import 'package:freezed_annotation/freezed_annotation.dart';

part 'data_grid_state.freezed.dart';

/// State for a DataGrid instance.
@freezed
class DataGridState<T> with _$DataGridState<T> {
  const factory DataGridState({
    /// Current items being displayed.
    @Default([]) List<T> items,

    /// Total count of items (may differ from items.length for pagination).
    @Default(0) int totalCount,

    /// Whether data is currently loading.
    @Default(false) bool isLoading,

    /// Whether initial load is in progress.
    @Default(true) bool isInitialLoad,

    /// Error that occurred during loading.
    Object? error,

    /// Current search query.
    @Default('') String searchQuery,

    /// Index of the column currently sorted by.
    int? sortColumnIndex,

    /// Whether sort is descending.
    @Default(false) bool sortDescending,

    /// Currently selected item IDs (if selectable).
    @Default({}) Set<Object> selectedIds,

    /// Current page (for paginated mode).
    @Default(0) int currentPage,

    /// Whether more items can be loaded (for infinite scroll).
    @Default(false) bool hasMore,
  }) = _DataGridState<T>;
}

/// Extension methods for DataGridState.
extension DataGridStateX<T> on DataGridState<T> {
  /// Whether the grid has an error.
  bool get hasError => error != null;

  /// Whether the grid is empty (no items and not loading).
  bool get isEmpty => items.isEmpty && !isLoading && !hasError;

  /// Whether all visible items are selected.
  bool get allSelected =>
      items.isNotEmpty && selectedIds.length == items.length;

  /// Whether some (but not all) items are selected.
  bool get someSelected =>
      selectedIds.isNotEmpty && selectedIds.length < items.length;

  /// Number of selected items.
  int get selectedCount => selectedIds.length;
}