import 'package:flutter/material.dart';

/// Column width specification for DataGrid columns.
sealed class DataGridColumnWidth {
  const DataGridColumnWidth._();

  /// Fixed width in logical pixels.
  const factory DataGridColumnWidth.fixed(double width) = GridFixedWidth;

  /// Flexible width with flex factor (like Expanded).
  const factory DataGridColumnWidth.flex([int flex]) = GridFlexWidth;

  /// Fraction of available width (0.0 to 1.0).
  const factory DataGridColumnWidth.fraction(double fraction) =
      GridFractionWidth;
}

/// Fixed column width.
final class GridFixedWidth extends DataGridColumnWidth {
  const GridFixedWidth(this.width) : super._();
  final double width;
}

/// Flexible column width.
final class GridFlexWidth extends DataGridColumnWidth {
  const GridFlexWidth([this.flex = 1]) : super._();
  final int flex;
}

/// Fractional column width.
final class GridFractionWidth extends DataGridColumnWidth {
  const GridFractionWidth(this.fraction)
      : assert(fraction > 0 && fraction <= 1),
        super._();
  final double fraction;
}

/// Column alignment options.
enum DataGridColumnAlignment {
  start,
  center,
  end,
}

/// Column definition for DataGrid.
class DataGridColumn<T> {
  const DataGridColumn({
    required this.id,
    required this.header,
    required this.valueBuilder,
    this.cellBuilder,
    this.cellControlsBuilder,
    this.width = const DataGridColumnWidth.flex(1),
    this.alignment = DataGridColumnAlignment.start,
    this.sortable = false,
    this.sortField,
    this.searchable = false,
    this.visible = true,
    this.tooltip,
  });

  /// Unique identifier for this column (used in URL deep-linking).
  final String id;

  /// Column header text.
  final String header;

  /// Extracts the string value from an item for sorting/searching.
  final String Function(T item) valueBuilder;

  /// Custom cell widget builder. If null, displays valueBuilder result as text.
  final Widget Function(BuildContext context, T item)? cellBuilder;

  /// Additional controls to show in the cell (e.g., quick actions).
  final Widget Function(BuildContext context, T item)? cellControlsBuilder;

  /// Column width specification.
  final DataGridColumnWidth width;

  /// Text alignment within the column.
  final DataGridColumnAlignment alignment;

  /// Whether this column can be sorted.
  final bool sortable;

  /// API field name for server-side sorting. Defaults to using header if null.
  final String? sortField;

  /// Whether this column is included in search.
  final bool searchable;

  /// Whether this column is visible.
  final bool visible;

  /// Tooltip builder for cell hover.
  final String Function(T item)? tooltip;

  /// Gets the effective sort field name.
  String get effectiveSortField => sortField ?? header.toLowerCase();

  /// Converts alignment enum to CrossAxisAlignment.
  CrossAxisAlignment get crossAxisAlignment => switch (alignment) {
        DataGridColumnAlignment.start => CrossAxisAlignment.start,
        DataGridColumnAlignment.center => CrossAxisAlignment.center,
        DataGridColumnAlignment.end => CrossAxisAlignment.end,
      };

  /// Converts alignment enum to TextAlign.
  TextAlign get textAlign => switch (alignment) {
        DataGridColumnAlignment.start => TextAlign.start,
        DataGridColumnAlignment.center => TextAlign.center,
        DataGridColumnAlignment.end => TextAlign.end,
      };
}