#!/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" '
    BEGIN {
      output = virt
      sub(/^effect_input\./, "effect_output.", output)
    }
    /^Sink Input #/ {target = ""}
    /^[[:space:]]*Sink:/ {target = $2}
    /node\.name = / {
      name = $0
      sub(/.*node\.name = "/, "", name)
      sub(/"$/, "", name)
      if (target != "" && (name == output || (output == virt && index(name, virt) == 1))) {selected = target; exit}
      if (target != "" && fallback == "" && index(name, virt) == 1) fallback = target
    }
    /application\.name = "EasyEffects"/ {
      if (virt == "easyeffects_sink" && target != "") {selected = target; exit}
    }
    END {
      if (selected != "") print selected
      else if (fallback != "") print fallback
    }')"

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

# EasyEffects 8 does not play into the physical sink through a stream of its
# own: its output node links its ports straight to the sink's playback ports,
# so the sink-input search above finds nothing and the keys would move the
# EasyEffects sink -- whose volume its monitor, the input of the processing,
# does not follow. Follow the port links instead: the first ALSA or Bluetooth
# sink any EasyEffects output port is linked to.
if [[ $sink == "easyeffects_sink" ]]; then
  linked="$(pw-link -l 2>/dev/null |
    awk '
      /^[^ ]/ {src = $0}
      /^[[:space:]]*\|->/ {
        if (src ~ /^ee_/ && $2 ~ /^(alsa|bluez)_output\..*:playback_/) {
          sub(/:playback_.*$/, "", $2); print $2; exit
        }
      }')"

  # Idle, EasyEffects drops those links: fall back to the output device it is
  # configured to feed, when that sink exists.
  if [[ -z $linked ]]; then
    configured="$(sed -n 's/^outputDevice=//p' \
      "${XDG_CONFIG_HOME:-$HOME/.config}/easyeffects/db/easyeffectsrc" 2>/dev/null)"
    if [[ -n $configured ]] && pactl list sinks short 2>/dev/null | awk '{print $2}' | grep -qxF -- "$configured"; then
      linked="$configured"
    fi
  fi

  if [[ -n $linked ]]; then
    printf '%s\n' "$linked"
    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"