@startuml Release Parsing Decision Tree
skinparam ActivityBackgroundColor #f8f8f8
skinparam ActivityBorderColor #333333
skinparam DiamondBackgroundColor #fffde7
skinparam NoteBackgroundColor #e3f2fd

title Release Parsing Decision Tree

start

partition "1. Resolve Torrent Data" {
  if (DownloadLink starts\nwith "magnet:?") then (yes)
    :MagnetResolver.Resolve(magnetURI);
    note right
      DHT lookup via anacrolix/torrent
      30s timeout, 15s early exit
      if peers but none active
    end note
    if (Resolve succeeded?) then (yes)
      :torrentData = resolved bytes;
    else (no)
      :fallback to **title-only parse**;
      note right
        parser.Parse(item.Title)
        No torrent data available
        No info_hash computed
      end note
      goto TitleOnlyParse
    endif
  else (HTTP link)
    :downloadTorrentData(url);
    note right
      HTTP GET with 30s timeout
      Expects .torrent file bytes
    end note
    if (Download succeeded?) then (yes)
      :torrentData = downloaded bytes;
    else (no)
      :fallback to **title-only parse**;
      goto TitleOnlyParse
    endif
  endif
}

partition "2. ParseTorrent (torrentData + metadata album)" {

  partition "2a. Fill from Metadata Album" {
    :Artist = album.Artists[0].Name;
    :Album = album.Title;
    :Year = album.ReleaseDate[:4];
    :Type = album.AlbumType
    (album/ep/single/compilation/...);
    :Genres = album.Genres[].Name;
    :Label = album.Label.Name;
    :TrackCount = album.TotalTracks;
    :ReleaseCount = album.TotalDiscs;
  }

  partition "2b. Fill from Torrent Data" {
    :metainfo.Load(torrentData);
    note right
      Bencode decode via
      anacrolix/torrent/metainfo
    end note
    if (Parse failed?) then (yes)
      :Append to ParseErrors;
      :Skip torrent analysis;
    else (no)
      :info = mi.UnmarshalInfo();
      if (Unmarshal failed?) then (yes)
        :Append to ParseErrors;
        :Skip torrent analysis;
      else (no)
        :RawTitle = info.Name;
        :InfoHash = SHA1(info dict);

        if (info.Files is empty?\n(single-file torrent)) then (yes)
          :ext = filepath.Ext(info.Name);
          if (ext is audio?\n(.flac/.mp3/.aac/...)) then (yes)
            :Format = audioExtensions[ext];
            :AudioFileCount = 1;
            :TotalAudioSize = info.Length;
          else (no)
            :Format = unknown;
          endif
        else (multi-file torrent)
          :Iterate all files in torrent;

          repeat
            :file = next torrent file;
            :ext = filepath.Ext(file.Path);

            if (ext is audio?) then (yes)
              :formatCounts[ext]++;
              :formatSizes[ext] += file.Length;
              :TrackNames += cleanTrackName(file);
              note right
                Strip leading "01. " or "1 - "
                from filename
              end note
            elseif (ext is .jpg/.jpeg/.png?) then (yes)
              :HasCoverArt = true;
            elseif (ext is .cue?) then (yes)
              :HasCueSheet = true;
            elseif (ext is .log?) then (yes)
              :HasRipLog = true;
            endif
          repeat while (more files?)

          :Format = dominant format\n(most audio files);
          :AudioFileCount = count of dominant;
          :TotalAudioSize = sum of dominant;
        endif

        if (HasRipLog?) then (yes)
          :Source = CD;
          note right
            .log file = EAC/XLD rip log
            implies CD source
          end note
        endif

        if (TrackCount == 0?) then (yes)
          :TrackCount = AudioFileCount;
        endif
      endif
    endif
  }

  partition "2c. Fill from Title (torrent name)" #f0f0f0 {
    label TitleParsing
    :title = info.Name (or item.Title for fallback);

    if (title matches\n"(\\d{2,3})\\s*kbps"?) then (yes)
      :Bitrate = matched value + " kbps";
    endif

    :Try hi-res patterns (in order):;
    note right
      1. "24Bit-96kHz" / "24 Bit / 48 kHz"
      2. "FLAC 24-96" / "Flac 24-44"
      3. "24Bit" (bit depth only)
      First match wins.
    end note
    if (Hi-res pattern matched?) then (yes)
      if (BitDepth still 0?) then (yes)
        :BitDepth = matched group 1;
      endif
      if (SampleRate still 0\nand group 2 exists?) then (yes)
        :SampleRate = matched × 1000;
      endif
    endif

    if (title matches\n"\\[(CD|WEB|Vinyl|...)\\]"\nand Source still unknown?) then (yes)
      :Source = matched value;
      note right
        CD, WEB, Vinyl/LP,
        Cassette/MC, DVD,
        Blu-Ray
      end note
    endif

    if (title matches\nrip type pattern?) then (yes)
      :RipType = matched value;
      note right
        vinyl rip, SACD-R,
        HDCD, DSD, tape rip
      end note
    endif
  }

  :ParsedSuccessfully = (Artist != "" && Album != "");
  if (not ParsedSuccessfully?) then (yes)
    :ParseErrors += "missing artist or album";
  endif

  :Return Release;
  stop
}

partition "3. Title-Only Parse (fallback)" #fff3e0 {
  label TitleOnlyParse
  :r = Release{RawTitle: item.Title};
  note right
    No torrent data available.
    No InfoHash. No file analysis.
    No TrackNames. No cover/cue/log.
    Format stays **unknown**.
  end note
  goto TitleParsing
}

@enduml