// lib/widgets/activity/activity_data_loader.dart

import 'package:aves/model/activity/activity_entry.dart';
import 'package:aves/model/activity/activity_grouping.dart';
import 'package:aves/model/activity/activity_preview_point.dart';
import 'package:aves/model/db/folder_content_type.dart';
import 'package:aves/model/db/folder_stats.dart';
import 'package:aves/services/common/services.dart';

class ActivityEntriesLoadResult {
  final List<ActivityEntry> entries;
  final Map<int, List<ActivityPreviewPoint>> previewPointsByActivityId;

  const ActivityEntriesLoadResult({
    required this.entries,
    required this.previewPointsByActivityId,
  });
}

class ActivityGroupsLoadResult<T> {
  final List<T> groups;
  final Map<int, List<ActivityPreviewPoint>> previewPointsByActivityId;

  const ActivityGroupsLoadResult({
    required this.groups,
    required this.previewPointsByActivityId,
  });
}

class ActivityDataLoader {
  const ActivityDataLoader._();

  static Future<ActivityEntriesLoadResult> loadEntries({
    required bool favouriteOnly,
    required bool withoutSportOnly,
    String? sport,
    String? directory,
  }) async {
    final loadedActivities = await localMediaDb.loadActivities(
      sport: withoutSportOnly ? null : sport,
      directory: directory,
      favourite: favouriteOnly ? true : null,
    );

    Iterable<ActivityEntry> activities = loadedActivities;

    if (withoutSportOnly) {
      activities = activities.where((entry) {
        final sport = entry.sport?.trim();
        return sport == null || sport.isEmpty;
      });
    }

    final entries = activities.toList();

    final ids = entries.map((entry) => entry.id).whereType<int>().toSet();

    final previewPoints = await localMediaDb.loadActivityPreviewPointsByActivityIds(ids);

    return ActivityEntriesLoadResult(
      entries: entries,
      previewPointsByActivityId: previewPoints,
    );
  }

  static Future<ActivityGroupsLoadResult<ActivitySportGroup>> loadSportGroups() async {
    final activities = await localMediaDb.loadActivities();
    final groups = ActivityGrouping.buildSportGroups(activities);

    final ids = groups.map((group) => group.coverEntry?.id).whereType<int>().toSet();

    final previewPoints = await localMediaDb.loadActivityPreviewPointsByActivityIds(ids);

    return ActivityGroupsLoadResult<ActivitySportGroup>(
      groups: groups,
      previewPointsByActivityId: previewPoints,
    );
  }

  static Future<ActivityGroupsLoadResult<ActivityAlbumGroup>> loadAlbumGroups() async {
    final folders = await localMediaDb.loadFolders(
      contentType: FolderContentType.activity,
    );

    final activities = await localMediaDb.loadActivities();

    // Fallback utile finché non hai fatto una nuova scansione dopo
    // l'introduzione di folders.content_type = activity.
    if (folders.isEmpty) {
      final groups = ActivityGrouping.buildAlbumGroups(activities);

      final ids = groups.map((group) => group.coverEntry?.id).whereType<int>().toSet();

      final previewPoints = await localMediaDb.loadActivityPreviewPointsByActivityIds(ids);

      return ActivityGroupsLoadResult<ActivityAlbumGroup>(
        groups: groups,
        previewPointsByActivityId: previewPoints,
      );
    }

    final activitiesById = <int, ActivityEntry>{};

    for (final entry in activities) {
      final id = entry.id;
      if (id != null) {
        activitiesById[id] = entry;
      }
    }

    final groups =
        folders.where((folder) => folder.hidden == 0).map((folder) {
          final coverEntry = _coverEntryForFolder(
            folder: folder,
            activities: activities,
            activitiesById: activitiesById,
          );

          return ActivityAlbumGroup(
            displayName: _folderDisplayName(folder),
            directoryFilter: folder.path,
            count: folder.fileCount,
            coverEntry: coverEntry,
          );
        }).toList()..sort(
          (a, b) => a.displayName.toLowerCase().compareTo(
            b.displayName.toLowerCase(),
          ),
        );

    final ids = groups.map((group) => group.coverEntry?.id).whereType<int>().toSet();

    final previewPoints = await localMediaDb.loadActivityPreviewPointsByActivityIds(ids);

    return ActivityGroupsLoadResult<ActivityAlbumGroup>(
      groups: groups,
      previewPointsByActivityId: previewPoints,
    );
  }

  static ActivityEntry? _coverEntryForFolder({
    required FolderStats folder,
    required Iterable<ActivityEntry> activities,
    required Map<int, ActivityEntry> activitiesById,
  }) {
    final thumbEntryId = folder.thumbEntryId;

    if (thumbEntryId != null) {
      final entry = activitiesById[thumbEntryId];
      if (entry != null) return entry;
    }

    final normalizedFolderPath = _normalizePath(folder.path);

    final matching =
        activities.where((entry) {
          return _folderPathForEntry(entry) == normalizedFolderPath;
        }).toList()..sort((a, b) {
          final aDate = a.startTimeMillis ?? a.dateModifiedMillis;
          final bDate = b.startTimeMillis ?? b.dateModifiedMillis;
          return bDate.compareTo(aDate);
        });

    if (matching.isEmpty) return null;

    return matching.first;
  }

  static String _folderDisplayName(FolderStats folder) {
    final displayName = folder.displayName.trim();

    if (displayName.isNotEmpty) {
      return displayName;
    }

    return _displayNameForPath(folder.path);
  }

  static String _folderPathForEntry(ActivityEntry entry) {
    final relativePath = entry.relativePath?.trim();

    if (relativePath != null && relativePath.isNotEmpty) {
      return _normalizePath(relativePath);
    }

    final directoryName = entry.directoryName?.trim();

    if (directoryName != null && directoryName.isNotEmpty) {
      return _normalizePath(directoryName);
    }

    return 'Activity';
  }

  static String _normalizePath(String path) {
    var normalized = path.replaceAll('\\', '/').trim();

    while (normalized.contains('//')) {
      normalized = normalized.replaceAll('//', '/');
    }

    if (normalized.endsWith('/')) {
      normalized = normalized.substring(0, normalized.length - 1);
    }

    return normalized.isEmpty ? 'Activity' : normalized;
  }

  static String _displayNameForPath(String path) {
    final normalized = _normalizePath(path);
    final parts = normalized.split('/').where((part) => part.isNotEmpty);

    if (parts.isEmpty) return 'Activity';

    return parts.last;
  }
}