#!/bin/bash

# Borrowed from:
# - http://bytefreaks.net/gnulinux/bash/howto-make-terminator-terminal-act-like-guake-terminal-in-fedora-20ubuntu-14-10

# The purpose of this script is to allow the user to toggle the visibility of
# (almost) any window.  Please note it will work on the first match, so if there
# are multiple instances of an application it would be a random window of them
# the one to be affected.

# Only checks dependencies on request to keep toggling behavior as fast as
# possible.
if [ "$1" == "--install-deps" ]; then
  # Checking that all dependencies are met, since we cannot proceed without
  # them.
  DEPENDENCIES=("xdotool" "wmctrl")
  MANAGERS=("yum" "apt-get")

  echo "Checking dependencies:"
  for DEPENDENCY in ${DEPENDENCIES[@]}; do
    if hash $DEPENDENCY 2>/dev/null; then
      echo "- $DEPENDENCY: ok"
    else
      echo "- $DEPENDENCY: not found"
      for MANAGER in ${MANAGERS[@]}; do
        if hash $MANAGER 2>/dev/null; then
          echo -n "$DEPENDENCY is missing, would you like to try and install " \
               "it via $MANAGER now? [Y/N] (default is Y): "
          read ANSWER
          if [[ "$ANSWER" == "Y" || "$ANSWER" == "y" || "$ANSWER" == "" ]]; then
            sudo "$MANAGER" install "$DEPENDENCY"
          else
            echo "Terminating"
            exit -1
          fi
        fi
      done
    fi
  done

  exit 0
fi

if [ "$1" == "-a" ]; then
  MOVE_TO="yes"
  shift 1
fi

APP_NAME="$1"

if [ -n "$2" ]; then
  APP_BIN="$2"
else
  APP_BIN="$APP_NAME"
fi

if [ -n "$3" ]; then
  WIN_NAME="$3"
else
  WIN_NAME="$APP_NAME"
fi

# Checking if the application name provided by the user exists
if ! command -v "$APP_BIN" 2>/dev/null; then
  echo -e "$APP_BIN does not seem to be a valid executable\nTerminating"
  exit -2
fi

# Check if a process matching APP_NAME exists, and in the case of multiple
# processes (for example Slack), limit it to the first process which has a
# window who's title matches WIN_NAME.
PID=""
for pid in $(pgrep "$APP_NAME"); do
  if xdotool search --all --onlyvisible --pid "$pid" --name "$WIN_NAME" &>/dev/null; then
    PID="$pid"
    break
  fi
done

# If the application is not running, we will try to launch it.
if [ -z "$PID" ]; then
  echo "$APP_NAME not running, launching it.."
  "$APP_BIN"
else
  # Since the application has a live instance, we can proceed with the rest of
  # the code.  We will get the PID of the application that is currently focused,
  # if it is not the application we passed as parameter we will change the focus
  # to that. In the other case, we will minimize the application.
  echo -n "$APP_NAME instance found - "
  FOCUSED="$(xdotool getactivewindow getwindowpid)"
  if [[ "$PID" == "$FOCUSED" ]]; then
    echo "It was focused so we are minimizing it"
    # We minimize the active window which we know in this case that it is the
    # application we passed as parameter.
    xdotool getactivewindow windowminimize
  else
    echo "We are setting the focus on it"
    # We set the focus to the application we passed as parameter. If it is
    # minimized it will be raised as well.
    if [ "$MOVE_TO" == "yes" ]; then
      xdotool search --all --onlyvisible --pid "$PID" --name "$WIN_NAME" \
              windowactivate
    else
      # This allows window name to be a regular expression
      WIN_TITLE="$(xdotool search --all --onlyvisible --pid "$PID" --name "$WIN_NAME" getwindowname)"
      wmctrl -R "$WIN_TITLE"
    fi
  fi
fi