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

sink_ids=()
current_index=-1

while IFS=$'\t' read -r id is_default; do
  [[ -n "$id" ]] || continue
  sink_ids+=("$id")
  [[ "$is_default" == true ]] && current_index=$((${#sink_ids[@]} - 1))
done < <(
  wpctl status -n | awk '
    /^Audio$/ {in_audio = 1; next}
    /^Video$/ {in_audio = 0; in_sinks = 0}
    in_audio && /Sinks:/ {in_sinks = 1; next}
    /Sources:/ {in_sinks = 0}
    in_audio && in_sinks && match($0, /[0-9]+\./) {
      id = substr($0, RSTART, RLENGTH - 1)
      print id "\t" (index($0, "*") ? "true" : "false")
    }
  '
)

((${#sink_ids[@]} > 0)) || exit 0
next_index=$(((current_index + 1) % ${#sink_ids[@]}))
next_sink_id="${sink_ids[$next_index]}"
wpctl set-default "$next_sink_id"

# Move existing playback streams too; set-default alone only affects new ones.
while read -r stream_id; do
  [[ -n "$stream_id" ]] || continue
  if wpctl inspect "$stream_id" 2>/dev/null | grep -q 'media.class = "Stream/Output/Audio"'; then
    wpctl set-target "$stream_id" "$next_sink_id" 2>/dev/null || true
  fi
done < <(
  wpctl status -n | awk '
    /^Audio$/ {in_audio = 1; next}
    /^Video$/ {in_audio = 0; in_streams = 0}
    in_audio && /Streams:/ {in_streams = 1; next}
    in_audio && in_streams && match($0, /[0-9]+\./) {
      print substr($0, RSTART, RLENGTH - 1)
    }
  '
)

sink_name=$(
  wpctl inspect "$next_sink_id" \
    | awk -F' = ' '/node.nick/ {gsub(/^"|"$/, "", $2); print $2; exit}'
)
[[ -n "$sink_name" ]] || sink_name="Output $next_sink_id"
notify-send -a Waybar -u low -r 9102 "Audio output changed" "$sink_name"