#!/bin/bash
# ${PIPELINE_DIR:-/app/pipeline}/lib/prep-audio.sh
#
# Shared helper sourced by run-playlist.sh and import-track.sh.
# Pre-tags newly-arrived audio with ReplayGain (loudgain, track-mode) and
# Liquidsoap autocue tags (cue_file from Moonbase59/autocue) before beets
# ingests them, so AzuraCast sees fully-prepped files the moment they land
# in /music.
#
# Usage:  prep_audio <scan_dir> <log_file>
# Returns: number of files processed (via stdout)

prep_audio() {
  local scan_dir="$1"
  local log="$2"

  local files=()
  while IFS= read -r -d '' f; do
    files+=("$f")
  done < <(find "$scan_dir" -type f \
              \( -iname "*.flac" -o -iname "*.mp3" -o -iname "*.m4a" \
              -o -iname "*.ogg" -o -iname "*.opus" \) -print0)

  if [[ ${#files[@]} -eq 0 ]]; then
    echo 0
    return 0
  fi

  # loudgain (ReplayGain) and cue_file (Liquidsoap autocue) are optional. They
  # are not in the base image, so only run them if present -- otherwise skip
  # cleanly with a note instead of failing on a missing binary. Install them in
  # the image if you want ReplayGain/autocue tags written at prep time.
  if command -v loudgain >/dev/null 2>&1; then
    echo "[prep-audio] loudgain (track-mode RG, clip-safe) on ${#files[@]} file(s)" >>"$log"
    # -q quiet, -k lower track gain to avoid clipping >-1 dBFS,
    # -s e write extended ReplayGain2 + R128 tags, -I 4 ID3v2.4 for MP3.
    # No -a, so each file gets its own track gain (track-mode).
    if ! loudgain -q -k -s e -I 4 "${files[@]}" >>"$log" 2>&1; then
      echo "[prep-audio] loudgain returned non-zero (see log)" >>"$log"
    fi
  else
    echo "[prep-audio] loudgain not installed, skipping ReplayGain" >>"$log"
  fi

  if command -v cue_file >/dev/null 2>&1; then
    echo "[prep-audio] cue_file (autocue liq_* tags) on ${#files[@]} file(s)" >>"$log"
    # -w write tags into file, -k true-peak clipping prevention.
    # Skips files that already have liq_cue_file=true (use -f to force).
    local failed=0
    for f in "${files[@]}"; do
      if ! cue_file -w -k "$f" >>"$log" 2>&1; then
        echo "[prep-audio] cue_file failed on $f" >>"$log"
        failed=$((failed + 1))
      fi
    done
    [[ $failed -gt 0 ]] && echo "[prep-audio] cue_file errors: $failed" >>"$log"
  else
    echo "[prep-audio] cue_file not installed, skipping autocue tags" >>"$log"
  fi

  echo "${#files[@]}"
}