import 'package:freezed_annotation/freezed_annotation.dart';
import 'package:worldhopper/models/entry.dart';
import 'package:worldhopper/models/link.dart';

part 'feed.freezed.dart';
part 'feed.g.dart';

/// Represents an OPDS feed (navigation or acquisition)
@freezed
class Feed with _$Feed {
  const factory Feed({
    /// Feed ID
    required String id,

    /// Feed title
    required String title,

    /// Feed subtitle
    String? subtitle,

    /// Feed icon URL
    String? icon,

    /// Last update timestamp
    DateTime? updated,

    /// Feed author
    String? author,

    /// All links in the feed
    @Default([]) List<Link> links,

    /// All entries in the feed
    @Default([]) List<Entry> entries,

    /// Total results (for paginated feeds)
    int? totalResults,

    /// Items per page (for paginated feeds)
    int? itemsPerPage,

    /// Start index (for paginated feeds)
    int? startIndex,
  }) = _Feed;

  const Feed._();

  /// Create Feed from JSON
  factory Feed.fromJson(Map<String, dynamic> json) => _$FeedFromJson(json);

  /// Check if this is a navigation feed
  bool get isNavigationFeed => entries.any((entry) => entry.isNavigation);

  /// Check if this is an acquisition feed (contains publications)
  bool get isAcquisitionFeed => !isNavigationFeed;

  /// Get the start (root) link
  Link? get startLink => links.cast<Link?>().firstWhere(
        (link) => link?.rel == 'start',
        orElse: () => null,
      );

  /// Get the self link
  Link? get selfLink => links.cast<Link?>().firstWhere(
        (link) => link?.rel == 'self',
        orElse: () => null,
      );

  /// Get the next page link
  Link? get nextLink => links.cast<Link?>().firstWhere(
        (link) => link?.rel == 'next',
        orElse: () => null,
      );

  /// Get the previous page link
  Link? get previousLink => links.cast<Link?>().firstWhere(
        (link) => link?.rel == 'previous' || link?.rel == 'prev',
        orElse: () => null,
      );
}