/*
 * Copyright (C) 2017, David PHAM-VAN <dev.nfet.net@gmail.com>
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import '../../../pdf.dart';
import '../basic.dart';
import '../container.dart';
import '../decoration.dart';
import '../flex.dart';
import '../geometry.dart';
import '../text.dart';
import '../text_style.dart';
import '../theme.dart';
import '../widget.dart';
import '../wrap.dart';
import 'chart.dart';

class ChartLegend extends StatelessWidget {
  ChartLegend({
    this.textStyle,
    this.position = Alignment.topRight,
    this.direction = Axis.vertical,
    this.decoration,
    this.padding = const EdgeInsets.all(5),
  });

  final TextStyle? textStyle;

  final Alignment position;

  final Axis direction;

  final BoxDecoration? decoration;

  final EdgeInsets padding;

  Widget _buildLegend(Context context, Dataset dataset) {
    final style = Theme.of(context).defaultTextStyle.merge(textStyle);

    return Row(
      mainAxisSize: MainAxisSize.min,
      children: <Widget>[
        Container(
          width: style.fontSize,
          height: style.fontSize,
          margin: const EdgeInsets.only(right: 5),
          child: dataset.legendShape(context),
        ),
        Text(
          dataset.legend!,
          style: textStyle,
        ),
      ],
    );
  }

  @override
  Widget build(Context context) {
    final datasets = Chart.of(context).datasets;

    final Widget wrap = Wrap(
      direction: direction,
      spacing: 10,
      runSpacing: 10,
      crossAxisAlignment: direction == Axis.horizontal
          ? WrapCrossAlignment.center
          : WrapCrossAlignment.start,
      children: <Widget>[
        for (final Dataset dataset in datasets)
          if (dataset.legend != null) _buildLegend(context, dataset)
      ],
    );

    return Align(
      alignment: position,
      child: Container(
        decoration: decoration ?? const BoxDecoration(color: PdfColors.white),
        padding: padding,
        child: wrap,
      ),
    );
  }
}