#!/bin/bash

version=0.0.4
tmpdir=$TMPDIR
if test -z "$tmpdir"; then
	tmpdir="/tmp"
fi
tmpdir=$tmpdir/alsa-delay-script

delay=
pcard=
pdev=
ccard=
cdev=

yes=
quiet=
clean=

pdevice="default:%s"
cdevice="plughw:%s,%s,%s"
pctl=
cctl=
one=
arg=
mix=

fuser_prg=fuser
insmod_prg=insmod
rmmod_prg=rmmod
lsmod_prg=lsmod
modprobe_prg=modprobe
chkconfig_prg=chkconfig
alsaloop_prg=alsaloop
amixer_prg=amixer
test -x /sbin/fuser && fuser_prg=/sbin/fuser
test -x /sbin/insmod && insmod_prg=/sbin/insmod
test -x /sbin/rmmod && rmmod_prg=/sbin/rmmod
test -x /sbin/lsmod && lsmod_prg=/sbin/lsmod
test -x /sbin/modprobe && modprobe_prg=/sbin/modprobe
test -x /sbin/chkconfig && chkconfig_prg=/sbin/chkconfig
test -x /usr/bin/alsaloop && alsaloop_prg=/usr/bin/alsaloop
test -x /usr/local/bin/alsaloop && alsaloop_prg=/usr/local/bin/alsaloop
test -x /usr/bin/amixer && amixer_prg=/usr/bin/amixer

modprobeconf=/etc/modprobe.conf
alsaloopconf=/etc/alsaloop.conf

test -r modprobe.work && modprobeconf=modprobe.work
test -r modprobe.work && alsaloopconf=alsaloop.conf

usage() {
	echo "Usage: $0 [OPTION]... <requested_delay_in_ms> [<output_card>[,<device>]]"
	cat <<EOF

This is a delay utility version $version. The snd-aloop ALSA driver is
used to send all PCM streams back to the user space and the alsaloop
utility is used to send this stream to a real hardware.

<output_card> is ALSA card index (number) or string card identifier
<device> is ALSA device number

Use 'aplay -l' to list available cards and devices.

Operation modes:
  -h, --help		print this help, then exit
  -q, --quiet		quiet mode
  -y, --yes		do not ask any questions - answer is always yes
  -c, --clean           clean temporary directory
  --tmpdir=<DIR>        set temporary directory
Alsaloop options:
  --pdevice=<DEV>       force playback device
  --cdevice=<DEV>       force capture device
  --pctl=<DEV>          force playback ctl device
  --cctl=<DEV>          force capture ctl device
  --one=<ARG>           pass this argument to first thread
  --arg=<ARG>           pass this argument to all threads
  --mix=<ARG>           redirect ALSA mixer controls to OSS mixer
			(default is Master)

Note: For devices, the string %s is replaced with the card index
      and second string %s is replaced with the device index
      and third string %s is replaced the substream index (0-7).
      Example: hw:%s,%s,%s    (card, device, substream)
EOF
}

while :
do
	case "$1" in
	-h|--help)
		usage
		exit 0
		;;
	-q|--quiet)
		quiet=true ;;
	-y|--yes)
		yes=true ;;
	-c)
		clean="full" ;;
	--tmpdir*)
		case "$#,$1" in
		*,*=*)
			tmpdir=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
		1,*)
			usage ;;
		*)
			tmpdir="$2"
			shift ;;
		esac
		tmpdir="$tmpdir/alsa-compile-script"
		;;
	--pdevice*)
		case "$#,$1" in
		*,*=*)
			pdevice=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
		1,*)
			usage ;;
		*)
			pdevice="$2"
			shift ;;
		esac
		;;
	--cdevice*)
		case "$#,$1" in
		*,*=*)
			cdevice=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
		1,*)
			usage ;;
		*)
			cdevice="$2"
			shift ;;
		esac
		;;
	--pctl*)
		case "$#,$1" in
		*,*=*)
			pctl=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
		1,*)
			usage ;;
		*)
			pctl="$2"
			shift ;;
		esac
		;;
	--cctl*)
		case "$#,$1" in
		*,*=*)
			cctl=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
		1,*)
			usage ;;
		*)
			cctl="$2"
			shift ;;
		esac
		;;
	--one*)
		case "$#,$1" in
		*,*=*)
			one1=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
		1,*)
			usage ;;
		*)
			one1="$2"
			shift ;;
		esac
		one="$one $one1"
		;;
	--arg*)
		case "$#,$1" in
		*,*=*)
			arg1=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
		1,*)
			usage ;;
		*)
			arg1="$2"
			shift ;;
		esac
		arg="$arg $arg1"
		;;
	--mix*)
		case "$#,$1" in
		*,*=*)
			mix=`expr "z$1" : 'z-[^=]*=\(.*\)'` ;;
		1,*)
			usage ;;
		*)
			mix="$2"
			shift ;;
		esac
		arg="$arg $arg1"
		;;
	*)
		if test -n "$1"; then
			ok=
			if test -z "$delay"; then
				delay="$1"
				if test "$delay" -lt 1000; then
					delay=$[$delay * 1000]
				fi
				ok=true
			fi
			if test -z "$ok" -a -z "$pcard"; then
				pcard="$1"
				ok=true
			fi
			if test -z "$ok"; then
				echo "Unknown parameter '$1'"
				break
			fi
		else
			break
		fi
		;;
	esac
	shift
done

test -z "$delay" && delay="50000"
test -z "$pcard" && pcard="1"
pdev=$(echo $pcard | cut -s -d , -f 2)
pcard=$(echo $pcard | cut -d , -f 1)
test -z "$pdev" && pdev="0"
test -z "$ccard" && ccard="Loopback,1"
cdev=$(echo $ccard | cut -s -d , -f 2)
ccard=$(echo $ccard | cut -d , -f 1)
test -z "$cdev" && cdev="0"

# Echo "true" or "false", depending on $yes and user response to prompt
# $1 is prompt message
question_bool() {
	if test "$yes" = "yes"; then
		echo "true"
	else
		echo >&2 -n "$1 (Y/ ) "
		read i
		local i=${i:0:1}
		if test "$i" = "Y" -o "$i" = "y"; then
			echo "true"
		else
			echo "false"
		fi
	fi
}	

# Log and execute $@ and check success
do_cmd() {
	if test -z "$quiet"; then
		echo "> $@"
	fi
	$@ || exit 1
}

# Cache or restore $protocol and $url and $package in $tmpdir
check_environment() {
	if ! test -d $tmpdir ; then
        	mkdir -p $tmpdir
		if ! test -d $tmpdir; then
			echo >&2 "Unable to create directory $tmpdir."
			exit 1
		fi
	fi
	echo "Using temporary tree: $tmpdir"
	test -x /bin/depmod && depmodbin=/bin/depmod
	test -x /sbin/depmod && depmodbin=/sbin/depmod
	if test -z "$depmodbin"; then
		echo >&2 "Unable to find depmod utility."
		exit 1
	fi	
	test -x /bin/modinfo && modinfobin=/bin/modinfo
	test -x /sbin/modinfo && modinfobin=/sbin/modinfo
	if test -z "$modinfobin"; then
		echo >&2 "Unable to find modinfo utility."
		exit 1
	fi	
}

# Kill processes currently accessing the audio devices
kill_audio_apps() {
	local pids0=$($fuser_prg /dev/snd/* 2> /dev/null)
	local pids1=$($fuser_prg /dev/mixer* 2> /dev/null)
	local pids2=$($fuser_prg /dev/sequencer* 2> /dev/null)
	local pids=
	for pid in $pids0 $pids1 $pids2; do
		local pids="$pids $pid"
	done
	if ! test -z "$pids"; then
		echo
		echo "WARNING! An audio application uses ALSA driver:"
		echo
		for pid in $pids; do
			ps --no-headers -p $pids || exit 1
		done
		echo
		if test $(question_bool "Would you like to kill these apps?") = "true"; then
			for pid in $pids; do
				do_cmd kill $pid
			done
			sleep 2
			local killed=
			for pid in $pids; do
				local a=$(ps --no-headers -p $pids)
				if test -n "$a"; then
					do_cmd kill -9 $pid
					local killed="true"
				fi
			done
			if test "$killed" = "true"; then
				sleep 2
				for pid in $pids; do
					local a=$(ps --no-headers -p $pids)
					if test -n "$a"; then
						echo >&2 "Unable to kill application:"
						echo >&2 "  $a"
						exit 1
					fi
				done
			fi
		else
			echo >&2 "Cannot continue with running audio applications."
			exit 1
		fi
	fi
}

# Echo the list of configured sound modules
configured_modules() {
	cat $modprobeconf | grep -E "^alias snd-card-" | cut -d ' ' -f 3
}

# Echo the list of loaded sound modules
current_modules() {
	$lsmod_prg | cut -d ' ' -f 1 | grep -E "^(snd[_-])"
}

# Remove kernel modules, using two phases
# $@ is module names
my_rmmod() {
	local phase2=
	while test -n "$1"; do
		if ! $rmmod_prg $1 2> /dev/null > /dev/null; then
			local phase2="$phase2 $1"
		else
			echo "> rmmod $1"
		fi
		shift
	done
	for mod in $phase2; do
		echo "> rmmod $mod"
		if ! $rmmod_prg $mod ; then
			echo >&2 "Unable to remove kernel module $mod."
			exit 1
		fi
	done
}

# Reload kernel modules
kernel_modules() {
	local curmods=$(current_modules)
	local usermods=$(configured_modules)
	kill_audio_apps
	my_rmmod $curmods
	$modprobe_prg soundcore || exit 1
	for mod in $usermods; do
		if ! $modprobe_prg $mod; then
			echo >&2 "Unable to install kernel module $mod."
			exit 1
		fi
	done
	echo "Kernel modules ready:"
	cat /proc/asound/cards
	sleep 0.5
}

# If $package is alsa-driver then remove current modules
kernel_modules_remove() {
	local curmods=$(current_modules)
	if test -z "$curmods"; then
		echo "No ALSA kernel modules to remove."
		exit 0
	fi
	kill_audio_apps
	my_rmmod $curmods
	echo "ALSA kernel modules removed."
}

function clean() {
	echo -n "Removing tree $tmpdir:"
	if test -d "$tmpdir"; then
		if ! rm -rf "$tmpdir"; then
			echo " failed"
			exit 1
		fi
	fi
	echo " success"
}

function reindex_modprobe_conf() {
	cat > $tmpdir/run.awk <<EOF
function rewrite_line(line,   res, c, i, j) {
	split(line, l, " ")
	if (l[1] == "alias") {
		printf(l[1])
		c = int(substr(l[2], 9)) + 1
		printf(" snd-card-%i %s\n", c, l[3])
	} else if (l[1] == "options") {
		printf(l[1])
		for (i = 2; i <= length(l); i++) {
			c = substr(l[i], 0, 9)
			if (c == "snd-card-") {
				c = int(substr(l[i], 9)) + 1
				printf(" snd-card-%i", c)
				continue
			}
			c = substr(l[i], 0, 6)
			if (c == "index=") {
				printf(" index=")
				c = substr(l[i], 6)
				split(c, y, ",")
				for (j = 1; j <= length(y); j++) {
					c = int(y[j]) + 1
					if (j > 1)
						printf(",")
					printf("%i", c)
				}
				continue
			}
			printf(" %s", l[i])
		}
		printf("\n")
	} else if (l[1] == "remove") {
		printf(l[1])
		flag = 0
		for (i = 2; i <= length(l); i++) {
			if (l[i] == "/usr/sbin/alsactl" || l[i] == "store") {
				flag++;
				printf(" %s", l[i]);
				continue;
			}
			if (flag == 2) {
				c = int(l[i]) + 1;
				printf(" %i", c);
				flag = 0;
				continue;
			}
			flag = 0;
			printf(" %s", l[i]);
		}
		printf("\n")
	} else {
		print line
	}
}

BEGIN			{ aloop=0; }
/alias snd-card-0 snd-aloop/ { aloop=1; next; }
/options snd-card-0 index=0/ { if (aloop) next; }
/options snd-aloop/	{ next; }
/alias snd-card-/	{ rewrite_line(\$0); next; }
/options snd-/		{ rewrite_line(\$0); next; }
/remove snd-/		{ rewrite_line(\$0); next; }
			{ print \$0; }
EOF
	cat $modprobeconf | awk -f $tmpdir/run.awk > $modprobeconf.new
	rm $tmpdir/run.awk || exit 1
cat >> $modprobeconf.new <<EOF
alias snd-card-0 snd-aloop
options snd-card-0 index=0
options snd-aloop index=0
EOF
	mv $modprobeconf.new $modprobeconf || exit 1
}

function modify_modprobe_conf() {
	local check=$(cat $modprobeconf | grep -E "^alias snd-card-0 snd-aloop")
	if test -n "$check"; then
		echo "Module snd-aloop is already installed."
	else
		reindex_modprobe_conf
		kernel_modules
	fi
}

function myprintf() {
	local cnt=$(echo "$1" | grep -o "%" | wc -l)
	if test $cnt -eq 1; then
		printf "$1" "$2"
	else if test $cnt -eq 2; then
		printf "$1" "$2" "$3"
	else
		printf "$1" "$2" "$3" "$4"
	fi
	fi
}

function check_ctl_name() {
	$amixer_prg -D "$1" contents | grep "name='$2'"
}

function generate_alsaloop_line() {
	local file="$1"
	local idx="$2"
	local carg=$(myprintf "$cdevice" $ccard $cdev $idx)
	local parg=$(myprintf "$pdevice" $pcard $pdev $idx)
	local res="-C $carg -P $parg -T $idx -t $delay"
	if test -n "$cctl"; then
		local carg=$(myprintf "$cctl" $pcard $cdev $idx)
		local res="$res -Y $carg"
	fi
	if test -n "$pctl"; then
		local parg=$(myprintf "$pctl" $pcard $pdev $idx)
		local res="$res -X $parg"
	fi
	if test -n "$arg"; then
		local res="$res $arg"
	fi
	if test $idx -eq 7; then
		if test -n "$one"; then
			local res="$res $one"
		fi
		if test -z "$pctl"; then
			local res="$res -X hw:$pcard"
		fi
		local mymix="$mix"
		if test -z "$mymix"; then
			local mymix="Master"
			for mymix in Master Front PCM ; do
				local check=$(check_ctl_name hw:$pcard "$mymix Playback Volume")
				if test -n "$check"; then
					break
				fi
			done
		fi
		local check=$(check_ctl_name hw:$pcard "$mymix Playback Switch")
		if test -n "$check"; then
			local res="$res -m \"name='$mymix Playback Switch'\""
		fi
		local check=$(check_ctl_name hw:$pcard "$mymix Playback Volume")
		if test -n "$check"; then
			local res="$res -m \"name='$mymix Playback Volume'\""
		fi
		local res="$res -O \"$mymix@VOLUME\""
	fi
	echo $res >> $file
}

function generate_alsaloop_conf() {
	local idx=0
	rm -f $alsaloopconf.new
	while test $idx -lt 8; do
		generate_alsaloop_line $alsaloopconf.new $idx
		idx=$(expr $idx + 1)
	done
	mv $alsaloopconf.new $alsaloopconf || exit 1
}

function kill_alsaloop() {
	pid=$(pidof alsaloop)
	if test -n "$pid"; then
		echo "Killing alsaloop..."
	fi
	while test -n "$pid"; do
		kill $pid
		sleep 0.01
		pid=$(pidof alsaloop)
	done
}

function restart_alsaloop() {
	echo "Restarting alsaloop: delay $delay us."
	/etc/init.d/alsaloop start
	sleep 0.4
	local pid=$(pidof alsaloop)
	if test -z "$pid"; then
		echo "ERROR: Not started, check /var/log/messages for details"
	else
		ps -p $pid
	fi
}

function create_initd() {
	if test -x /etc/init.d/alsaloop; then
		echo "/etc/init.d/alsaloop is created"
	else
		cat >> /etc/init.d/alsaloop <<EOF
#! /bin/sh

# alsaloop init file
# Copyright (C) 2010 Jaroslav Kysela <jkysela@redhat.com>

# For RedHat and cousins:
# chkconfig: 2345 99 01
# description: Start alsaloop daemon
# processname: alsaloop

### BEGIN INIT INFO
# Provides: alsaloop
# Required-Start: \$local_fs
# Required-Stop: \$local_fs
# Should-Start:
# Short-Description: ALSALOOP
# Description: ALSALOOP
### END INIT INFO

# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the Free
# Software Foundation; either version 2, or (at your option) any later
# version. 
# You should have received a copy of the GNU General Public License (for
# example COPYING); if not, write to the Free Software Foundation, Inc., 675
# Mass Ave, Cambridge, MA 02139, USA.
# This code was originally developed as a Senior Thesis by Michael Cornwell
# at the Concurrent Systems Laboratory (now part of the Storage Systems
# Research Center), Jack Baskin School of Engineering, University of
# California, Santa Cruz. http://ssrc.soe.ucsc.edu/.

alsaloop_opts="--daemonize --workaround serialopen --config $alsaloopconf"

ALSALOOP_BIN=/usr/bin/alsaloop
test -x /usr/local/bin/alsaloop && ALSALOOP_BIN=/usr/local/bin/alsaloop

# Source function library
. /etc/rc.d/init.d/functions

RETVAL=0
prog=alsaloop
pidfile=/var/lock/subsys/alsaloop

start()
{
	echo -n \$"Starting \$prog: "
	daemon \$ALSALOOP_BIN \$alsaloop_opts
	RETVAL=\$?
	echo
	[ \$RETVAL = 0 ] && touch \$pidfile
	return \$RETVAL
}

stop()
{
	echo -n \$"Shutting down \$prog: "
	killproc \$ALSALOOP_BIN
	RETVAL=\$?
	echo
	rm -f \$pidfile
	return \$RETVAL
}

case "\$1" in
	start)
		start
		;;
	stop)
		stop
		;;
	restart)
		stop
		start
		;;
	try-restart)
		if [ -f \$pidfile ]; then
			stop
			start
		fi
		;;
	*)
		echo \$"Usage: \$0 {start|stop|restart|try-restart}"
		RETVAL=3
esac

exit \$RETVAL
EOF
		chmod 755 /etc/init.d/alsaloop || exit 1
		$chkconfig_prg --add alsaloop
		$chkconfig_prg alsaloop on
	fi
}

rundir=$(pwd)
export LC_ALL=C
export LANGUAGE=C

check_environment

if test -n "$clean"; then
	clean
fi

kill_alsaloop
create_initd
modify_modprobe_conf
generate_alsaloop_conf
restart_alsaloop

clean

exit 0