#!/bin/bash
# Description: Switch PulseAudio/PipeWire audio output sinks

STATE_FILE="${XDG_CACHE_HOME:-$HOME/.cache}/audio-toggle-prev-sink"

usage() {
  cat <<EOF
Usage: $(basename "$0") [OPTION]

Toggle or switch PulseAudio/PipeWire audio output sinks.

Options:
  --to <pattern>     Switch to a sink whose name matches <pattern>
  --prev, --previous Switch back to the previously active sink
  --list             List available sinks
  --current          Show the current default sink
  --move-streams     Also move existing audio streams to the new sink
  --help, -h         Show this help message
EOF
  exit 0
}

get_current_sink() {
  pactl info | sed -En 's/Default Sink: (.*)/\1/p'
}

get_sink_description() {
  local sink="$1"
  pactl list sinks | awk -v s="$sink" '
    /^[[:space:]]*Sink #[0-9]+/ { in_block=""; name="" }
    $1 == "Name:" { name = $2 }
    name == s && /Description:/ { $1=""; sub(/^[[:space:]]+/, ""); print; exit }
  '
}

MOVE_STREAMS=0
MODE="toggle"
TARGET_SINK=""

while [ $# -gt 0 ]; do
  case "$1" in
    --help|-h) usage ;;
    --list)
      pactl list short sinks | grep -v easyeffects | while read -r line; do
        name=$(echo "$line" | awk '{print $2}')
        desc=$(get_sink_description "$name")
        echo "$name  ($desc)"
      done
      exit 0
      ;;
    --current)
      sink=$(get_current_sink)
      desc=$(get_sink_description "$sink")
      echo "$sink  ($desc)"
      exit 0
      ;;
    --prev|--previous)
      if [ ! -f "$STATE_FILE" ]; then
        notify-send "Audio Toggle" "No previous sink saved"
        exit 1
      fi
      prev=$(cat "$STATE_FILE")
      if ! pactl list short sinks | awk '{print $2}' | grep -qxF "$prev"; then
        notify-send "Audio Toggle" "Previous sink no longer available"
        exit 1
      fi
      current=$(get_current_sink)
      echo "$current" > "$STATE_FILE"
      TARGET_SINK="$prev"
      MODE="switch"
      ;;
    --to)
      shift
      [ $# -eq 0 ] && echo "Error: --to requires a pattern" >&2 && exit 1
      matched=$(pactl list short sinks | grep -v easyeffects | awk '{print $2}' | grep -i "$1" | head -1)
      [ -z "$matched" ] && echo "Error: no sink matching '$1'" >&2 && exit 1
      current=$(get_current_sink)
      echo "$current" > "$STATE_FILE"
      TARGET_SINK="$matched"
      MODE="switch"
      ;;
    --move-streams) MOVE_STREAMS=1 ;;
    *)
      echo "Unknown option: $1" >&2
      usage
      exit 1
      ;;
  esac
  shift
done

SINKS=$(pactl list short sinks | grep -v easyeffects)
SINK_COUNT=$(echo "$SINKS" | wc -l)

if [ "$SINK_COUNT" -eq 0 ]; then
  notify-send -u critical "Audio Toggle" "No audio sinks available"
  exit 1
fi

CURRENT_SINK=$(get_current_sink)

if [ "$MODE" = "switch" ] && [ -n "$TARGET_SINK" ]; then
  NEW_SINK="$TARGET_SINK"
else
  SINK_INDEX=$(echo "$SINKS" | awk -v s="$CURRENT_SINK" '$2 == s { print NR; exit }')
  SINK_INDEX=${SINK_INDEX:-0}
  NEXT_INDEX=$((SINK_INDEX % SINK_COUNT + 1))
  NEW_SINK=$(echo "$SINKS" | awk "NR == $NEXT_INDEX { print \$2; exit }")
  echo "$CURRENT_SINK" > "$STATE_FILE"
fi

NEW_DESC=$(get_sink_description "$NEW_SINK")
notify-send "Audio Output" "Switched to $NEW_DESC" --icon=audio-speakers

MAX_RETRIES=6
RETRIES=0

while true; do
  [ "$RETRIES" -ge "$MAX_RETRIES" ] && notify-send -u critical "Audio Toggle" "Failed after $MAX_RETRIES attempts" && break

  pactl set-default-sink "$NEW_SINK"

  [ "$(get_current_sink)" = "$NEW_SINK" ] && break

  RETRIES=$((RETRIES + 1))
  NEXT_INDEX=$(((SINK_INDEX + RETRIES) % SINK_COUNT + 1))
  NEW_SINK=$(echo "$SINKS" | awk "NR == $NEXT_INDEX { print \$2; exit }")
  NEW_DESC=$(get_sink_description "$NEW_SINK")
  notify-send "Audio Toggle" "Sink unavailable, trying $NEW_DESC..."
done

if [ "$MOVE_STREAMS" = 1 ]; then
  pactl list short sink-inputs | grep -Eo '^[0-9]+' | while read -r id; do
    pactl move-sink-input "$id" "$NEW_SINK"
  done
fi