/*
Copyright (C) 2010-2012 Paul Gardner-Stephen, Serval Project.
 
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; either version 2
of the License, or (at your option) any later version.
 
This program 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 this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
*/

/*
  Android does unix domain sockets, but only stream sockets, not datagram sockets.
  So we need a separate monitor interface for Android. A bit of a pain, but in
  fact it lets us make a very Android/Java-friendly interface, without any binary
  data structures (except for a binary extent for an audio sample block).
*/

#include "serval.h"
#include "rhizome.h"
#include <sys/stat.h>

#ifdef HAVE_UCRED_H
#include <ucred.h>
#endif

#if defined(LOCAL_PEERCRED) && !defined(SO_PEERCRED)
#define SO_PEERCRED LOCAL_PEERCRED
#endif

#define MONITOR_LINE_LENGTH 160
#define MONITOR_DATA_SIZE MAX_AUDIO_BYTES
struct monitor_context {
  struct sched_ent alarm;
  int flags;
  char line[MONITOR_LINE_LENGTH];
  int line_length;
#define MONITOR_STATE_COMMAND 1
#define MONITOR_STATE_DATA 2
  int state;
  unsigned char buffer[MONITOR_DATA_SIZE];
  int data_expected;
  int data_offset;
  int sample_codec;
  int sample_call_session_token;
};

#define MAX_MONITOR_SOCKETS 8
int monitor_socket_count=0;
struct monitor_context monitor_sockets[MAX_MONITOR_SOCKETS];

int monitor_process_command(struct monitor_context *c);
int monitor_process_data(struct monitor_context *c);
static void monitor_new_client(int s);

struct sched_ent named_socket;
struct profile_total named_stats;
struct profile_total client_stats;

int monitor_socket_name(struct sockaddr_un *name){
  int len;
#ifdef linux
  /* Use abstract namespace as Android has no writable FS which supports sockets.
   Abstract namespace is just plain better, anyway, as no dead files end up
   hanging around. */
  name->sun_path[0]=0;
  /* XXX: 104 comes from OSX sys/un.h - no #define (note Linux has UNIX_PATH_MAX and it's 108(!)) */
  snprintf(&name->sun_path[1],104-2,
	   confValueGet("monitor.socket",DEFAULT_MONITOR_SOCKET_NAME));
  /* Doesn't include trailing nul */
  len = 1+strlen(&name->sun_path[1]) + sizeof(name->sun_family);
#else
  snprintf(name->sun_path,104-1,"%s/%s",
	   serval_instancepath(),
	   confValueGet("monitor.socket",DEFAULT_MONITOR_SOCKET_NAME));
  /* Includes trailing nul */
  len = 1+strlen(name->sun_path) + sizeof(name->sun_family);
#endif
  return len;
}

int monitor_setup_sockets()
{
  struct sockaddr_un name;
  int len;
  int sock;
  
  bzero(&name, sizeof(name));
  name.sun_family = AF_UNIX;
  
  if ((sock = socket(AF_UNIX, SOCK_STREAM, 0))==-1) {
    WHY_perror("socket");
    goto error;
  }

  len = monitor_socket_name(&name);
#ifndef linux
  unlink(name.sun_path);
#endif

  if(bind(sock, (struct sockaddr *)&name, len)==-1) {
    WHY_perror("bind");
    goto error;
  }
  if(listen(sock,MAX_MONITOR_SOCKETS)==-1) {
    WHY_perror("listen");
    goto error;
  }

  int reuseP=1;
  if(setsockopt(sock, SOL_SOCKET, SO_REUSEADDR, 
		&reuseP, sizeof(reuseP)) < 0) {
    WHY_perror("setsockopt");
    WHY("Could not indicate reuse addresses. Not necessarily a problem (yet)");
  }
  
  int send_buffer_size=64*1024;    
  if(setsockopt(sock, SOL_SOCKET, SO_RCVBUF, 
		&send_buffer_size, sizeof(send_buffer_size))==-1)
    WHY_perror("setsockopt");
  if (debug&(DEBUG_IO|DEBUG_VERBOSE_IO)) DEBUG("Monitor server socket setup");

  named_socket.function=monitor_poll;
  named_stats.name="monitor_poll";
  named_socket.stats=&named_stats;
  named_socket.poll.fd=sock;
  named_socket.poll.events=POLLIN;
  watch(&named_socket);
  return 0;
  
  error:
  close(sock);
  return -1;
}

void monitor_poll(struct sched_ent *alarm)
{
  int s;
  unsigned char buffer[1024];
  struct sockaddr *ignored_address=(struct sockaddr *)&buffer[0];
  socklen_t ignored_length=sizeof(ignored_address);

  /* Check for new connections */
  /* We don't care about the peer's address */
  ignored_length = 0;
  while (
#ifdef HAVE_LINUX_IF_H
	 (s = accept4(alarm->poll.fd, NULL, &ignored_length,O_NONBLOCK))
#else
	 (s = accept(alarm->poll.fd,NULL, &ignored_length))
#endif
      != -1
  ) {
    monitor_new_client(s);
  }
  if (errno != EAGAIN) {
#ifdef HAVE_LINUX_IF_H
    WHY_perror("accept4(O_NONBLOCK)");
#else
    WHY_perror("accept");
#endif
  }
}

void monitor_client_close(struct monitor_context *c){
  struct monitor_context *last;
  
  unwatch(&c->alarm);
  close(c->alarm.poll.fd);
  c->alarm.poll.fd=-1;
  
  monitor_socket_count--;
  last = &monitor_sockets[monitor_socket_count];
  if (last != c){
    unwatch(&last->alarm);
    bcopy(last, c,
	  sizeof(struct monitor_context));
    watch(&c->alarm);
  }
}

void monitor_client_poll(struct sched_ent *alarm)
{
  /* Read available data from a monitor socket */
  struct monitor_context *c=(struct monitor_context *)alarm;
  errno=0;
  int bytes;
  
  switch(c->state) {
  case MONITOR_STATE_COMMAND:
    bytes = 1;
    while(bytes == 1) {
      if (c->line_length >= MONITOR_LINE_LENGTH) {
	/* line too long */
	c->line[MONITOR_LINE_LENGTH-1] = 0;
	monitor_process_command(c);
	bytes = -1;
	break;
      }
      bytes = read(c->alarm.poll.fd, &c->line[c->line_length], 1);
      if (bytes < 1) {
	switch(errno) {
	case EINTR:
	case ENOTRECOVERABLE:
	  /* transient errors */
	  WHY_perror("read");
	  break;
	case EAGAIN:
	  break;
	default:
	  WHY_perror("read");
	  /* all other errors; close socket */
	  INFO("Tearing down monitor client");
	  monitor_client_close(c);
	  return;
	}
      }
      if (bytes > 0 && (c->line[c->line_length] != '\r')) {
	  c->line_length += bytes;
	  if (c->line[c->line_length-1] == '\n') {
	    /* got command */
	    c->line[c->line_length-1] = 0; /* trim new line for easier parsing */
	    monitor_process_command(c);
	    break;
	  }
	}
    }
    break;
  case MONITOR_STATE_DATA:
    bytes = read(c->alarm.poll.fd,
		 &c->buffer[c->data_offset],
		 c->data_expected-c->data_offset);
    if (bytes < 1) {
      switch(errno) {
      case EAGAIN: case EINTR: 
	/* transient errors */
	break;
      default:
	/* all other errors; close socket */
	  WHYF("Tearing down monitor client due to errno=%d",
	       errno);
	  monitor_client_close(c);
	  return;
      }
    } else {
      c->data_offset += bytes;
      if (c->data_offset >= c->data_expected)
	{
	  /* we have the binary data we were expecting. */
	  monitor_process_data(c);
	  c->state = MONITOR_STATE_COMMAND;
	}
    }
    break;
  default:
    c->state = MONITOR_STATE_COMMAND;
    WHY("fixed monitor connection state");
  }
  return;
}
 
static void monitor_new_client(int s) {
#ifdef SO_PEERCRED
  struct ucred			ucred;
  socklen_t			len;
  int				res;
#elif defined(HAVE_GETPEEREID)
  gid_t				othergid;
#elif defined(HAVE_UCRED_H)
  ucred_t			*ucred;
#endif
  uid_t				otheruid;
  struct monitor_context	*c;

  if (set_nonblock(s) == -1)
    goto error;

#ifdef SO_PEERCRED
  /* Linux way */
  len = sizeof(ucred);
  res = getsockopt(s, SOL_SOCKET, SO_PEERCRED, &ucred, &len);
  if (res) { 
    WHY_perror("getsockopt(SO_PEERCRED)");
    goto error;
  }
  if (len < sizeof(ucred)) {
    WHYF("getsockopt(SO_PEERCRED) returned the wrong size (Got %d expected %d)", len, sizeof(ucred));
    goto error;
  }
  otheruid = ucred.uid;
#elif defined(HAVE_UCRED_H)
  /* Solaris way */
  if (getpeerucred(s, &ucred) != 0) {
    WHY_perror("getpeerucred()");
    goto error;
  }
  otheruid = ucred_geteuid(ucred);
  ucred_free(ucred);
#elif defined(HAVE_GETPEEREID)
  /* BSD way */
  if (getpeereid(s, &otheruid, &othergid) != 0) {
    WHY_perror("getpeereid()");
    goto error;
  }
#else
#error No way to get socket peer credentials
#endif

  if (otheruid != getuid()) {
    int allowed_id = confValueGetInt64("monitor.uid",-1);
    if (otheruid != allowed_id){
      WHYF("monitor.socket client has wrong uid (%d versus %d)", otheruid,getuid());
      write_str(s, "\nCLOSE:Incorrect UID\n");
      goto error;
    }
  }
  if (monitor_socket_count >= MAX_MONITOR_SOCKETS
	     ||monitor_socket_count < 0) {
    write_str(s, "\nCLOSE:All sockets busy\n");
    goto error;
  }
  
  c = &monitor_sockets[monitor_socket_count++];
  c->alarm.function = monitor_client_poll;
  client_stats.name = "monitor_client_poll";
  c->alarm.stats=&client_stats;
  c->alarm.poll.fd = s;
  c->alarm.poll.events=POLLIN;
  c->line_length = 0;
  c->state = MONITOR_STATE_COMMAND;
  write_str(s,"\nMONITOR:You are talking to servald\n");
  INFOF("Got %d clients", monitor_socket_count);
  watch(&c->alarm);  
  
  return;
  
  error:
    close(s);
    return;
}

int monitor_send_lookup_response(const char *sid, const int port, const char *ext, const char *name){
  struct sockaddr_mdp addr={
    .port = port
  };
  
  if (stowSid((unsigned char *)&addr.sid, 0, sid)==-1)
    return WHYF("Invalid SID %s", sid);
  
  int cn=0, in=0, kp=0;
  if (!keyring_next_identity(keyring, &cn, &in, &kp))
    WHY("No local identity, cannot send DNA LOOKUP reply");
  else{
    char uri[256];
    snprintf(uri, sizeof(uri), "sid://%s/%s", alloca_tohex_sid(keyring->contexts[cn]->identities[in]->keypairs[kp]->public_key), ext);
    DEBUGF("Sending response to %s for %s", sid, uri);
    overlay_mdp_dnalookup_reply(&addr, keyring->contexts[cn]->identities[in]->keypairs[kp]->public_key, uri, ext, name);
  }
  return 0;
}

int monitor_process_command(struct monitor_context *c) 
{
  int callSessionToken,sampleType,bytes;
  char sid[MONITOR_LINE_LENGTH],localDid[MONITOR_LINE_LENGTH];
  char remoteDid[MONITOR_LINE_LENGTH],digits[MONITOR_LINE_LENGTH];
  int port;
  
  char *cmd = c->line;
  IN();
  
  remoteDid[0]='\0';
  c->line_length=0;

  if (strlen(cmd)>MONITOR_LINE_LENGTH) {
    write_str(c->alarm.poll.fd,"\nERROR:Command too long\n");
    RETURN(-1);
  }

  char msg[1024];

  if (cmd[0]=='*') {
    /* command with content */
    int ofs=0;
    if (sscanf(cmd,"*%d:%n",&bytes,&ofs)==1) {
      /* work out rest of command */
      cmd=&cmd[ofs];
      c->state=MONITOR_STATE_DATA;
      c->data_expected=bytes;
      c->data_offset=0;
      c->sample_codec=-1;

      if (sscanf(cmd,"AUDIO %x %d",
		 &callSessionToken,&sampleType)==2)
	{
	  /* Start getting sample */
	  c->sample_call_session_token=callSessionToken;
	  c->sample_codec=sampleType;
	  RETURN(0);
	}
    }
  }
  else if (strcase_startswith(cmd,"monitor vomp",NULL))
    // TODO add supported codec list argument
    c->flags|=MONITOR_VOMP;
  else if (strcase_startswith(cmd,"ignore vomp",NULL))
    c->flags&=~MONITOR_VOMP;
  else if (strcase_startswith(cmd,"monitor rhizome", NULL))
    c->flags|=MONITOR_RHIZOME;
  else if (strcase_startswith(cmd,"ignore rhizome", NULL))
    c->flags&=~MONITOR_RHIZOME;
  else if (strcase_startswith(cmd,"monitor peers", NULL))
    c->flags|=MONITOR_PEERS;
  else if (strcase_startswith(cmd,"ignore peers", NULL))
    c->flags&=~MONITOR_PEERS;
  else if (strcase_startswith(cmd,"monitor dnahelper", NULL))
    c->flags|=MONITOR_DNAHELPER;
  else if (strcase_startswith(cmd,"ignore dnahelper", NULL))
    c->flags&=~MONITOR_DNAHELPER;
  else if (sscanf(cmd,"lookup match %s %d %s %s",sid,&port,localDid,remoteDid)>=3) {
    monitor_send_lookup_response(sid,port,localDid,remoteDid);
  }else if (sscanf(cmd,"call %s %s %s",sid,localDid,remoteDid)==3) {
    int gotSid = 0;
    if (sid[0]=='*') {
      /* For testing, pick any peer and call them */
      int bin, slot;
      for (bin = 0; bin < overlay_bin_count; bin++)
	for (slot = 0; slot < overlay_bin_size; slot++) {
	  if (overlay_nodes[bin][slot].sid[0]) {
	    memcpy(sid, overlay_nodes[bin][slot].sid, SID_SIZE);
	    gotSid = 1;
	    break;
	  }
	}
      if (!gotSid)
	write_str(c->alarm.poll.fd,"\nERROR:no known peers, so cannot place call\n");
    } else {
      // pack the binary representation of the sid into the same buffer.
      if (stowSid((unsigned char*)sid, 0, sid) == -1)
	write_str(c->alarm.poll.fd,"\nERROR:invalid SID, so cannot place call\n");
      else
	gotSid = 1;
    }
    if (gotSid) {
      int cn=0, in=0, kp=0;
      if (!keyring_next_identity(keyring, &cn, &in, &kp))
	write_str(c->alarm.poll.fd,"\nERROR:no local identity, so cannot place call\n");
      else {
	vomp_dial(keyring->contexts[cn]->identities[in]->keypairs[kp]->public_key, (unsigned char *)sid, localDid, remoteDid);
      }
    }
  } else if (sscanf(cmd,"ringing %x",&callSessionToken)==1) {
    struct vomp_call_state *call=vomp_find_call_by_session(callSessionToken);
    vomp_ringing(call);
  } else if (sscanf(cmd,"pickup %x",&callSessionToken)==1) {
    struct vomp_call_state *call=vomp_find_call_by_session(callSessionToken);
    vomp_pickup(call);
  }
  else if (sscanf(cmd,"hangup %x",&callSessionToken)==1) {
    struct vomp_call_state *call=vomp_find_call_by_session(callSessionToken);
    vomp_hangup(call);
  } else if (sscanf(cmd,"dtmf %x %s",&callSessionToken,digits)==2) {
    struct vomp_call_state *call=vomp_find_call_by_session(callSessionToken);
    if (call){
      int i;
      for(i=0;i<strlen(digits);i++) {
	int digit=vomp_parse_dtmf_digit(digits[i]);
	if (digit<0) {
	  snprintf(msg,1024,"\nERROR: invalid DTMF digit 0x%02x\n",digit);
	  write_str(c->alarm.poll.fd,msg);
	}
	/* 80ms standard tone duration, so that it is a multiple
	 of the majority of codec time units (70ms is the nominal
	 DTMF tone length for most systems). */
	unsigned char code = digit <<4;
	vomp_received_audio(call, VOMP_CODEC_DTMF, &code, 1);
      }
    }
  }

  snprintf(msg,1024,"\nMONITORSTATUS:%d\n",c->flags);
  write_str(c->alarm.poll.fd,msg);

  RETURN(0);
}

int monitor_process_data(struct monitor_context *c) 
{
  IN();
  /* Called when we have received an entire data sample */
  c->state=MONITOR_STATE_COMMAND;

  struct vomp_call_state *call=vomp_find_call_by_session(c->sample_call_session_token);
  if (!call) {
    write_str(c->alarm.poll.fd,"\nERROR:No such call\n");
    RETURN(-1);
  }

  vomp_received_audio(call, c->sample_codec, &c->buffer[0], vomp_sample_size(c->sample_codec));

  RETURN(0);
}

int monitor_announce_bundle(rhizome_manifest *m)
{
  int i;
  char msg[1024];
  const char *service = rhizome_manifest_get(m, "service", NULL, 0);
  const char *sender = rhizome_manifest_get(m, "sender", NULL, 0);
  const char *recipient = rhizome_manifest_get(m, "recipient", NULL, 0);
  snprintf(msg,1024,"\nBUNDLE:%s:%s:%lld:%lld:%s:%s:%s\n",
	   /* XXX bit of a hack here, since SIDs and cryptosign public keys have the same length */
	   alloca_tohex_sid(m->cryptoSignPublic),
	   service ? service : "",
	   m->version,
	   m->fileLength,
	   sender,
	   recipient,
	   m->dataFileName?m->dataFileName:"");
  for(i=monitor_socket_count -1;i>=0;i--) {
    if (monitor_sockets[i].flags & MONITOR_RHIZOME) {
      if ( set_nonblock(monitor_sockets[i].alarm.poll.fd) == -1
	|| write_str_nonblock(monitor_sockets[i].alarm.poll.fd, msg) == -1
	|| set_block(monitor_sockets[i].alarm.poll.fd) == -1
      ) {
	INFO("Tearing down monitor client");
	monitor_client_close(&monitor_sockets[i]);
      }
    }
  }
  return 0;
}

int monitor_announce_peer(const unsigned char *sid)
{
  return monitor_tell_formatted(MONITOR_PEERS, "\nNEWPEER:%s\n", alloca_tohex_sid(sid));
}

int monitor_announce_unreachable_peer(const unsigned char *sid)
{
  return monitor_tell_formatted(MONITOR_PEERS, "\nOLDPEER:%s\n", alloca_tohex_sid(sid));
}

// test if any monitor clients are interested in a particular type of event
int monitor_client_interested(int mask){
  int i;
  for(i=monitor_socket_count -1;i>=0;i--) {
    if (monitor_sockets[i].flags & mask)
      return 1;
  }
  return 0;
}

int monitor_tell_clients(char *msg, int msglen, int mask)
{
  int i;
  IN();
  for(i=monitor_socket_count -1;i>=0;i--) {
    if (monitor_sockets[i].flags & mask) {
      // DEBUG("Writing AUDIOPACKET to client");
      if ( set_nonblock(monitor_sockets[i].alarm.poll.fd) == -1
	|| write_all_nonblock(monitor_sockets[i].alarm.poll.fd, msg, msglen) == -1
	|| set_block(monitor_sockets[i].alarm.poll.fd) == -1
      ) {
	INFOF("Tearing down monitor client #%d", i);
	monitor_client_close(&monitor_sockets[i]);
      }
    }
  }
  RETURN(0);
}

int monitor_tell_formatted(int mask, char *fmt, ...){
  char msg[1024];
  int n;
  va_list ap;
  
  va_start(ap, fmt);
  n=vsnprintf(msg, sizeof(msg), fmt, ap);
  va_end(ap);
  monitor_tell_clients(msg, n, mask);
  return 0;
}