// server.cpp: little more than enhanced multicaster
// runs dedicated or as client coroutine

#include "cube.h"

enum { ST_EMPTY, ST_LOCAL, ST_TCPIP };

struct client // server side version of "dynent" type
{
	int type;
	ENetPeer *peer;
	string hostname;
	string mapvote;
	string name;
	int modevote;
};

vector<client> clients;

int maxclients = 8;
string smapname;

struct server_entity // server side version of "entity" type
{
	bool spawned;
	int spawnsecs;
};

vector<server_entity> sents;

bool notgotitems =
    true; // true when map has changed and waiting for clients to send item
int mode = 0;

void
restoreserverstate(
    vector<entity> &ents) // hack: called from savegame code, only works in SP
{
	loopv(sents)
	{
		sents[i].spawned = ents[i].spawned;
		sents[i].spawnsecs = 0;
	};
};

int interm = 0, minremain = 0, mapend = 0;
bool mapreload = false;

char *serverpassword = "";

bool isdedicated;
ENetHost *serverhost = NULL;
int bsend = 0, brec = 0, laststatus = 0, lastsec = 0;

#define MAXOBUF 100000

void process(ENetPacket *packet, int sender);
void multicast(ENetPacket *packet, int sender);
void disconnect_client(int n, char *reason);

void
send(int n, ENetPacket *packet)
{
	if (!packet)
		return;
	switch (clients[n].type) {
	case ST_TCPIP: {
		enet_peer_send(clients[n].peer, 0, packet);
		bsend += packet->dataLength;
		break;
	};

	case ST_LOCAL:
		localservertoclient(packet->data, packet->dataLength);
		break;
	};
};

void
send2(bool rel, int cn, int a, int b)
{
	ENetPacket *packet =
	    enet_packet_create(NULL, 32, rel ? ENET_PACKET_FLAG_RELIABLE : 0);
	uchar *start = packet->data;
	uchar *p = start + 2;
	putint(p, a);
	putint(p, b);
	*(ushort *)start = ENET_HOST_TO_NET_16(p - start);
	enet_packet_resize(packet, p - start);
	if (cn < 0)
		process(packet, -1);
	else
		send(cn, packet);
	if (packet->referenceCount == 0)
		enet_packet_destroy(packet);
};

void
sendservmsg(char *msg)
{
	ENetPacket *packet = enet_packet_create(
	    NULL, _MAXDEFSTR + 10, ENET_PACKET_FLAG_RELIABLE);
	uchar *start = packet->data;
	uchar *p = start + 2;
	putint(p, SV_SERVMSG);
	sendstring(msg, p);
	*(ushort *)start = ENET_HOST_TO_NET_16(p - start);
	enet_packet_resize(packet, p - start);
	multicast(packet, -1);
	if (packet->referenceCount == 0)
		enet_packet_destroy(packet);
};

void
disconnect_client(int n, char *reason)
{
	printf("disconnecting client (%s) [%s]\n", clients[n].hostname, reason);
	enet_peer_disconnect(clients[n].peer);
	clients[n].type = ST_EMPTY;
	send2(true, -1, SV_CDIS, n);
};

void
resetitems()
{
	sents.setsize(0);
	notgotitems = true;
};

void
pickup(uint i, int sec, int sender) // server side item pickup, acknowledge
                                    // first client that gets it
{
	if (i >= (uint)sents.length())
		return;
	if (sents[i].spawned) {
		sents[i].spawned = false;
		sents[i].spawnsecs = sec;
		send2(true, sender, SV_ITEMACC, i);
	};
};

void
resetvotes()
{
	loopv(clients) clients[i].mapvote[0] = 0;
};

bool
vote(char *map, int reqmode, int sender)
{
	strcpy_s(clients[sender].mapvote, map);
	clients[sender].modevote = reqmode;
	int yes = 0, no = 0;
	loopv(clients) if (clients[i].type != ST_EMPTY)
	{
		if (clients[i].mapvote[0]) {
			if (strcmp(clients[i].mapvote, map) == 0 &&
			    clients[i].modevote == reqmode)
				yes++;
			else
				no++;
		} else
			no++;
	};
	if (yes == 1 && no == 0)
		return true; // single player
	sprintf_sd(msg)("%s suggests %s on map %s (set map to vote)",
	    clients[sender].name, modestr(reqmode), map);
	sendservmsg(msg);
	if (yes / (float)(yes + no) <= 0.5f)
		return false;
	sendservmsg("vote passed");
	resetvotes();
	return true;
};

// server side processing of updates: does very little and most state is tracked
// client only could be extended to move more gameplay to server (at expense of
// lag)

void
process(ENetPacket *packet, int sender) // sender may be -1
{
	if (ENET_NET_TO_HOST_16(*(ushort *)packet->data) !=
	    packet->dataLength) {
		disconnect_client(sender, "packet length");
		return;
	};

	uchar *end = packet->data + packet->dataLength;
	uchar *p = packet->data + 2;
	char text[MAXTRANS];
	int cn = -1, type;

	while (p < end)
		switch (type = getint(p)) {
		case SV_TEXT:
			sgetstr();
			break;

		case SV_INITC2S:
			sgetstr();
			strcpy_s(clients[cn].name, text);
			sgetstr();
			getint(p);
			break;

		case SV_MAPCHANGE: {
			sgetstr();
			int reqmode = getint(p);
			if (reqmode < 0)
				reqmode = 0;
			if (smapname[0] && !mapreload &&
			    !vote(text, reqmode, sender))
				return;
			mapreload = false;
			mode = reqmode;
			minremain = mode & 1 ? 15 : 10;
			mapend = lastsec + minremain * 60;
			interm = 0;
			strcpy_s(smapname, text);
			resetitems();
			sender = -1;
			break;
		};

		case SV_ITEMLIST: {
			int n;
			while ((n = getint(p)) != -1)
				if (notgotitems) {
					server_entity se = {false, 0};
					while (sents.length() <= n)
						sents.add(se);
					sents[n].spawned = true;
				};
			notgotitems = false;
			break;
		};

		case SV_ITEMPICKUP: {
			int n = getint(p);
			pickup(n, getint(p), sender);
			break;
		};

		case SV_PING:
			send2(false, cn, SV_PONG, getint(p));
			break;

		case SV_POS: {
			cn = getint(p);
			if (cn < 0 || cn >= clients.length() ||
			    clients[cn].type == ST_EMPTY) {
				disconnect_client(sender, "client num");
				return;
			};
			int size = msgsizelookup(type);
			assert(size != -1);
			loopi(size - 2) getint(p);
			break;
		};

		case SV_SENDMAP: {
			sgetstr();
			int mapsize = getint(p);
			sendmaps(sender, text, mapsize, p);
			return;
		}

		case SV_RECVMAP:
			send(sender, recvmap(sender));
			return;

		case SV_EXT: // allows for new features that require no server
		             // updates
		{
			for (int n = getint(p); n; n--)
				getint(p);
			break;
		};

		default: {
			int size = msgsizelookup(type);
			if (size == -1) {
				disconnect_client(sender, "tag type");
				return;
			};
			loopi(size - 1) getint(p);
		};
		};

	if (p > end) {
		disconnect_client(sender, "end of packet");
		return;
	};
	multicast(packet, sender);
};

void
send_welcome(int n)
{
	ENetPacket *packet =
	    enet_packet_create(NULL, MAXTRANS, ENET_PACKET_FLAG_RELIABLE);
	uchar *start = packet->data;
	uchar *p = start + 2;
	putint(p, SV_INITS2C);
	putint(p, n);
	putint(p, PROTOCOL_VERSION);
	putint(p, smapname[0]);
	sendstring(serverpassword, p);
	putint(p, clients.length() > maxclients);
	if (smapname[0]) {
		putint(p, SV_MAPCHANGE);
		sendstring(smapname, p);
		putint(p, mode);
		putint(p, SV_ITEMLIST);
		loopv(sents) if (sents[i].spawned) putint(p, i);
		putint(p, -1);
	};
	*(ushort *)start = ENET_HOST_TO_NET_16(p - start);
	enet_packet_resize(packet, p - start);
	send(n, packet);
};

void
multicast(ENetPacket *packet, int sender)
{
	loopv(clients)
	{
		if (i == sender)
			continue;
		send(i, packet);
	};
};

void
localclienttoserver(ENetPacket *packet)
{
	process(packet, 0);
	if (!packet->referenceCount)
		enet_packet_destroy(packet);
};

client &
addclient()
{
	loopv(clients) if (clients[i].type == ST_EMPTY) return clients[i];
	return clients.add();
};

void
checkintermission()
{
	if (!minremain) {
		interm = lastsec + 10;
		mapend = lastsec + 1000;
	};
	send2(true, -1, SV_TIMEUP, minremain--);
};

void
startintermission()
{
	minremain = 0;
	checkintermission();
};

void
resetserverifempty()
{
	loopv(clients) if (clients[i].type != ST_EMPTY) return;
	clients.setsize(0);
	smapname[0] = 0;
	resetvotes();
	resetitems();
	mode = 0;
	mapreload = false;
	minremain = 10;
	mapend = lastsec + minremain * 60;
	interm = 0;
};

int nonlocalclients = 0;
int lastconnect = 0;

void
serverslice(int seconds,
    unsigned int timeout) // main server update, called from cube main loop in
                          // sp, or dedicated server loop
{
	loopv(sents) // spawn entities when timer reached
	{
		if (sents[i].spawnsecs &&
		    (sents[i].spawnsecs -= seconds - lastsec) <= 0) {
			sents[i].spawnsecs = 0;
			sents[i].spawned = true;
			send2(true, -1, SV_ITEMSPAWN, i);
		};
	};

	lastsec = seconds;

	if ((mode > 1 || (mode == 0 && nonlocalclients)) &&
	    seconds > mapend - minremain * 60)
		checkintermission();
	if (interm && seconds > interm) {
		interm = 0;
		loopv(clients) if (clients[i].type != ST_EMPTY)
		{
			send2(true, i, SV_MAPRELOAD,
			    0); // ask a client to trigger map reload
			mapreload = true;
			break;
		};
	};

	resetserverifempty();

	if (!isdedicated)
		return; // below is network only

	int numplayers = 0;
	loopv(clients) if (clients[i].type != ST_EMPTY)++ numplayers;
	serverms(mode, numplayers, minremain, smapname, seconds,
	    clients.length() >= maxclients);

	if (seconds - laststatus >
	    60) // display bandwidth stats, useful for server ops
	{
		nonlocalclients = 0;
		loopv(clients) if (clients[i].type == ST_TCPIP)
		    nonlocalclients++;
		laststatus = seconds;
		if (nonlocalclients || bsend || brec)
			printf("status: %d remote clients, %.1f send, %.1f rec "
			       "(K/sec)\n",
			    nonlocalclients, bsend / 60.0f / 1024,
			    brec / 60.0f / 1024);
		bsend = brec = 0;
	};

	ENetEvent event;
	if (enet_host_service(serverhost, &event, timeout) > 0) {
		switch (event.type) {
		case ENET_EVENT_TYPE_CONNECT: {
			client &c = addclient();
			c.type = ST_TCPIP;
			c.peer = event.peer;
			c.peer->data = (void *)(&c - &clients[0]);
			char hn[1024];
			strcpy_s(
			    c.hostname, (enet_address_get_host(&c.peer->address,
			                     hn, sizeof(hn)) == 0)
			                    ? hn
			                    : "localhost");
			printf("client connected (%s)\n", c.hostname);
			send_welcome(lastconnect = &c - &clients[0]);
			break;
		}
		case ENET_EVENT_TYPE_RECEIVE:
			brec += event.packet->dataLength;
			process(event.packet, (intptr_t)event.peer->data);
			if (event.packet->referenceCount == 0)
				enet_packet_destroy(event.packet);
			break;

		case ENET_EVENT_TYPE_DISCONNECT:
			if ((intptr_t)event.peer->data < 0)
				break;
			printf("disconnected client (%s)\n",
			    clients[(intptr_t)event.peer->data].hostname);
			clients[(intptr_t)event.peer->data].type = ST_EMPTY;
			send2(true, -1, SV_CDIS, (intptr_t)event.peer->data);
			event.peer->data = (void *)-1;
			break;
		};

		if (numplayers > maxclients) {
			disconnect_client(lastconnect, "maxclients reached");
		};
	};
#ifndef _WIN32
	fflush(stdout);
#endif
};

void
cleanupserver()
{
	if (serverhost)
		enet_host_destroy(serverhost);
};

void
localdisconnect()
{
	loopv(clients) if (clients[i].type == ST_LOCAL) clients[i].type =
	    ST_EMPTY;
};

void
localconnect()
{
	client &c = addclient();
	c.type = ST_LOCAL;
	strcpy_s(c.hostname, "local");
	send_welcome(&c - &clients[0]);
};

void
initserver(bool dedicated, int uprate, char *sdesc, char *ip, char *master,
    char *passwd, int maxcl)
{
	serverpassword = passwd;
	maxclients = maxcl;
	servermsinit(master ? master : "wouter.fov120.com/cube/masterserver/",
	    sdesc, dedicated);

	if (isdedicated = dedicated) {
		ENetAddress address = {ENET_HOST_ANY, CUBE_SERVER_PORT};
		if (*ip && enet_address_set_host(&address, ip) < 0)
			printf("WARNING: server ip not resolved");
		serverhost = enet_host_create(&address, MAXCLIENTS, 0, uprate);
		if (!serverhost)
			fatal("could not create server host\n");
		loopi(MAXCLIENTS) serverhost->peers[i].data = (void *)-1;
	};

	resetserverifempty();

	if (isdedicated) // do not return, this becomes main loop
	{
#ifdef _WIN32
		SetPriorityClass(GetCurrentProcess(), HIGH_PRIORITY_CLASS);
#endif
		printf("dedicated server started, waiting for "
		       "clients...\nCtrl-C to exit\n\n");
		atexit(cleanupserver);
		atexit(enet_deinitialize);
		for (;;)
			serverslice(/*enet_time_get_sec()*/ time(NULL), 5);
	};
};