/* Copyright (c) 2014-2018, Michael Santos <michael.santos@gmail.com>
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include "alcove.h"
#include "alcove_call.h"

static int count_pid(alcove_state_t *ap, alcove_child_t *c, void *arg1,
                     void *arg2);
static int cons_pid(alcove_state_t *ap, alcove_child_t *c, void *arg1,
                    void *arg2);

ssize_t alcove_sys_cpid(alcove_state_t *ap, const char *arg, size_t len,
                        char *reply, size_t rlen) {
  int rindex = 0;
  size_t count = 0;

  UNUSED(arg);
  UNUSED(len);

  /* Count the number of PIDs */
  if (pid_foreach(ap, 0, &count, NULL, pid_not_equal, count_pid) < 0)
    return -1;

  /* Ensure the buffer is large enough to hold the PIDs
   * version = 1 byte
   *     list header = 5 bytes
   *     tuple header = 5 bytes
   *     atom = 1 byte
   *     alcove_pid = 10 bytes
   *     5 * int (7) = 35 bytes
   * tail = 1 byte
   *
   * length = 1 + (count * 56) + 1
   */
  if (2 + count * 56 > rlen)
    return -1;

  ALCOVE_ERR(alcove_encode_version(reply, rlen, &rindex));

  if (pid_foreach(ap, 0, reply, &rindex, pid_not_equal, cons_pid) < 0)
    return -1;

  ALCOVE_ERR(alcove_encode_empty_list(reply, rlen, &rindex));

  return rindex;
}

static int count_pid(alcove_state_t *ap, alcove_child_t *c, void *arg1,
                     void *arg2) {
  size_t *n = arg1;

  UNUSED(ap);
  UNUSED(c);
  UNUSED(arg2);

  *n += 1;
  return 1;
}

static int cons_pid(alcove_state_t *ap, alcove_child_t *c, void *arg1,
                    void *arg2) {
  char *buf = arg1;
  int *index = arg2;

  UNUSED(ap);

  if (ei_encode_list_header(buf, index, 1) < 0)
    return -1;

  if (ei_encode_tuple_header(buf, index, 8) < 0)
    return -1;

  if (ei_encode_atom(buf, index, "alcove_pid") < 0)
    return -1;

  if (ei_encode_long(buf, index, c->pid) < 0)
    return -1;

  if (ei_encode_long(buf, index, c->flowcontrol) < 0)
    return -1;

  if (ei_encode_long(buf, index, c->signaloneof) < 0)
    return -1;

  if (ei_encode_long(buf, index, c->fdctl) < 0)
    return -1;

  if (ei_encode_long(buf, index, c->fdin) < 0)
    return -1;

  if (ei_encode_long(buf, index, c->fdout) < 0)
    return -1;

  if (ei_encode_long(buf, index, c->fderr) < 0)
    return -1;

  return 1;
}