virtual-mic-toggle

#!/usr/bin/env bash
set -euo pipefail

STATE_DIR="${XDG_RUNTIME_DIR:-/tmp}/virtual-mic-toggle"
STATE_FILE="$STATE_DIR/state.env"

VIRTUAL_SINK_NAME="virtual_sink"
VIRTUAL_SINK_DESC="VirtualSink"

VIRTUAL_MIC_NAME="virtual_mic"
VIRTUAL_MIC_DESC="VirtualMic"

DUAL_SINK_NAME="dual_sink"
DUAL_SINK_DESC="DualSink"

mkdir -p "$STATE_DIR"

require_sink_exists() {
  local name="$1"
  pactl list short sinks | awk '{print $2}' | grep -Fxq "$name"
}

require_source_exists() {
  local name="$1"
  pactl list short sources | awk '{print $2}' | grep -Fxq "$name"
}

get_sink_id_by_name() {
  local name="$1"
  pactl list short sinks | awk -v target="$name" '$2 == target { print $1; exit }'
}

status() {
  if [[ -f "$STATE_FILE" ]]; then
    echo "on"
  else
    echo "off"
  fi
}

enable() {
  if [[ -f "$STATE_FILE" ]]; then
    echo "Virtual mic is already ON"
    exit 0
  fi

  local real_sink
  real_sink="$(pactl get-default-sink)"

  local sink_module_id
  sink_module_id="$(
    pactl load-module module-null-sink \
      sink_name="$VIRTUAL_SINK_NAME" \
      sink_properties="device.description=$VIRTUAL_SINK_DESC"
  )"

  require_sink_exists "$VIRTUAL_SINK_NAME" || {
    echo "Failed to create $VIRTUAL_SINK_NAME"
    exit 1
  }

  local mic_module_id
  mic_module_id="$(
    pactl load-module module-remap-source \
      master="${VIRTUAL_SINK_NAME}.monitor" \
      source_name="$VIRTUAL_MIC_NAME" \
      source_properties="device.description=$VIRTUAL_MIC_DESC"
  )"

  require_source_exists "$VIRTUAL_MIC_NAME" || {
    echo "Failed to create $VIRTUAL_MIC_NAME"
    pactl unload-module "$sink_module_id" 2>/dev/null || true
    exit 1
  }

  local dual_module_id
  dual_module_id="$(
    pactl load-module module-combine-sink \
      sink_name="$DUAL_SINK_NAME" \
      sink_properties="device.description=$DUAL_SINK_DESC" \
      slaves="$real_sink,$VIRTUAL_SINK_NAME"
  )"

  require_sink_exists "$DUAL_SINK_NAME" || {
    echo "Failed to create $DUAL_SINK_NAME"
    pactl unload-module "$dual_module_id" 2>/dev/null || true
    pactl unload-module "$mic_module_id" 2>/dev/null || true
    pactl unload-module "$sink_module_id" 2>/dev/null || true
    exit 1
  }

  cat >"$STATE_FILE" <<EOF
REAL_SINK=$real_sink
SINK_MODULE_ID=$sink_module_id
MIC_MODULE_ID=$mic_module_id
DUAL_MODULE_ID=$dual_module_id
EOF

  echo "Virtual mic enabled"
  echo "Move app streams to '$DUAL_SINK_NAME'"
  echo "Select '$VIRTUAL_MIC_NAME' or '$VIRTUAL_MIC_DESC' as microphone in Meet/Jitsi"
}

disable() {
  if [[ ! -f "$STATE_FILE" ]]; then
    echo "Virtual mic is already OFF"
    exit 0
  fi

  # shellcheck disable=SC1090
  source "$STATE_FILE"

  pactl unload-module "${DUAL_MODULE_ID:-}" 2>/dev/null || true
  pactl unload-module "${MIC_MODULE_ID:-}" 2>/dev/null || true
  pactl unload-module "${SINK_MODULE_ID:-}" 2>/dev/null || true

  rm -f "$STATE_FILE"
  echo "Virtual mic disabled"
}

toggle() {
  if [[ -f "$STATE_FILE" ]]; then
    disable
  else
    enable
  fi
}

list_apps() {
  declare -A sink_names

  while IFS=$'\t' read -r id name _; do
    sink_names["$id"]="$name"
  done < <(pactl list short sinks)

  printf "%-6s %-25s %-25s %s\n" "ID" "APP" "MEDIA" "SINK"

  while IFS='|' read -r id app media sink_id; do
    [[ -z "$id" ]] && continue
    [[ "$media" == "dual_sink output" ]] && continue
    [[ "$media" == "VirtualSink" ]] && continue
    printf "%-6s %-25s %-25s %s\n" \
      "$id" "$app" "$media" "${sink_names[$sink_id]:-$sink_id}"
  done < <(
    pactl list sink-inputs | awk '
      /^Sink Input #[0-9]+/ {
        id=$3
        sub("#","",id)
        app_name="-"
        media_name="-"
        sink="-"
      }
      /application.name = / {
        app_name=$0
        sub(/.*application.name = "/, "", app_name)
        sub(/"$/, "", app_name)
      }
      /media.name = / {
        media_name=$0
        sub(/.*media.name = "/, "", media_name)
        sub(/"$/, "", media_name)
      }
      /Sink: / {
        sink=$2
      }
      /^$/ {
        if (id != "") {
          print id "|" app_name "|" media_name "|" sink
          id=""
        }
      }
      END {
        if (id != "") {
          print id "|" app_name "|" media_name "|" sink
        }
      }
    '
  )
}

move_app() {
  [[ -f "$STATE_FILE" ]] || {
    echo "Virtual mic is OFF"
    exit 1
  }
  require_sink_exists "$DUAL_SINK_NAME" || {
    echo "$DUAL_SINK_NAME does not exist"
    exit 1
  }

  if [[ $# -ne 1 ]]; then
    echo "Usage: $0 move-app <sink-input-id>"
    exit 1
  fi

  pactl move-sink-input "$1" "$DUAL_SINK_NAME"
  echo "Moved sink-input $1 to $DUAL_SINK_NAME"
}

move_name() {
  [[ -f "$STATE_FILE" ]] || {
    echo "Virtual mic is OFF"
    exit 1
  }
  require_sink_exists "$DUAL_SINK_NAME" || {
    echo "$DUAL_SINK_NAME does not exist"
    exit 1
  }

  if [[ $# -lt 1 ]]; then
    echo "Usage: $0 move-name <text>"
    exit 1
  fi

  local query="$*"
  local ids

  ids="$(
    pactl list sink-inputs | awk -v q="$query" '
      BEGIN { IGNORECASE=1 }
      /^Sink Input #[0-9]+/ {
        id=$3
        sub("#","",id)
        app_name=""
        media_name=""
      }
      /application.name = / {
        app_name=$0
        sub(/.*application.name = "/, "", app_name)
        sub(/"$/, "", app_name)
      }
      /media.name = / {
        media_name=$0
        sub(/.*media.name = "/, "", media_name)
        sub(/"$/, "", media_name)
      }
      /^$/ {
        text = app_name " " media_name
        if (id != "" && text ~ q && media_name != "dual_sink output") {
          print id
        }
        id=""
        app_name=""
        media_name=""
      }
      END {
        text = app_name " " media_name
        if (id != "" && text ~ q && media_name != "dual_sink output") {
          print id
        }
      }
    '
  )"

  [[ -n "$ids" ]] || {
    echo "No matching app found"
    exit 1
  }

  while read -r id; do
    [[ -n "$id" ]] || continue
    pactl move-sink-input "$id" "$DUAL_SINK_NAME"
    echo "Moved sink-input $id to $DUAL_SINK_NAME"
  done <<<"$ids"
}

restore_app() {
  [[ -f "$STATE_FILE" ]] || {
    echo "Virtual mic is OFF"
    exit 1
  }

  # shellcheck disable=SC1090
  source "$STATE_FILE"

  if [[ $# -ne 1 ]]; then
    echo "Usage: $0 restore-app <sink-input-id>"
    exit 1
  fi

  pactl move-sink-input "$1" "$REAL_SINK"
  echo "Moved sink-input $1 back to $REAL_SINK"
}

show_sinks() {
  pactl list short sinks
}

show_sources() {
  pactl list short sources
}

case "${1:-toggle}" in
on | enable)
  enable
  ;;
off | disable)
  disable
  ;;
toggle)
  toggle
  ;;
status)
  status
  ;;
list-apps)
  list_apps
  ;;
move-app)
  shift
  move_app "$@"
  ;;
move-name)
  shift
  move_name "$@"
  ;;
restore-app)
  shift
  restore_app "$@"
  ;;
sinks)
  show_sinks
  ;;
sources)
  show_sources
  ;;
*)
  echo "Usage: $0 [on|off|toggle|status|list-apps|move-app <id>|move-name <text>|restore-app <id>|sinks|sources]"
  exit 1
  ;;
esac