#!/usr/bin/env zsh
emulate -L zsh
setopt err_exit pipefail no_unset

prune_root="${BEET_PRUNE_ROOT:-/music/pruned}"
dry_run=0
vim_keys="${BEET_PRUNE_VIM_KEYS:-0}"

usage() {
  cat >&2 <<'EOF'
usage:
  beet-prune-albums [options] [beets-query...]

Interactively select albums with fzf, move them to a pruned quarantine folder,
then remove them from the beets database.

Options:
  --dest DIR       Quarantine root. Default: /music/pruned
  --dry-run        Show what would happen, but do not move or remove anything.
  --vim-keys       Bind raw j/k for down/up. This makes typing j/k into search unusable.
  -h, --help       Show this help.

Environment:
  BEET_PRUNE_ROOT=/music/pruned
  BEET_PRUNE_VIM_KEYS=1

Examples:
  beet-prune-albums
  beet-prune-albums --vim-keys
  beet-prune-albums albumartist:=~"Taylor Swift"
  beet-prune-albums genre:soundtrack
  beet-prune-albums --dry-run
EOF
}

while (( $# )); do
  case "$1" in
    --dest)
      prune_root="${2:?missing argument for --dest}"
      shift 2
      ;;
    --dry-run)
      dry_run=1
      shift
      ;;
    --vim-keys)
      vim_keys=1
      shift
      ;;
    -h|--help)
      usage
      exit 0
      ;;
    --)
      shift
      break
      ;;
    -*)
      print -u2 "error: unknown option: $1"
      usage
      exit 2
      ;;
    *)
      break
      ;;
  esac
done

query=( "$@" )

if ! command -v fzf >/dev/null 2>&1; then
  print -u2 "error: fzf is required"
  print -u2 "install with: brew install fzf"
  exit 1
fi

if ! command -v beet >/dev/null 2>&1; then
  print -u2 "error: beet is not in PATH"
  exit 1
fi

timestamp="$(date +%Y%m%d-%H%M%S)"
batch_dir="$prune_root/$timestamp"
marker="prune_candidate_$timestamp"

tmpdir="$(mktemp -d)"
trap 'rm -rf "$tmpdir"' EXIT

albums_raw="$tmpdir/albums.raw.tsv"
counts="$tmpdir/counts.tsv"
all="$tmpdir/all.tsv"
selected="$tmpdir/selected.tsv"

# Album rows. Keep this simple and stable.
# id, artist, album, year
beet ls -a -f $'$id\t$albumartist\t$album\t$year' "${query[@]}" > "$albums_raw"

if [[ ! -s "$albums_raw" ]]; then
  print "No albums matched."
  exit 0
fi

# Compute album track counts from item rows.
# This avoids using $tracktotal, which is not reliable in album-mode formatting.
beet ls -f '$album_id' |
  awk 'NF { count[$0]++ } END { for (id in count) print id "\t" count[id] }' |
  sort -n > "$counts"

# Build fzf input.
#
# Full row structure:
#   1 = album id, hidden
#   2 = fixed-width display row, shown
#   3 = albumartist
#   4 = album
#   5 = year
#   6 = track count
#
# Widths are intentionally conservative for normal terminal widths.
awk -F '\t' '
  NR == FNR {
    count[$1] = $2
    next
  }

  {
    id = $1
    artist = $2
    album = $3
    year = $4
    tracks = ((id in count) ? count[id] : "?")

    if (year == "") year = "----"

    display = sprintf("%-30.30s  %-72.72s  %4.4s  %4s tracks", artist, album, year, tracks)

    printf "%s\t%s\t%s\t%s\t%s\t%s\n", id, display, artist, album, year, tracks
  }
' "$counts" "$albums_raw" > "$all"

fzf_binds=(
  '--bind=space:toggle'
  '--bind=ctrl-a:select-all'
  '--bind=ctrl-x:deselect-all'
  '--bind=ctrl-t:toggle-all'
  '--bind=ctrl-j:down,ctrl-k:up'
  '--bind=ctrl-d:preview-half-page-down,ctrl-u:preview-half-page-up'
  '--bind=ctrl-f:preview-page-down,ctrl-b:preview-page-up'
)

if [[ "$vim_keys" == "1" ]]; then
  fzf_binds+=( '--bind=j:down,k:up' )
fi

# Clear inherited FZF_DEFAULT_OPTS so a global --height or layout setting
# does not make this cramped.
FZF_DEFAULT_OPTS= fzf \
  --multi \
  --height=100% \
  --layout=reverse \
  --border=rounded \
  --info=inline \
  --prompt='prune albums > ' \
  --pointer='▶' \
  --marker='✓' \
  --delimiter=$'\t' \
  --with-nth='2' \
  --header=$'SPACE = toggle  |  CTRL-A = select matches  |  CTRL-X = deselect matches  |  CTRL-T = toggle matches  |  ENTER = confirm  |  CTRL-J/K = down/up  |  ESC = cancel' \
  --preview=$'beet ls -f \'$disc-$track $artist - $title\' album_id:{1} | sed -n \'1,240p\'' \
  --preview-window='right,55%,border-left' \
  "${fzf_binds[@]}" \
  < "$all" > "$selected" || {
    print "Cancelled."
    exit 0
  }

if [[ ! -s "$selected" ]]; then
  print "Nothing selected."
  exit 0
fi

print
print "Selected albums:"
awk -F '\t' '{ printf "  [%s] %s\n", $1, $2 }' "$selected"

print
print "Marking selected albums with temporary marker: $marker"

while IFS=$'\t' read -r album_id _rest; do
  beet modify -a -y "id:$album_id" "$marker=1" >/dev/null
done < "$selected"

cleanup_marker() {
  beet modify -a -y "$marker:1" "$marker!" >/dev/null 2>&1 || true
}

trap 'cleanup_marker; rm -rf "$tmpdir"' EXIT

print
print "Albums marked for pruning:"
beet ls -a "$marker:1"

print
beet stats "$marker:1" || true

print
print "Quarantine destination:"
print "  $batch_dir"

if (( dry_run )); then
  print
  print "Dry run. No files moved and no database rows removed."
  print
  print "Preview move command:"
  print "  beet move -a -d ${(q)batch_dir} ${(q)marker:1}"
  print
  print "Preview DB removal command:"
  print "  beet remove -a ${(q)marker:1}"
  exit 0
fi

print
print "This will:"
print "  1. Move selected albums out of the active library into:"
print "     $batch_dir"
print "  2. Remove those albums from the beets database."
print "  3. Leave the moved files in the quarantine folder."

print
read -q "confirm?Proceed? [y/N] "
print

if [[ "$confirm" != "y" && "$confirm" != "Y" ]]; then
  print "Aborted. Cleaning temporary marker."
  exit 1
fi

mkdir -p "$batch_dir"

print
print "Moving selected albums to quarantine..."
beet move -a -d "$batch_dir" "$marker:1"

print
print "Verifying moved files exist under quarantine..."

missing=0

while IFS=$'\t' read -r album_id _rest; do
  paths="$(beet ls -f '$path' "album_id:$album_id" || true)"

  if [[ -z "$paths" ]]; then
    print -u2 "warning: no paths found in DB for album id $album_id after move"
    missing=1
    continue
  fi

  while IFS= read -r filepath; do
    [[ -z "$filepath" ]] && continue

    if [[ "$filepath" != "$batch_dir"/* ]]; then
      print -u2 "warning: path is not under quarantine for album id $album_id:"
      print -u2 "  $filepath"
      missing=1
    elif [[ ! -e "$filepath" ]]; then
      print -u2 "warning: moved path does not exist for album id $album_id:"
      print -u2 "  $filepath"
      missing=1
    fi
  done <<< "$paths"
done < "$selected"

if (( missing )); then
  print -u2
  print -u2 "Refusing to remove albums from the DB because verification failed."
  print -u2 "The DB may now point some selected albums at the quarantine folder."
  print -u2 "Inspect with:"
  print -u2 "  beet ls -a '$marker:1'"
  print -u2 "  beet ls -f '\$path' '$marker:1'"
  exit 1
fi

print
print "Removing selected albums from beets DB only..."
beet remove -a -f "$marker:1"

print
print "Done."
print "Pruned files are here:"
print "  $batch_dir"