#!/bin/bash
# encode_all encodes the whole library into specified format
#
ulimit -n "$(ulimit -Hn)"
. env_parallel.bash

src_library="${HOME}/flac"
output_dir="${HOME}/opus"
log="${HOME}/encode_log_$(date '+%Y-%m-%d_%H:%M')"

function encode() {
  file="$1"

  # file is full original path + filename
  src_dir="$(dirname "$file")"
  file_name="$(basename "$file")"
  final_dir="$(sed "s_${HOME}/flac_${HOME}/opus_" <<< "$src_dir")"
  final_opus="$(sed -e 's/\.flac$/.opus/' -e "s_${HOME}/flac_${HOME}/opus_" <<< "$file")"
  if [[ -f "$final_opus" ]]; then
    return
  fi
  unset tags
  unset dest_dir

  declare -A tags
  while read -r line; do
    tag_type="$(cut -d= -f1 <<< "$line")"
    tag_type="${tag_type^^}"
    tag_val="$(cut -d= -f2- <<< "$line")"
    tags["$tag_type"]="$tag_val"
  done < <(metaflac --list --block-type=VORBIS_COMMENT "$file" | grep 'comment\[' | cut -d: -f2- | sed 's/^ //')
  album="$(basename "$final_dir")"
  if [[ "$file_name" =~ ^D[0-9]+ ]]; then
    disk="$(cut -d\  -f1 <<< "$file_name")"
    tags[DISK]="${disk#D}"
  fi
  declare -a tag_ensure
  tag_ensure=( TRACKNUMBER TITLE DATE ALBUM ARTIST )
  for tag_type in "${tag_ensure[@]}"; do
    if [[ -z "${tags[$tag_type]}" ]]; then
      tags[$tag_type]="missing $tag_type"
    fi
  done

  [[ -d "$final_dir" ]] || mkdir -p "$final_dir"
  if [[ -n "${tags[DISK]}" ]]; then
    err="$(opusenc --quiet --discard-comments --discard-pictures \
         --title "${tags[TITLE]}" --artist "${tags[ARTIST]}" \
         --album "${tags[ALBUM]}" --tracknumber "${tags[TRACKNUMBER]}" \
         --date "${tags[DATE]}" --comment "DISK=${tags[DISK]}" "$file" "$final_opus" 2>&1)"
  else
    err="$(opusenc --quiet --discard-comments --discard-pictures \
         --title "${tags[TITLE]}" --artist "${tags[ARTIST]}" \
         --album "${tags[ALBUM]}" --tracknumber "${tags[TRACKNUMBER]}" \
         --date "${tags[DATE]}" "$file" "$final_opus" 2>&1)"
  fi
  if [[ -n "$err" ]]; then
    printf '%s\n' "$err" >> "$log"
  fi
}

time find "$src_library" -type f -name '*.flac' -print0 | env_parallel -P 0 -0 --bar encode {}