#!/bin/bash
# alsatest-ihda.sh

# useful variables
MODELS_PATH="${0%/*}/ihda-models.dat"
OPTION_IHDA="options snd-hda-intel model="
ALSACONF_PATH="/etc/modules.d/alsa"
BKUP_PATH="/var/tmp/alsatest-ihda-models.alsa.bkup"
TMP_ALSACONF_PATH="/var/tmp/tmp.alsatest-ihda-models"

# our update / test commands
# four channels are used for (hopeful) completeness
function test_alsaconf {
  modules-update
  /etc/init.d/alsasound restart
  speaker-test -c4 -l2
}

# first we save our existing configuration in case of crash of failure
if [ -f $BKUP_PATH ]
then
  echo "alsatest: Backup already exists at ${BKUP_PATH}!"
  echo "alsatest: Skipping backup..."
else
  echo "alsatest: Backing up your existing alsaconf to ${BKUP_PATH}..."
  cp $ALSACONF_PATH $BKUP_PATH
fi

# the guts of it
exec < $MODELS_PATH  # reads in our models from file
while read line  # loops
  do
    MODEL=$line  # reads current model in
    echo "alsatest: Changing ALSA snd-hda-intel model to: ${MODEL}"
    sed "/${OPTION_IHDA}*/c${OPTION_IHDA}${MODEL}" $ALSACONF_PATH >> $TMP_ALSACONF_PATH  # replaces options line in alsa conf
    mv $TMP_ALSACONF_PATH $ALSACONF_PATH 
    echo "alsatest: Restarting ALSA and testing new model..."
    test_alsaconf  # runs the update and test
  done

if [ -f $BKUP_PATH ]
then
  echo "alsatest: Restoring the model to original before alsatest-ihda-models.sh..."
  mv $BKUP_PATH $ALSACONF_PATH
  modules-update
  /etc/init.d/alsasound restart
else
  echo "alsatest: Oh no! You've lost your backup!"
  echo "alsatest: For now you're stuck with what you've got."
fi

echo "alsatest: Script finished."