// lib/metadata/metadata_normalizer.dart
import 'metadata_model.dart';

class MetadataNormalizer {
  NormalizedMetadata normalize(RawMetadata raw,
      {String fileName = '', String filePath = ''}) {
    final title = raw.title.trim();
    final artist = raw.artist.trim();

    final finalTitle =
        title.isNotEmpty ? title : _inferTitleFromFileName(fileName);
    final finalArtist =
        artist.isNotEmpty ? artist : _inferArtistFromPath(filePath);
    final finalArtist2 = finalArtist.isNotEmpty
        ? finalArtist
        : (raw.performers.isNotEmpty ? raw.performers.first : '未知艺术家');

    return NormalizedMetadata(
      title: finalTitle,
      artist: finalArtist2,
      album: raw.album,
      genres: raw.genres,
      performers: raw.performers,
      year: raw.year,
      trackNumber: raw.trackNumber,
      trackTotal: raw.trackTotal,
      discNumber: raw.discNumber,
      totalDisc: raw.totalDisc,
      duration: raw.duration,
      artwork: raw.artwork,
    );
  }

  String _inferTitleFromFileName(String fileName) {
    final dotIndex = fileName.lastIndexOf('.');
    return dotIndex > 0
        ? fileName.substring(0, dotIndex).trim()
        : fileName.trim();
  }

  String _inferArtistFromPath(String filePath) {
    final parts = filePath.split(RegExp(r'[/\\]'));
    if (parts.length >= 2) {
      final candidate = parts[parts.length - 2].trim();
      if (candidate.isNotEmpty && !candidate.startsWith('http')) {
        return candidate;
      }
    }
    return '未知艺术家';
  }

  CandidateMetadata evaluate(
      NormalizedMetadata normalized, List<Map<String, dynamic>> history) {
    // 第一版：直接接受，置信度 0.8
    return CandidateMetadata(
      metadata: normalized,
      confidence: 0.8,
      evidence: {'normalized': 0.8},
    );
  }

  FinalMetadata decide(CandidateMetadata candidate, {double threshold = 0.6}) {
    return FinalMetadata(
      title: candidate.metadata.title,
      artist: candidate.metadata.artist,
      album: candidate.metadata.album,
      genre: candidate.metadata.genres.isNotEmpty
          ? candidate.metadata.genres.first
          : '',
      genres: candidate.metadata.genres,
      performers: candidate.metadata.performers,
      year: candidate.metadata.year,
      trackNumber: candidate.metadata.trackNumber,
      trackTotal: candidate.metadata.trackTotal,
      discNumber: candidate.metadata.discNumber,
      totalDisc: candidate.metadata.totalDisc,
      duration: candidate.metadata.duration,
      artwork: candidate.metadata.artwork,
      source: 'normalized',
    );
  }
}