#!/bin/bash
# Clean poll-based volume bridge (pure ALSA, no PipeWire).
# Windows "Source/Sink" speaker volume -> gadget control numid=7 (PCM Capture
# Volume, 0-100). Applied to ES8323 analog output (Output 1/2, 0-33) only when it
# actually changes (poll every 200ms) so we don't hammer the mixer on the gadget's
# ~10Hz async rate-feedback events.
set -u
CG=UAC2Gadget
CE=0
last=-1; lastm=-1
while true; do
  v=$(amixer -c "$CG" cget numid=7 2>/dev/null | awk -F= '/: values=/{print $2; exit}')
  m=$(amixer -c "$CG" cget numid=6 2>/dev/null | awk -F= '/: values=/{print $2; exit}')
  if [ -n "$v" ] && { [ "$v" != "$last" ] || [ "$m" != "$lastm" ]; }; then
    o=$(( v * 25 / 100 ))
    amixer -c "$CE" sset 'Output 1' "$o" >/dev/null 2>&1
    amixer -c "$CE" sset 'Output 2' "$o" >/dev/null 2>&1
    case "$m" in
      off|0) amixer -c "$CE" sset 'Headphone' off >/dev/null 2>&1 ;;
      *)     amixer -c "$CE" sset 'Headphone' on  >/dev/null 2>&1 ;;
    esac
    last="$v"; lastm="$m"
  fi
  sleep 0.2
done