/*
* Copyright (c) 2015-2017 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/vnet.h>
#include <vlibmemory/api.h>
#include <vnet/session/application.h>
#include <vnet/session/application_interface.h>

/* define message IDs */
#include <vpp/api/vpe_msg_enum.h>

/* define message structures */
#define vl_typedefs
#include <vpp/api/vpe_all_api_h.h>
#undef vl_typedefs

/* define generated endian-swappers */
#define vl_endianfun
#include <vpp/api/vpe_all_api_h.h>
#undef vl_endianfun

/* instantiate all the print functions we know about */
#define vl_print(handle, ...) vlib_cli_output (handle, __VA_ARGS__)
#define vl_printfun
#include <vpp/api/vpe_all_api_h.h>
#undef vl_printfun

typedef enum
{
  EVENT_WAKEUP = 1,
} http_process_event_t;

typedef struct
{
  u8 *rx_buf;
  unix_shared_memory_queue_t **vpp_queue;
  u64 byte_index;

  uword *handler_by_get_request;

  u32 *free_http_cli_process_node_indices;

  /* Sever's event queue */
  unix_shared_memory_queue_t *vl_input_queue;

  /* API client handle */
  u32 my_client_index;

  u32 app_index;

  /* process node index for evnt scheduling */
  u32 node_index;
  vlib_main_t *vlib_main;
} http_server_main_t;

http_server_main_t http_server_main;

static void
free_http_process (stream_session_t * s)
{
  vlib_node_runtime_t *rt;
  vlib_main_t *vm = &vlib_global_main;
  http_server_main_t *hsm = &http_server_main;
  vlib_node_t *n;
  u32 node_index;
  stream_session_t **save_s;

  node_index = (u64) (s->opaque[0]);
  ASSERT (node_index != 0);

  n = vlib_get_node (vm, node_index);
  rt = vlib_node_get_runtime (vm, n->runtime_index);
  save_s = (stream_session_t **) vlib_node_get_runtime (vm, n->runtime_index);

  /* Reset session saved node index */
  s->opaque[0] = 0;
  /* Reset process session pointer */
  *save_s = 0;

  /* Turn off the process node */
  vlib_node_set_state (vm, rt->node_index, VLIB_NODE_STATE_DISABLED);

  /* add node index to the freelist */
  vec_add1 (hsm->free_http_cli_process_node_indices, node_index);
}

static const char
  *http_response = "HTTP/1.1 200 OK\r\n"
  "Content-Type: text/html\r\n"
  "Expires: Mon, 11 Jan 1970 10:10:10 GMT\r\n"
  "Connection: close\r\n"
  "Pragma: no-cache\r\n" "Content-Length: %d\r\n\r\n%s";

static const char
  *http_error_template = "HTTP/1.1 %s\r\n"
  "Content-Type: text/html\r\n"
  "Expires: Mon, 11 Jan 1970 10:10:10 GMT\r\n"
  "Connection: close\r\n" "Pragma: no-cache\r\n" "Content-Length: 0\r\n\r\n";

/* Header, including incantation to suppress favicon.ico requests */
static const char
  *html_header_template = "<html><head><title>%v</title>"
  "</head><link rel=\"icon\" href=\"data:,\"><body><pre>";

static const char *html_footer = "</pre></body></html>\r\n";

static void
http_cli_output (uword arg, u8 * buffer, uword buffer_bytes)
{
  u8 **output_vecp = (u8 **) arg;
  u8 *output_vec;
  u32 offset;

  output_vec = *output_vecp;

  offset = vec_len (output_vec);
  vec_validate (output_vec, offset + buffer_bytes - 1);
  clib_memcpy (output_vec + offset, buffer, buffer_bytes);

  *output_vecp = output_vec;
}

void
send_data (stream_session_t * s, u8 * data)
{
  session_fifo_event_t evt;
  u32 offset, bytes_to_send;
  f64 delay = 10e-3;
  http_server_main_t *hsm = &http_server_main;
  vlib_main_t *vm = hsm->vlib_main;
  f64 last_sent_timer = vlib_time_now (vm);

  bytes_to_send = vec_len (data);
  offset = 0;

  while (bytes_to_send > 0)
    {
      int actual_transfer;

      actual_transfer = svm_fifo_enqueue_nowait
	(s->server_tx_fifo, bytes_to_send, data + offset);

      /* Made any progress? */
      if (actual_transfer <= 0)
	{
	  vlib_process_suspend (vm, delay);
	  /* 10s deadman timer */
	  if (vlib_time_now (vm) > last_sent_timer + 10.0)
	    {
	      /* $$$$ FC: reset transport session here? */
	      break;
	    }
	  /* Exponential backoff, within reason */
	  if (delay < 1.0)
	    delay = delay * 2.0;
	}
      else
	{
	  last_sent_timer = vlib_time_now (vm);
	  offset += actual_transfer;
	  bytes_to_send -= actual_transfer;

	  if (svm_fifo_set_event (s->server_tx_fifo))
	    {
	      /* Fabricate TX event, send to vpp */
	      evt.fifo = s->server_tx_fifo;
	      evt.event_type = FIFO_EVENT_APP_TX;
	      evt.event_id = 0;

	      unix_shared_memory_queue_add (hsm->vpp_queue[s->thread_index],
					    (u8 *) & evt,
					    0 /* do wait for mutex */ );
	    }
	  delay = 10e-3;
	}
    }
}

static void
send_error (stream_session_t * s, char *str)
{
  u8 *data;

  data = format (0, http_error_template, str);
  send_data (s, data);
  vec_free (data);
}

static uword
http_cli_process (vlib_main_t * vm,
		  vlib_node_runtime_t * rt, vlib_frame_t * f)
{
  http_server_main_t *hsm = &http_server_main;
  u8 *request = 0, *reply = 0;
  stream_session_t **save_s;
  stream_session_t *s;
  unformat_input_t input;
  int i;
  u8 *http = 0, *html = 0;

  save_s = vlib_node_get_runtime_data (hsm->vlib_main, rt->node_index);
  s = *save_s;

  request = (u8 *) (void *) (s->opaque[1]);
  s->opaque[1] = 0;

  if (vec_len (request) < 7)
    {
      send_error (s, "400 Bad Request");
      goto out;
    }

  for (i = 0; i < vec_len (request) - 4; i++)
    {
      if (request[i] == 'G' &&
	  request[i + 1] == 'E' &&
	  request[i + 2] == 'T' && request[i + 3] == ' ')
	goto found;
    }
bad_request:
  send_error (s, "400 Bad Request");
  goto out;

found:
  /* Lose "GET " */
  vec_delete (request, i + 5, 0);

  /* Replace slashes with spaces, stop at the end of the path */
  i = 0;
  while (1)
    {
      if (request[i] == '/')
	request[i] = ' ';
      else if (request[i] == ' ')
	{
	  /* vlib_cli_input is vector-based, no need for a NULL */
	  _vec_len (request) = i;
	  break;
	}
      i++;
      /* Should never happen */
      if (i == vec_len (request))
	goto bad_request;
    }

  /* Generate the html header */
  html = format (0, html_header_template, request /* title */ );

  /* Run the command */
  unformat_init_vector (&input, request);
  vlib_cli_input (vm, &input, http_cli_output, (uword) & reply);
  unformat_free (&input);
  request = 0;

  /* Generate the html page */
  html = format (html, "%v", reply);
  html = format (html, html_footer);
  /* And the http reply */
  http = format (0, http_response, vec_len (html), html);

  /* Send it */
  send_data (s, http);

out:
  /* Cleanup */
  vec_free (request);
  vec_free (reply);
  vec_free (html);
  vec_free (http);

  free_http_process (s);
  return (0);
}

static void
alloc_http_process (stream_session_t * s)
{
  char *name;
  vlib_node_t *n;
  http_server_main_t *hsm = &http_server_main;
  vlib_main_t *vm = hsm->vlib_main;
  uword l = vec_len (hsm->free_http_cli_process_node_indices);
  stream_session_t **save_s;

  if (vec_len (hsm->free_http_cli_process_node_indices) > 0)
    {
      n = vlib_get_node (vm, hsm->free_http_cli_process_node_indices[l - 1]);

      vlib_node_set_state (vm, n->index, VLIB_NODE_STATE_POLLING);

      _vec_len (hsm->free_http_cli_process_node_indices) = l - 1;
    }
  else
    {
      static vlib_node_registration_t r = {
	.function = http_cli_process,
	.type = VLIB_NODE_TYPE_PROCESS,
	.process_log2_n_stack_bytes = 16,
	.runtime_data_bytes = sizeof (void *),
      };

      name = (char *) format (0, "http-cli-%d", l);

      r.name = name;
      vlib_register_node (vm, &r);
      vec_free (name);

      n = vlib_get_node (vm, r.index);
    }

  /* Save the node index in the stream_session_t. It won't be zero. */
  s->opaque[0] = (u64) n->index;

  /* Save the stream_session_t (pointer) in the node runtime */
  save_s = vlib_node_get_runtime_data (vm, n->index);
  *save_s = s;

  vlib_start_process (vm, n->runtime_index);
}

static int
builtin_session_accept_callback (stream_session_t * s)
{
  http_server_main_t *bsm = &http_server_main;

  bsm->vpp_queue[s->thread_index] =
    session_manager_get_vpp_event_queue (s->thread_index);
  s->session_state = SESSION_STATE_READY;
  bsm->byte_index = 0;
  return 0;
}

static void
builtin_session_disconnect_callback (stream_session_t * s)
{
  http_server_main_t *bsm = &http_server_main;
  vnet_disconnect_args_t _a, *a = &_a;

  a->handle = stream_session_handle (s);
  a->app_index = bsm->app_index;
  vnet_disconnect_session (a);
}

static void
builtin_session_reset_callback (stream_session_t * s)
{
  clib_warning ("called.. ");

  stream_session_cleanup (s);
}


static int
builtin_session_connected_callback (u32 app_index, u32 api_context,
				    stream_session_t * s, u8 is_fail)
{
  clib_warning ("called...");
  return -1;
}

static int
builtin_add_segment_callback (u32 client_index,
			      const u8 * seg_name, u32 seg_size)
{
  clib_warning ("called...");
  return -1;
}

static int
builtin_redirect_connect_callback (u32 client_index, void *mp)
{
  clib_warning ("called...");
  return -1;
}

static void
alloc_http_process_callback (void *s_arg)
{
  stream_session_t *s = (stream_session_t *) s_arg;
  alloc_http_process (s);
}

static int
http_server_rx_callback (stream_session_t * s)
{
  u32 max_dequeue;
  int actual_transfer;
  http_server_main_t *hsm = &http_server_main;
  svm_fifo_t *rx_fifo;

  rx_fifo = s->server_rx_fifo;

  max_dequeue = svm_fifo_max_dequeue (rx_fifo);

  svm_fifo_unset_event (rx_fifo);

  if (PREDICT_FALSE (max_dequeue == 0))
    return 0;

  vec_validate (hsm->rx_buf, max_dequeue - 1);
  _vec_len (hsm->rx_buf) = max_dequeue;

  actual_transfer = svm_fifo_dequeue_nowait (rx_fifo, max_dequeue,
					     hsm->rx_buf);
  ASSERT (actual_transfer > 0);

  _vec_len (hsm->rx_buf) = actual_transfer;

  /* send the command to a new/recycled vlib process */
  s->opaque[1] = (u64) vec_dup (hsm->rx_buf);

  /* Send an RPC request via the thread-0 input node */
  if (vlib_get_thread_index () != 0)
    {
      session_fifo_event_t evt;
      evt.rpc_args.fp = alloc_http_process_callback;
      evt.rpc_args.arg = s;
      evt.event_type = FIFO_EVENT_RPC;
      unix_shared_memory_queue_add
	(session_manager_get_vpp_event_queue (0 /* main thread */ ),
	 (u8 *) & evt, 0 /* do wait for mutex */ );
    }
  else
    alloc_http_process (s);
  return 0;
}

static session_cb_vft_t builtin_session_cb_vft = {
  .session_accept_callback = builtin_session_accept_callback,
  .session_disconnect_callback = builtin_session_disconnect_callback,
  .session_connected_callback = builtin_session_connected_callback,
  .add_segment_callback = builtin_add_segment_callback,
  .redirect_connect_callback = builtin_redirect_connect_callback,
  .builtin_server_rx_callback = http_server_rx_callback,
  .session_reset_callback = builtin_session_reset_callback
};

/* Abuse VPP's input queue */
static int
create_api_loopback (vlib_main_t * vm)
{
  http_server_main_t *hsm = &http_server_main;
  vl_api_memclnt_create_t _m, *mp = &_m;
  extern void vl_api_memclnt_create_t_handler (vl_api_memclnt_create_t *);
  api_main_t *am = &api_main;
  vl_shmem_hdr_t *shmem_hdr;
  uword *event_data = 0, event_type;
  int resolved = 0;

  /*
   * Create a "loopback" API client connection
   * Don't do things like this unless you know what you're doing...
   */

  shmem_hdr = am->shmem_hdr;
  hsm->vl_input_queue = shmem_hdr->vl_input_queue;
  memset (mp, 0, sizeof (*mp));
  mp->_vl_msg_id = VL_API_MEMCLNT_CREATE;
  mp->context = 0xFEEDFACE;
  mp->input_queue = (u64) hsm->vl_input_queue;
  strncpy ((char *) mp->name, "tcp_http_server", sizeof (mp->name) - 1);

  vl_api_memclnt_create_t_handler (mp);

  /* Wait for reply */
  hsm->node_index = vlib_get_current_process (vm)->node_runtime.node_index;
  vlib_process_wait_for_event_or_clock (vm, 1.0);
  event_type = vlib_process_get_events (vm, &event_data);
  switch (event_type)
    {
    case 1:
      resolved = 1;
      break;
    case ~0:
      /* timed out */
      break;
    default:
      clib_warning ("unknown event_type %d", event_type);
    }
  if (!resolved)
    return -1;

  return 0;
}

static int
server_attach ()
{
  http_server_main_t *hsm = &http_server_main;
  u8 segment_name[128];
  u64 options[SESSION_OPTIONS_N_OPTIONS];
  vnet_app_attach_args_t _a, *a = &_a;

  memset (a, 0, sizeof (*a));
  memset (options, 0, sizeof (options));

  a->api_client_index = hsm->my_client_index;
  a->session_cb_vft = &builtin_session_cb_vft;
  a->options = options;
  a->options[SESSION_OPTIONS_SEGMENT_SIZE] = 128 << 20;
  a->options[SESSION_OPTIONS_RX_FIFO_SIZE] = 8 << 10;
  a->options[SESSION_OPTIONS_TX_FIFO_SIZE] = 32 << 10;
  a->options[APP_OPTIONS_FLAGS] = APP_OPTIONS_FLAGS_BUILTIN_APP;
  a->options[APP_OPTIONS_PREALLOC_FIFO_PAIRS] = 16;
  a->segment_name = segment_name;
  a->segment_name_length = ARRAY_LEN (segment_name);

  if (vnet_application_attach (a))
    {
      clib_warning ("failed to attach server");
      return -1;
    }
  hsm->app_index = a->app_index;
  return 0;
}

static int
server_listen ()
{
  http_server_main_t *hsm = &http_server_main;
  vnet_bind_args_t _a, *a = &_a;
  memset (a, 0, sizeof (*a));
  a->app_index = hsm->app_index;
  a->uri = "tcp://0.0.0.0/80";
  return vnet_bind_uri (a);
}

static int
server_create (vlib_main_t * vm)
{
  http_server_main_t *hsm = &http_server_main;
  u32 num_threads;
  vlib_thread_main_t *vtm = vlib_get_thread_main ();

  if (hsm->my_client_index == (u32) ~ 0)
    {
      if (create_api_loopback (vm))
	return -1;
    }

  num_threads = 1 /* main thread */  + vtm->n_threads;
  vec_validate (http_server_main.vpp_queue, num_threads - 1);

  if (server_attach ())
    {
      clib_warning ("failed to attach server");
      return -1;
    }
  if (server_listen ())
    {
      clib_warning ("failed to start listening");
      return -1;
    }
  return 0;
}

/* Get our api client index */
static void
vl_api_memclnt_create_reply_t_handler (vl_api_memclnt_create_reply_t * mp)
{
  vlib_main_t *vm = vlib_get_main ();
  http_server_main_t *hsm = &http_server_main;
  hsm->my_client_index = mp->index;
  vlib_process_signal_event (vm, hsm->node_index, 1 /* evt */ ,
			     0 /* data */ );
}

#define foreach_tcp_http_server_api_msg      		\
_(MEMCLNT_CREATE_REPLY, memclnt_create_reply)   		\

static clib_error_t *
tcp_http_server_api_hookup (vlib_main_t * vm)
{
  vl_msg_api_msg_config_t _c, *c = &_c;

  /* Hook up client-side static APIs to our handlers */
#define _(N,n) do {                                             \
    c->id = VL_API_##N;                                         \
    c->name = #n;                                               \
    c->handler = vl_api_##n##_t_handler;                        \
    c->cleanup = vl_noop_handler;                               \
    c->endian = vl_api_##n##_t_endian;                          \
    c->print = vl_api_##n##_t_print;                            \
    c->size = sizeof(vl_api_##n##_t);                           \
    c->traced = 1; /* trace, so these msgs print */             \
    c->replay = 0; /* don't replay client create/delete msgs */ \
    c->message_bounce = 0; /* don't bounce this message */	\
    vl_msg_api_config(c);} while (0);

  foreach_tcp_http_server_api_msg;
#undef _

  return 0;
}

static clib_error_t *
server_create_command_fn (vlib_main_t * vm,
			  unformat_input_t * input, vlib_cli_command_t * cmd)
{
  int rv;

  tcp_http_server_api_hookup (vm);
  vnet_session_enable_disable (vm, 1 /* turn on TCP, etc. */ );
  rv = server_create (vm);
  switch (rv)
    {
    case 0:
      break;
    default:
      return clib_error_return (0, "server_create returned %d", rv);
    }
  return 0;
}

/* *INDENT-OFF* */
VLIB_CLI_COMMAND (server_create_command, static) =
{
  .path = "test http server",
  .short_help = "test http server",
  .function = server_create_command_fn,
};
/* *INDENT-ON* */

static clib_error_t *
builtin_http_server_main_init (vlib_main_t * vm)
{
  http_server_main_t *hsm = &http_server_main;
  hsm->my_client_index = ~0;
  hsm->vlib_main = vm;

  return 0;
}

VLIB_INIT_FUNCTION (builtin_http_server_main_init);

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