/*
 * 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 1.0  (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.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
 */

#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

#include <signal.h>
#include <time.h>
#include <errno.h>

#include "assertions.h"
#include "intertask_interface.h"
#include "timer.h"
#include "log.h"
#include "queue.h"

#if defined (LOG_D) && defined (LOG_E)
# define TMR_DEBUG(x, args...)  LOG_D(TMR, x, ##args)
# define TMR_ERROR(x, args...)  LOG_E(TMR, x, ##args)
#endif

#ifndef TMR_DEBUG
# define TMR_DEBUG(x, args...)  do { fprintf(stdout, "[TMR][D]"x, ##args); } while(0)
#endif
#ifndef TMR_ERROR
# define TMR_ERROR(x, args...)  do { fprintf(stdout, "[TMR][E]"x, ##args); } while(0)
#endif

int timer_handle_signal(siginfo_t *info);

struct timer_elm_s {
  task_id_t                 task_id;  ///< Task ID which has requested the timer
  int32_t                   instance; ///< Instance of the task which has requested the timer
  timer_t                   timer;    ///< Unique timer id
  timer_type_t              type;     ///< Timer type
  void                     *timer_arg;      ///< Optional argument that will be passed when timer expires
  STAILQ_ENTRY(timer_elm_s) entries;  ///< Pointer to next element
};

typedef struct timer_desc_s {
  STAILQ_HEAD(timer_list_head, timer_elm_s) timer_queue;
  pthread_mutex_t timer_list_mutex;
  struct timespec timeout;
} timer_desc_t;

static timer_desc_t timer_desc;

#define TIMER_SEARCH(vAR, tIMERfIELD, tIMERvALUE, tIMERqUEUE)   \
do {                                                            \
    STAILQ_FOREACH(vAR, tIMERqUEUE, entries) {                  \
    if (((vAR)->tIMERfIELD == tIMERvALUE))                  \
            break;                                              \
    }                                                           \
} while(0)

int timer_handle_signal(siginfo_t *info)
{
  struct timer_elm_s  *timer_p;
  MessageDef          *message_p;
  timer_has_expired_t *timer_expired_p;
  task_id_t            task_id;
  int32_t              instance;

  /* Get back pointer to timer list element */
  timer_p = (struct timer_elm_s *)info->si_ptr;

  // LG: To many traces for msc timer:
  // TMR_DEBUG("Timer with id 0x%lx has expired\n", (long)timer_p->timer);

  task_id = timer_p->task_id;
  instance = timer_p->instance;
  message_p = itti_alloc_new_message(TASK_TIMER, TIMER_HAS_EXPIRED);

  timer_expired_p = &message_p->ittiMsg.timer_has_expired;

  timer_expired_p->timer_id = (long)timer_p->timer;
  timer_expired_p->arg      = timer_p->timer_arg;

  /* Timer is a one shot timer, remove it */
  if (timer_p->type == TIMER_ONE_SHOT) {
    //         if (timer_delete(timer_p->timer) < 0) {
    //             TMR_DEBUG("Failed to delete timer 0x%lx\n", (long)timer_p->timer);
    //         }
    //         TMR_DEBUG("Removed timer 0x%lx\n", (long)timer_p->timer);
    //         pthread_mutex_lock(&timer_desc.timer_list_mutex);
    //         STAILQ_REMOVE(&timer_desc.timer_queue, timer_p, timer_elm_s, entries);
    //         pthread_mutex_unlock(&timer_desc.timer_list_mutex);
    //         free(timer_p);
    //         timer_p = NULL;
    if (timer_remove((long)timer_p->timer) != 0) {
      TMR_DEBUG("Failed to delete timer 0x%lx\n", (long)timer_p->timer);
    }
  }

  /* Notify task of timer expiry */
  if (itti_send_msg_to_task(task_id, instance, message_p) < 0) {
    TMR_DEBUG("Failed to send msg TIMER_HAS_EXPIRED to task %u\n", task_id);
    free(message_p);
    return -1;
  }

  return 0;
}

int timer_setup(
  uint32_t      interval_sec,
  uint32_t      interval_us,
  task_id_t     task_id,
  int32_t       instance,
  timer_type_t  type,
  void         *timer_arg,
  long         *timer_id)
{
  struct sigevent     se;
  struct itimerspec   its;
  struct timer_elm_s *timer_p;
  timer_t             timer;

  if (timer_id == NULL) {
    return -1;
  }

  AssertFatal (type < TIMER_TYPE_MAX, "Invalid timer type (%d/%d)!\n", type, TIMER_TYPE_MAX);

  /* Allocate new timer list element */
  timer_p = malloc(sizeof(struct timer_elm_s));

  if (timer_p == NULL) {
    TMR_ERROR("Failed to create new timer element\n");
    return -1;
  }

  memset(&timer, 0, sizeof(timer_t));
  memset(&se, 0, sizeof(struct sigevent));

  timer_p->task_id   = task_id;
  timer_p->instance  = instance;
  timer_p->type      = type;
  timer_p->timer_arg = timer_arg;

  /* Setting up alarm */
  /* Set and enable alarm */
  se.sigev_notify = SIGEV_SIGNAL;
  se.sigev_signo = SIGTIMER;
  se.sigev_value.sival_ptr = timer_p;

  /* At the timer creation, the timer structure will be filled in with timer_id,
   * which is unique for this process. This id is allocated by kernel and the
   * value might be used to distinguish timers.
   */
  if (timer_create(CLOCK_REALTIME, &se, &timer) < 0) {
    TMR_ERROR("Failed to create timer: (%s:%d)\n", strerror(errno), errno);
    free(timer_p);
    return -1;
  }

  /* Fill in the first expiration value. */
  its.it_value.tv_sec  = interval_sec;
  its.it_value.tv_nsec = interval_us * 1000;

  if (type == TIMER_PERIODIC) {
    /* Asked for periodic timer. We set the interval time */
    its.it_interval.tv_sec  = interval_sec;
    its.it_interval.tv_nsec = interval_us * 1000;
  } else {
    /* Asked for one-shot timer. Do not set the interval field */
    its.it_interval.tv_sec  = 0;
    its.it_interval.tv_nsec = 0;
  }

  timer_settime(timer, 0, &its, NULL);
  /* Simply set the timer_id argument. so it can be used by caller */
  *timer_id = (long)timer;
  TMR_DEBUG("Requesting new %s timer with id 0x%lx that expires within "
            "%d sec and %d usec\n",
            type == TIMER_PERIODIC ? "periodic" : "single shot",
            *timer_id, interval_sec, interval_us);

  timer_p->timer = timer;

  /* Lock the queue and insert the timer at the tail */
  pthread_mutex_lock(&timer_desc.timer_list_mutex);
  STAILQ_INSERT_TAIL(&timer_desc.timer_queue, timer_p, entries);
  pthread_mutex_unlock(&timer_desc.timer_list_mutex);

  return 0;
}

int timer_remove(long timer_id)
{
  int rc = 0;
  struct timer_elm_s *timer_p;

  TMR_DEBUG("Removing timer 0x%lx\n", timer_id);

  pthread_mutex_lock(&timer_desc.timer_list_mutex);
  TIMER_SEARCH(timer_p, timer, ((timer_t)timer_id), &timer_desc.timer_queue);

  /* We didn't find the timer in list */
  if (timer_p == NULL) {
    pthread_mutex_unlock(&timer_desc.timer_list_mutex);
    TMR_ERROR("Didn't find timer 0x%lx in list\n", timer_id);
    return -1;
  }

  STAILQ_REMOVE(&timer_desc.timer_queue, timer_p, timer_elm_s, entries);
  pthread_mutex_unlock(&timer_desc.timer_list_mutex);

  if (timer_delete(timer_p->timer) < 0) {
    TMR_ERROR("Failed to delete timer 0x%lx\n", (long)timer_p->timer);
    rc = -1;
  }

  free(timer_p);
  timer_p = NULL;
  return rc;
}

int timer_init(void)
{
  TMR_DEBUG("Initializing TIMER task interface\n");

  memset(&timer_desc, 0, sizeof(timer_desc_t));

  STAILQ_INIT(&timer_desc.timer_queue);
  pthread_mutex_init(&timer_desc.timer_list_mutex, NULL);

  TMR_DEBUG("Initializing TIMER task interface: DONE\n");
  return 0;
}
