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

usage() {
  cat <<'EOF'
Usage: cleanup-library.sh --library PATH [--dry-run|--execute]

Default mode is --dry-run. --execute is required to delete files.
The script only handles audio files below PATH and same-basename sidecars.
EOF
}

LIBRARY=""
MODE="dry-run"
while [[ $# -gt 0 ]]; do
  case "$1" in
    --library) [[ $# -ge 2 ]] || { usage >&2; exit 2; }; LIBRARY="$2"; shift 2 ;;
    --dry-run) MODE="dry-run"; shift ;;
    --execute) MODE="execute"; shift ;;
    -h|--help) usage; exit 0 ;;
    *) echo "Unknown option: $1" >&2; usage >&2; exit 2 ;;
  esac
done

[[ -n "$LIBRARY" && -d "$LIBRARY" ]] || { echo "Library directory is required" >&2; exit 2; }
command -v ffprobe >/dev/null || { echo "ffprobe is required" >&2; exit 2; }
command -v ffmpeg >/dev/null || { echo "ffmpeg is required" >&2; exit 2; }

is_audio() {
  local ext="${1##*.}"
  ext="${ext,,}"
  case "$ext" in
    mp3|m4a|mp4|aac|flac|ogg|oga|opus|wma|wav|ape|aiff|aif|wv|tta) return 0 ;;
    *) return 1 ;;
  esac
}

has_cover_file() {
  [[ -s "$1/cover.jpg" || -s "$1/cover.jpeg" || -s "$1/cover.png" ]]
}

embedded_stream() {
  ffprobe -v error -select_streams v \
    -show_entries stream=index:stream_disposition=attached_pic \
    -of csv=p=0 "$1" 2>/dev/null | awk -F, '$2 == 1 { print $1; exit }'
}

extract_cover() {
  local audio="$1" album_dir="$2" stream codec ext target
  stream="$(embedded_stream "$audio")"
  [[ -n "$stream" ]] || return 1
  codec="$(ffprobe -v error -show_entries stream=index,codec_name -of csv=p=0 "$audio" 2>/dev/null | awk -F, -v idx="$stream" '$1 == idx { print $2; exit }')"
  case "$codec" in
    mjpeg|jpeg) ext="jpg"; target="$album_dir/cover.jpg" ;;
    png) ext="png"; target="$album_dir/cover.png" ;;
    *) ext="jpg"; target="$album_dir/cover.jpg" ;;
  esac
  [[ -e "$target" ]] && return 0
  if [[ "$MODE" == "dry-run" ]]; then
    echo "WOULD EXTRACT $target FROM $audio"
    return 0
  fi
  if [[ "$ext" == "jpg" && "$codec" =~ ^(mjpeg|jpeg)$ || "$ext" == "png" ]]; then
    ffmpeg -v error -y -i "$audio" -map "0:$stream" -frames:v 1 -c copy "$target" 2>/dev/null
  else
    ffmpeg -v error -y -i "$audio" -map "0:$stream" -frames:v 1 "$target" 2>/dev/null
  fi
  [[ -s "$target" ]]
}

delete_sidecars() {
  local audio="$1" dir base sidecar ext
  dir="${audio%/*}"; base="${audio##*/}"; base="${base%.*}"
  for sidecar in "$dir/$base".*; do
    [[ -f "$sidecar" && "$sidecar" != "$audio" ]] || continue
    ext="${sidecar##*.}"
    case "${ext,,}" in
      lrc|cue|json|txt|jpg|jpeg|png|webp) 
        [[ "${sidecar##*/}" == cover.jpg || "${sidecar##*/}" == cover.jpeg || "${sidecar##*/}" == cover.png ]] && continue
        if [[ "$MODE" == "dry-run" ]]; then echo "WOULD DELETE SIDECAR $sidecar"; else rm -f -- "$sidecar"; fi ;;
    esac
  done
}

removed=0
sidecars=0
extracted=0
while IFS= read -r -d '' audio; do
  album_dir="${audio%/*}"
  if has_cover_file "$album_dir"; then continue; fi
  if extract_cover "$audio" "$album_dir"; then
    ((extracted += 1)) || true
    continue
  fi
  if [[ "$MODE" == "dry-run" ]]; then
    echo "WOULD DELETE AUDIO $audio"
  else
    rm -f -- "$audio"
  fi
  delete_sidecars "$audio"
  ((removed += 1)) || true
done < <(find "$LIBRARY" -type f -print0 | while IFS= read -r -d '' f; do is_audio "$f" && printf '%s\0' "$f"; done)

echo "mode=$MODE extracted=$extracted audio_removed=$removed"