/**
 * A program to execute automation when a socket is unreachable
 * Copyright (C) 2022  Aaron Ball <nullspoon@oper.io>
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
#include <stdio.h>
#include <string.h>

#include "net.h"
#include "runconfig.h"

void usage() {
  fputs(
    "Usage:\n"
    "  react-tcp-down --ip <host_ip> --port <port> --cmd <command>\n\n"
    "Arguments:\n"
    "  -i,--ip    IP Address to check for port availability\n"
    "  -p,--port  Port to check\n"
    "  -c,--cmd   Command to run if port is down\n"
    "  -h,--help  Print this help text\n"
  , stderr);
}

int parse_args(struct runconfig* cfg, int argc, char* argv[]) {
  int i = 0;
  int status = 0;
  while(i < argc) {
    if(strcmp(argv[i], "--help") == 0 || strcmp(argv[i], "-h") == 0) {
      usage();
      return 1;
    } else if(strcmp(argv[i], "--ip") == 0 || strcmp(argv[i], "-i") == 0) {
      i++;
      strcpy(cfg->ip, argv[i]);

    } else if(strcmp(argv[i], "--port") == 0 || strcmp(argv[i], "-p") == 0) {
      i++;
      cfg->port = strtol(argv[i], NULL, 10);

    } else if(strcmp(argv[i], "--cmd") == 0 || strcmp(argv[i], "-c") == 0) {
      i++;
      strncpy(cfg->cmd, argv[i], RUNCONFIG_CMD_MAX);
      cfg->cmd[RUNCONFIG_CMD_MAX - 1] = '\0';
    }
    i++;
  }

  if(cfg->ip[0] == '\0') {
    fputs("Host IP address required (--ip, -i)\n", stderr);
    status = -1;
  } else if(cfg->port <= 0 || cfg->port > 65535) {
    fputs("Valid port required (--port, -p)\n", stderr);
    status = -1;
  } else if(cfg->cmd[0] == '\0') {
    fputs("Command to execute on port down required (--cmd,-c)\n", stderr);
    status = -1;
  }

  return status;
}

int main(int argc, char* argv[]) {
  struct runconfig cfg;

  runconfig_init(&cfg);
  if(parse_args(&cfg, argc, argv) != 0)
    return 1;

  if(net_tcp_is_up(cfg.ip, cfg.port) == -1)
    system(cfg.cmd);
  return 0;
}