#!/bin/bash
# license: gpl-3

show_help="conn: a quick and dirty server availability check

usage:
  "$0" <args> [IP(s)/hostname(s)]

arguments:
  -h / --help       show help page (this)
  -6 / --force-ipv6 force ipv6 portscanning (also forces portscanning)
  -4 / --force-ipv4 force ipv4 portscanning (also forces portscanning)
  -y / --yes        portscan without asking
  -n / --no         dont portscan
  -w / --wait       wait for active connection
  -u / --update     update the script
  -f / --fast       disable os check
  -s / --simple     simplify output"

function check_update {
  if [[ $(curl -s https://raw.githubusercontent.com/byReqz/conn/main/hash) != $(md5sum $0 | cut -c -32) ]] && [[ -z $1 ]] || [[ $(curl -s https://raw.githubusercontent.com/byReqz/conn/main/hash) != $(md5sum $0 | cut -c -32) ]] && [[ $1 != "--update" ]] || [[ $(curl -s https://raw.githubusercontent.com/byReqz/conn/main/hash) != $(md5sum $0 | cut -c -32) ]] && [[ $1 != "-u" ]];then
    echo "#############################################"
    echo -e "\e[4mnote: newer version detected, use -u to update\e[0m"
    echo "#############################################"
    echo ""
  fi
}

function run_update {
  if [[ $(curl -s https://raw.githubusercontent.com/byReqz/conn/main/hash) != $(md5sum $0 | cut -c -32) ]];then
    wget -O $0 --quiet "https://raw.githubusercontent.com/byReqz/conn/main/conn.sh"
    echo "#############################################"
    echo -e "\e[4mscript has been updated to the newest version\e[0m"
    echo "#############################################"
    exit
  elif [[ $(curl -s https://raw.githubusercontent.com/byReqz/conn/main/hash) = $(md5sum $0 | cut -c -32) ]];then
    echo "#############################################"
    echo "no newer version found"
    echo "#############################################"
    exit
  fi
}

function prepare {
  check_update
  get_args "$@"
  set_argvars $args
  validate $input
}

function get_args {
  input=$(echo " $@")
  args=$(echo "$input" | grep -o -e "-h" -e "--help" -e "-6" -e "--force-ipv6" -e "-4" -e "--force-ipv4" -e "-y" -e "--yes" -e "-n" -e "--no" -e "-w" -e "--wait" -e "-u" -e "--update" -e "-f" -e "--fast" -e "-s" -e "--simple" | xargs)
  for arg in $args; do
    input=$(echo "$input" | sed "s/$arg//g")
  done

  #quick fix to prevent nslookups interactive mode being triggered by invalid arguments
  #some other places in the code have also gotten a leading space to prevent similar issues
  input=$(echo "$input" | tr -d "-")
}

function set_argvars {
  if [[ $@ =~ -6 ]] || [[ $@ =~ --force-ipv6 ]];then
    only="-6"
  fi
  if [[ $@ =~ -4 ]] || [[ $@ =~ --force-ipv4 ]];then
    only="-4"
  fi
  if [[ $@ =~ -y ]] || [[ $@ =~ --yes ]];then
    doportscan=true
  fi
  if [[ $@ =~ -n ]] || [[ $@ =~ --no ]];then
    doportscan=false
  fi
  if [[ $@ =~ -s ]] || [[ $@ =~ --simple ]];then
    simpleoutput=true
  fi
  if [[ $@ =~ -w ]] || [[ $@ =~ --wait ]];then
    waitcheck=true
  fi
  if [[ $@ =~ -f ]] || [[ $@ =~ --fast ]];then
    oscheck=false
  fi
}

function validate {
  for arg in $@; do
    if [[ ! "$arg" =~ : ]];then
      arg=" $arg" # fixes issue with leading space on ipv6 adresses
    else
      only="-6" # enable ipv6, this needs a more complex function to avoid treating every argument as v6
    fi
    if ip route show "$arg" 2&> /dev/null;then
      hosts="$hosts $arg"
    elif nslookup "$arg" > /dev/null;then
      hosts="$hosts $arg"
    else
      echo "invalid input: $arg"
    fi
  done
}

function main {
  if [[ $simpleoutput == true ]] && [[ -n $hosts ]];then
    echo "-------------------Availability----------------------"
    fping $only -e $@
    if [[ $oscheck != "false" ]];then
      echo ""
      for host in $@;do
        linuxping=$(nping $only -c1 -p22,222 "$host")
        if [[ -n $(echo "$linuxping" | grep -e "Successful connections: 1") ]];then
          echo "$host seems to be booted into a Linux system"
        elif [[ -n $(echo "$linuxping" | grep -e "Successful connections: 2") ]];then
          echo "$host seems to be booted into the rescue system"
        fi
        winping135=$(nping $only -c1 -p135 "$host")
        winping3389=$(nping $only -c1 -p3389 "$host")
        if [[ -n $(echo "$winping135" | grep -e "Successful connections: 1") ]] && [[ -n $(echo "$winping3389" | grep -e "Successful connections: 1") ]];then
          echo "$host seems to be booted into Windows"
        elif [[ -z $(fping $only -a $host) ]] && [[ -n $(echo "$winping3389" | grep -e "Successful connections: 1") ]];then
          echo "$host seems to be booted into (desktop) Windows"
        fi
    done
    fi
    echo "-----------------------------------------------------"
  else
    for host in $hosts;do
      if [[ $waitcheck == true ]];then
        echo "-w used, waiting for active connection"
        echo "checking connection status for $host"
        fping=$(fping $only -a $host)
        if [[ ! $oscheck == false ]];then
          p135=$(nping $only -q1 -c1 -p135 $host)
          p3389=$(nping $only -q1 -c1 -p3389 $host)
        fi
        if [[ $fping != "$host" ]] && [[ -n $(echo $p135 | grep "Successful connections: 1") ]] || [[ $fping != "$host" ]] && [[ -n $(echo $p3389 | grep "Successful connections: 1") ]];then
          echo "-------------------Availability----------------------"
          echo "note: this seems to be a windows machine which does not respond to ICMP"
          notify-send "$host is now reachable" "and seems to be a windows machine" -u normal -t 30000 -a conn
          echo "-----------------------------------------------------"
        elif [[ $fping = "$host" ]] && [[ -n $(echo $p135 | grep "Successful connections: 1") ]];then
          echo "-------------------Availability----------------------"
          echo "note: this seems to be a windows machine which does respond to ICMP"
          fping -e $host
          notify-send "$host is now reachable" "and seems to be a windows machine" -u normal -t 30000 -a conn
          echo "-----------------------------------------------------" 
        else
          while [[ "$(fping $only -m -q -u $host)" == "$host" ]]; do :
            done
          echo "-------------------Availability----------------------"
          fping -e $host
          if [[ ! $oscheck == false ]];then
            rescue=$(nping $only -q1 -c1 -p22,222 $host)
          fi
          if [[ -n $(echo $rescue | grep "Successful connections: 1") ]];then
            echo "note: this seems to be a linux machine"
            notify-send "$host is now reachable" "and seems to be in a linux system" -u normal -t 30000 -a conn
          elif [[ -n $(echo $rescue | grep "Successful connections: 2") ]];then
            echo "note: this machine seems to be in the rescue system"
            notify-send "$host is now reachable" "and seems to be in the rescue system" -u normal -t 30000 -a conn
          elif [[ -n $(echo $p135 | grep "Successful connections: 1") ]] || [[ -n $(echo $p3389 | grep "Successful connections: 1") ]];then
            echo "note: this machine seems to be booted into windows"
            notify-send "$host is now reachable" "and seems to be booted into windows" -u normal -t 30000 -a conn
          else
            notify-send "$host is now reachable" -u normal -t 30000 -a conn
          fi
          echo "-----------------------------------------------------"
        fi
      else
        echo "checking connection status for $host"
        fping=$(fping $only -a $host)
        if [[ ! $oscheck == false ]];then
          p135=$(nping $only -q1 -c1 -p135 $host)
          p3389=$(nping $only -q1 -c1 -p3389 $host)
        fi
        if [[ $fping != "$host" ]] && [[ -n $(echo $p135 | grep "Successful connections: 1") ]] || [[ $fping != "$host" ]] && [[ -n $(echo $p3389 | grep "Successful connections: 1") ]];then
          echo "-------------------Availability----------------------"
          echo "note: this seems to be a windows machine which does not respond to ICMP"
          echo "-----------------------------------------------------"
        elif [[ $fping != "$host" ]] && [[ -z $(echo $p135 | grep "Successful connections: 1") ]] || [[ $fping != "$host" ]] && [[ -z $(echo $p3389 | grep "Successful connections: 1") ]];then
          echo "-------------------Availability----------------------"
          echo "$host is not reachable"
          echo "-----------------------------------------------------"
        else
          echo "-------------------Availability----------------------"
          fping $only -e $host
          if [[ ! $oscheck == false ]];then
            rescue=$(nping $only -q1 -c1 -p22,222 $host)
            if [[ -n $(echo $rescue | grep "Successful connections: 1") ]];then
              echo "note: this seems to be a linux machine"
            elif [[ -n $(echo $rescue | grep "Successful connections: 2") ]];then
              echo "note: this machine seems to be in the rescue system"
            elif [[ -n $(echo $p135 | grep "Successful connections: 1") ]] || [[ -n $(echo $p3389 | grep "Successful connections: 1") ]];then
              echo "note: this machine seems to be booted into windows"
            fi
          fi
          echo "-----------------------------------------------------"
        fi
      fi
      if [[ ! $doportscan == false ]];then
        if [[ $doportscan == true ]];then
          portscan=y
        else
          echo "portscan? (y/n) (default: y)"
          read portscan
        fi
        if [[ "$portscan" = "y" ]] || [[ -z "$portscan" ]]; then
          echo "-------------------Portscan---------------------"
          nmap $only --reason -Pn $host
          echo ""
          fping $only -c 4 $host
          echo "------------------------------------------------"
          echo ""
        else
          echo ""
        fi
      fi
    done
  fi
}

if [[ -n $1 ]];then
  prepare "$@"
  main "$hosts"
elif [[ "$1" == "-u" ]];then
  run_update
elif [[ "$1" == "-h" ]];then
  check_update
  echo "$show_help"
else
  check_update
  echo "$show_help"
fi