ampctl

#!/usr/bin/env bash
# ampctl - control amplifier power via GPIO SHDN pins
#
# GPIO mapping is read from speaker_config.json's `amplifiers.<id>.gpio`
# field per amp. Amps without a `gpio` field are treated as ALWAYS ON:
# status reports "on" and on/off are no-ops (so powermanager/webui keep
# working when an amp is wired straight to power and has no SHDN line).
#
# Usage:
#   ampctl status          Show status of all amps (JSON)
#   ampctl status amp1     Show status of one amp ("amp on" / "amp off")
#   ampctl on  [amp]       Power on (one amp, or all)
#   ampctl off [amp]       Power off (one amp, or all)

SPEAKER_CONFIG="${SPEAKER_CONFIG:-/home/tobias/multiroom-tooling/speaker_config.json}"

_amp_gpio() {
  python3 - "$SPEAKER_CONFIG" "$1" <<'PY' 2>/dev/null
import json, sys
try:
    c = json.load(open(sys.argv[1]))
except Exception:
    sys.exit(0)
amp = (c.get('amplifiers') or {}).get(sys.argv[2]) or {}
g = amp.get('gpio')
if isinstance(g, int):
    print(g)
PY
}

_all_amps() {
  python3 - "$SPEAKER_CONFIG" <<'PY' 2>/dev/null
import json, sys
try:
    c = json.load(open(sys.argv[1]))
except Exception:
    sys.exit(0)
for k in sorted((c.get('amplifiers') or {}).keys()):
    print(k)
PY
}

_amp_known() {
  _all_amps | grep -qx "$1"
}

get_state() {
  local amp=$1
  local gpio
  gpio=$(_amp_gpio "$amp")
  if [[ -z "$gpio" ]]; then
    # No GPIO configured → amp is hard-wired on (or has no SHDN line);
    # we have no way to read or change its state, so report "on".
    echo "on"
    return
  fi
  local output
  output=$(pinctrl get "$gpio" 2>/dev/null)
  if [[ "$output" == *"| hi"* ]]; then
    echo "on"
  elif [[ "$output" == *"| lo"* ]]; then
    echo "off"
  else
    echo "unknown"
  fi
}

amp_on() {
  local amp=$1
  local gpio
  gpio=$(_amp_gpio "$amp")
  [[ -n "$gpio" ]] && pinctrl set "$gpio" op dh 2>/dev/null
  # else: no GPIO → always on, nothing to toggle
}

amp_off() {
  local amp=$1
  local gpio
  gpio=$(_amp_gpio "$amp")
  [[ -n "$gpio" ]] && pinctrl set "$gpio" op dl 2>/dev/null
  # else: no GPIO → always on, nothing to toggle (off is a no-op)
}

case "${1:-}" in
  status)
    if [[ -n "${2:-}" ]]; then
      amp="$2"
      if ! _amp_known "$amp"; then
        echo "Unknown amp: $amp" >&2
        exit 1
      fi
      state=$(get_state "$amp")
      echo "$amp $state"
    else
      echo "{"
      first=true
      mapfile -t _amps < <(_all_amps)
      for amp in "${_amps[@]}"; do
        state=$(get_state "$amp")
        $first || echo ","
        printf '  "%s": "%s"' "$amp" "$state"
        first=false
      done
      echo ""
      echo "}"
    fi
    ;;
  on)
    if [[ -n "${2:-}" ]]; then
      amp="$2"
      if ! _amp_known "$amp"; then
        echo "Unknown amp: $amp" >&2
        exit 1
      fi
      amp_on "$amp"
      echo "$amp on"
    else
      mapfile -t _amps < <(_all_amps)
      for amp in "${_amps[@]}"; do
        amp_on "$amp"
        echo "$amp on"
      done
    fi
    ;;
  off)
    if [[ -n "${2:-}" ]]; then
      amp="$2"
      if ! _amp_known "$amp"; then
        echo "Unknown amp: $amp" >&2
        exit 1
      fi
      amp_off "$amp"
      echo "$amp off"
    else
      mapfile -t _amps < <(_all_amps)
      for amp in "${_amps[@]}"; do
        amp_off "$amp"
        echo "$amp off"
      done
    fi
    ;;
  *)
    cat <<USAGE >&2
Usage: ampctl {status|on|off} [amp_id]

GPIO mapping is read from $SPEAKER_CONFIG
(amplifiers.<id>.gpio). Amps without a gpio field are treated as
always-on (status: on; on/off are no-ops).
USAGE
    exit 1
    ;;
esac