/*
 * Licensed to the OpenAirInterface (OAI) Software Alliance under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The OpenAirInterface Software Alliance licenses this file to You under
 * the OAI Public License, Version 1.1  (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.openairinterface.org/?page_id=698
 *
 * 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.
 *-------------------------------------------------------------------------------
 * For more information about the OpenAirInterface (OAI) Software Alliance:
 *      contact@openairinterface.org
 */

/*
                                enb_app.c
                             -------------------
  AUTHOR  : Laurent Winckel, Sebastien ROUX, Lionel GAUTHIER, Navid Nikaein
  COMPANY : EURECOM
  EMAIL   : Lionel.Gauthier@eurecom.fr and Navid Nikaein
*/

#include <string.h>
#include <stdio.h>

#include "enb_app.h"
#include "enb_config.h"
#include "assertions.h"
#include "common/ran_context.h"

#include "common/utils/LOG/log.h"

# include "intertask_interface.h"
#   include "s1ap_eNB.h"
#   include "sctp_eNB_task.h"
#   include "gtpv1u_eNB_task.h"

#   include "x2ap_eNB.h"
#   include "x2ap_messages_types.h"
#   define X2AP_ENB_REGISTER_RETRY_DELAY   10

#include "openair1/PHY/INIT/phy_init.h"
extern unsigned char NB_eNB_INST;


extern RAN_CONTEXT_t RC;



/*------------------------------------------------------------------------------*/

#   define ENB_REGISTER_RETRY_DELAY 10


#include "targets/RT/USER/lte-softmodem.h"

/*------------------------------------------------------------------------------*/

/*
static void configure_phy(module_id_t enb_id, const Enb_properties_array_t* enb_properties)
{
  MessageDef *msg_p;
  int CC_id;

  msg_p = itti_alloc_new_message (TASK_ENB_APP, PHY_CONFIGURATION_REQ);

  for (CC_id=0; CC_id<MAX_NUM_CCs; CC_id++) {
    PHY_CONFIGURATION_REQ (msg_p).frame_type[CC_id]              = enb_properties->properties[enb_id]->frame_type[CC_id];
    PHY_CONFIGURATION_REQ (msg_p).prefix_type[CC_id]             = enb_properties->properties[enb_id]->prefix_type[CC_id];
    PHY_CONFIGURATION_REQ (msg_p).downlink_frequency[CC_id]      = enb_properties->properties[enb_id]->downlink_frequency[CC_id];
    PHY_CONFIGURATION_REQ (msg_p).uplink_frequency_offset[CC_id] = enb_properties->properties[enb_id]->uplink_frequency_offset[CC_id];
    PHY_CONFIGURATION_REQ (msg_p).nb_antennas_tx[CC_id]          = enb_properties->properties[enb_id]->nb_antennas_tx[CC_id];
    PHY_CONFIGURATION_REQ (msg_p).nb_antennas_rx[CC_id]          = enb_properties->properties[enb_id]->nb_antennas_rx[CC_id];
    PHY_CONFIGURATION_REQ (msg_p).tx_gain[CC_id]                 = enb_properties->properties[enb_id]->tx_gain[CC_id];
    PHY_CONFIGURATION_REQ (msg_p).rx_gain[CC_id]                 = enb_properties->properties[enb_id]->rx_gain[CC_id];
  }

  itti_send_msg_to_task (TASK_PHY_ENB, ENB_MODULE_ID_TO_INSTANCE(enb_id), msg_p);
}
*/

/*------------------------------------------------------------------------------*/
static void configure_rrc(uint32_t enb_id) {
  MessageDef *msg_p = NULL;
  //  int CC_id;
  msg_p = itti_alloc_new_message (TASK_ENB_APP, RRC_CONFIGURATION_REQ);

  if (RC.rrc[enb_id]) {
    RCconfig_RRC(msg_p,enb_id, RC.rrc[enb_id]);
    LOG_I(ENB_APP,"Sending configuration message to RRC task\n");
    itti_send_msg_to_task (TASK_RRC_ENB, ENB_MODULE_ID_TO_INSTANCE(enb_id), msg_p);
  } else AssertFatal(0,"RRC context for eNB %d not allocated\n",enb_id);
}

/*------------------------------------------------------------------------------*/

static uint32_t eNB_app_register(uint32_t enb_id_start, uint32_t enb_id_end) { //, const Enb_properties_array_t *enb_properties)
  uint32_t         enb_id;
  MessageDef      *msg_p;
  uint32_t         register_enb_pending = 0;

  for (enb_id = enb_id_start; (enb_id < enb_id_end) ; enb_id++) {
    {
      /* note:  there is an implicit relationship between the data structure and the message name */
      msg_p = itti_alloc_new_message (TASK_ENB_APP, S1AP_REGISTER_ENB_REQ);
      RCconfig_S1(msg_p, enb_id);

      if (enb_id == 0) RCconfig_gtpu();

      LOG_I(ENB_APP,"default drx %d\n",((S1AP_REGISTER_ENB_REQ(msg_p)).default_drx));
      LOG_I(ENB_APP,"[eNB %d] eNB_app_register for instance %d\n", enb_id, ENB_MODULE_ID_TO_INSTANCE(enb_id));
      itti_send_msg_to_task (TASK_S1AP, ENB_MODULE_ID_TO_INSTANCE(enb_id), msg_p);
      register_enb_pending++;
    }
  }

  return register_enb_pending;
}


/*------------------------------------------------------------------------------*/
static uint32_t eNB_app_register_x2(uint32_t enb_id_start, uint32_t enb_id_end) {
  uint32_t         enb_id;
  MessageDef      *msg_p;
  uint32_t         register_enb_x2_pending = 0;

  for (enb_id = enb_id_start; (enb_id < enb_id_end) ; enb_id++) {
    {
      msg_p = itti_alloc_new_message (TASK_ENB_APP, X2AP_REGISTER_ENB_REQ);
      RCconfig_X2(msg_p, enb_id);
      itti_send_msg_to_task (TASK_X2AP, ENB_MODULE_ID_TO_INSTANCE(enb_id), msg_p);
      register_enb_x2_pending++;
    }
  }

  return register_enb_x2_pending;
}

/*------------------------------------------------------------------------------*/
void *eNB_app_task(void *args_p) {
  uint32_t                        enb_nb = RC.nb_inst;
  uint32_t                        enb_id_start = 0;
  uint32_t                        enb_id_end = enb_id_start + enb_nb;
  uint32_t                        register_enb_pending=0;
  uint32_t                        registered_enb;
  long                            enb_register_retry_timer_id;
  uint32_t                        x2_register_enb_pending;
  uint32_t                        x2_registered_enb;
  long                            x2_enb_register_retry_timer_id;
  uint32_t                        enb_id;
  MessageDef                     *msg_p           = NULL;
  instance_t                      instance;
  int                             result;
  /* for no gcc warnings */
  (void)instance;
  itti_mark_task_ready (TASK_ENB_APP);
  LOG_I(PHY, "%s() Task ready initialise structures\n", __FUNCTION__);
  RCconfig_L1();
  RCconfig_macrlc();
  LOG_I(PHY, "%s() RC.nb_L1_inst:%d\n", __FUNCTION__, RC.nb_L1_inst);

  if (RC.nb_L1_inst>0) AssertFatal(l1_north_init_eNB()==0,"could not initialize L1 north interface\n");

  AssertFatal (enb_nb <= RC.nb_inst,
               "Number of eNB is greater than eNB defined in configuration file (%d/%d)!",
               enb_nb, RC.nb_inst);
  LOG_I(ENB_APP,"Allocating eNB_RRC_INST for %d instances\n",RC.nb_inst);
  RC.rrc = (eNB_RRC_INST **)malloc(RC.nb_inst*sizeof(eNB_RRC_INST *));
  LOG_I(PHY, "%s() RC.nb_inst:%d RC.rrc:%p\n", __FUNCTION__, RC.nb_inst, RC.rrc);

  for (enb_id = enb_id_start; (enb_id < enb_id_end) ; enb_id++) {
    RC.rrc[enb_id] = (eNB_RRC_INST *)malloc(sizeof(eNB_RRC_INST));
    LOG_I(PHY, "%s() Creating RRC instance RC.rrc[%d]:%p (%d of %d)\n", __FUNCTION__, enb_id, RC.rrc[enb_id], enb_id+1, enb_id_end);
    memset((void *)RC.rrc[enb_id],0,sizeof(eNB_RRC_INST));
    configure_rrc(enb_id);
  }

  if (EPC_MODE_ENABLED) {
    /* Try to register each eNB */
    registered_enb = 0;
    register_enb_pending = eNB_app_register (enb_id_start, enb_id_end);//, enb_properties_p);
  }

  /* Try to register each eNB with each other */
  x2_registered_enb = 0;
  x2_register_enb_pending = eNB_app_register_x2 (enb_id_start, enb_id_end);

  do {
    // Wait for a message
    itti_receive_msg (TASK_ENB_APP, &msg_p);
    instance = ITTI_MSG_INSTANCE (msg_p);

    switch (ITTI_MSG_ID(msg_p)) {
      case TERMINATE_MESSAGE:
        LOG_W(ENB_APP, " *** Exiting ENB_APP thread\n");
        itti_exit_task ();
        break;

      case MESSAGE_TEST:
        LOG_I(ENB_APP, "Received %s\n", ITTI_MSG_NAME(msg_p));
        break;

      case SOFT_RESTART_MESSAGE:
        handle_reconfiguration(instance);
        break;

      case S1AP_REGISTER_ENB_CNF:
        if (EPC_MODE_ENABLED) {
          LOG_I(ENB_APP, "[eNB %d] Received %s: associated MME %d\n", instance, ITTI_MSG_NAME (msg_p),
                S1AP_REGISTER_ENB_CNF(msg_p).nb_mme);
          DevAssert(register_enb_pending > 0);
          register_enb_pending--;

          /* Check if at least eNB is registered with one MME */
          if (S1AP_REGISTER_ENB_CNF(msg_p).nb_mme > 0) {
            registered_enb++;
          }

          /* Check if all register eNB requests have been processed */
          if (register_enb_pending == 0) {
            if (registered_enb == enb_nb) {
              /* If all eNB are registered, start L2L1 task */
              MessageDef *msg_init_p;
              msg_init_p = itti_alloc_new_message (TASK_ENB_APP, INITIALIZE_MESSAGE);
              itti_send_msg_to_task (TASK_L2L1, INSTANCE_DEFAULT, msg_init_p);
            } else {
              LOG_W(ENB_APP, " %d eNB not associated with a MME, retrying registration in %d seconds ...\n",
                    enb_nb - registered_enb,  ENB_REGISTER_RETRY_DELAY);

              /* Restart the eNB registration process in ENB_REGISTER_RETRY_DELAY seconds */
              if (timer_setup (ENB_REGISTER_RETRY_DELAY, 0, TASK_ENB_APP, INSTANCE_DEFAULT, TIMER_ONE_SHOT,
                               NULL, &enb_register_retry_timer_id) < 0) {
                LOG_E(ENB_APP, " Can not start eNB register retry timer, use \"sleep\" instead!\n");
                sleep(ENB_REGISTER_RETRY_DELAY);
                /* Restart the registration process */
                registered_enb = 0;
                register_enb_pending = eNB_app_register (enb_id_start, enb_id_end);//, enb_properties_p);
              }
            }
          }
        } /* if (EPC_MODE_ENABLED) */

        break;

      case S1AP_DEREGISTERED_ENB_IND:
        if (EPC_MODE_ENABLED) {
          LOG_W(ENB_APP, "[eNB %d] Received %s: associated MME %d\n", instance, ITTI_MSG_NAME (msg_p),
                S1AP_DEREGISTERED_ENB_IND(msg_p).nb_mme);
          /* TODO handle recovering of registration */
        }

        break;

      case TIMER_HAS_EXPIRED:
        if (EPC_MODE_ENABLED) {
          LOG_I(ENB_APP, " Received %s: timer_id %ld\n", ITTI_MSG_NAME (msg_p), TIMER_HAS_EXPIRED(msg_p).timer_id);

          if (TIMER_HAS_EXPIRED (msg_p).timer_id == enb_register_retry_timer_id) {
            /* Restart the registration process */
            registered_enb = 0;
            register_enb_pending = eNB_app_register (enb_id_start, enb_id_end);//, enb_properties_p);
          }

          if (TIMER_HAS_EXPIRED (msg_p).timer_id == x2_enb_register_retry_timer_id) {
            /* Restart the registration process */
            x2_registered_enb = 0;
            x2_register_enb_pending = eNB_app_register_x2 (enb_id_start, enb_id_end);
          }
        } /* if (EPC_MODE_ENABLED) */

        break;

      case X2AP_DEREGISTERED_ENB_IND:
        LOG_W(ENB_APP, "[eNB %d] Received %s: associated eNB %d\n", instance, ITTI_MSG_NAME (msg_p),
              X2AP_DEREGISTERED_ENB_IND(msg_p).nb_x2);
        /* TODO handle recovering of registration */
        break;

      case X2AP_REGISTER_ENB_CNF:
        LOG_I(ENB_APP, "[eNB %d] Received %s: associated eNB %d\n", instance, ITTI_MSG_NAME (msg_p),
              X2AP_REGISTER_ENB_CNF(msg_p).nb_x2);
        DevAssert(x2_register_enb_pending > 0);
        x2_register_enb_pending--;

        /* Check if at least eNB is registered with one target eNB */
        if (X2AP_REGISTER_ENB_CNF(msg_p).nb_x2 > 0) {
          x2_registered_enb++;
        }

        /* Check if all register eNB requests have been processed */
        if (x2_register_enb_pending == 0) {
          if (x2_registered_enb == enb_nb) {
            /* If all eNB are registered, start RRC HO task */
          } else {
            uint32_t x2_not_associated = enb_nb - x2_registered_enb;
            LOG_W(ENB_APP, " %d eNB %s not associated with the target\n",
                  x2_not_associated, x2_not_associated > 1 ? "are" : "is");

            // timer to retry
            /* Restart the eNB registration process in ENB_REGISTER_RETRY_DELAY seconds */
            if (timer_setup (X2AP_ENB_REGISTER_RETRY_DELAY, 0, TASK_ENB_APP,
                             INSTANCE_DEFAULT, TIMER_ONE_SHOT, NULL,
                             &x2_enb_register_retry_timer_id) < 0) {
              LOG_E(ENB_APP, " Can not start eNB X2AP register: retry timer, use \"sleep\" instead!\n");
              sleep(X2AP_ENB_REGISTER_RETRY_DELAY);
              /* Restart the registration process */
              x2_registered_enb = 0;
              x2_register_enb_pending = eNB_app_register_x2 (enb_id_start, enb_id_end);
            }
          }
        }

        break;

      default:
        LOG_E(ENB_APP, "Received unexpected message %s\n", ITTI_MSG_NAME (msg_p));
        break;
    }

    result = itti_free (ITTI_MSG_ORIGIN_ID(msg_p), msg_p);
    AssertFatal (result == EXIT_SUCCESS, "Failed to free memory (%d)!\n", result);
  } while (1);

  return NULL;
}

void handle_reconfiguration(module_id_t mod_id) {
  struct timespec start, end;
  clock_gettime(CLOCK_MONOTONIC, &start);
  flexran_agent_info_t *flexran = RC.flexran[mod_id];
  LOG_I(ENB_APP, "lte-softmodem soft-restart requested\n");

  if (ENB_WAIT == flexran->node_ctrl_state) {
    /* this is already waiting, just release */
    pthread_mutex_lock(&flexran->mutex_node_ctrl);
    flexran->node_ctrl_state = ENB_NORMAL_OPERATION;
    pthread_mutex_unlock(&flexran->mutex_node_ctrl);
    pthread_cond_signal(&flexran->cond_node_ctrl);
    return;
  }

  if (stop_L1L2(mod_id) < 0) {
    LOG_E(ENB_APP, "can not stop lte-softmodem, aborting restart\n");
    return;
  }

  /* node_ctrl_state should have value ENB_MAKE_WAIT only if this method is not
   * executed by the FlexRAN thread */
  if (ENB_MAKE_WAIT == flexran->node_ctrl_state) {
    LOG_I(ENB_APP, " * eNB %d: Waiting for FlexRAN RTController command *\n", mod_id);
    pthread_mutex_lock(&flexran->mutex_node_ctrl);
    flexran->node_ctrl_state = ENB_WAIT;

    while (ENB_NORMAL_OPERATION != flexran->node_ctrl_state)
      pthread_cond_wait(&flexran->cond_node_ctrl, &flexran->mutex_node_ctrl);

    pthread_mutex_unlock(&flexran->mutex_node_ctrl);
  }

  if (restart_L1L2(mod_id) < 0) {
    LOG_E(ENB_APP, "can not restart, killing lte-softmodem\n");
    exit_fun("can not restart L1L2, killing lte-softmodem");
    return;
  }

  clock_gettime(CLOCK_MONOTONIC, &end);
  end.tv_sec -= start.tv_sec;

  if (end.tv_nsec >= start.tv_nsec) {
    end.tv_nsec -= start.tv_nsec;
  } else {
    end.tv_sec -= 1;
    end.tv_nsec = end.tv_nsec - start.tv_nsec + 1000000000;
  }

  LOG_I(ENB_APP, "lte-softmodem restart succeeded in %ld.%ld s\n", end.tv_sec, end.tv_nsec / 1000000);
}
