#!/bin/bash
# What action to take on closing the laptop lid,
# depending on whether a screen is attached or not.
# This implies setting HandleLidSwitch=ignore in /etc/systemd/logind.conf
# Call this script from /etc/acpi/handler.sh (or other properly set up script
# for handling button/lid acpi event) with parameter 0 and 1 for close and open respectively

set -e -u

# Find current Xsession user through loginctl list-sessions (excluding lightdm)
# TODO: make available for desktop manager, too!
declare x_user="$(loginctl list-sessions --no-legend| sed -e 's/\s\{2,\}/ /g;s/^[[:space:]]*//' | \
  cut -d ' ' -f 3| grep -v "lightdm"|uniq)"

# Fail if there is no user set
if [ -z "$x_user" ]; then
  echo "error no user!"
  exit 1
fi

# Export Xorg DISPLAY and XAUTHORITY
# TODO: Get number of X DISPLAY from tmp
#declare x_display="/tmp/.X11-unix/X*"
export DISPLAY=:0
export XAUTHORITY=/home/$x_user/.Xauthority

# Define the log file
declare log="/home/$x_user/.cache/$(basename $0)"
if [[ ! -w "$log" ]]; then
  touch "$log"
  chown ${x_user}:${x_user} "$log"
#  exec > "$log" 2>&1
fi

declare -a arguments=( )
declare -a connections=( )
declare -a active_connections=( )
declare -a available_connections=( )
declare -a non_primary=( "eDP1" )
declare -a pan=( "DP2-1" "eDP1" )
declare -a pan_vertical=( 'empty' 'empty' ) # with empty placeholders!
declare internal="eDP1"
declare current_primary=""
declare action=""

# declare keywords (xrandr arguments)
declare pre_output=" --output "
declare post_auto=" --auto "
declare post_primary=" --primary "
declare post_pos_rightof=" --right-of"
declare post_pos_leftof=" --left-of"
declare post_off=" --off "

function setup_xscreen()
{
  local outputs=( )
  local connection_counter=0
  case "$action" in
    "open")
      if [ ${#available_connections[@]} -gt 1 ]; then
        for connection in ${pan[@]}
        do
          echo "$connection" >> $log
          set +e
          find_component_in "$connection" ${available_connections[@]}
          if [ $? -eq 0 ]; then
            echo "$connection is amongst the available outputs." >> $log
            # adding --output argument
            outputs=( ${outputs[@]:+${outputs[@]}} "$pre_output" )
            # adding name of output
            outputs=( ${outputs[@]:+${outputs[@]}} "$connection" )
            # check whether output should not be primary in a multi output setup
            find_component_in "$connection" ${non_primary[@]}
            if [ $? -eq 0 ]; then
              echo "$connection is setup for non-primary." >> $log
            else
              echo "$connection is NOT setup for non-primary." >> $log
              # adding --primary argument
              outputs=( ${outputs[@]:+${outputs[@]}} "$post_primary" )
            fi
            if [ $connection_counter -gt 0 ]; then
              # adding a --right-of <connection before this one> argument
              outputs=( ${outputs[@]:+${outputs[@]}} "$post_pos_rightof" "${pan[$((connection_counter-1))]}" )
            fi
            # adding --auto argument
            outputs=( ${outputs[@]:+${outputs[@]}}"$post_auto" )
            connection_counter=$(( $connection_counter + 1 ))
          fi
          set -e
        done
      fi
      ;;
    "close")
      if [ ${#available_connections[@]} -gt 1 ]; then
        for connection in ${pan[@]}
        do
          echo "$connection" >> $log
          set +e
          find_component_in "$connection" ${available_connections[@]}
          if [ $? -eq 0 ]; then
            echo "$connection is amongst the available outputs." >> $log
            # adding --output argument
            outputs=( ${outputs[@]:+${outputs[@]}} "$pre_output" )
            # adding name of output
            outputs=( ${outputs[@]:+${outputs[@]}} "$connection" )
            # if the connection is not the internal output
            if [ $connection != $internal ]; then
              # check whether output should not be primary in a multi output setup
              find_component_in "$connection" ${non_primary[@]}
              if [ $? -eq 0 ]; then
                echo "$connection is setup for non-primary." >> $log
              else
                echo "$connection is NOT setup for non-primary." >> $log
                # adding --primary argument
                outputs=( ${outputs[@]:+${outputs[@]}} "$post_primary" )
              fi
              if [ $connection_counter -gt 0 ]; then
                # adding a --right-of <connection before this one> argument
                outputs=( ${outputs[@]:+${outputs[@]}} "$post_pos_rightof" "${pan[$((connection_counter-1))]}" )
              fi
              # adding --auto argument
              outputs=( ${outputs[@]:+${outputs[@]}}"$post_auto" )
              connection_counter=$(( $connection_counter + 1 ))
            else
              # adding a --off argument for the interal screen
              outputs=( ${outputs[@]:+${outputs[@]}} "$post_off" )
            fi
          fi
          set -e
        done
      fi
      ;;
  esac
echo "Calling: xrandr ${outputs[@]}" >> $log
xrandr ${outputs[@]}
}

function find_component_in()
{
  local -r component=$1
  shift
  local value
  for value in "$@"
  do
    [[ $value == "$component" ]] && return 0
  done
  return 1
}

function get_current_x_information()
{
  # get current xrandr settings
  current_xrandr=$(xrandr)
  # get current primary output from xrandr
  current_primary=$(echo "$current_xrandr" | \
  grep -wE '(\bconnected.*primary.*[0-9]{1,5}\x[0-9]{1,5}\+[0-9]{1,5}\+[0-9]{1,5})' | \
  cut -d ' ' -f 1)
  echo "Current primary output: $current_primary" >> $log
  # get all current active connections
  active_connections=( "${active_connections[@]:+${active_connections[@]}}" $(echo "$current_xrandr" | \
  grep -wE '(\bconnected.*[0-9]{1,5}\x[0-9]{1,5}\+[0-9]{1,5}\+[0-9]{1,5})' | cut -d ' ' -f 1) )
  echo "Current active connections: ${active_connections[@]}" >> $log
  # get all currently available connections
  available_connections=( "${available_connections[@]:+${available_connections[@]}}" $(echo "$current_xrandr" | \
  grep -wE '(\bconnected.*)' | cut -d ' ' -f 1) )
  echo "Currently available connections: ${available_connections[@]}" >> $log
  # get all available connections
  connections=( "${connections[@]:+${connections[@]}}" $(echo "$current_xrandr"| grep -v 'Screen' | cut -d ' ' -f 1))
  echo "All current connections: ${connections[@]}" >> $log
}

function get_action()
{
  arguments=( "${arguments[@]:+${arguments[@]}}" "${@:+$@}" )
#  echo "${@:+$@}" >> $log
#  echo "${arguments[@]:+${arguments[@]}}" >> $log
  if [ ${#arguments[@]} -gt 0 ];then
    if [ "${arguments[0]}" = "button/lid" ]; then
      case "${arguments[2]}" in
        "open")
          action="open"
          ;;
        "close")
          action="close"
          ;;
      esac
    elif [ "${arguments[0]}" = "login" ]; then
      action="open"
    fi
  fi
  echo "Action set: $action" >> $log
}

# pass arguments to the script to the get_action function
get_action "${@:+$@}"
get_current_x_information
setup_xscreen