/*
 * This is a proprietary software. See COPYING for further details.
 *
 * (c) 2013 Copyright Askele, inc. <http://askele.com>
 * (c) 2013 Copyright Askele Ingria, inc. <http://askele-ingria.com>
 * (c) 2014 Copyright Confident, inc. (granted permission to use in commercial software)
 */

#include <stdlib.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <string.h>
#include <pthread.h>

#include <tdata/usrtc.h>

#include <sntl/pth_queue.h>

#define MAX_QUEUE_SIZE  4096
#define MAX_QUEUE_POOL  256

static long __cmp_uint(const void *a, const void *b)
{
  return (long)(*(unsigned int *)a - *(unsigned int *)b);
}

static inline pth_msg_t *__get_newmsg(pth_queue_t *queue)
{
  usrtc_t *tree = &queue->msgcache;
  usrtc_node_t *node;
  pth_msg_t *tmp;

  if(usrtc_count(tree)) {
    node = usrtc_first(tree);
    tmp = (pth_msg_t *)usrtc_node_getdata(node);
    usrtc_delete(tree, node);
  } else {
    tmp = malloc(sizeof(pth_msg_t));
    tree = &queue->qtree;
    node = &tmp->node;
    usrtc_node_init(node, tmp);
  }
  /* insert it */
  tree = &queue->qtree;
  tmp->qlength = usrtc_count(tree);
  usrtc_insert(tree, node, (void *)(&tmp->qlength));

  return tmp;
}

static inline void __release_msg(pth_queue_t *queue, pth_msg_t *msg)
{
  usrtc_node_t *node = &msg->node;
  usrtc_t *tree = &queue->qtree;

  tree = &queue->qtree; /* remove from queue */
  usrtc_delete(tree, node);

  tree = &queue->msgcache;

  if(usrtc_count(tree) >= MAX_QUEUE_POOL)
    free(msg);
  else {
    msg->data = NULL;
    msg->msgtype = NIL_MSG;
    usrtc_insert(tree, node, (void *)&msg->qlength);
  }

  return;
}

int pth_queue_init(pth_queue_t *queue)
{
  int r = 0;

  memset(queue, 0, sizeof(pth_queue_t));
  if((r = pthread_cond_init(&queue->cond, NULL)))
    return r;

  if((r = pthread_mutex_init(&queue->mutex, NULL))) {
    pthread_cond_destroy(&queue->cond);
    return r;
  }

  usrtc_init(&queue->qtree, USRTC_AVL, MAX_QUEUE_SIZE, __cmp_uint);
  usrtc_init(&queue->msgcache, USRTC_AVL, MAX_QUEUE_POOL, __cmp_uint);

  return r;
}

int pth_queue_add(pth_queue_t *queue, void *data, unsigned int msgtype)
{
  pth_msg_t *newmsg;

  pthread_mutex_lock(&queue->mutex);
  newmsg = __get_newmsg(queue);
  if (newmsg == NULL) {
    pthread_mutex_unlock(&queue->mutex);
    return ENOMEM;
  }

  newmsg->data = data;
  newmsg->msgtype = msgtype;

  if(queue->length == 0)
    pthread_cond_broadcast(&queue->cond);
  queue->length++;
  pthread_mutex_unlock(&queue->mutex);

  return 0;
}

int pth_queue_get(pth_queue_t *queue, const struct timespec *timeout, pth_msg_t *msg)
{
  usrtc_t *tree;
  usrtc_node_t *node = NULL;
  pth_msg_t *tmp;
  int r = 0;
  struct timespec abstimeout;

  if (queue == NULL || msg == NULL)
    return EINVAL;
  else
    tree = &queue->qtree;

  if (timeout) { /* setup timeout */
    struct timeval now;

    gettimeofday(&now, NULL);
    abstimeout.tv_sec = now.tv_sec + timeout->tv_sec;
    abstimeout.tv_nsec = (now.tv_usec * 1000) + timeout->tv_nsec;
    if (abstimeout.tv_nsec >= 1000000000) {
      abstimeout.tv_sec++;
      abstimeout.tv_nsec -= 1000000000;
    }
  }

  pthread_mutex_lock(&queue->mutex);

  /* Will wait until awakened by a signal or broadcast */
  while ((node = usrtc_first(tree)) == NULL && r != ETIMEDOUT) {  /* Need to loop to handle spurious wakeups */
    if (timeout)
      r = pthread_cond_timedwait(&queue->cond, &queue->mutex, &abstimeout);
    else
      pthread_cond_wait(&queue->cond, &queue->mutex);
  }
  if (r == ETIMEDOUT) {
    pthread_mutex_unlock(&queue->mutex);
    return r;
  }

  tmp = (pth_msg_t *)usrtc_node_getdata(node);
  queue->length--;

  msg->data = tmp->data;
  msg->msgtype = tmp->msgtype;
  msg->qlength = tmp->qlength; /* we will hold the msg id instead of size here */

  __release_msg(queue, tmp);
  pthread_mutex_unlock(&queue->mutex);

  return 0;
}

int pth_queue_destroy(pth_queue_t *queue, int freedata, void (*free_msg)(void *))
{
  int r = 0;
  usrtc_t *tree = &queue->qtree;
  usrtc_node_t *node = NULL;
  pth_msg_t *msg;

  if (queue == NULL)     return EINVAL;

  pthread_mutex_lock(&queue->mutex);

  for (node = usrtc_first(tree); node != NULL; node = usrtc_first(tree)) {
    usrtc_delete(tree, node);
    msg = (pth_msg_t *)usrtc_node_getdata(node);

    if(freedata) free(msg->data);
    else if(free_msg) free_msg(msg->data);

    free(msg);
  }
  /* free cache */
  tree = &queue->msgcache;
  for (node = usrtc_first(tree); node != NULL; node = usrtc_first(tree)) {
    usrtc_delete(tree, node);
    free(usrtc_node_getdata(node));
  }

  pthread_mutex_unlock(&queue->mutex);
  r = pthread_mutex_destroy(&queue->mutex);
  pthread_cond_destroy(&queue->cond);

  return r;
}

unsigned int pth_queue_length(pth_queue_t *queue)
{
  unsigned int c;

  pthread_mutex_lock(&queue->mutex);
  c = queue->length;
  pthread_mutex_unlock(&queue->mutex);

  return c;
}

/* dynamic queue thread poll */

static void *__poll_thread(void *poll)
{
  int r = 0;
  pth_msg_t msgbuf;
  pth_dqtpoll_t *p = (pth_dqtpoll_t *)poll;
  pth_queue_t *q = p->queue;

  while(1) {
    r = pth_queue_get(q, NULL, &msgbuf);
    if(r) continue;
    switch(msgbuf.msgtype) {
    case USR_MSG:
      p->jobdata_callback(msgbuf.data);
      break;
    default:
      /* TODO: do something ... */
      break;
    }
  }

  return NULL;
}

/* init poll, structure must be allocated */
int pth_dqtpoll_init(pth_dqtpoll_t *tpoll, int (*jobdata_callback)(void *))
{
  int r = 0;
  pth_queue_t *queue = malloc(sizeof(pth_queue_t));
  pthread_t *poll = malloc(sizeof(pthread_t)*MAX_POLL_VALUE);
  idx_allocator_t *idx = malloc(sizeof(idx_allocator_t));

  /* check it for allocation */
  if(!idx) goto __enomem;
  if(!queue) goto __enomem;
  if(!poll) goto __enomem;

  /* init all the stuff */
  if(idx_allocator_init(idx, MAX_POLL_VALUE, 0)) {
  __enomem:
    r = ENOMEM;
    goto __finish;
  }
  if(pth_queue_init(queue)) goto __enomem; /* init queue */
  if(pthread_rwlock_init(&(tpoll->stats_lock), NULL)) goto __enomem;

  /* set parameters */
  memset(poll, 0, sizeof(pthread_t)*MAX_POLL_VALUE);
  tpoll->flags = 0;
  tpoll->idx = idx;
  tpoll->poll = poll;
  tpoll->queue = queue;
  tpoll->poll_value = 1;
  tpoll->sleep_value = 0;
  tpoll->spurious_wakeups = 0;
  tpoll->jobdata_callback = jobdata_callback;

  /* first thread initiation */
  idx_reserve(idx, 0);
  if(pthread_create(&(poll[0]), NULL, __poll_thread, tpoll)) {
    pthread_rwlock_destroy(&(tpoll->stats_lock));
    goto __enomem;
  }

 __finish:
  if(r) {
    if(idx) free(idx);
    if(queue) {
      pth_queue_destroy(queue, 0, NULL);
      free(queue);
    }
    if(poll) free(poll);
  }
  return r;
}

/* run poll: poll */
int pth_dqtpoll_run(pth_dqtpoll_t *tpoll)
{
  int r = 0;

  pthread_rwlock_wrlock(&(tpoll->stats_lock));
  if((tpoll->flags & DQTPOLL_RUNNING) || (tpoll->flags & DQTPOLL_DEADSTAGE)) r = EINVAL;
  else {
    tpoll->flags |= DQTPOLL_RUNNING;
    tpoll->sleep_value = 1;
  }
  pthread_rwlock_unlock(&(tpoll->stats_lock));

  return r;
}

/* add the job to the queue: poll, job data, message type  */
int pth_dqtpoll_add(pth_dqtpoll_t *tpoll, void *job, unsigned int type)
{
  int r = 0;

  r = pth_queue_add(tpoll->queue, job, type);

  return r;
}

/* destroy the poll: poll, force flag
 * if force flag is set (!= 0), give up
 * about jobs, if no, do the job, but don't
 * accept the new ones, and destroy all poll
 * with last thread.
 */
int pth_dqtpoll_destroy(pth_dqtpoll_t *tpoll, int force)
{
  int r = 0;
  return r;
}