#!/usr/bin/env bash

# Written by Eric Ma (https://www.ericzma.com)

# For an introduction and how to use ths tool, please check
# https://www.systutorials.com/turning-gnome-terminal-to-a-pop-up-terminal/

# Required tools: xdotool

terminal="gnome-terminal"
termtype="Terminal"
maxterm=false
wait_sec=1
max_wait_cnt=4
slot=0

usage() {
  echo "$0 [--terminal <terminal cmd> --maximize <true or false> --slot <slot id>]"
}

# parse options first
while (($# > 1)); do
  key=$1
  shift
  case "$key" in
    --terminal)
      terminal=$1
      shift
      ;;
    --slot)
      slot=$1
      shift
      ;;
    --maximize)
      maxterm=$1
      shift
      ;;
    *)
      ;;
  esac
done

# assign values
stat_file="/dev/shm/actiavte-termianl.term.$USER.${slot}"

term_exists () {
  allterms=`xdotool search --class "$termtype"`
  for e in $allterms; do [[ "$e" == "$1" ]] && return 0; done
  return 1
}

create_terminal () {
  echo "Create new terminal"
  if [[ "${maxterm}" == "true" ]]; then
    $terminal --maximize &
  else
    $terminal &
  fi

  exists=1
  wait_cnt=0
  until [ "$exists" == "0" ]; do
    # sleep a while
    sleep $wait_sec

    # Note that the focus window may be from a terminal that
    # already exists; the makes create_terminal choose the existing terminal
    # Making the wait_sec large enough so that the terminal can be created and
    # displayed can make the false choosing more unlikely.

    term=$(xdotool getwindowfocus)
    term_exists "$term"
    exists=$?
    # avoid infinite wait
    let wait_cnt=wait_cnt+1
    if [ $wait_cnt -gt $max_wait_cnt ]; then
      echo "Wait for too long. Give up."
      term=""
      exists=0
    fi
  done

  echo "Created terminal window $term for slot $slot ."
  # save the state
  echo "$term" >$stat_file
}

# read the state
if [ -f $stat_file ]; then
  term=$(cat $stat_file)
fi

# check whether it exists
term_exists "$term"
exists=$?
if [[ "$exists" != "0" ]]; then
  create_terminal
  exit 0
fi

# check whether it is already activated
curwin=$(xdotool getwindowfocus)

if [ "$term" == "$curwin" ]; then
  # deactivate (minimize) the terminal if it is currently activated
  xdotool windowminimize $curwin
else
  # activate the terminal if it is not currently activated
  xdotool windowactivate $term
fi

exit 0