#include "lnm/loop.h"

lnm_err lnm_loop_queue_init(lnm_loop_queue **out, size_t cap) {
  lnm_loop_conn **arr = malloc(cap * sizeof(lnm_loop_conn *));

  if (arr == NULL) {
    return lnm_err_failed_alloc;
  }

  lnm_loop_queue *q = calloc(1, sizeof(lnm_loop_queue));

  if (q == NULL) {
    free(arr);

    return lnm_err_failed_alloc;
  }

  q->buf.arr = arr;
  q->buf.len = cap;

  pthread_mutex_init(&q->mutex, NULL);
  pthread_cond_init(&q->cond, NULL);

  *out = q;

  return lnm_err_ok;
}

void lnm_loop_queue_push(lnm_loop_queue *q, lnm_loop_conn *conn) {
  pthread_mutex_lock(&q->mutex);

  while (q->tail == q->head) {
    pthread_cond_wait(&q->cond, &q->mutex);
  }

  q->buf.arr[q->tail] = conn;

  // Make sure the index wraps around
  q->tail = (q->tail + 1) % q->buf.len;

  // Unlock mutex and signal to waiting threads
  pthread_mutex_unlock(&q->mutex);
  pthread_cond_signal(&q->cond);
}

lnm_loop_conn *lnm_loop_queue_pop(lnm_loop_queue *q) {
  pthread_mutex_lock(&q->mutex);

  while (q->tail == q->head) {
    pthread_cond_wait(&q->cond, &q->mutex);
  }

  lnm_loop_conn *out = q->buf.arr[q->head];
  q->head = (q->head + 1) % q->buf.len;

  // Unlock mutex and signal to waiting threads
  pthread_mutex_unlock(&q->mutex);
  pthread_cond_signal(&q->cond);

  return out;
}