/*
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 <sys/stat.h>

#ifndef HAVE_STRUCT_UCRED
struct ucred {
  pid_t pid;
  uid_t uid;
  gid_t gid;
};
#endif // HAVE_STRUCT_UCRED

/* really shouldn't need more than 2:
   1 for rhizome
   1 for VoMP call 
   but spares never hurt, and the cost is low
*/
#define MONITOR_LINE_LENGTH 160
#define MONITOR_DATA_SIZE MAX_AUDIO_BYTES
struct monitor_context {
#define MONITOR_VOMP (1<<0)
#define MONITOR_RHIZOME (1<<1)
  int flags;
  int socket;
  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];
long long monitor_last_update_time=0;

int monitor_process_command(int index,char *cmd);
int monitor_process_data(int index);

int monitor_named_socket=-1;
int monitor_setup_sockets()
{
  struct sockaddr_un name;
  int len;
  
  name.sun_family = AF_UNIX;
  
  if (monitor_named_socket==-1) {
    /* ignore SIGPIPE so that we don't explode */
    signal(SIGPIPE, SIG_IGN);

    name.sun_path[0]=0;
    snprintf(&name.sun_path[1],100,"org.servalproject.servald.monitor.socket");
    if (name.sun_path[0]) unlink(&name.sun_path[0]);    
    /* DONT include the null if forming an abstract socket, but DO include it
       if forming a file-system */
    len = 1+strlen(&name.sun_path[1]) + sizeof(name.sun_family);
    monitor_named_socket = socket(AF_UNIX, SOCK_STREAM, 0);
    if (monitor_named_socket>-1) {
      int dud=0;
      int r=bind(monitor_named_socket, (struct sockaddr *)&name, len);
      if (r) { dud=1; r=0; 
	WHY("bind() of named unix domain monitor socket failed"); }
      r=listen(monitor_named_socket,MAX_MONITOR_SOCKETS);
      if (r) { dud=1; r=0;
	WHY("listen() of named unix domain monitor socket failed");
      }
      if (dud) {
	close(monitor_named_socket);
	monitor_named_socket=-1;
	WHY("Could not open named unix domain socket.");
      }

      int send_buffer_size=64*1024;    
      int res = setsockopt(monitor_named_socket, SOL_SOCKET, SO_RCVBUF, 
		       &send_buffer_size, sizeof(send_buffer_size));
      if (res) WHYF("setsockopt() failed: errno=%d",errno);
      else WHY("Monitor server socket setup");
    }
  }

  return 0;
  
}

int monitor_get_fds(struct pollfd *fds,int *fdcount,int fdmax)
{
  /* Make sure sockets are open */
  monitor_setup_sockets();

  /* This block should work, but in reality it doesn't.
     poll() on linux is ALWAYS claiming that accept() can be
     run.  So we just have to check it whenever some other fd triggers
     poll to break, which fortunately is fairly often. */
  if ((*fdcount)>=fdmax) return -1;
  if (monitor_named_socket>-1)
    {
      if (debug&(DEBUG_IO|DEBUG_VERBOSE_IO)) {
	WHYF("Monitor named unix domain socket is poll() slot #%d (fd %d)\n",
	     *fdcount,monitor_named_socket);
      }
      fds[*fdcount].fd=monitor_named_socket;
      fds[*fdcount].events=POLLIN;
      (*fdcount)++;
    }

  int i;
  if (debug&(DEBUG_IO|DEBUG_VERBOSE_IO)) 
    WHYF("looking at %d monitor clients",monitor_socket_count);
  for(i=0;i<monitor_socket_count;i++) {
    if ((*fdcount)>=fdmax) return -1;
    if (debug&(DEBUG_IO|DEBUG_VERBOSE_IO)) {
      WHYF("Monitor named unix domain client socket is poll() slot #%d (fd %d)\n",
	  *fdcount,monitor_sockets[i].socket);
      }
      fds[*fdcount].fd=monitor_sockets[i].socket;
      fds[*fdcount].events=POLLIN;
      (*fdcount)++;
  }

  return 0;
}

int monitor_poll()
{
  int s;
  struct sockaddr ignored_address;
  socklen_t ignored_length=sizeof(ignored_address);

  /* tell all monitor clients about status of all calls periodically */
  long long now=overlay_gettime_ms();
  if (now>(monitor_last_update_time+1000)) {
    monitor_last_update_time=now;
    int i;
    for(i=0;i<vomp_call_count;i++)
      monitor_call_status(&vomp_call_states[i]);
  }

  /* Check for new connections */
  fcntl(monitor_named_socket,F_SETFL,
	fcntl(monitor_named_socket, F_GETFL, NULL)|O_NONBLOCK);
  while((
#ifdef HAVE_LINUX_IF_H
	 s=accept4(monitor_named_socket,&ignored_address,&ignored_length,O_NONBLOCK)
#else
	 s=accept(monitor_named_socket,&ignored_address,&ignored_length)
#endif
)>-1) {
    int res = fcntl(s,F_SETFL, O_NONBLOCK);
    if (res) { close(s); continue; }
    struct ucred ucred;
    socklen_t len=sizeof(ucred);
    res = getsockopt(s,SOL_SOCKET,SO_PEERCRED,&ucred,&len);
    if (res) { 
      WHY("Failed to read credentials of monitor.socket client");
      close(s); continue; }
    if (ucred.uid&&(ucred.uid!=getuid())) {
      WHYF("monitor.socket client has wrong uid (%d versus %d)",
	   ucred.uid,getuid());
      write(s,"CLOSE:Incorrect UID\n",strlen("CLOSE:Incorrect UID\n"));
      close(s); continue;
    }
    else if (monitor_socket_count>=MAX_MONITOR_SOCKETS) {
      write(s,"CLOSE:All sockets busy\n",strlen("CLOSE:All sockets busy\n"));
      close(s);
    } else {
      struct monitor_context *c=&monitor_sockets[monitor_socket_count];
      c->socket=s;
      c->line_length=0;
      c->state=MONITOR_STATE_COMMAND;
      monitor_socket_count++;
      write(s,"MONITOR:You are talking to servald\n",
	    strlen("MONITOR:You are talking to servald\n"));
      WHYF("Got %d clients",monitor_socket_count);
    }
    
    ignored_length=sizeof(ignored_address);
    fcntl(monitor_named_socket,F_SETFL,
	  fcntl(monitor_named_socket, F_GETFL, NULL)|O_NONBLOCK);
  }

  /* Read from any open connections */
  int i;
  for(i=0;i<monitor_socket_count;i++) {
  nextInSameSlot:
    errno=0;
    int bytes;
    struct monitor_context *c=&monitor_sockets[i];
    fcntl(c->socket,F_SETFL,
	  fcntl(c->socket, F_GETFL, NULL)|O_NONBLOCK);
    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(i,c->line);
	  bytes=-1;
	  break;
	}
	errno=0;
	bytes=read(c->socket,&c->line[c->line_length],1);
	if (bytes<1) {
	  switch(errno) {
	  case EAGAIN: case EINTR: case ENOTRECOVERABLE:
	    /* transient errors */
	    break;
	  default:
	    /* all other errors; close socket */
	    WHYF("Tearing down monitor client #%d due to errno=%d (%s)",
		 i,errno,strerror(errno));
	    close(c->socket);
	    if (i==monitor_socket_count-1) {
	      monitor_socket_count--;
	      continue;
	    } else {
	      bcopy(&monitor_sockets[monitor_socket_count-1],
		    &monitor_sockets[i],
		    sizeof(struct monitor_context));
	      monitor_socket_count--;
	      goto nextInSameSlot;
	    }
	  }
	}
	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(i,c->line);
	      break;
	    }
	  }
      }
      break;
    case MONITOR_STATE_DATA:
      errno=0;
      bytes=read(c->socket,
		 &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 #%d due to errno=%d",
		 i,errno);
	    close(c->socket);
	    if (i==monitor_socket_count-1) {
	      monitor_socket_count--;
	      continue;
	    } else {
	      bcopy(&monitor_sockets[monitor_socket_count-1],
		    &monitor_sockets[i],
		    sizeof(struct monitor_context));
	      monitor_socket_count--;
	      goto nextInSameSlot;
	    }
	}
      } else {
	c->data_offset+=bytes;
	if (c->data_offset>=c->data_expected)
	  {
	    /* we have the binary data we were expecting. */
	    monitor_process_data(i);
	    c->state=MONITOR_STATE_COMMAND;
	  }
      }
      break;
    default:
      c->state=MONITOR_STATE_COMMAND;
      WHY("fixed monitor connection state");
    }
      
  }
  return 0;
}

int monitor_process_command(int index,char *cmd) 
{
  int callSessionToken,sampleType,bytes;
  char sid[MONITOR_LINE_LENGTH],localDid[MONITOR_LINE_LENGTH];
  char remoteDid[MONITOR_LINE_LENGTH],digits[MONITOR_LINE_LENGTH];
  overlay_mdp_frame mdp;
  mdp.packetTypeAndFlags=MDP_VOMPEVENT;  

  WHYF("Received monitor instruction: '%s'",cmd);

  struct monitor_context *c=&monitor_sockets[index];
  c->line_length=0;

  fcntl(c->socket,F_SETFL,
	fcntl(c->socket, F_GETFL, NULL)|O_NONBLOCK);

  if (strlen(cmd)>MONITOR_LINE_LENGTH) {
    write(c->socket,"ERROR:Command too long\n",
	  strlen("ERROR: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 (!strcasecmp(cmd,"monitor vomp"))
    c->flags|=MONITOR_VOMP;
  else if (!strcasecmp(cmd,"ignore vomp"))
    c->flags&=~MONITOR_VOMP;
  else if (!strcasecmp(cmd,"monitor rhizome"))
    c->flags|=MONITOR_RHIZOME;
  else if (!strcasecmp(cmd,"ignore rhizome"))
    c->flags&=~MONITOR_RHIZOME;
  else if (sscanf(cmd,"call %s %s %s",sid,localDid,remoteDid)==3) {
    mdp.vompevent.flags=VOMPEVENT_DIAL;
    int cn=0,in=0,kp=0;
    if(!keyring_next_identity(keyring,&cn,&in,&kp))
      {
	snprintf(msg,1024,"ERROR:no local identity, so cannot place call\n");
	write(c->socket,msg,strlen(msg));
      }
    else {
      bcopy(keyring->contexts[cn]->identities[in]
	    ->keypairs[kp]->public_key,
	    &mdp.vompevent.local_sid[0],SID_SIZE);
      stowSid(&mdp.vompevent.remote_sid[0],0,sid);
      vomp_mdp_event(&mdp,NULL,0);
    }
  } 
  else if (sscanf(cmd,"pickup %x",&callSessionToken)==1) {
     mdp.vompevent.flags=VOMPEVENT_PICKUP;
     mdp.vompevent.call_session_token=callSessionToken;
     vomp_mdp_event(&mdp,NULL,0);
  }
  else if (sscanf(cmd,"hangup %x",&callSessionToken)==1) {
     mdp.vompevent.flags=VOMPEVENT_HANGUP;
     mdp.vompevent.call_session_token=callSessionToken;
     vomp_mdp_event(&mdp,NULL,0);
  } else if (sscanf(cmd,"dtmf %x %s",&callSessionToken,digits)==2) {
    mdp.vompevent.flags=VOMPEVENT_AUDIOPACKET;
    mdp.vompevent.call_session_token=callSessionToken;

    /* One digit per sample block. */
    mdp.vompevent.audio_sample_codec=VOMP_CODEC_DTMF;
    mdp.vompevent.audio_sample_bytes=1;
    
    int i;
    for(i=0;i<strlen(digits);i++) {
      int digit=vomp_parse_dtmf_digit(digits[i]);
      if (digit<0) {
	snprintf(msg,1024,"ERROR: invalid DTMF digit 0x%02x\n",digit);
	write(c->socket,msg,strlen(msg));
      }
      mdp.vompevent.audio_bytes[mdp.vompevent.audio_sample_bytes]
	=(digit<<4); /* 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). */
      if (overlay_mdp_send(&mdp,0,0)) WHY("Send DTMF failed.");
    }
    
  }

  fcntl(c->socket,F_SETFL,
	fcntl(c->socket, F_GETFL, NULL)|O_NONBLOCK);

  snprintf(msg,1024,"MONITORSTATUS:%d\n",c->flags);
  write(c->socket,msg,strlen(msg));

  return 0;
}

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

  if (vomp_sample_size(c->sample_codec)!=c->data_offset)
    return WHY("Ignoring sample block of incorrect size");

  fcntl(c->socket,F_SETFL,
	fcntl(c->socket, F_GETFL, NULL)|O_NONBLOCK);

  vomp_call_state *call=vomp_find_call_by_session(c->sample_call_session_token);
  if (!call) {
    write(c->socket,"ERROR:No such call\n",strlen("ERROR:No such call\n"));
    return -1;
  }

  overlay_mdp_frame mdp;
  mdp.packetTypeAndFlags=MDP_VOMPEVENT;
  mdp.vompevent.flags=VOMPEVENT_AUDIOPACKET;
  mdp.vompevent.call_session_token=c->sample_call_session_token;
  mdp.vompevent.audio_sample_codec=c->sample_codec;
  bcopy(&c->buffer[0],&mdp.vompevent.audio_bytes[0],
	vomp_sample_size(c->sample_codec));

  vomp_send_status(call,VOMP_TELLREMOTE|VOMP_SENDAUDIO,&mdp);

  return 0;
}

int monitor_call_status(vomp_call_state *call)
{
  int i;
  char msg[1024];
  int show=0;
  if (call->local.state>call->local.last_state) show=1;
  if (call->remote.state>call->remote.last_state) show=1;
  call->local.last_state=call->local.state;
  call->remote.last_state=call->remote.state;
  if (show) {
    snprintf(msg,1024,"CALLSTATUS:%06x:%06x:%d:%d:%s:%s:%s:%s\n",
	     call->local.session,call->remote.session,
	     call->local.state,call->remote.state,
	     overlay_render_sid(call->local.sid),
	     overlay_render_sid(call->remote.sid),
	     call->local.did,call->remote.did);
    for(i=0;i<monitor_socket_count;i++)
      {
	if (!(monitor_sockets[i].flags&MONITOR_VOMP))
	  continue;
      nextInSameSlot:
	errno=0;
	fcntl(monitor_sockets[i].socket,F_SETFL,
	      fcntl(monitor_sockets[i].socket, F_GETFL, NULL)|O_NONBLOCK);
	write(monitor_sockets[i].socket,msg,strlen(msg));
	if (errno&&(errno!=EINTR)&&(errno!=EAGAIN)) {
	  /* error sending update, so kill monitor socket */
	  WHYF("Tearing down monitor client #%d due to errno=%d",
	       i,errno);
	  close(monitor_sockets[i].socket);
	  if (i==monitor_socket_count-1) {
	    monitor_socket_count--;
	    continue;
	  } else {
	    bcopy(&monitor_sockets[monitor_socket_count-1],
		  &monitor_sockets[i],
		  sizeof(struct monitor_context));
	    monitor_socket_count--;
	    goto nextInSameSlot;
	  }
	}
      }
  }
  return 0;
}

int monitor_send_audio(vomp_call_state *call,overlay_mdp_frame *audio)
{
  WHYF("Tell call monitor about audio for call %06x:%06x",
       call->local.session,call->remote.session);

  int sample_bytes=vomp_sample_size(audio->vompevent.audio_sample_codec);
  unsigned char msg[1024+MAX_AUDIO_BYTES];
  /* All commands followed by binary data start with *len:, so that 
     they can be easily parsed at the far end, even if not supported. */
  snprintf((char *)msg,1024,
	   "*%d:AUDIOPACKET:%06x:%06x:%d:%d:%d:%lld:%lld\n",
	   sample_bytes,
	   call->local.session,call->remote.session,
	   call->local.state,call->remote.state,
	   audio->vompevent.audio_sample_codec,
	   audio->vompevent.audio_sample_starttime,
	   audio->vompevent.audio_sample_endtime);
  int msglen=strlen((char *)msg);
  bcopy(&audio->vompevent.audio_bytes[0],
	&msg[msglen],sample_bytes);
  msglen+=sample_bytes;

  int i;
  for(i=0;i<monitor_socket_count;i++)
    {
      if (!(monitor_sockets[i].flags&MONITOR_VOMP))
	continue;
    nextInSameSlot:
      errno=0;
      fcntl(monitor_sockets[i].socket,F_SETFL,
	    fcntl(monitor_sockets[i].socket, F_GETFL, NULL)|O_NONBLOCK);
      write(monitor_sockets[i].socket,msg,msglen);
      if (errno&&(errno!=EINTR)&&(errno!=EAGAIN)) {
	/* error sending update, so kill monitor socket */
	WHYF("Tearing down monitor client #%d due to errno=%d",
	     i,errno);
	close(monitor_sockets[i].socket);
	if (i==monitor_socket_count-1) {
	  monitor_socket_count--;
	  continue;
	} else {
	  bcopy(&monitor_sockets[monitor_socket_count-1],
		&monitor_sockets[i],
		sizeof(struct monitor_context));
	  monitor_socket_count--;
	  goto nextInSameSlot;
	}
      }
    }


  return 0;
}