#!/bin/bash

source stdlib.sh

while getopts 'vsasp' opt ; do
   case "$opt" in
      v) verbosity=VERBOSE ;;
      q) verbosity=QUIET;;
      a) relative=ADD;;
      s) relative=SUBTRACT;;
      p) percentage=true ;;
   esac
done

value=${@:$OPTIND:1}
log "value: ${value}"

if [ -z "$value" ]; then
    error "Usage: $0 [OPTION] <volume>"
    error " -v     print verbose output"
    error " -q     quiet; don't print any output"
    error " -a     relative; add value to current volume"
    error " -s     relative; subtract value from current volume"
    error " -p     interpret value as a percentage instead of an abosolute value"
    exit 1
fi

default_sink=`pactl info 2> >(error) | grep "Default Sink" | cut -d ' ' -f 3`
default_sink_id=`pactl list sinks short | grep "$default_sink" | cut -f 1`
log "default sink: #${default_sink_id}: ${default_sink}"

if [ -n "$relative" ]; then
   if [ "$percentage" = 'true' ]; then
      current_percentage=`pactl list sinks 2> >(error) | grep '^[[:space:]]Volume:' | head -n $(( ${default_sink_id} + 1 )) | tail -n 1 | sed -e 's,.* \([0-9][0-9]*\)%.*,\1,'`
      log "current percentage: ${current_percentage}"
      value_percentage=$(echo "scale=2; "$value" / 65536 * 100" | bc 2> >(error) )
      log "value percentage: ${value_percentage}"

      if [ "$relative" = 'ADD' ]; then
         value=$((current_percentage + value ))
      elif [ "$relative" = 'SUBTRACT' ]; then
         value=$((current_percentage - value ))
      fi
      log "new percentage: ${value}"
   else
      current_volume=`pactl list sinks 2> >(error) | grep '^[[:space:]]Volume:' | head -n $(( ${default_sink_id} + 1 )) | tail -n 1 | cut -d ' ' -f 3`
      log "current volume: ${current_volume}"

      if [ "$relative" = 'ADD' ]; then
         value=$((current_volume + value))
      elif [ "$relative" = 'SUBTRACT' ]; then
         value=$((current_volume - value))
      fi
      log "new volume: ${value}"
   fi
fi

if [ "$percentage" = 'true' ]; then
   value=$(echo "scale=2; 65536 * ("$value" / 100)" | bc 2> >(error) )
   log "new volume: ${value}"
fi
value=$( printf "%.0f" "$value" 2> >(error) )
if [ "$value" -lt 0 ]; then value=0; fi
if [ "$value" -gt 98304 ]; then value=98304; fi
log "rounded value: ${value}"

pactl set-sink-volume "$default_sink" "$value" > >(log) 2> >(error)