/*
   * Copyright (C) 2015 Engineering-Spirit
   *
   * This file is subject to the terms and conditions of the GNU Lesser
   * General Public License v2.1. See the file LICENSE in the top level
   * directory for more details.
   */
  
  /**
   * @ingroup     examples
   * @{
   *
   * @file
   * @brief       Demonstrating the sending and receiving of data via the TFTP client
   *
   * @author      Nick van IJzendoorn <nijzendoorn@engineering-spirit.nl>
   *
   * @}
   */
  
  #include <stdio.h>
  #include <string.h>
  #include <inttypes.h>
  
  #include "net/gnrc/tftp.h"
  
  static const char *_tftp_default_host = "::1";
  
  /* default server text which can be received */
  static const char _tftp_client_hello[] = "Hello,\n"
                                           "\n"
                                           "Client text would also need to exist to be able to put data.\n"
                                           "\n"
                                           "Enjoy the RIOT-OS\n";
  
  static tftp_action_t _tftp_action;
  
  /**
   * @brief called at every transaction start
   */
  static bool _tftp_client_start_cb(tftp_action_t action, tftp_mode_t mode,
                                    const char *file_name, size_t *len)
  {
      /* translate the mode */
      const char *str_mode = "ascii";
  
      if (mode == TTM_OCTET) {
          str_mode = "bin";
      }
      else if (mode == TTM_MAIL) {
          str_mode = "mail";
      }
  
      /* translate the action */
      const char *str_action = "read";
      if (action == TFTP_WRITE) {
          str_action = "write";
      }
  
      /* display the action being performed */
      printf("tftp_client: %s %s %s:%lu\n", str_mode, str_action, file_name, (unsigned long)*len);
  
      /* return the length of the text, if this is an read action */
      if (action == TFTP_READ) {
          *len = sizeof(_tftp_client_hello);
      }
  
      /* remember the action of the current transfer */
      _tftp_action = action;
  
      /* we accept the transfer to take place so we return true */
      return true;
  }
  
  /**
   * @brief called to get or put data, depending on the mode received by `_tftp_start_cb(action, ...)`
   */
  static int _tftp_client_data_cb(uint32_t offset, void *data, size_t data_len)
  {
      char *c = (char *) data;
  
      /* if we are reading return the part of the data that is being requested */
      if (_tftp_action == TFTP_WRITE) {
          /* calculate the length of the data block to transfer */
          if (offset + data_len > sizeof(_tftp_client_hello)) {
              data_len -= (offset + data_len) - sizeof(_tftp_client_hello);
          }
  
          /* copy the block to the output buffer */
          memcpy(data, _tftp_client_hello + offset, data_len);
      }
      else {
          /* we received a data block which we output to the console */
          printf("\n -- CLIENT DATA --\n%.*s\n -- CLIENT DATA --\n", (int)data_len, c);
      }
  
      /* return the length of the data block */
      return data_len;
  }
  
  /**
   * @brief the transfer has stopped, see the event argument to determined if it was successful
   *        or not.
   */
  static void _tftp_client_stop_cb(tftp_event_t event, const char *msg)
  {
      /* decode the stop event received */
      const char *cause = "UNKOWN";
  
      if (event == TFTP_SUCCESS) {
          cause = "SUCCESS";
      }
      else if (event == TFTP_PEER_ERROR) {
          cause = "ERROR From Client";
      }
      else if (event == TFTP_INTERN_ERROR) {
          cause = "ERROR Internal Server Error";
      }
  
      /* print the transfer result to the console */
      printf("tftp_client: %s: %s\n", cause, msg);
  }
  
  static int _tftp_client_cmd(int argc, char * *argv)
  {
      ipv6_addr_t ip;
      const char *file_name = argv[2];
      tftp_mode_t mode = TTM_OCTET;
      bool use_options = true;
  
      ipv6_addr_from_str(&ip, _tftp_default_host);
  
      if (argc >= 3 && argc <= 6) {
          /* decode the action */
          if (strcmp(argv[1], "get") == 0) {
              _tftp_action = TFTP_READ;
          }
          else if (strcmp(argv[1], "put") == 0) {
              _tftp_action = TFTP_WRITE;
          }
          else {
              return -1;
          }
  
          /* get the transfer mode */
          if (argc >= 4) {
              if (strcmp(argv[3], "octet") == 0) {
                  mode = TTM_OCTET;
              }
              else if (strcmp(argv[3], "ascii") == 0) {
                  mode = TTM_ASCII;
              }
              else if (strcmp(argv[3], "mail") == 0) {
                  mode = TTM_MAIL;
              }
              else {
                  puts("tftp: couldn't parse the TFTP transfer mode");
                  return -1;
              }
          }
  
          /* decode if we must use the TFTP option extension or not */
          if (argc >= 5) {
              if (strcmp(argv[4], "0") == 0) {
                  use_options = false;
              }
              else if (strcmp(argv[4], "1") == 0) {
                  use_options = true;
              }
              else {
                  puts("tftp: invalid options choose 0 or 1");
                  return -1;
              }
          }
  
          /* decode the address */
          if (argc >= 6) {
              if (!ipv6_addr_from_str(&ip, argv[5])) {
                  puts("tftp: invalid IP address");
                  return -1;
              }
          }
      }
      else {
          return -1;
      }
  
      if (_tftp_action == TFTP_READ) {
          puts("tftp: starting read request");
  
          gnrc_tftp_client_read(&ip, file_name, mode, _tftp_client_data_cb,
                                _tftp_client_start_cb, _tftp_client_stop_cb, use_options);
      }
      else if (_tftp_action == TFTP_WRITE) {
          puts("tftp: starting write request");
  
          gnrc_tftp_client_write(&ip, file_name, mode, _tftp_client_data_cb,
                                 sizeof(_tftp_client_hello), _tftp_client_stop_cb, use_options);
      }
  
      return 0;
  }
  
  /**
   * @brief start the TFTP server by creating a thread
   */
  int tftp_client_cmd(int argc, char * *argv)
  {
      if (_tftp_client_cmd(argc, argv) < 0) {
          printf("usage: %s <action[get|put]> <file_name> <mode[ascii | octet(default) | mail]>\n"
                 "\t<use_options[1 (default) | 0]> <addr(default: ::1)>\n", argv[0]);
      }
  
      return 0;
  }