#!/usr/bin/bash

set -e

usage() {
  echo "Usage: $(basename "$0") <path-to-poweramp-backup> <playlist-name> <dest-directory>"
}

if [ $# != 3 ]; then
  usage >&2
  exit 1
fi

music_prefix="/m/media/music/active/"
backup="$1"
playlist_name="$2"
dst="$3"

unzip -o "$backup"
playlist_id="$(
  sqlite3 -list -noheader lists-export "select _id from playlists where name = '$playlist_name';"
)"
i=0
sqlite3 -list -noheader lists-export "select path from tracks where playlist_id = $playlist_id;" \
  | sed "s#^primary/Music/#$music_prefix#" \
  | while read -r path; do
      i=$((i+1))
      track_number="$(printf '%02d' "$i")"
      base="$(basename "$path" | sed 's/^[-_.0-9 ]\+//')"
      newbase="$track_number - $base"
      cp -a "$path" "$dst/$newbase"
    done