#!/bin/bash

# Name and description
name="mixer-osd"
description="Provides an OSD (On Screen Display) for basic mixer operations."

# Some variables
default_color="green"
acolor=$default_color

# This program depends on aosd_cat and amixer (alsa-utils in Debian)
deps="aosd_cat amixer"

function usage()
{
   show_name=$1
   error=$2

   # Show name and description only if explicitly stated
   if [[ $show_name == 1 ]] ; then
      echo -e " $name - $description\n"
   fi

   # Show an error message, if present
   if [[ $error != '' ]] ; then
      echo -e "\033[1m$error\033[0m\n"
   fi

   cat << EOF
Usage:
   $name -u|-d|-m
   $name -h

Options:
   -u   Volume up
   -d   Volume down
   -m   Mute/Unmute
   
   -h   Shows this help.

EOF
}

# Check for dependencies
for dep in $deps ; do
   if [[ `which $dep` == '' ]] ; then
      echo "Please, install $dep for $name to work!"
      exit 1
   fi
done

# Managing options
while getopts "hudm" option ; do
   case $option in
      h )
         usage 1
         exit 0
         ;;
      u )
         aarg="Volume ↑ $(amixer -c 0 sset Master 2+ unmute | tail -1 | awk '{print $4}' | tr -d '[]')"
         acolor="royalblue"
         ;;
      d )
         aarg="Volume ↓ $(amixer -c 0 sset Master 2- unmute | tail -1 | awk '{print $4}' | tr -d '[]')"
         acolor="gray50"
         ;;
      m )
         case $(amixer -c 0 sset Master toggle | tail -1 | awk '{print $6}' | tr -d '[]') in
            on )
               aarg="UNMUTED"
               acolor="green"
               ;;
            off )
               aarg="MUTED"
               acolor="red"
               ;;
         esac
         ;;
      \? )
         echo -e "Please type ${name} -h for help on usage."
         exit 1
         ;;
   esac
done
shift $(($OPTIND - 1))

# This program doesn't accept any other argument than flag-options
if [[ $# -gt 0 ]] ; then
   usage 0 "Invalid argument (\`$1')."
   exit 1
fi

# One have to either mute/unmute or change the volume,
# otherwise program will exit with error code 1
if [[ -z $aarg ]] ; then
   usage 0 "Please, mute/unmute or change the volume!"
   exit 1
fi

# Kills any instance of aosd_cat
pkill aosd_cat >/dev/null 2>&1

# Performs osd-ized volume changes
echo "$aarg" | aosd_cat \
            --fore-color=$acolor \
            --position 4 \
            --font="Droid Sans Bold 32" \
            --y-offset=300 \
            --transparency=2 \
            --back-color="gray10" \
            --back-opacity=50 \
            --padding=20 \
            --fade-full=1500 >/dev/null 2>&1 &

exit $?