#!/bin/bash
# DAC3100 speaker-path helper
# Usage: ./volume.sh [dac] [driver] [analog]
#   dac:     0-175  (digital volume, 127=0dB)
#   driver:  0-3    (class-D gain: 6/12/18/24 dB)
#   analog:  0-127  (analog volume, 127=0dB)

set -euo pipefail

CARD_ID="barepiaudio"
CARD_NAME="barepi-audio"
DEFAULT_DAC=127
DEFAULT_DRIVER=0
DEFAULT_ANALOG=50

find_card() {
  awk -v id="$CARD_ID" -v name="$CARD_NAME" '
    index($0, "[" id "]") || index($0, name) { print $1; exit }
  ' /proc/asound/cards
}

show_status() {
  echo "Using ALSA card: $CARD ($CARD_NAME)"
  amixer -c "$CARD" sget 'DAC' || true
  amixer -c "$CARD" sget 'DAC Left Input' || true
  amixer -c "$CARD" sget 'DAC Right Input' || true
  amixer -c "$CARD" sget 'Output Left From Left DAC' || true
  amixer -c "$CARD" sget 'Output Right From Right DAC' || true
  amixer -c "$CARD" sget 'Speaker' || true
  amixer -c "$CARD" sget 'Speaker Driver' || true
  amixer -c "$CARD" sget 'Speaker Analog' || true
}

enable_speaker_path() {
  echo "Enabling TLV320 speaker path..."
  amixer -c "$CARD" sset 'DAC Left Input' 'Left Data' >/dev/null || true
  amixer -c "$CARD" sset 'DAC Right Input' 'Right Data' >/dev/null || true
  amixer -c "$CARD" sset 'Output Left From Left DAC' on >/dev/null || true
  amixer -c "$CARD" sset 'Output Right From Right DAC' on >/dev/null || true
  amixer -c "$CARD" sset 'Speaker' on >/dev/null || true
  amixer -c "$CARD" sset 'HP Left' off >/dev/null || true
  amixer -c "$CARD" sset 'HP Right' off >/dev/null || true
  amixer -c "$CARD" sset 'HP Driver' 0 >/dev/null || true
  amixer -c "$CARD" sset 'HP Driver' off >/dev/null || true
}

CARD="$(find_card || true)"
if [ -z "$CARD" ]; then
  echo "Could not find ALSA card for $CARD_NAME." >&2
  echo "Reboot after setup, then check /proc/asound/cards." >&2
  exit 1
fi

if [ $# -eq 0 ]; then
  show_status
  exit 0
fi

DAC=${1:-$DEFAULT_DAC}
DRIVER=${2:-$DEFAULT_DRIVER}
ANALOG=${3:-$DEFAULT_ANALOG}

enable_speaker_path

echo "Setting levels..."
amixer -c "$CARD" sset 'DAC' "$DAC" "$DAC" >/dev/null
amixer -c "$CARD" sset 'Speaker Driver' "$DRIVER" >/dev/null || true
amixer -c "$CARD" sset 'Speaker Driver' on >/dev/null || true
amixer -c "$CARD" sset 'Speaker Analog' "$ANALOG" >/dev/null || true

alsactl store "$CARD" >/dev/null 2>&1 || alsactl store >/dev/null 2>&1 || true

echo ""
echo "Using ALSA card: $CARD ($CARD_NAME)"
echo "Set: dac=$DAC driver=$DRIVER analog=$ANALOG"
echo "Example: ./volume.sh 127 0 50"