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

source_ids=()
current_index=-1

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

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

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