/* GStreamer
 * Copyright (C) 2005 Andy Wingo <wingo@pobox.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */


#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "gstnettimeprovider.h"
#include <unistd.h>
#include <sys/ioctl.h>

#ifdef HAVE_FIONREAD_IN_SYS_FILIO
#include <sys/filio.h>
#endif

GST_DEBUG_CATEGORY (ntp_debug);
#define GST_CAT_DEFAULT (ntp_debug)

/* the select call is also performed on the control sockets, that way
 * we can send special commands to unblock or restart the select call */
#define CONTROL_RESTART        'R'      /* restart the select call */
#define CONTROL_STOP           'S'      /* stop the select call */
#define CONTROL_SOCKETS(self)   self->control_sock
#define WRITE_SOCKET(self)      self->control_sock[1]
#define READ_SOCKET(self)       self->control_sock[0]

#define SEND_COMMAND(self, command)             	\
G_STMT_START {                                 	\
  unsigned char c; c = command;                	\
  write (WRITE_SOCKET(self), &c, 1);         	\
} G_STMT_END

#define READ_COMMAND(self, command, res)        	\
G_STMT_START {                                	\
  res = read(READ_SOCKET(self), &command, 1);    \
} G_STMT_END

#define DEFAULT_ADDRESS		"0.0.0.0"
#define DEFAULT_PORT		5637

typedef struct
{
  GstClockTime slave_time_sent;
  GstClockTime master_time_received;
} NetworkTimePacket;

 /* 2 * sizeof(GstClockTime), verified in base_init */
#define NETWORK_TIME_PACKET_SIZE 16
#define NETWORK_TIME_PACKET_SET_MASTER_TIME(p, t) \
  GST_WRITE_UINT64_BE(p+8, t)

enum
{
  PROP_0,
  PROP_PORT,
  PROP_ADDRESS,
  PROP_CLOCK
      /* FILL ME */
};

static gboolean gst_net_time_provider_start (GstNetTimeProvider * bself);
static void gst_net_time_provider_stop (GstNetTimeProvider * bself);

static gpointer gst_net_time_provider_thread (gpointer data);

static void gst_net_time_provider_finalize (GObject * object);
static void gst_net_time_provider_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec);
static void gst_net_time_provider_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec);

#define _do_init(type) \
  GST_DEBUG_CATEGORY_INIT (ntp_debug, "nettime", 0, "Network time provider");

GST_BOILERPLATE_FULL (GstNetTimeProvider, gst_net_time_provider, GstObject,
    GST_TYPE_OBJECT, _do_init);

static void
gst_net_time_provider_base_init (gpointer g_class)
{
  g_assert (sizeof (GstClockTime) == 8);
}

static void
gst_net_time_provider_class_init (GstNetTimeProviderClass * klass)
{
  GObjectClass *gobject_class;

  gobject_class = (GObjectClass *) klass;

  gobject_class->finalize = gst_net_time_provider_finalize;
  gobject_class->set_property = gst_net_time_provider_set_property;
  gobject_class->get_property = gst_net_time_provider_get_property;

  g_object_class_install_property (G_OBJECT_CLASS (klass), PROP_PORT,
      g_param_spec_int ("port", "port",
          "The port to receive the packets from, -1=allocate", -1, 32768,
          DEFAULT_PORT, G_PARAM_READWRITE));
  g_object_class_install_property (gobject_class, PROP_ADDRESS,
      g_param_spec_string ("address", "address",
          "The address to bind on, as a dotted quad (x.x.x.x)",
          DEFAULT_ADDRESS, G_PARAM_READWRITE));
  g_object_class_install_property (gobject_class, PROP_CLOCK,
      g_param_spec_object ("clock", "Clock",
          "The clock to export over the network", GST_TYPE_CLOCK,
          G_PARAM_READWRITE));
}

static void
gst_net_time_provider_init (GstNetTimeProvider * self,
    GstNetTimeProviderClass * g_class)
{
  self->port = DEFAULT_PORT;
  self->sock = -1;
  self->address = g_strdup (DEFAULT_ADDRESS);
  self->thread = NULL;

  READ_SOCKET (self) = -1;
  WRITE_SOCKET (self) = -1;
}

static void
gst_net_time_provider_finalize (GObject * object)
{
  GstNetTimeProvider *self = GST_NET_TIME_PROVIDER (object);

  if (self->thread) {
    gst_net_time_provider_stop (self);
    g_assert (self->thread == NULL);
  }

  if (READ_SOCKET (self) != -1) {
    close (READ_SOCKET (self));
    close (WRITE_SOCKET (self));
    READ_SOCKET (self) = -1;
    WRITE_SOCKET (self) = -1;
  }

  g_free (self->address);
  self->address = NULL;

  if (self->clock)
    gst_object_unref (self->clock);
  self->clock = NULL;

  G_OBJECT_CLASS (parent_class)->finalize (object);
}

static gpointer
gst_net_time_provider_thread (gpointer data)
{
  GstNetTimeProvider *self = data;
  struct sockaddr_in tmpaddr;
  socklen_t len;
  fd_set read_fds;
  guint max_sock;
  gchar *pktdata;
  gint ret;

  while (TRUE) {
    FD_ZERO (&read_fds);
    FD_SET (self->sock, &read_fds);
    FD_SET (READ_SOCKET (self), &read_fds);
    max_sock = MAX (self->sock, READ_SOCKET (self));

    GST_LOG_OBJECT (self, "doing select");
    ret = select (max_sock + 1, &read_fds, NULL, NULL, NULL);
    GST_LOG_OBJECT (self, "select returned %d", ret);

    if (ret <= 0) {
      if (errno != EAGAIN && errno != EINTR)
        goto select_error;
      else
        continue;
    } else if (FD_ISSET (READ_SOCKET (self), &read_fds)) {
      /* got control message */
      while (TRUE) {
        gchar command;
        int res;

        READ_COMMAND (self, command, res);
        if (res < 0) {
          GST_LOG_OBJECT (self, "no more commands");
          break;
        }

        switch (command) {
          case CONTROL_STOP:
            /* break out of the select loop */
            GST_LOG_OBJECT (self, "stop");
            goto stopped;
          default:
            GST_WARNING_OBJECT (self, "unkown");
            g_warning ("nettimeprovider: unknown control message received");
            continue;
        }

        g_assert_not_reached ();
      }

      continue;
    } else {
      /* got data in */
      pktdata = g_malloc (NETWORK_TIME_PACKET_SIZE);

      len = sizeof (struct sockaddr);
      while (TRUE) {
        ret = recvfrom (self->sock, pktdata, NETWORK_TIME_PACKET_SIZE,
            0, (struct sockaddr *) &tmpaddr, &len);
        if (ret < 0) {
          if (errno != EAGAIN && errno != EINTR)
            goto receive_error;
          else
            continue;
        } else if (ret < NETWORK_TIME_PACKET_SIZE) {
          goto short_packet;
        } else {
          GstClockTime now;

          now = gst_clock_get_time (self->clock);

          NETWORK_TIME_PACKET_SET_MASTER_TIME (pktdata, time);

          /* ignore errors */
          sendto (self->sock, pktdata, ret, MSG_DONTWAIT,
              (struct sockaddr *) &tmpaddr, len);

          break;
        }

        g_assert_not_reached ();
      }

      continue;
    }

    g_assert_not_reached ();

    /* log errors and keep going */
  select_error:
    {
      GST_DEBUG_OBJECT (self, "select error %d: %s (%d)", ret,
          g_strerror (errno), errno);
      continue;
    }
  short_packet:
    {
      GST_DEBUG_OBJECT (self, "someone sent us a short packet (%d < %d)",
          ret, NETWORK_TIME_PACKET_SIZE);
      continue;
    }
  stopped:
    {
      GST_DEBUG_OBJECT (self, "shutting down");
      /* close socket */
      return NULL;
    }
  receive_error:
    {
      g_free (pktdata);
      GST_DEBUG_OBJECT (self, "receive error %d: %s (%d)", ret,
          g_strerror (errno), errno);
      continue;
    }

    g_assert_not_reached ();

  }

  g_assert_not_reached ();

  return NULL;
}

static void
gst_net_time_provider_set_property (GObject * object, guint prop_id,
    const GValue * value, GParamSpec * pspec)
{
  GstNetTimeProvider *self = GST_NET_TIME_PROVIDER (object);

  switch (prop_id) {
    case PROP_PORT:
      self->port = g_value_get_int (value);
      break;
    case PROP_ADDRESS:
      g_free (self->address);
      if (g_value_get_string (value) == NULL)
        self->address = g_strdup (DEFAULT_ADDRESS);
      else
        self->address = g_strdup (g_value_get_string (value));
      break;
    case PROP_CLOCK:
      gst_object_replace ((GstObject **) & self->clock,
          (GstObject *) g_value_get_object (value));
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static void
gst_net_time_provider_get_property (GObject * object, guint prop_id,
    GValue * value, GParamSpec * pspec)
{
  GstNetTimeProvider *self = GST_NET_TIME_PROVIDER (object);

  switch (prop_id) {
    case PROP_PORT:
      g_value_set_int (value, self->port);
      break;
    case PROP_ADDRESS:
      g_value_set_string (value, self->address);
      break;
    case PROP_CLOCK:
      g_value_set_object (value, self->clock);
      break;
    default:
      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
      break;
  }
}

static gboolean
gst_net_time_provider_start (GstNetTimeProvider * self)
{
  gint ru;
  struct sockaddr_in my_addr;
  guint len;
  int port;
  gint ret;
  GError *error;

  if ((ret = socket (AF_INET, SOCK_DGRAM, 0)) < 0)
    goto no_socket;

  self->sock = ret;

  ru = 1;
  ret = setsockopt (self->sock, SOL_SOCKET, SO_REUSEADDR, &ru, sizeof (ru));
  if (ret < 0)
    goto setsockopt_error;

  memset (&my_addr, 0, sizeof (my_addr));
  my_addr.sin_family = AF_INET; /* host byte order */
  my_addr.sin_port = htons (self->port);        /* short, network byte order */
  my_addr.sin_addr.s_addr = INADDR_ANY;
  if (self->address)
    inet_aton (self->address, &my_addr.sin_addr);

  GST_DEBUG_OBJECT (self, "binding on port %d", self->port);
  ret = bind (self->sock, (struct sockaddr *) &my_addr, sizeof (my_addr));
  if (ret < 0)
    goto bind_error;

  len = sizeof (my_addr);
  ret = getsockname (self->sock, (struct sockaddr *) &my_addr, &len);
  if (ret < 0)
    goto getsockname_error;

  port = ntohs (my_addr.sin_port);
  GST_DEBUG_OBJECT (self, "bound, on port %d", port);
  if (port != self->port) {
    self->port = port;
    GST_DEBUG_OBJECT (self, "notifying %d", port);
    g_object_notify (G_OBJECT (self), "port");
  }

  self->thread = g_thread_create (gst_net_time_provider_thread, self, TRUE,
      &error);
  if (!self->thread)
    goto no_thread;

  return TRUE;

  /* ERRORS */
no_socket:
  {
    GST_ERROR_OBJECT (self, "socket failed %d: %s (%d)", ret,
        g_strerror (errno), errno);
    return FALSE;
  }
setsockopt_error:
  {
    close (self->sock);
    self->sock = -1;
    GST_ERROR_OBJECT (self, "setsockopt failed %d: %s (%d)", ret,
        g_strerror (errno), errno);
    return FALSE;
  }
bind_error:
  {
    close (self->sock);
    self->sock = -1;
    GST_ERROR_OBJECT (self, "bind failed %d: %s (%d)", ret,
        g_strerror (errno), errno);
    return FALSE;
  }
getsockname_error:
  {
    close (self->sock);
    self->sock = -1;
    GST_ERROR_OBJECT (self, "getsockname failed %d: %s (%d)", ret,
        g_strerror (errno), errno);
    return FALSE;
  }
no_thread:
  {
    close (self->sock);
    self->sock = -1;
    GST_ERROR_OBJECT (self, "could not create thread: %s", error->message);
    g_error_free (error);
    return FALSE;
  }
}

static void
gst_net_time_provider_stop (GstNetTimeProvider * self)
{
  SEND_COMMAND (self, CONTROL_STOP);
  g_thread_join (self->thread);
  self->thread = NULL;

  if (self->sock != -1) {
    close (self->sock);
    self->sock = -1;
  }
}

/**
 * gst_net_time_provider_new:
 * @clock: a #GstClock to export over the network
 * @address: an address to bind on as a dotted quad (xxx.xxx.xxx.xxx), or NULL
 *           to bind to all addresses
 * @port: a port to bind on, or -1 to let the kernel choose
 *
 * Allows network clients to get the current time of @clock.
 *
 * Returns: The new #GstNetTimeProvider, or NULL on error.
 */
GstNetTimeProvider *
gst_net_time_provider_new (GstClock * clock, const gchar * address, gint port)
{
  GstNetTimeProvider *ret;
  gint iret;

  g_return_val_if_fail (clock && GST_IS_CLOCK (clock), NULL);
  g_return_val_if_fail (port == -1 || port >= 0, NULL);

  ret = g_object_new (GST_TYPE_NET_TIME_PROVIDER, "clock", clock, "address",
      address, "port", port, NULL);

  GST_DEBUG_OBJECT (ret, "creating socket pair");
  if ((iret = socketpair (PF_UNIX, SOCK_STREAM, 0, CONTROL_SOCKETS (ret))) < 0)
    goto no_socket_pair;

  fcntl (READ_SOCKET (ret), F_SETFL, O_NONBLOCK);
  fcntl (WRITE_SOCKET (ret), F_SETFL, O_NONBLOCK);

  if (!gst_net_time_provider_start (ret))
    goto failed_start;

  /* all systems go, cap'n */
  return ret;

no_socket_pair:
  {
    GST_ERROR_OBJECT (ret, "no socket pair %d: %s (%d)", iret,
        g_strerror (errno), errno);
    gst_object_unref (ret);
    return NULL;
  }
failed_start:
  {
    /* already printed a nice error */
    gst_object_unref (ret);
    return NULL;
  }

}