/*
 * Copyright (c) 2017 Cisco and/or its affiliates.
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at:
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include <vnet/session/application.h>
#include <vnet/session/application_interface.h>
#include <vnet/session/session.h>

/**
 * Pool from which we allocate all applications
 */
static application_t *app_pool;

/**
 * Hash table of apps by api client index
 */
static uword *app_by_api_client_index;

/**
 * Default application event queue size
 */
static u32 default_app_evt_queue_size = 128;

int
application_api_queue_is_full (application_t * app)
{
  unix_shared_memory_queue_t *q;

  /* builtin servers are always OK */
  if (app->api_client_index == ~0)
    return 0;

  q = vl_api_client_index_to_input_queue (app->api_client_index);
  if (!q)
    return 1;

  if (q->cursize == q->maxsize)
    return 1;
  return 0;
}

static void
application_table_add (application_t * app)
{
  hash_set (app_by_api_client_index, app->api_client_index, app->index);
}

static void
application_table_del (application_t * app)
{
  hash_unset (app_by_api_client_index, app->api_client_index);
}

application_t *
application_lookup (u32 api_client_index)
{
  uword *p;
  p = hash_get (app_by_api_client_index, api_client_index);
  if (p)
    return application_get (p[0]);

  return 0;
}

application_t *
application_new ()
{
  application_t *app;
  pool_get (app_pool, app);
  memset (app, 0, sizeof (*app));
  app->index = application_get_index (app);
  app->connects_seg_manager = APP_INVALID_SEGMENT_MANAGER_INDEX;
  app->first_segment_manager = APP_INVALID_SEGMENT_MANAGER_INDEX;
  if (CLIB_DEBUG > 1)
    clib_warning ("[%d] New app (%d)", getpid (), app->index);
  return app;
}

void
application_del (application_t * app)
{
  segment_manager_t *sm;
  u64 handle;
  u32 index, *handles = 0;
  int i;
  vnet_unbind_args_t _a, *a = &_a;

  /*
   * The app event queue allocated in first segment is cleared with
   * the segment manager. No need to explicitly free it.
   */
  if (CLIB_DEBUG > 1)
    clib_warning ("[%d] Delete app (%d)", getpid (), app->index);

  /*
   *  Listener cleanup
   */

  /* *INDENT-OFF* */
  hash_foreach (handle, index, app->listeners_table,
  ({
    vec_add1 (handles, handle);
  }));
  /* *INDENT-ON* */

  for (i = 0; i < vec_len (handles); i++)
    {
      a->app_index = app->index;
      a->handle = handles[i];
      /* seg manager is removed when unbind completes */
      vnet_unbind (a);
    }

  /*
   * Connects segment manager cleanup
   */

  if (app->connects_seg_manager != APP_INVALID_SEGMENT_MANAGER_INDEX)
    {
      sm = segment_manager_get (app->connects_seg_manager);
      sm->app_index = SEGMENT_MANAGER_INVALID_APP_INDEX;
      segment_manager_init_del (sm);
    }


  /* If first segment manager is used by a listener */
  if (app->first_segment_manager != APP_INVALID_SEGMENT_MANAGER_INDEX
      && app->first_segment_manager != app->connects_seg_manager)
    {
      sm = segment_manager_get (app->first_segment_manager);
      /* .. and has no fifos, e.g. it might be used for redirected sessions,
       * remove it */
      if (!segment_manager_has_fifos (sm))
	{
	  sm->app_index = SEGMENT_MANAGER_INVALID_APP_INDEX;
	  segment_manager_del (sm);
	}
    }

  application_table_del (app);
  pool_put (app_pool, app);
}

static void
application_verify_cb_fns (session_cb_vft_t * cb_fns)
{
  if (cb_fns->session_accept_callback == 0)
    clib_warning ("No accept callback function provided");
  if (cb_fns->session_connected_callback == 0)
    clib_warning ("No session connected callback function provided");
  if (cb_fns->session_disconnect_callback == 0)
    clib_warning ("No session disconnect callback function provided");
  if (cb_fns->session_reset_callback == 0)
    clib_warning ("No session reset callback function provided");
}

int
application_init (application_t * app, u32 api_client_index, u64 * options,
		  session_cb_vft_t * cb_fns)
{
  segment_manager_t *sm;
  segment_manager_properties_t *props;
  u32 app_evt_queue_size, first_seg_size;
  u32 default_rx_fifo_size = 16 << 10, default_tx_fifo_size = 16 << 10;
  int rv;

  app_evt_queue_size = options[APP_EVT_QUEUE_SIZE] > 0 ?
    options[APP_EVT_QUEUE_SIZE] : default_app_evt_queue_size;

  /* Setup segment manager */
  sm = segment_manager_new ();
  sm->app_index = app->index;
  props = &app->sm_properties;
  props->add_segment_size = options[SESSION_OPTIONS_ADD_SEGMENT_SIZE];
  props->rx_fifo_size = options[SESSION_OPTIONS_RX_FIFO_SIZE];
  props->rx_fifo_size =
    props->rx_fifo_size ? props->rx_fifo_size : default_rx_fifo_size;
  props->tx_fifo_size = options[SESSION_OPTIONS_TX_FIFO_SIZE];
  props->tx_fifo_size =
    props->tx_fifo_size ? props->tx_fifo_size : default_tx_fifo_size;
  props->add_segment = props->add_segment_size != 0;
  props->preallocated_fifo_pairs = options[APP_OPTIONS_PREALLOC_FIFO_PAIRS];
  props->use_private_segment = options[APP_OPTIONS_FLAGS]
    & APP_OPTIONS_FLAGS_BUILTIN_APP;
  props->private_segment_count = options[APP_OPTIONS_PRIVATE_SEGMENT_COUNT];
  props->private_segment_size = options[APP_OPTIONS_PRIVATE_SEGMENT_SIZE];

  first_seg_size = options[SESSION_OPTIONS_SEGMENT_SIZE];
  if ((rv = segment_manager_init (sm, props, first_seg_size)))
    return rv;
  sm->first_is_protected = 1;

  app->first_segment_manager = segment_manager_index (sm);
  app->api_client_index = api_client_index;
  app->flags = options[APP_OPTIONS_FLAGS];
  app->cb_fns = *cb_fns;

  /* Allocate app event queue in the first shared-memory segment */
  app->event_queue = segment_manager_alloc_queue (sm, app_evt_queue_size);

  /* Check that the obvious things are properly set up */
  application_verify_cb_fns (cb_fns);

  /* Add app to lookup by api_client_index table */
  application_table_add (app);

  return 0;
}

application_t *
application_get (u32 index)
{
  return pool_elt_at_index (app_pool, index);
}

application_t *
application_get_if_valid (u32 index)
{
  if (pool_is_free_index (app_pool, index))
    return 0;

  return pool_elt_at_index (app_pool, index);
}

u32
application_get_index (application_t * app)
{
  return app - app_pool;
}

static segment_manager_t *
application_alloc_segment_manager (application_t * app)
{
  segment_manager_t *sm = 0;

  /* If the first segment manager is not in use, don't allocate a new one */
  if (app->first_segment_manager != APP_INVALID_SEGMENT_MANAGER_INDEX
      && app->first_segment_manager_in_use == 0)
    {
      sm = segment_manager_get (app->first_segment_manager);
      app->first_segment_manager_in_use = 1;
      return sm;
    }

  sm = segment_manager_new ();
  sm->properties = &app->sm_properties;

  return sm;
}

/**
 * Start listening local transport endpoint for requested transport.
 *
 * Creates a 'dummy' stream session with state LISTENING to be used in session
 * lookups, prior to establishing connection. Requests transport to build
 * it's own specific listening connection.
 */
int
application_start_listen (application_t * srv, session_type_t session_type,
			  transport_endpoint_t * tep, u64 * res)
{
  segment_manager_t *sm;
  stream_session_t *s;
  u64 handle;

  s = listen_session_new (session_type);
  s->app_index = srv->index;

  if (stream_session_listen (s, tep))
    goto err;

  /* Allocate segment manager. All sessions derived out of a listen session
   * have fifos allocated by the same segment manager. */
  sm = application_alloc_segment_manager (srv);
  if (sm == 0)
    goto err;

  /* Add to app's listener table. Useful to find all child listeners
   * when app goes down, although, just for unbinding this is not needed */
  handle = listen_session_get_handle (s);
  hash_set (srv->listeners_table, handle, segment_manager_index (sm));

  *res = handle;
  return 0;

err:
  listen_session_del (s);
  return -1;
}

/**
 * Stop listening on session associated to handle
 */
int
application_stop_listen (application_t * srv, u64 handle)
{
  stream_session_t *listener;
  uword *indexp;
  segment_manager_t *sm;

  if (srv && hash_get (srv->listeners_table, handle) == 0)
    {
      clib_warning ("app doesn't own handle %llu!", handle);
      return -1;
    }

  listener = listen_session_get_from_handle (handle);
  stream_session_stop_listen (listener);

  indexp = hash_get (srv->listeners_table, handle);
  ASSERT (indexp);

  sm = segment_manager_get (*indexp);
  if (srv->first_segment_manager == *indexp)
    {
      /* Delete sessions but don't remove segment manager */
      srv->first_segment_manager_in_use = 0;
      segment_manager_del_sessions (sm);
    }
  else
    {
      segment_manager_init_del (sm);
    }
  hash_unset (srv->listeners_table, handle);
  listen_session_del (listener);

  return 0;
}

int
application_open_session (application_t * app, session_type_t sst,
			  transport_endpoint_t * tep, u32 api_context)
{
  segment_manager_t *sm;
  transport_connection_t *tc = 0;
  int rv;

  /* Make sure we have a segment manager for connects */
  if (app->connects_seg_manager == (u32) ~ 0)
    {
      sm = application_alloc_segment_manager (app);
      if (sm == 0)
	return -1;
      app->connects_seg_manager = segment_manager_index (sm);
    }

  if ((rv = stream_session_open (app->index, sst, tep, &tc)))
    return rv;

  /* Store api_context for when the reply comes. Not the nicest thing
   * but better than allocating a separate half-open pool. */
  tc->s_index = api_context;

  return 0;
}

segment_manager_t *
application_get_connect_segment_manager (application_t * app)
{
  ASSERT (app->connects_seg_manager != (u32) ~ 0);
  return segment_manager_get (app->connects_seg_manager);
}

segment_manager_t *
application_get_listen_segment_manager (application_t * app,
					stream_session_t * s)
{
  uword *smp;
  smp = hash_get (app->listeners_table, listen_session_get_handle (s));
  ASSERT (smp != 0);
  return segment_manager_get (*smp);
}

static u8 *
app_get_name_from_reg_index (application_t * app)
{
  u8 *app_name;

  vl_api_registration_t *regp;
  regp = vl_api_client_index_to_registration (app->api_client_index);
  if (!regp)
    app_name = format (0, "builtin-%d%c", app->index, 0);
  else
    app_name = format (0, "%s%c", regp->name, 0);

  return app_name;
}

int
application_is_proxy (application_t * app)
{
  return !(app->flags & APP_OPTIONS_FLAGS_IS_PROXY);
}

int
application_add_segment_notify (u32 app_index, u32 fifo_segment_index)
{
  application_t *app = application_get (app_index);
  u32 seg_size = 0;
  u8 *seg_name;

  /* Send an API message to the external app, to map new segment */
  ASSERT (app->cb_fns.add_segment_callback);

  segment_manager_get_segment_info (fifo_segment_index, &seg_name, &seg_size);
  return app->cb_fns.add_segment_callback (app->api_client_index, seg_name,
					   seg_size);
}

u8 *
format_application_listener (u8 * s, va_list * args)
{
  application_t *app = va_arg (*args, application_t *);
  u64 handle = va_arg (*args, u64);
  u32 index = va_arg (*args, u32);
  int verbose = va_arg (*args, int);
  stream_session_t *listener;
  u8 *app_name, *str;

  if (app == 0)
    {
      if (verbose)
	s = format (s, "%-40s%-20s%-15s%-15s%-10s", "Connection", "App",
		    "API Client", "ListenerID", "SegManager");
      else
	s = format (s, "%-40s%-20s", "Connection", "App");

      return s;
    }

  app_name = app_get_name_from_reg_index (app);
  listener = listen_session_get_from_handle (handle);
  str = format (0, "%U", format_stream_session, listener, verbose);

  if (verbose)
    {
      s = format (s, "%-40s%-20s%-15u%-15u%-10u", str, app_name,
		  app->api_client_index, handle, index);
    }
  else
    s = format (s, "%-40s%-20s", str, app_name);

  vec_free (app_name);
  return s;
}

void
application_format_connects (application_t * app, int verbose)
{
  vlib_main_t *vm = vlib_get_main ();
  segment_manager_t *sm;
  u8 *app_name, *s = 0;
  int j;

  /* Header */
  if (app == 0)
    {
      if (verbose)
	vlib_cli_output (vm, "%-40s%-20s%-15s%-10s", "Connection", "App",
			 "API Client", "SegManager");
      else
	vlib_cli_output (vm, "%-40s%-20s", "Connection", "App");
      return;
    }

  /* make sure */
  if (app->connects_seg_manager == (u32) ~ 0)
    return;

  app_name = app_get_name_from_reg_index (app);

  /* Across all fifo segments */
  sm = segment_manager_get (app->connects_seg_manager);
  for (j = 0; j < vec_len (sm->segment_indices); j++)
    {
      svm_fifo_segment_private_t *fifo_segment;
      svm_fifo_t *fifo;
      u8 *str;

      fifo_segment = svm_fifo_segment_get_segment (sm->segment_indices[j]);
      fifo = svm_fifo_segment_get_fifo_list (fifo_segment);
      while (fifo)
	{
	  u32 session_index, thread_index;
	  stream_session_t *session;

	  session_index = fifo->master_session_index;
	  thread_index = fifo->master_thread_index;

	  session = stream_session_get (session_index, thread_index);
	  str = format (0, "%U", format_stream_session, session, verbose);

	  if (verbose)
	    s = format (s, "%-40s%-20s%-15u%-10u", str, app_name,
			app->api_client_index, app->connects_seg_manager);
	  else
	    s = format (s, "%-40s%-20s", str, app_name);

	  vlib_cli_output (vm, "%v", s);
	  vec_reset_length (s);
	  vec_free (str);

	  fifo = fifo->next;
	}
      vec_free (s);
    }

  vec_free (app_name);
}

u8 *
format_application (u8 * s, va_list * args)
{
  application_t *app = va_arg (*args, application_t *);
  CLIB_UNUSED (int verbose) = va_arg (*args, int);
  u8 *app_name;

  if (app == 0)
    {
      if (verbose)
	s = format (s, "%-10s%-20s%-15s%-15s%-15s%-15s", "Index", "Name",
		    "API Client", "Add seg size", "Rx fifo size",
		    "Tx fifo size");
      else
	s = format (s, "%-10s%-20s%-20s", "Index", "Name", "API Client");
      return s;
    }

  app_name = app_get_name_from_reg_index (app);
  if (verbose)
    s = format (s, "%-10d%-20s%-15d%-15d%-15d%-15d", app->index, app_name,
		app->api_client_index, app->sm_properties.add_segment_size,
		app->sm_properties.rx_fifo_size,
		app->sm_properties.tx_fifo_size);
  else
    s = format (s, "%-10d%-20s%-20d", app->index, app_name,
		app->api_client_index);
  return s;
}

static clib_error_t *
show_app_command_fn (vlib_main_t * vm, unformat_input_t * input,
		     vlib_cli_command_t * cmd)
{
  application_t *app;
  int do_server = 0;
  int do_client = 0;
  int verbose = 0;

  if (!session_manager_is_enabled ())
    {
      clib_error_return (0, "session layer is not enabled");
    }

  while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
    {
      if (unformat (input, "server"))
	do_server = 1;
      else if (unformat (input, "client"))
	do_client = 1;
      else if (unformat (input, "verbose"))
	verbose = 1;
      else
	break;
    }

  if (do_server)
    {
      u64 handle;
      u32 index;
      if (pool_elts (app_pool))
	{
	  vlib_cli_output (vm, "%U", format_application_listener,
			   0 /* header */ , 0, 0,
			   verbose);
          /* *INDENT-OFF* */
          pool_foreach (app, app_pool,
          ({
            /* App's listener sessions */
            if (hash_elts (app->listeners_table) == 0)
              continue;
            hash_foreach (handle, index, app->listeners_table,
	    ({
              vlib_cli_output (vm, "%U", format_application_listener, app,
              			       handle, index, verbose);
            }));
          }));
          /* *INDENT-ON* */
	}
      else
	vlib_cli_output (vm, "No active server bindings");
    }

  if (do_client)
    {
      if (pool_elts (app_pool))
	{
	  application_format_connects (0, verbose);

          /* *INDENT-OFF* */
          pool_foreach (app, app_pool,
          ({
            if (app->connects_seg_manager == (u32)~0)
              continue;
            application_format_connects (app, verbose);
          }));
          /* *INDENT-ON* */
	}
      else
	vlib_cli_output (vm, "No active client bindings");
    }

  /* Print app related info */
  if (!do_server && !do_client)
    {
      vlib_cli_output (vm, "%U", format_application, 0, verbose);
      pool_foreach (app, app_pool, (
				     {
				     vlib_cli_output (vm, "%U",
						      format_application, app,
						      verbose);
				     }
		    ));
    }

  return 0;
}

/* *INDENT-OFF* */
VLIB_CLI_COMMAND (show_app_command, static) =
{
  .path = "show app",
  .short_help = "show app [server|client] [verbose]",
  .function = show_app_command_fn,
};
/* *INDENT-ON* */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */