> conn,
	EQ::Net::DbProtocolStatus from,
	EQ::Net::DbProtocolStatus to
)
{
	if (to == EQ::Net::StatusConnected) {
		LogF(
			Logs::Detail,
			Logs::Login_Server,
			"[{0}] == EQ::Net::StatusConnected",
			__func__
		);
		LoginSendSessionReady();
	}

	if (to == EQ::Net::StatusDisconnecting || to == EQ::Net::StatusDisconnected) {
		LogF(
			Logs::Detail,
			Logs::Login_Server,
			"[{0}] == EQ::Net::StatusDisconnecting || EQ::Net::StatusDisconnected",
			__func__
		);
		DoFailedLogin();
	}
}

/**
 * @param conn
 * @param from
 * @param to
 */
void Client::LoginOnStatusChangeIgnored(
	std::shared_ptr<EQ::Net::DaybreakConnection> conn,
	EQ::Net::DbProtocolStatus from,
	EQ::Net::DbProtocolStatus to
)
{
}

/**
 * @param conn
 * @param p
 */
void Client::LoginOnPacketRecv(std::shared_ptr<EQ::Net::DaybreakConnection> conn, const EQ::Net::Packet &p)
{
	auto opcode = p.GetUInt16(0);
	LogF(Logs::Detail, Logs::Login_Server, "[{0}] [{1}]", __func__, opcode);
	switch (opcode) {
		case 0x0017: //OP_ChatMessage
			LoginSendLogin();
			break;
		case 0x0018:
			LoginProcessLoginResponse(p);
			break;
	}
}

void Client::LoginSendSessionReady()
{
	EQ::Net::DynamicPacket p;
	p.PutUInt16(0, 1); //OP_SessionReady
	p.PutUInt32(2, 2);

	login_connection->QueuePacket(p);
}

void Client::LoginSendLogin()
{
	size_t                  buffer_len = stored_user.length() + stored_pass.length() + 2;
	std::unique_ptr<char[]> buffer(new char[buffer_len]);

	strcpy(&buffer[0], stored_user.c_str());
	strcpy(&buffer[stored_user.length() + 1], stored_pass.c_str());

	size_t encrypted_len = buffer_len;

	if (encrypted_len % 8 > 0) {
		encrypted_len = ((encrypted_len / 8) + 1) * 8;
	}

	EQ::Net::DynamicPacket p;
	p.Resize(12 + encrypted_len);
	p.PutUInt16(0, 2); //OP_Login
	p.PutUInt32(2, 3);

	eqcrypt_block(&buffer[0], buffer_len, (char *) p.Data() + 12, true);

	login_connection->QueuePacket(p);
}

/**
 * @param p
 */
void Client::LoginProcessLoginResponse(const EQ::Net::Packet &p)
{
	auto encrypt_size                    = p.Length() - 12;
	if (encrypt_size % 8 > 0) {
		encrypt_size = (encrypt_size / 8) * 8;
	}

	std::unique_ptr<char[]> decrypted(new char[encrypt_size]);

	eqcrypt_block((char *) p.Data() + 12, encrypt_size, &decrypted[0], false);

	EQ::Net::StaticPacket sp(&decrypted[0], encrypt_size);
	auto                  response_error = sp.GetUInt16(1);

	login_connection_manager->OnConnectionStateChange(
		std::bind(
			&Client::LoginOnStatusChangeIgnored,
			this,
			std::placeholders::_1,
			std::placeholders::_2,
			std::placeholders::_3
		)
	);

	if (response_error > 101) {
		LogF(Logs::Detail, Logs::Login_Server, "[{0}] response [{1}] failed login", __func__, response_error);
		DoFailedLogin();
		login_connection->Close();
	}
	else {
		LogF(
			Logs::Detail,
			Logs::Login_Server,
			"[{0}] response [{1}] login succeeded user [{2}]",
			__func__,
			response_error,
			stored_user
		);

		auto m_dbid = sp.GetUInt32(8);

		CreateEQEmuAccount(stored_user, stored_pass, m_dbid);
		login_connection->Close();
	}
}