/******************************************************************************
 *
 *  Copyright (C) 2014 Google, Inc.
 *
 *  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 "bt_defs.h"
#include "allocator.h"
#include "fixed_queue.h"
#include "list.h"
#include "osi.h"
#include "bt_trace.h"

typedef struct fixed_queue_t {
  
  list_t *list;
  //semaphore_t *enqueue_sem;
  //semaphore_t *dequeue_sem;
  pthread_mutex_t lock;
  size_t capacity;

  fixed_queue_cb dequeue_ready;
/*
  reactor_object_t *dequeue_object;
  fixed_queue_cb dequeue_ready;
  void *dequeue_context;
*/
} fixed_queue_t;

//static void internal_dequeue_ready(void *context);

fixed_queue_t *fixed_queue_new(size_t capacity) {
  fixed_queue_t *ret = osi_calloc(sizeof(fixed_queue_t));
  if (!ret)
    goto error;

  pthread_mutex_init(&ret->lock, NULL);
  ret->capacity = capacity;

  ret->list = list_new(NULL);
  if (!ret->list)
    goto error;

/*
  ret->enqueue_sem = semaphore_new(capacity);
  if (!ret->enqueue_sem)
    goto error;

  ret->dequeue_sem = semaphore_new(0);
  if (!ret->dequeue_sem)
    goto error;
*/
  return ret;

error:;
  fixed_queue_free(ret, NULL);
  return NULL;
}

void fixed_queue_free(fixed_queue_t *queue, fixed_queue_free_cb free_cb) {
  const list_node_t *node;
  if (!queue)
    return;

//  fixed_queue_unregister_dequeue(queue);

  if (free_cb)
    for (node = list_begin(queue->list); node != list_end(queue->list); node = list_next(node))
      free_cb(list_node(node));

  list_free(queue->list);
//  semaphore_free(queue->enqueue_sem);
//  semaphore_free(queue->dequeue_sem);
  pthread_mutex_destroy(&queue->lock);
  osi_free(queue);
}

bool fixed_queue_is_empty(fixed_queue_t *queue) {
  bool is_empty = false;
  assert(queue != NULL);

  pthread_mutex_lock(&queue->lock);
  is_empty = list_is_empty(queue->list);
  pthread_mutex_unlock(&queue->lock);

  return is_empty;
}

size_t fixed_queue_capacity(fixed_queue_t *queue) {
  assert(queue != NULL);

  return queue->capacity;
}

void fixed_queue_enqueue(fixed_queue_t *queue, void *data) {
  assert(queue != NULL);
  assert(data != NULL);

//  semaphore_wait(queue->enqueue_sem);

  pthread_mutex_lock(&queue->lock);

  list_append(queue->list, data);
  pthread_mutex_unlock(&queue->lock);

//  semaphore_post(queue->dequeue_sem);
}

void *fixed_queue_dequeue(fixed_queue_t *queue) {
  void *ret = NULL;
  assert(queue != NULL);

//  semaphore_wait(queue->dequeue_sem);

  pthread_mutex_lock(&queue->lock);
  ret = list_front(queue->list);
  list_remove(queue->list, ret);
  pthread_mutex_unlock(&queue->lock);

//  semaphore_post(queue->enqueue_sem);

  return ret;
}

/*
void *fixed_queue_try_dequeue(fixed_queue_t *queue) {
  void *ret = NULL;
  assert(queue != NULL);

  if (!semaphore_try_wait(queue->dequeue_sem))
    return NULL;

  pthread_mutex_lock(&queue->lock);
  ret = list_front(queue->list);
  list_remove(queue->list, ret);
  pthread_mutex_unlock(&queue->lock);

  semaphore_post(queue->enqueue_sem);

  return ret;
}

int fixed_queue_get_dequeue_fd(const fixed_queue_t *queue) {
  assert(queue != NULL);
  return semaphore_get_fd(queue->dequeue_sem);
}
*/
void fixed_queue_register_dequeue(fixed_queue_t *queue, fixed_queue_cb ready_cb) {
  assert(queue != NULL);
  assert(ready_cb != NULL);

  queue->dequeue_ready = ready_cb;
}

void fixed_queue_unregister_dequeue(fixed_queue_t *queue) {
  assert(queue != NULL);

  queue->dequeue_ready = NULL;
}

void fixed_queue_process(fixed_queue_t *queue) {
  if (queue == NULL)
    return;

  if (queue->dequeue_ready)
    queue->dequeue_ready(queue);
}
/*
static void internal_dequeue_ready(void *context) {
  assert(context != NULL);

  fixed_queue_t *queue = context;
  queue->dequeue_ready(queue, queue->dequeue_context);
}
*/