#!/bin/bash

CONFDIR="$HOME/.config/ssh-tunnelier"
CONF="$CONFDIR/config"
MAGIC_TIME=873749328

function _helpexit() {
  echo "SSH tunnel manager
Runs and monitors preconfigured background ssh tunnels, with the ability
to kill existing ssh processes. You don't need to keep the program on
to remember connected sessions.

Configuration stored in: $CONF

If run with arguments, runs an ssh tunnel with arguments:
  ssh-tunnelier hostname [local-port] remote-port
  
If local port missing, the same port assumed in local
"
  exit 0
}

for (( i=1; i<=$#; i++ )); do 
  [[ ${!i} = "-h" ]] && _helpexit
  [[ ${!i} = "--help" ]] && _helpexit
done

[[ -f "$CONF" ]]  || {
  echo No config file.
  echo "$CONF" each line like:
  echo -L 8888:localhost:8888 servername
  mkdir -p "$CONFDIR"
  echo -e "# example:\n -L 8888:localhost:8888 servername" > "$CONF"
}
number_re='^[0-9]+$'

colZ="\033[0m"
colTitle="\033[0;1;32m"
colRow="\033[0;1m"
colMenu="\033[0;33m"
colWarn="\033[0;1;31m"

function fpgrep() { 
  pgrep -x -u $UID "$@" | xargs --no-run-if-empty ps -o pid,bsdstart,args; 
  test ${PIPESTATUS[0]} -ne 0 && echo '----'
}

function get_id() {
  id=$( printf "%s" "$line" | base64 -w 0 )
  echo -n $id
}

function get_command() {
  switches=$( echo "$1" | base64 -d )
  echo -n "ssh -f -n $switches \"sleep $MAGIC_TIME; echo tunneler $1\""
}

function get_pid() {
  pgrep -f "$MAGIC_TIME.*echo tunneler $1" | head -n 1
}

function list_all_ssh() {
  printf "\n${colTitle}=============================================\n"
  printf "${colTitle}                List of SSH:${colZ}\n"
  printf "${colTitle}Enter PID to kill, empty to return $colZ\n"
  printf "${colTitle}Outgoing SSH processes\n"
  printf "${colTitle}=============================================\n${colRow}"
  fpgrep ssh 
  printf "${colTitle}Incoming SSH processes\n"
  printf "${colTitle}=============================================\n${colRow}"
  fpgrep sshd 
  read -t 600 inputpid

  [[ "$inputpid" =~ $number_re ]] && {
    ask_to_kill $inputpid
  }
}

function read_config() {
  while read line; do
    id=$( get_id "$line" )
    pid=$( get_pid "$id" )
    printf "%-3d %-7s %s\n" $i "$pid" "$line"
    ids+=( $id )
    i=$(( i + 1 ))
  done < <( grep -v ^# "$CONF" | grep '[a-zA-Z]' )
}

function run_args() {
    HOST="$1"
    LOCAL="$2"
    REMOTE="$3"
    [[ -z "$REMOTE" ]] && REMOTE="$LOCAL"
    echo Connect to $HOST
    ssh -f -n -L "${LOCAL}:localhost:${REMOTE}" "$HOST" "sleep $MAGIC_TIME"
}

function run_command() {
  eval $( get_command "$1" )
}

function ask_to_kill() {
  printf "${colRow}\nPID: $1\n  k kill\n  t terminate${colZ}\n"
  read -t 600 input2
  [[ "$input2" = "k" ]] && kill $1
  [[ "$input2" = "t" ]] && kill -9 $1
}


[[ -n "$2" ]] && { 
    run_args "$@"
}

while true; do
  ids=()
  i=1
  printf "\n${colTitle}=============================================\n"
  printf "${colTitle}              List of tunnels:${colZ}\n" 
  printf "${colTitle} (q)uit (e)dit (l)ist ssh             [%s]${colZ}\n" $( date +%H:%M )
  printf "${colTitle}=============================================\n"
  printf "${colRow}ID  PID     command\n"
  read_config
  printf "$colZ"
  read -t 600 input

  [[ "$input" = "q" ]] && exit 0
  [[ "$input" = "e" ]] && vim "$CONF"
  [[ "$input" = "l" ]] && list_all_ssh
  [[ "$input" = "0" ]] && continue
  [[ "$input" =~ $number_re ]] && {
    j=$(( $input - 1 ))
    [[ $j -gt $(( $i - 1 )) ]] && { 
        printf  "${colWarn}No such tunnel number${colZ}\n"
        continue
    }
    
    printf "\n${colTitle}Tunnel command: %s${colZ}\n" "$( echo  "${ids[$j]}" | base64 -d )" 
    this_pid="$( get_pid "${ids[$j]}" )"
    [[ -n "$this_pid" ]] && {
	  # PID exists, ask to kill
	  ask_to_kill "$this_pid"
  	}
    [[ -z "$this_pid" ]] && {
	  # PID empty, run
      run_command "${ids[$j]}"
      sleep 1
    }
  }
done