#!/bin/bash

# omarchy:summary=Print the sink whose volume and mute a given output really uses
# omarchy:args=[sink-name]
# omarchy:group=audio
# omarchy:examples=omarchy audio output sink | omarchy audio output sink omarchy_speaker_tuning

set -uo pipefail

# A DSP sink -- a speaker tuning filter-chain, or EasyEffects -- can be the
# selected output without being where loudness lives. Changing its volume alters
# the level going *into* the processing: the display moves while the speakers do
# not, and on a chain with a compressor or limiter the tone changes too. Resolve
# through it to the physical sink it feeds.
#
# With no argument this resolves the current default output, so when headphones or
# HDMI are selected it returns those, not the speakers a tuning happens to front.
# Callers that need to describe some *other* output -- an output switcher naming
# the next one in the rotation -- pass that sink explicitly.

sink="${1:-$(pactl get-default-sink 2>/dev/null)}"

if [[ -z $sink || $sink == alsa_output.* ]]; then
  printf '%s\n' "$sink"
  exit 0
fi

# A DSP sink feeds its physical output through a stream of its own; follow that
# stream down to the sink underneath.
downstream="$(pactl list sink-inputs 2>/dev/null |
  awk -v virt="$sink" '
    /^Sink Input #/ {target = ""}
    /^[[:space:]]*Sink:/ {target = $2}
    /node\.name = / {
      name = $0
      sub(/.*node\.name = "/, "", name)
      sub(/"$/, "", name)
      if (index(name, virt) == 1 && target != "") {print target; exit}
    }
    /application\.name = "EasyEffects"/ {
      if (virt == "easyeffects_sink" && target != "") {print target; exit}
    }')"

if [[ -n $downstream ]]; then
  name="$(pactl list sinks short 2>/dev/null |
    awk -v id="$downstream" '$1 == id {print $2; exit}')"
  if [[ -n $name ]]; then
    printf '%s\n' "$name"
    exit 0
  fi
fi

# Nothing resolvable downstream -- the DSP sink may simply be idle and unlinked.
# Fall back to the sink itself so callers still have something to act on.
printf '%s\n' "$sink"