/*
 *	The Unix Channel
 *
 *	by Michel Beaudouin-Lafon
 *
 *	Copyright 1990-1997
 *	Laboratoire de Recherche en Informatique (LRI)
 *
 *	CENA bus access, by Stephane Chatty
 *
 *	$Id$
 *	$CurLog$
 */

#include "BusAccess.h"
#include "Multiplexer.h"
#include "BufStream.h"
#include "ccu/String.h"
#include "dnn/Trigger.h"
#include "dnn/Reaction.h"
#include "ccu/Signal.h"
#include <stdlib.h>
#include <stdio.h>
#include <ostream.h>
#include <regex.h>
#include <stdarg.h>
#include <ctype.h>

int UchBusAccess::Version = 3;
const char* const UchBusAccess::DefaultBus = "127:2010";
const sword UchBusAccess::DefaultBusPort = 2010;
const char* const UchBusAccess::DefaultBusNet = "127";

static int _BusDebug = 0;

const unsigned char STX = '\002';
const unsigned char ETX = '\003';

typedef enum {
	BusBye,		/* quitte l'application */
	BusRegexp,		/* expression reguliere d'un client */
	BusMsg,		/* message reel */
	BusError,		/* error message */
	BusDelRegexp,	/* Remove expression reguliere */ 
	BusReady,
	BusHello,
	BusDirectMsg,
	BusDie
} BusMsgType;




class UchBusSubscription {
protected:
	int	Id;
	CcuString	Regexp;
	regex_t	Compiled;
public:
		UchBusSubscription (int, const char*);
inline	int	GetId () const	{ return Id; }
inline	const char*	GetRegexp () const	{ return Regexp; }
inline	const regex_t*	GetCompiled () const	{ return &Compiled; }
};

class UchBusTrigger : public DnnTrigger {
protected:
	int	Id;
	CcuString	Regexp;
public:
		UchBusTrigger (const char*);
inline	int	GetId () const	{ return Id; }
inline	void	SetId (int id)		{ Id = id; }
inline	const char*	GetRegexp () const	{ return Regexp; }
};

class UchBusServer : public UchStream {
public:
	UchBusAccess*	MyBus;

		UchBusServer (UchBusAccess*);
	void	HandleRead ();
};

/* this is used for local subscriptions */
UchBusTrigger :: UchBusTrigger (const char* r)
: Id (-1),
  Regexp (r)
{
}

/* this is used for remote subscriptions */
UchBusSubscription :: UchBusSubscription (int id, const char* r)
: Id (id),
  Regexp (r)
{
	int reg = regcomp (&Compiled, r, REG_ICASE|REG_EXTENDED);
	if (reg != 0)
		cerr << "bad regexp " << r << "\n";
}

UchBusServer :: UchBusServer (UchBusAccess* bus)
: UchStream (new UchInetAddress (ANYADDR)),
  MyBus (bus)
{
	if (Listen () < 0) {
		cerr << "cannot listen on bus server\n";
		return;
	}
	SetMode (IORead);
	Add (UchMpx);
}

/* this happens when another agent opens a connection with us */
void
UchBusServer :: HandleRead ()
{
	/* Accept connection */
	int fd = Accept ();
	if (fd < 0) {
		cerr << "cannot accept connection on server\n";
		return;
	}

	/* create agent handle */
	if (_BusDebug)
		cout << "Someone was there. Hello!\n";
	UchBusAgent* a = new UchBusAgent (fd, MyBus);

	/* send name and subscriptions */
	a->SayHello ();
}

UchBusAgent :: UchBusAgent (int fd, UchBusAccess* bus)
: UchBufStream (),
  RemoteSubscriptions (),
  MyBus (bus),
  DirectMsg (16)
{
//	SetMode (IOReadWrite);
	SetMode (IORead);
	UchChannel::Open (fd);
	Add (UchMpx);
	MyBus->Agents.Append (this);
}


UchBusAgent :: UchBusAgent (const char* host, sword port, UchBusAccess *bus)
: UchBufStream (0, new UchInetAddress (host, port)),
  RemoteSubscriptions (),
  MyBus (bus),
  DirectMsg (16)
{
	if (!Setup ()) {
		cerr << "cannot set up stream on " << host << ":" << port << "\n";
		return;
	}
	SetMode (IORead);
	Add (UchMpx);
	MyBus->Agents.Append (this);
}


UchBusAgent :: ~UchBusAgent ()
{
	MyBus->Agents.Remove (this);
	Remove ();
	Close ();
}


/* this had to be redefined because UchChannel adds null character
and we don't want it */
void
UchBusAgent :: WriteString (const char* s)
{
	/* now that this is a BufStream, perhaps we should use Buffer? */
	Write ((byte*) s, strlen (s));
}

void
UchBusAgent :: SayHello ()
{
	CcuSignalBlocker b (SigPipe);
	char buf[32];

	/* Say hello */
	sprintf (buf, "%d %d%c", BusHello, MyBus->ListenPort, STX);
	WriteString (buf);
	WriteString (MyBus->Name);
	WriteString ("\n");

	if (_BusDebug)
		cout << "sending subscriptions\n";
	CcuListIterOf<UchBusTrigger> s = MyBus->LocalSubscriptions;
	while (++s)
		SendLocalSubscription (*s);

	/* say I'm ready */
	sprintf (buf, "%d 0%c\n", BusReady, STX);
	WriteString (buf);
}

void
UchBusAgent :: SendLocalSubscription (const UchBusTrigger* s)
{
	char buf[32];
	sprintf (buf, "%d %d%c", BusRegexp, s->GetId (), STX);
	WriteString (buf);
	WriteString (s->GetRegexp ());
	WriteString ("\n");
	if (_BusDebug)
		cout << "Sending regexp: " << buf << s->GetRegexp () << '\n';
}

void
UchBusAgent :: SayBye ()
{
	CcuSignalBlocker b (SigPipe);
	char buf[32];

	/* Say bye */
	sprintf (buf, "%d 0%c\n", BusBye, STX);
	WriteString (buf);
}


/* this happens when another agent talks */
void
UchBusAgent :: HandleRead ()
{
	/* read in buffer */
	if (InBuffer.BufLength () == 0)
		InBuffer.NeedSize (128);
	int n = Read (InBuffer);

	/* handle errors */
	if (n == -2) {
		InBuffer.Grow ();
		n = Read (InBuffer);
	}
	if (n <= 0) {
		delete this;
		return;
	}

	/* slice input */
	char* start = (char*) InBuffer.Buffer ();
	char* stop = start + InBuffer.BufLength ();
	for (char* p = start; p < stop; p++) {
		if (*p == '\n') {
			*p = '\0';
			ProcessLine (start);
			start = p+1;
			InBuffer.Flush ((byte*) start);
		}
	}
}

static int id = 0;

static int
has_id (UchBusSubscription* s)
{
	return (s->GetId () == id);
}

void
UchBusAgent :: ProcessLine (const char* line)
{
	/* message structure is:
		Bye:	"0 0\002"
		Regexp:	"1 23\002b(la)bl(a*)b(la)"
		Msg:	"2 23\002match1\003match2\003match3"
		Error:	"3 0\002error!"
		DelRegexp:	"4 0\002"
		Ready:	"5 0\002"
		Hello:	"6 12526\002TESTAGENT"
		DirectMsg:	"7 23\002blablabla"
	*/

	/* extract message header */
	int msg_type, id, nb_chars;
	int nb_fields = sscanf (line,"%d %d%n", &msg_type, &id, &nb_chars);
	if (nb_fields != 2) {
		cerr << "Bad format: " << line;
		return;
	}

	const char* p = (const char*) (line+nb_chars);
	DnnEvent* ev;
	switch (msg_type) {
	case BusBye:
		if (_BusDebug)
			cout << "[bye " << Name << "]\n";
		ev = new UchAgentEvent (this, UchAgentEvent::BusAgentBye);
		Bye.Dispatch (*ev);
		delete this;
		break;
	case BusRegexp:
		if (_BusDebug)
			cout << "[regexp " << Name << " " << p+1 << "]\n";
		RemoteSubscriptions.Append (new UchBusSubscription (id, p+1));
		break;
	case BusMsg:
		if (_BusDebug)
			cout << "[event " << Name << " " << p+1 << "]\n";
		MyBus->HandleEvent (id, p+1);
		break;
	case BusDelRegexp:
		if (_BusDebug)
			cout << "[del " << Name << " " << id << "]\n";
		::id = id;
		RemoteSubscriptions.Remove (has_id);
		break;
	case BusReady:
		if (_BusDebug)
			cout << "[ready " << Name << "]\n";
		ev = new UchAgentEvent (this, UchAgentEvent::BusNewAgent);
		MyBus->NewAgents.Dispatch (*ev);
		break;
	case BusDirectMsg:
		{
		if (_BusDebug)
			cout << "[direct " << Name << id << " " << p+1 << "]\n";
		ev = new UchDirectEvent (this, p+1);
		DnnTrigger* t = DirectMsg[id];
		t->Dispatch (*ev);
		break;
		}
	case BusHello:
		Name = p+1;
		if (_BusDebug)
			cout << "[hello " << Name << "]\n";
		if (id && !MyBus->CheckUnicity (this, id))
			delete this;
		else
			RemoteId = id;
		break;
	case BusError:
		break;
	case BusDie:
		/* too violent */
		if (_BusDebug)
			cout << "[die]\n";
		exit (0);
	}
}

void
UchBusAgent :: EmitEvent (const char* msg)
{
	CcuSignalBlocker b (SigPipe);
	const int MAX_MATCHING_ARGS = 20;
	regmatch_t pmatch[MAX_MATCHING_ARGS+1];

	/* scan all subscriptions from this agent */
	CcuListIterOf<UchBusSubscription> r = RemoteSubscriptions;
	while (++r) {
		UchBusSubscription* s = *r;
		/* does the message match the regexp? */
		if (regexec (s->GetCompiled (), msg, MAX_MATCHING_ARGS, pmatch, 0) != 0)
			continue;

		/* if yes, emit it as such */
		if (_BusDebug)
			cout << msg << " matches " << s->GetRegexp () << "\n";
		char buf[64];
		sprintf (buf, "%d %d%c", BusMsg, s->GetId (), STX);
		WriteString (buf);
#ifdef GNU_REGEXP
		regmatch_t* p = &pmatch[1];
		while (p->rm_so != -1) {
			char buf[4096];
			sprintf (buf, "%.*s%c", p->rm_eo - p->rm_so, msg + p->rm_so, ETX);
			WriteString (buf);
			++p;
		}
#else
		for (int i = 1; i < s->GetCompiled ()->re_nsub+1; i ++ ) {
			if (pmatch[i].rm_so != -1 ) {
				sprintf (buf, "%.*s%c", pmatch[i].rm_eo - pmatch[i].rm_so, msg + pmatch[i].rm_so, ETX);
			} else {
				sprintf (buf, "%c", ETX);
			}
			WriteString (buf);
		}
#endif
		WriteString ("\n");
	}
}

/* emit direct message */
void
UchBusAgent :: Emit (int id, const char* fmt, ...)
{
	/* build message */
	char message[4096];
	va_list ap;
	
	va_start (ap, fmt);
	vsprintf (message, fmt, ap);
	va_end (ap );

	/* send it */
	CcuSignalBlocker b (SigPipe);
	char buf[32];
	sprintf (buf, "%d %d%c", BusDirectMsg, id, STX);
	WriteString (buf);
	WriteString (message);
	WriteString ("\n");
}

UchBusAccess :: UchBusAccess (const char* name, const char* bus)
: UchDatagram (),
  UchBaseSignalHandler (*UchMpx, SigInt),
  Name (name),
  ListenPort (0),
  BroadcastPort (0),
  Server (0),
  Agents (),
  IdToSubscription (256),
  LocalSubscriptions ()
{


	/** determine network list as well as broadcast port **/
	/* (we accept addresses such as 123.231,123.123:2000 or 123.231 or :2000) */

	/* first, let's find something to parse */
	if (!bus || !*bus)
		bus = getenv ("IVYBUS");
	if (!bus || !*bus)
		bus = DefaultBus;

	/* then, let's get a port number. We'll parse network list later.*/
	sword port;
	char* q = strchr (bus, ':');
	if (bus && (port = atoi (q+1)))
		BroadcastPort = port;
	else
		BroadcastPort = DefaultBusPort;


	/** set up UDP broadcast socket **/
	UchInetAddress* a = new UchInetAddress (ANYADDR, BroadcastPort);
	BindTo (a);
	if (!Open ()) {
		perror ("Cannot open socket: ");
		return;
	}
	if (!AllowBroadcast ()) {
		perror ("socket won't broadcast: ");
		return;
	}
	if (!ReuseAddress ()) {
		perror ("socket won't let address be reused: ");
		return;
	}

	if (Bind () < 0) {
		cerr << "cannot bind socket to port " << BroadcastPort << "\n";
		return;
	}
//	SetMode (IOReadWrite);
	SetMode (IORead);

	/** set up stream **/
	Server = new UchBusServer (this);
	a = dynamic_cast<UchInetAddress*>(Server->BoundTo ());
	if (!a) {
		cerr << "bad address type?!\n";
		return;
	}
	ListenPort = a->Port ();
	
	/** broadcast handshakes on every network **/
	char handshake[32];
	sprintf (handshake, "%d %hu\n", Version, ListenPort);

	/* if we only have a port number, resort to default value for network */
	if (bus == q)
		bus = DefaultBusNet;

	/* parse network list and send broadcast handshakes.
	   This is long and painful but inet_aton is sloppy.
	   If someone knows other builtin routines that do that... */
	unsigned long mask = 0xffffffff; 
	unsigned char elem = 0;
	int numdigit = 0;
	int numelem = 0;
	int error = 0;

	for (;;) {
		/* address elements are up to 3 digits... */
		if (!error && isdigit (*bus)) {
			if (numdigit < 3 && numelem < 4) {
				elem = 10 * elem +  *bus -'0';
			} else {
				error = 1;
			}

		/* ... terminated by a point, a comma or a colon, or the end of string */
		} else if (!error && (*bus == '.' || *bus == ',' || *bus == ':' || *bus == '\0')) {
			mask = (mask ^ (0xff << (8*(3-numelem)))) | (elem << (8*(3-numelem)));

			/* after a point, expect next address element */
			if (*bus == '.') {
				numelem++;

			/* addresses are terminated by a comma or end of string */
			} else {
				printf ("Broadcasting on network %lx, port %d\n", mask, BroadcastPort);
				UchInetAddress ba (mask, BroadcastPort);
				Send ((byte*)handshake, strlen (handshake), ba);
				numelem = 0;
				mask = 0xffffffff;
			}
			numdigit = 0;
			elem = 0;

		/* recover from bad addresses at next comma or colon or at end of string */
		} else if (*bus == ',' || *bus == ':' || *bus == '\0') {
			fprintf (stderr, "bad broadcast address\n");
			elem = 0;
			numelem = 0;
			numdigit = 0;
			mask = 0xffffffff;
			error = 0;

		/* ignore spaces */
		} else if (*bus == ' ') {

		  /* everything else is illegal */
		} else {
			error = 1;
		}

		/* end of string or colon */
		if (*bus == '\0' || *bus == ':')
			break;
		++bus;
	}

	/* add to main loop */
	Add (UchMpx);
}

void
UchBusAccess :: Clear ()
{
	/* say bye to all remote agents, remove and delete them */

	UchBusAgent* a;
	while (a = Agents.RemoveFirst ()) {
		a->SayBye ();
		delete a;
	}
}

UchBusAccess :: ~UchBusAccess ()
{

}

/* this happens when someone sends a broadcast on the bus: a newcomer */
void
UchBusAccess :: HandleRead ()
{
	/* read data */
	byte buf [256];
	int nb_bytes = Receive (buf, 256);
	if (nb_bytes < 0) {
		cerr << "read error on broadcast port\n";
		return;
	}

	/* decode data: should be a handshake */
	int bus_version;
	sword remote_listen_port;
	int nb_infos = sscanf ((char*) buf, "%d %hu", &bus_version, &remote_listen_port);
	if (nb_infos < 2) {
		cerr << "bad data on broadcast port\n";
		return;
	}

	/* where did this come from? */
	UchInetAddress* a = dynamic_cast<UchInetAddress*> (From ());
	 if (!a) {
		cerr << "bad address!?\n";
		return;
	 }
	const char* remote_host = a->GetHostName ();
	sword remote_port = a->Port ();

	/* sanity checks: is it the same protocol version? is it myself calling? */
	if (remote_listen_port == ListenPort)
		return;
	if (bus_version != Version) {
		cerr << "bad protocol version\n";
		return;
	}

	if (_BusDebug)
		printf ("Arrivee de %s:%hu port %hu\n", remote_host, remote_port, remote_listen_port );

	/* Create agent handle */
	UchBusAgent* ag = new UchBusAgent (remote_host, remote_listen_port, this);

	/* send name and subscriptions */
	ag->SayHello ();
}


void
UchBusAccess :: HandleEvent (int id, const char* msg)
{
	UchBusTrigger* s = IdToSubscription.Get (id);
	if (!s) {
		cerr << "bad regexp id " << id << "\n";
		return;
	}

	if (_BusDebug)
		cout << "REGEXP " << s->GetId () << " MATCHED: " << msg << "\n";
	UchBusEvent* ev = new UchBusEvent (s->GetRegexp (), msg);
	s->Dispatch (*ev);
}

/* this is the handler for SIGINT */
void
UchBusAccess :: DeferredHandle (int)
{
	cerr << "quitting\n";
	Clear ();
	UchStop ();
}

bool
UchBusAccess :: CheckUnicity (UchBusAgent* a, sword id)
{
	CcuListIterOf<UchBusAgent> li = Agents;
	while (++li) {
		if ((*li)->RemoteId == id && a != (*li))
			return false;
	}
	return true;
}

void
UchBusAccess :: Subscribe (DnnBaseReaction& r, const char* fmt, ...)
{
	/* build regexp */
	char regexp[4096];
	va_list ap;
	
	va_start (ap, fmt);
	vsprintf (regexp, fmt, ap);
	va_end (ap );

	/* store new subscription */
	UchBusTrigger* s = new UchBusTrigger (regexp);
	LocalSubscriptions.Append (s);
	int id = IdToSubscription.Store (s);
	s->SetId (id);

	/* emit to current remote agents */
	CcuListIterOf<UchBusAgent> a = Agents;
	while (++a)
		(*a)->SendLocalSubscription (s);

	/* link to reaction */
	r.SubscribeTo (*s);
}


void
UchBusAccess :: Emit (const char* fmt, ...)
{
	/* build message */
	char message[4096];
	va_list ap;
	
	va_start (ap, fmt);
	vsprintf (message, fmt, ap);
	va_end (ap );

	CcuListIterOf <UchBusAgent> a = Agents;
	while (++a)
		(*a)->EmitEvent (message);
}
		

DnnEventType* UchAgentEvent::BusNewAgent = new DnnEventType ("new agent", 0, 0);
DnnEventType* UchAgentEvent::BusAgentBye = new DnnEventType ("agent bye", 0, 0);

UchBusEvent :: UchBusEvent (const char* r, const char* m)
: DnnEvent (),
  Regexp (r),
  NbMatches (0),
  Matches (m),
  MatchList ()
{
	register const char* p = m;
	register char* q = (char*) m;
	bool end = false;
	while (!end) {
		switch (*q) {
		case '\0':
			end = true;
			if (q == p)
				break;
			/* else fall through */
		case ETX:
			NbMatches++;
			*q = '\0';
			MatchList.Append (new CcuString (p));
			p = q + 1;
			/* fall through */
		default:
			++q;
		  }
	}
}


UchBusEvent :: ~UchBusEvent ()
{
	CcuListIterOf<CcuString> li = MatchList;
	while (++li)
		delete (*li);
}

UchAgentEvent :: UchAgentEvent (UchBusAgent* a, DnnEventType* t)
: DnnEvent (t),
  Agent (a)
{
}


UchAgentEvent :: ~UchAgentEvent ()
{
}

UchDirectEvent :: UchDirectEvent (UchBusAgent* a, const char* m)
: DnnEvent (),
  Agent (a),
  Msg (m)
{
}

  
UchDirectEvent::~UchDirectEvent ()
{
}