import 'package:commons_core/commons_core.dart';
import 'package:drift/drift.dart';

import '../db/database.dart';

/// One entry from the bundled catalog, before it is stored.
class SpeciesSeed {
  const SpeciesSeed({
    required this.scientificName,
    this.family,
    this.commonNames = const {},
    this.viabilityYears,
  });

  final String scientificName;
  final String? family;

  /// language code → list of common names.
  final Map<String, List<String>> commonNames;

  /// Typical seed longevity in years (bundled reference data); null if unknown.
  final int? viabilityYears;
}

/// A catalog match surfaced to the UI (with a best common name for the locale).
class SpeciesMatch {
  const SpeciesMatch({
    required this.id,
    required this.scientificName,
    this.family,
    this.commonName,
  });

  final String id;
  final String scientificName;
  final String? family;
  final String? commonName;

  /// Label shown in the autocomplete: common name (scientific) when both exist.
  String get displayLabel =>
      commonName == null ? scientificName : '$commonName ($scientificName)';
}

/// Reads and seeds the bundled species catalog. Bundled rows are marked
/// `is_bundled = true` and are not synced (data-model §2.2).
class SpeciesRepository {
  SpeciesRepository(this._db, {required this.idGen, this.nodeId = 'bundle'});

  final AppDatabase _db;
  final IdGen idGen;
  final String nodeId;

  /// Idempotently inserts bundled species (keyed by scientific name). Safe to
  /// call on every startup. Existing rows keep their identity, but a bundled
  /// row still missing [SpeciesSeed.viabilityYears] is backfilled — so the
  /// reference data reaches installs seeded before the field was bundled.
  Future<void> seedBundled(List<SpeciesSeed> seeds) async {
    final stamp = Hlc.zero(nodeId).pack();
    await _db.transaction(() async {
      for (final seed in seeds) {
        final existing =
            await (_db.select(_db.species)
                  ..where((s) => s.scientificName.equals(seed.scientificName)))
                .getSingleOrNull();
        if (existing != null) {
          // Backfill bundled reference data added after the row was seeded.
          if (existing.viabilityYears == null && seed.viabilityYears != null) {
            await (_db.update(_db.species)
                  ..where((s) => s.id.equals(existing.id)))
                .write(
                  SpeciesCompanion(
                    viabilityYears: Value(seed.viabilityYears),
                  ),
                );
          }
          continue;
        }

        final speciesId = idGen.newId();
        await _db
            .into(_db.species)
            .insert(
              SpeciesCompanion.insert(
                id: speciesId,
                createdAt: 0,
                updatedAt: stamp,
                lastAuthor: nodeId,
                scientificName: seed.scientificName,
                family: Value(seed.family),
                isBundled: const Value(true),
                viabilityYears: Value(seed.viabilityYears),
              ),
            );

        for (final entry in seed.commonNames.entries) {
          for (final name in entry.value) {
            await _db
                .into(_db.speciesCommonNames)
                .insert(
                  SpeciesCommonNamesCompanion.insert(
                    id: idGen.newId(),
                    createdAt: 0,
                    updatedAt: stamp,
                    lastAuthor: nodeId,
                    speciesId: speciesId,
                    name: name,
                    language: Value(entry.key),
                  ),
                );
          }
        }
      }
    });
  }

  /// Searches species by scientific name or a common name (case-insensitive
  /// substring). The catalog is small, so it is filtered in Dart. Returns up to
  /// [limit] matches, each with a best common name for [languageCode].
  Future<List<SpeciesMatch>> search(
    String query, {
    String languageCode = 'en',
    int limit = 8,
  }) async {
    final q = query.trim().toLowerCase();
    if (q.isEmpty) return const [];

    final species = await (_db.select(
      _db.species,
    )..where((s) => s.isDeleted.equals(false))).get();
    final commons = await (_db.select(
      _db.speciesCommonNames,
    )..where((n) => n.isDeleted.equals(false))).get();

    final namesBySpecies = <String, List<({String name, String? language})>>{};
    for (final c in commons) {
      namesBySpecies.putIfAbsent(c.speciesId, () => []).add((
        name: c.name,
        language: c.language,
      ));
    }

    final matches = <SpeciesMatch>[];
    for (final s in species) {
      final names = namesBySpecies[s.id] ?? const [];
      final matchesScientific = s.scientificName.toLowerCase().contains(q);
      final matchesCommon = names.any((n) => n.name.toLowerCase().contains(q));
      if (matchesScientific || matchesCommon) {
        matches.add(
          SpeciesMatch(
            id: s.id,
            scientificName: s.scientificName,
            family: s.family,
            commonName: _bestName(names, languageCode),
          ),
        );
      }
    }
    matches.sort((a, b) => a.scientificName.compareTo(b.scientificName));
    return matches.take(limit).toList();
  }

  String? _bestName(
    List<({String name, String? language})> names,
    String languageCode,
  ) {
    if (names.isEmpty) return null;
    final inLocale = names.where((n) => n.language == languageCode);
    return (inLocale.isNotEmpty ? inLocale.first : names.first).name;
  }
}