#!/bin/bash

function show_usage()
{
  progname=`basename "$0"`
  echo "$progname [night|day|toggle]"
  echo "Without parameters it will set dark theme from $SUNSET to $SUNRISE"
  echo 'Use `xfce4-settings-editor` -> `night-mode` to modify settings'
}

function parse_args()
{
  case $# in
    0)
      _get_mode_by_time
      ;;
    1)
      echo "$1"
      ;;
    *)
      exit 1
  esac
}

function _get_mode_by_time()
{
  now=`date +"%H%M"`

  if [ $now -ge "${SUNRISE/:/}" -a $now -le "${SUNSET/:/}" ]; then
    echo 'day'
  else
    echo 'night'
  fi
}

function set_night_mode()
{
  current_theme=`xfconf-query --channel $2 --property $3`
  if ( _is_mode_already_set "$current_theme" "$1" ); then
    return
  fi

  new_theme=`_set_$1 "$current_theme" 2> /dev/null`
  if [ $? != 0 ]; then
    show_usage
    exit 1
  fi

  xfconf-query --channel $2 --property $3 --set "$new_theme"
}

function _is_mode_already_set()
{
  if ( _is_dark "$1" ) && [ "$2" = "night" ]; then
    exit 0
  fi
  if ! ( _is_dark "$1" ) && [ "$2" = "day" ]; then
    exit 0
  fi
  exit 1
}

function _set_toggle()
{
  if ( _is_dark "$1" ); then
    _set_day "$1"
  else
    _set_night "$1"
  fi
}

function _is_dark()
{
  echo "$1" | grep '\-dark$' > /dev/null
}

function _set_day()
{
  echo "${1%-dark}"
}

function _set_night()
{
  if ( _is_dark "$1" ); then
    echo "$1"
  else
    echo "$1-dark"
  fi
}

function get_config()
{
  result=`xfconf-query --channel 'night-mode' --property "/$1" 2> /dev/null`
  if ! [ "$result" ]; then
    result="$3"
    xfconf-query --channel 'night-mode' --property "/$1" --set "$result" --create --type "$2"
  fi

  echo "$result"
}

TEXT=`get_config 'text' 'string' '<span size="xx-large">&#x262F;</span>'`
SUNRISE=`get_config 'sunrise' 'string' '7:30'`
SUNSET=`get_config 'sunset' 'string' '18:00'`

mode=`parse_args $@`
if [ $? != 0 ]; then
  show_usage
  exit 1
fi

# GTK theme
set_night_mode $mode xsettings /Net/ThemeName

# Icon theme
set_night_mode $mode xsettings /Net/IconThemeName

# Window manager theme
# set_night_mode $mode xfwm4 /general/theme

echo "<txt>$TEXT</txt>"
echo "<txtclick>$0 toggle</txtclick>"
echo "<tool>
  Night mode: $SUNSET - $SUNRISE
  Click to toggle mode for a while
  Use \`xfce4-settings-editor\` -> \`night-mode\` to modify settings
  </tool>"