/****************************************************************************
 * apps/netutils/netlib/netlib_getifstatistics.c
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.  The
 * ASF licenses this file to you 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.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <debug.h>

#include <sys/types.h>

#include "netutils/netlib.h"

#ifdef CONFIG_NETDEV_STATISTICS

/****************************************************************************
 * Pre-processor Definitions
 ****************************************************************************/

/* Determines the size of an intermediate buffer that must be large enough
 * to handle the longest line generated by this logic.
 */

#define PROCFS_LINELEN   80
#define PROCFS_NET_PATH "/proc/net/"

/* The form of the entry from the netstat file:
 *
 * wlan0   Link encap:Ethernet HWaddr 42:37:46:02:16:07 at UP mtu 1500
 *         inet addr:10.0.1.2 DRaddr:10.0.1.1 Mask:255.255.255.0
 *         inet6 DRaddr: ::
 *
 *         RX: Received Fragment Errors   Bytes
 *             000008c1 00000000 00000000 331ca8
 *             IPv4     IPv6     ARP      Dropped
 *             000008a7 00000018 00000002 00000000
 *         TX: Queued   Sent     Errors   Timeouts Bytes
 *             00000973 00000973 00000000 00000000 1b8d3
 *         Total Errors: 00000000
 */

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: netlib_getifstatistics
 *
 * Description:
 *   Read the DEV RX/TX statistics.
 *
 * Input Parameters:
 *   ifname - The interface to read.
 *   stat   - The pointer to return dev statistics.
 *
 * Returned Value:
 *   0 on success. A negated errno value is returned
 *   on any failure.
 ****************************************************************************/

int netlib_getifstatistics(FAR const char *ifname,
                           FAR struct netdev_statistics_s *stat)
{
  FAR FILE *stream;
  char path[32];
  char line[PROCFS_LINELEN];
  int ret = OK;

  snprintf(path, sizeof(path), "%s%s", PROCFS_NET_PATH, ifname);
  ninfo("get statistics from %s \n", path);

  stream = fopen(path, "r");
  if (stream == NULL)
    {
      fprintf(stderr, "ERROR: Failed to open path:%s \n", path);
      return -ENOTDIR;
    }

  while (fgets(line, sizeof(line), stream) != NULL)
    {
      /*  Read RX header and next is the data */

      if (strstr(line, "RX:") != NULL)
        {
          if (fgets(line, sizeof(line), stream) == NULL)
            {
              ret = -EINVAL;
              break;
            }

          if (sscanf(line, "%" SCNx32 "%" SCNx32 "%" SCNx32 "%" SCNx64,
                     &stat->rx_packets,
                     &stat->rx_fragments,
                     &stat->rx_errors,
                     &stat->rx_bytes) <= 0)
            {
              ret = -EINVAL;
              break;
            }
        }

      /*  Read TX header and next is the data */

      if (strstr(line, "TX:") != NULL)
        {
          if (fgets(line, sizeof(line), stream) == NULL)
            {
              ret = -EINVAL;
              break;
            }

          if (sscanf(line, "%" SCNx32 "%" SCNx32 "%" SCNx32 \
                     "%" SCNx32 "%" SCNx64,
                     &stat->tx_packets,
                     &stat->tx_done,
                     &stat->tx_errors,
                     &stat->tx_timeouts,
                     &stat->tx_bytes) <= 0)
            {
              ret = -EINVAL;
              break;
            }
        }
    }

  fclose(stream);
  return ret;
}

#endif /* CONFIG_NETDEV_STATISTICS */