/*
===========================================================================
Copyright (C) 2023 the OpenMoHAA team

This file is part of OpenMoHAA source code.

OpenMoHAA source code 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.

OpenMoHAA source code 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 OpenMoHAA source code; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
===========================================================================
*/

#include "sv_gqueryreporting.h"

#include <common/gsPlatformSocket.h>
#include <common/gsPlatformUtil.h>
#include <gutil.h>

static char* queries[] =
{
	"basic",
	"info",
	"rules",
	"players",
	"status",
	"packets",
	"echo",
	"secure"
};

static qr_implementation_t static_rec;
static qr_implementation_t* current_rec = &static_rec;
struct sockaddr_in hbaddr;
char qr_hostname[64];

void qr_check_queries(qr_t qrec);
void qr_check_send_heartbeat(qr_t qrec);
static void parse_query(qr_t qrec, char* query, struct sockaddr* sender);
static void send_heartbeat(qr_t qrec, int statechanged);

void qr_process_queries(qr_t qrec)
{
	if (!qrec)
		qrec = current_rec;

	qr_check_send_heartbeat(qrec);
	qr_check_queries(qrec);
}

void qr_process_queries_no_heartbeat(qr_t qrec)
{
	if (!qrec)
		qrec = current_rec;

	qr_check_queries(qrec);
}

void qr_check_queries(qr_t qrec)
{
#define INBUF_LEN 256
	static char indata[INBUF_LEN]; //256 byte input buffer
	struct sockaddr_in saddr;
	int error;

#if defined(_LINUX)
	unsigned int saddrlen = sizeof(struct sockaddr_in);
#else
	int saddrlen = sizeof(struct sockaddr_in);
#endif

	while (CanReceiveOnSocket((SOCKET)qrec->hbsock))
	{
		//else we have data
		error = (int)recvfrom((SOCKET)qrec->hbsock, indata, (INBUF_LEN - 1), 0, (struct sockaddr*)&saddr, &saddrlen);

		if (gsiSocketIsNotError(error))
		{
			indata[error] = '\0';
			parse_query(qrec, indata, (struct sockaddr*)&saddr);
		}
	}
}

void qr_check_send_heartbeat(qr_t qrec)
{
	unsigned long tc;

	tc = current_time();

	if ((SOCKET)qrec->hbsock != INVALID_SOCKET)
	{
		if (tc - qrec->lastheartbeat <= 300000 && qrec->lastheartbeat && tc >= qrec->lastheartbeat)
		{
			if (qrec->no_query > 0 && tc - qrec->lastheartbeat > 30000)
			{
				send_heartbeat(qrec, 0);
				if (qrec->no_query++ > 10)
					qrec->no_query = 0;
			}
		}
		else
		{
			send_heartbeat(qrec, 0);
		}
	}
}

void qr_send_statechanged(qr_t qrec)
{
	if (!qrec)
		qrec = current_rec;
	send_heartbeat(qrec, 1);
}

void qr_shutdown(qr_t qrec)
{
	if (qrec == NULL)
		qrec = current_rec;
	if (INVALID_SOCKET != (SOCKET)qrec->hbsock && (SOCKET)qrec->querysock) //if we own the socket
	{
		closesocket((SOCKET)qrec->hbsock);
	}
	qrec->hbsock = (void*)INVALID_SOCKET;
	qrec->lastheartbeat = 0;
	if (qrec->querysock) //if we own the socket
	{
		SocketShutDown();
	}
	if (qrec != &static_rec) //need to free it, it was dynamically allocated
	{
		free(qrec);
	}
}

/* Return a sockaddrin for the given host (numeric or DNS) and port)
Returns the hostent in savehent if it is not NULL */
static int get_sockaddrin(const char* host, int port, struct sockaddr_in* saddr, struct hostent** savehent)
{
	struct hostent* hent = NULL;

	saddr->sin_family = AF_INET;
	saddr->sin_port = htons((unsigned short)port);
	if (host == NULL)
		saddr->sin_addr.s_addr = INADDR_ANY;
	else
		saddr->sin_addr.s_addr = inet_addr(host);

	if (saddr->sin_addr.s_addr == INADDR_NONE && strcmp(host, "255.255.255.255") != 0)
	{
		hent = gethostbyname(host);
		if (!hent)
			return 0;
		saddr->sin_addr.s_addr = *(unsigned int*)hent->h_addr_list[0];
	}
	if (savehent != NULL)
		*savehent = hent;
	return 1;

}

/* value_for_key: this returns a value for a certain key in s, where s is a string
containing key\value pairs. If the key does not exist, it returns  NULL.
Note: the value is stored in a common buffer. If you want to keep it, make a copy! */
static char* value_for_key(const char* s, const char* key)
{
	static int valueindex;
	char* pos, * pos2;
	char keyspec[256] = "\\";
	static char value[2][256];

	valueindex ^= 1;
	strcat(keyspec, key);
	strcat(keyspec, "\\");
	pos = strstr(s, keyspec);
	if (!pos)
		return NULL;
	pos += strlen(keyspec);
	pos2 = value[valueindex];
	while (*pos && *pos != '\\')
		*pos2++ = *pos++;
	*pos2 = '\0';
	return value[valueindex];
}

static void packet_send(qr_t qrec, struct sockaddr* addr, char* buffer)
{
	char keyvalue[80];

	if (!strlen(buffer))
		return;

	sprintf(keyvalue, "\\queryid\\%d.%d", qrec->queryid, qrec->packetnumber++);
	strcat(buffer, keyvalue);

	sendto((SOCKET)qrec->querysock, buffer, (int)strlen(buffer), 0, addr, 16);
	*buffer = 0;
}

static void buffer_send(qr_t qrec, struct sockaddr* sender, char* buffer, char* newdata)
{
	int bcount;
	int i;
	char* lastkey;
	char* pos;

	bcount = 0;
	if (strlen(newdata) + strlen(buffer) < 1350)
	{
		strcat(buffer, newdata);
		return;
	}

	pos = newdata;
	while (strlen(pos) > 1350)
	{
		lastkey = pos;

		for (i = 0; i < 1350; ++i)
		{
			if (pos[i] == '\\')
			{
				if (!(bcount % 2))
					lastkey = pos + i;

				++bcount;
			}
		}

		if (lastkey == pos)
			return;

		*lastkey = 0;
		buffer_send(qrec, sender, buffer, pos);
		*lastkey = '\\';
		pos = lastkey;
		bcount = 0;

		if (strlen(buffer) + strlen(lastkey) < 1350)
		{
			strcat(buffer, pos);
			return;
		}
	}

	packet_send(qrec, sender, buffer);
	strcpy(buffer, pos);
}

static void send_basic(qr_t qrec, struct sockaddr* sender, char* outbuf)
{
	char keyvalue[1400] = { 0 };

	qrec->qr_basic_callback(keyvalue, 1400, qrec->udata);
	buffer_send(qrec, sender, outbuf, keyvalue);
}

static void send_info(qr_t qrec, struct sockaddr* sender, char* outbuf)
{
	char keyvalue[1400] = { 0 };

	qrec->qr_info_callback(keyvalue, 1400, qrec->udata);
	buffer_send(qrec, sender, outbuf, keyvalue);
}

static void send_rules(qr_t qrec, struct sockaddr* sender, char* outbuf)
{
	char keyvalue[1400] = { 0 };

	qrec->qr_rules_callback(keyvalue, 1400, qrec->udata);
	buffer_send(qrec, sender, outbuf, keyvalue);
}

static void send_players(qr_t qrec, struct sockaddr* sender, char* outbuf)
{
	char keyvalue[1400] = { 0 };

	qrec->qr_players_callback(keyvalue, 1400, qrec->udata);
	buffer_send(qrec, sender, outbuf, keyvalue);
}

static void send_echo(qr_t qrec, struct sockaddr* sender, char* outbuf, const char* echostr)
{
	char keyvalue[1400] = { 0 };

	if (strlen(echostr) <= 50)
	{
		sprintf(keyvalue, "\\echoresponse\\%s", echostr);
		buffer_send(qrec, sender, outbuf, keyvalue);
	}
}

static void send_final(qr_t qrec, struct sockaddr* sender, char* outbuf, char* validation)
{
	char keyvalue[256];
	char encrypted_val[128];
	char encoded_val[200];
	int keylen;

	if (*validation)
	{
		keylen = (int)strlen(validation);

		if (keylen > 128)
			return;

		strcpy(encrypted_val, validation);

		gs_encrypt((uchar*)qrec->secret_key, (int)strlen(qrec->secret_key), encrypted_val, keylen);
		gs_encode(encrypted_val, keylen, encoded_val);

		sprintf(keyvalue, "\\validate\\%s", encoded_val);
		buffer_send(qrec, sender, outbuf, keyvalue);
	}

	sprintf(keyvalue, "\\final\\");
	buffer_send(qrec, sender, outbuf, keyvalue);
	packet_send(qrec, sender, outbuf);
}

static void parse_query(qr_t qrec, char* query, struct sockaddr* sender)
{
	query_t querytype = qtunknown;
	char buffer[1400] = { 0 };
	const char* value;
	char validation[256] = { 0 };

	if (!qrec)
		qrec = current_rec;

	if (*query == ';')
	{
		// custom handler
		qrec->qr_custom_handler(query, sender);
		return;
	}

	qrec->packetnumber = 0;
	qrec->queryid++;

	if (qrec->no_query > 0)
		qrec->no_query = 0;

	for (querytype = qtbasic; querytype <= qtsecure; ++querytype)
	{
		value = value_for_key(query, queries[querytype]);
		if (value)
		{
			switch (querytype)
			{
			case qtbasic:
				send_basic(qrec, sender, buffer);
				break;
			case qtinfo:
				send_info(qrec, sender, buffer);
				break;
			case qtrules:
				send_rules(qrec, sender, buffer);
				break;
			case qtplayers:
				send_players(qrec, sender, buffer);
				break;
			case qtstatus:
				send_basic(qrec, sender, buffer);
				send_info(qrec, sender, buffer);
				send_rules(qrec, sender, buffer);
				send_players(qrec, sender, buffer);
				break;
			case qtpackets:
				send_basic(qrec, sender, buffer);
				packet_send(qrec, sender, buffer);
				send_info(qrec, sender, buffer);
				packet_send(qrec, sender, buffer);
				send_rules(qrec, sender, buffer);
				packet_send(qrec, sender, buffer);
				send_players(qrec, sender, buffer);
				break;
			case qtecho:
				send_echo(qrec, sender, buffer, value);
				break;
			case qtsecure:
				strcpy(validation, value);
				break;
			default:
				continue;
			}
		}
	}

	send_final(qrec, sender, buffer, validation);
}

static void send_heartbeat(qr_t qrec, int statechanged)
{
	char buf[256];

	sprintf(buf, "\\heartbeat\\%d\\gamename\\%s", qrec->qport, qrec->gamename);

	if (statechanged)
		sprintf(buf + strlen(buf), "\\statechanged\\%d", statechanged);

	sendto((SOCKET)qrec->hbsock, buf, (int)strlen(buf), 0, (const struct sockaddr*)&qrec->master_saddr, 16);
	qrec->lastheartbeat = current_time();
}

static int do_connect(void* sock, char* addr, int port, struct sockaddr_in* master_saddr)
{
	get_sockaddrin(addr, port, master_saddr, NULL);
	return 0;
}

void init_qrec(
	qr_t* qrec,
	int baseport,
	SOCKET hbsock,
	SOCKET querysock,
	char* gamename,
	char* secret_key,
	qr_querycallback_t qr_basic_callback,
	qr_querycallback_t qr_info_callback,
	qr_querycallback_t qr_rules_callback,
	qr_querycallback_t qr_players_callback,
	void* userdata
)
{
	qr_t qr;

	if (qrec)
	{
		qr = (qr_t)malloc(sizeof(qr_implementation_t));
		*qrec = qr;
	}
	else
	{
		qr = &static_rec;
	}

	strcpy(qr->gamename, gamename);
	strcpy(qr->secret_key, secret_key);

	qr->qport = baseport;
	qr->hbsock = (void*)hbsock;
	qr->querysock = (void*)querysock;
	qr->queryid = 1;
	qr->no_query = 1;
	qr->udata = userdata;
	qr->qr_basic_callback = qr_basic_callback;
	qr->qr_info_callback = qr_info_callback;
	qr->lastheartbeat = 0;
	qr->packetnumber = 0;
	qr->qr_players_callback = qr_players_callback;
	qr->qr_rules_callback = qr_rules_callback;
	qr->qr_custom_handler = 0;
}

#define NUM_PORTS_TO_TRY 100

int qr_init(
	qr_t* qrec,
	char* ip,
	int baseport,
	char* gamename,
	char* secret_key,
	qr_querycallback_t qr_basic_callback,
	qr_querycallback_t qr_info_callback,
	qr_querycallback_t qr_rules_callback,
	qr_querycallback_t qr_players_callback,
	void* userdata
)
{
	struct sockaddr_in saddr;
	SOCKET hbsock;
	int maxport;
	int lasterror = 0;

#if defined(_LINUX)
	unsigned int saddrlen;
#else
	int saddrlen;
#endif

	hbsock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
	if (hbsock == INVALID_SOCKET) {
		return 1;
	}

	maxport = baseport + NUM_PORTS_TO_TRY;
	while (baseport < maxport)
	{
		get_sockaddrin(ip, baseport, &saddr, NULL);
		if (saddr.sin_addr.s_addr == htonl(0x7F000001)) //localhost -- we don't want that!
			saddr.sin_addr.s_addr = INADDR_ANY;

		lasterror = bind(hbsock, (struct sockaddr*)&saddr, sizeof(saddr));
		if (lasterror == 0)
			break; //we found a port
		baseport++;
	}

	if (lasterror != 0) //we weren't able to find a port
	{
		return 2;
	}

	if (baseport == 0) //we bound it dynamically
	{
		saddrlen = sizeof(saddr);

		lasterror = getsockname(hbsock, (struct sockaddr*)&saddr, &saddrlen);

		if (lasterror)
		{
			return 2;
		}
		baseport = ntohs(saddr.sin_port);
	}

	init_qrec(
		qrec,
		baseport,
		hbsock,
		hbsock,
		gamename,
		secret_key,
		qr_basic_callback,
		qr_info_callback,
		qr_rules_callback,
		qr_players_callback,
		userdata);

	if (!qrec)
		qrec = &current_rec;

	return do_connect((void*)hbsock, "master.x-null.net", 27900, &(*qrec)->master_saddr);
}