#!/bin/sh
# qndl-artist — 아티스트 폴더/메타데이터 통일 헬퍼
export LC_ALL="${LC_ALL:-C.UTF-8}"

MUSIC="${XDG_MUSIC_DIR:-$HOME/Music}"
ALIASES="${QNDL_ALIASES:-${XDG_DOTFILES_DIR:-$HOME/.dotfiles}/global/Music/artist-aliases.tsv}"

# 이름 → 표준명. 맵 정확일치 → 기존 폴더 대소문자무시 매칭 → 원본.
cmd_normalize() {
  _name="$1"
  if [ -f "$ALIASES" ]; then
    _c="$(awk -F'\t' -v n="$_name" '/^#/ || NF < 2 { next } $1 == n { print $2; exit }' "$ALIASES")"
    [ -n "$_c" ] && { printf '%s\n' "$_c"; return 0; }
  fi
  if [ -d "$MUSIC" ]; then
    _m="$(find "$MUSIC" -mindepth 1 -maxdepth 1 -type d -printf '%f\n' 2>/dev/null |
      awk -v n="$_name" 'tolower($0) == tolower(n) { print; exit }')"
    [ -n "$_m" ] && { printf '%s\n' "$_m"; return 0; }
  fi
  printf '%s\n' "$_name"
}

# 후크용: 파일의 현재 아티스트 폴더명을 표준명으로 해석해 apply.
cmd_apply_download() {
  _fp="$1"
  case "$_fp" in
  "$MUSIC"/*) : ;;
  *) return 0 ;;   # Music 밖이면 무시
  esac
  _rel="${_fp#"$MUSIC"/}"
  _seg="${_rel%%/*}"
  _canon="$(cmd_normalize "$_seg")"
  cmd_apply "$_fp" "$_canon"
}

# mp3 1개를 표준 폴더로 이동(필요시) + album_artist 설정.
cmd_apply() {
  _fp="$1"; _canon="$2"
  [ -f "$_fp" ] || { printf 'apply: no such file: %s\n' "$_fp" >&2; return 1; }
  case "$_fp" in
  "$MUSIC"/*) : ;;
  *) printf 'apply: not under %s: %s\n' "$MUSIC" "$_fp" >&2; return 1 ;;
  esac
  _rel="${_fp#"$MUSIC"/}"
  _artist_seg="${_rel%%/*}"
  _subpath="${_rel#*/}"          # album/.../title.mp3
  if [ "$_artist_seg" != "$_canon" ]; then
    _destdir="$MUSIC/$_canon/$(dirname "$_subpath")"
    _dest="$_destdir/$(basename "$_fp")"
    if [ -e "$_dest" ]; then
      printf 'apply: skip (exists): %s\n' "$_dest" >&2
      return 0
    fi
    mkdir -p "$_destdir"
    mv "$_fp" "$_dest" || return 1
    # 빈 원본 앨범/아티스트 폴더 정리 (MUSIC 루트는 지우지 않음)
    rmdir "$MUSIC/$_artist_seg/$(dirname "$_subpath")" 2>/dev/null || true
    rmdir "$MUSIC/$_artist_seg" 2>/dev/null || true
    _fp="$_dest"
  fi
  _tmp="$(dirname "$_fp")/.qndl-tag-$$.mp3"
  if ffmpeg -v error -y -i "$_fp" -map 0 -c copy -metadata album_artist="$_canon" "$_tmp" 2>/dev/null; then
    mv "$_tmp" "$_fp" || { rm -f "$_tmp"; return 1; }
  else
    rm -f "$_tmp"
    printf 'apply: tag failed: %s\n' "$_fp" >&2
    return 1
  fi
}

# MUSIC의 모든 아티스트 폴더를 <name>\t<mp3수>로 출력.
_artist_counts() {
  find "$MUSIC" -mindepth 1 -maxdepth 1 -type d -printf '%f\n' 2>/dev/null |
    while IFS= read -r _d; do
      _n="$(find "$MUSIC/$_d" -type f -name '*.mp3' 2>/dev/null | wc -l)"
      printf '%s\t%s\n' "$_d" "$_n"
    done
}

# stdin: <name>\t<count>. stdout: 실제 중복 그룹만 <canonical>\t<m1>\t<m2>...
_group_awk() {
  awk -F'\t' '
    function norm(x,   y){ y=tolower(x); gsub(/[^[:alnum:]가-힣]/,"",y); return y }
    function find(a){ while(parent[a]!=a){ parent[a]=parent[parent[a]]; a=parent[a] } return a }
    function union(a,b,  ra,rb){ ra=find(a); rb=find(b); if(ra!=rb) parent[rb]=ra }
    function addtok(idx,chunk,  k){ k=norm(chunk); if(k=="") return; if(k in owner) union(owner[k],idx); else owner[k]=idx }
    function caserank(s,  u,l){ u=(s ~ /[A-Z]/); l=(s ~ /[a-z]/); return (u&&l)?2:1 }
    {
      name[NR]=$1; cnt[NR]=$2+0; parent[NR]=NR
      s=$1; gsub(/（/,"(",s); gsub(/）/,")",s); rest=s
      while (match(rest,/\([^)]*\)/)) {
        addtok(NR, substr(rest,RSTART+1,RLENGTH-2))
        rest=substr(rest,1,RSTART-1) " " substr(rest,RSTART+RLENGTH)
      }
      addtok(NR, rest)
    }
    END{
      for(i=1;i<=NR;i++){ r=find(i); members[r]=members[r] i " " }
      for(r in members){
        n=split(members[r], m, " ")
        real=0; for(j=1;j<=n;j++) if(m[j]!="") real++
        if(real<2) continue
        haveEng=0
        for(j=1;j<=n;j++){ if(m[j]=="") continue; if(name[m[j]] !~ /[가-힣]/) haveEng=1 }
        best=""; brank=-1; bcnt=-1
        for(j=1;j<=n;j++){
          if(m[j]=="") continue
          nm=name[m[j]]
          if(haveEng && nm ~ /[가-힣]/) continue
          cr=caserank(nm); c=cnt[m[j]]
          if(cr>brank || (cr==brank && c>bcnt) || (cr==brank && c==bcnt && (best=="" || nm<best))){
            best=nm; brank=cr; bcnt=c
          }
        }
        line=best
        for(j=1;j<=n;j++){ if(m[j]=="") continue; line=line "\t" name[m[j]] }
        print line
      }
    }
  '
}

# stdin(그룹 라인) → 각 그룹의 비표준 멤버 이동 파일 수 계산해 dry-run 한 줄 출력.
_merge_preview() {
  while IFS="$(printf '\t')" read -r _canon _rest; do
    [ -z "$_canon" ] && continue
    _others=""; _files=0
    _oldifs="$IFS"; IFS="$(printf '\t')"
    for _mem in $_rest; do
      [ "$_mem" = "$_canon" ] && continue
      _others="${_others:+$_others, }$_mem"
      _c="$(find "$MUSIC/$_mem" -type f -name '*.mp3' 2>/dev/null | wc -l)"
      _files=$((_files + _c))
    done
    IFS="$_oldifs"
    [ -z "$_others" ] && continue
    printf '%s → %s (move %s files)\n' "$_others" "$_canon" "$_files"
  done
}

cmd_merge() {
  _apply=0
  [ "${1:-}" = "--apply" ] && _apply=1
  _groups="$(_artist_counts | _group_awk)"
  if [ -z "$_groups" ]; then
    printf 'No case/paren duplicate groups found.\n'
    return 0
  fi
  if [ "$_apply" -eq 0 ]; then
    printf '%s\n' "$_groups" | _merge_preview
    printf '\n(dry-run) 실제 병합하려면: qndl-artist merge --apply\n'
    return 0
  fi
  cmd_merge_apply "$_groups"
}

_sub="${1:-}"
[ $# -gt 0 ] && shift
case "$_sub" in
normalize) cmd_normalize "$@" ;;
apply) cmd_apply "$@" ;;
apply-download) cmd_apply_download "$@" ;;
merge) cmd_merge "$@" ;;
*) printf 'usage: qndl-artist {normalize|apply|apply-download|merge} ...\n' >&2; exit 2 ;;
esac