custom_bar_chart.dart

import 'package:easy_localization/easy_localization.dart';
import 'package:fl_chart/fl_chart.dart';
import 'package:flutter/material.dart';

import 'package:scrobbles/config/app_colors.dart';
import 'package:scrobbles/utils/color_extensions.dart';

class CustomBarChart extends StatelessWidget {
  const CustomBarChart({super.key});

  final double chartHeight = 150.0;
  final double verticalTicksInterval = 10;
  final String verticalAxisTitleSuffix = '';
  final double titleFontSize = 10;

  @override
  Widget build(BuildContext context) {
    return Container(
      child: SizedBox(
        height: this.chartHeight,
      ),
    );
  }

  BarChart getBarChart({barWidth, backgroundColor}) {
    return BarChart(
      BarChartData(
        barGroups: getDataCounts(barWidth),
        backgroundColor: backgroundColor,
        borderData: getBorderData(),
        gridData: getGridData(),
        titlesData: getTitlesData(),
        barTouchData: BarTouchData(enabled: false),
        maxY: getNextRoundNumber(getMaxCountsValue(), this.verticalTicksInterval),
      ),
    );
  }

  double getBarWidth(double containerWidth, int barsCount) {
    return 0.65 * (containerWidth / barsCount);
  }

  List<BarChartGroupData> getDataCounts(double barWidth) {
    return [];
  }

  double getMaxCountsValue() {
    return 0.0;
  }

  double getNextRoundNumber(double number, double scale) {
    return scale * ((number ~/ scale).toInt() + 1);
  }

  BarChartGroupData getBarItem(
      {required int x,
      required List<double> values,
      required List<Color> barColors,
      required double barWidth}) {
    List<BarChartRodData> barRods = [];

    for (int i = 0; i < values.length; i++) {
      double value = values[i];
      Color barColor = barColors[i];

      final gradient = this.getGradient(barColor, value, this.getMaxCountsValue());
      final borderColor = barColor.darken(20);

      barRods.add(
        BarChartRodData(
          toY: value,
          color: barColor,
          gradient: gradient,
          width: barWidth,
          borderRadius: BorderRadius.all(Radius.zero),
          borderSide: BorderSide(
            color: borderColor,
          ),
        ),
      );
    }

    return BarChartGroupData(
      x: x,
      barRods: barRods,
    );
  }

  LinearGradient getGradient(Color baseColor, double value, double maxValue) {
    double alignmentTopValue = value != 0.0 ? -2 * maxValue / value + 1 : 0;

    return LinearGradient(
      begin: Alignment(-1, alignmentTopValue),
      end: Alignment(1, 1),
      colors: <Color>[
        baseColor.lighten(30),
        baseColor,
        baseColor.darken(30),
      ],
      tileMode: TileMode.mirror,
    );
  }

  FlBorderData getBorderData() {
    return FlBorderData(
      show: true,
      border: Border.all(
        color: AppColors.borderColor,
        width: 2,
      ),
    );
  }

  FlGridData getGridData() {
    return const FlGridData(
      show: true,
      drawHorizontalLine: true,
      drawVerticalLine: false,
    );
  }

  FlTitlesData getTitlesData() {
    const AxisTitles none = const AxisTitles(
      sideTitles: SideTitles(showTitles: false),
    );

    final AxisTitles verticalTitles = AxisTitles(
      sideTitles: SideTitles(
        showTitles: true,
        reservedSize: 35,
        getTitlesWidget: getVerticalTitlesWidget,
        interval: this.verticalTicksInterval,
      ),
    );

    final AxisTitles verticalSpacer = AxisTitles(
      sideTitles: SideTitles(
        showTitles: true,
        reservedSize: 35,
        getTitlesWidget: getVerticalTitlesSpacerWidget,
        interval: this.verticalTicksInterval,
      ),
    );

    final AxisTitles horizontalTitles = AxisTitles(
      sideTitles: SideTitles(
        showTitles: true,
        reservedSize: 20,
        getTitlesWidget: getHorizontalTitlesWidget,
      ),
    );

    return FlTitlesData(
      show: true,
      bottomTitles: horizontalTitles,
      leftTitles: verticalTitles,
      topTitles: none,
      rightTitles: verticalSpacer,
    );
  }

  Widget getVerticalTitlesWidget(double value, TitleMeta meta) {
    String suffix =
        this.verticalAxisTitleSuffix != '' ? ' ' + this.verticalAxisTitleSuffix : '';

    return SideTitleWidget(
      axisSide: meta.axisSide,
      space: 4,
      child: Text(
        value.toInt().toString() + suffix,
        style: TextStyle(
          color: AppColors.mainTextColor1,
          fontSize: this.titleFontSize,
        ),
      ),
    );
  }

  Widget getVerticalTitlesSpacerWidget(double value, TitleMeta meta) {
    return SideTitleWidget(
      axisSide: meta.axisSide,
      space: 4,
      child: Text(''),
    );
  }

  Widget getHorizontalTitlesWidget(double value, TitleMeta meta) {
    final DateFormat formatter = DateFormat('dd/MM');

    final DateTime date = DateTime.fromMillisecondsSinceEpoch(value.toInt());
    final String text = formatter.format(date);

    return SideTitleWidget(
      axisSide: meta.axisSide,
      space: 4,
      child: Padding(
        padding: EdgeInsets.only(right: 10),
        child: RotationTransition(
          turns: new AlwaysStoppedAnimation(-30 / 360),
          child: Text(
            text,
            style: TextStyle(
              color: AppColors.mainTextColor1,
              fontSize: this.titleFontSize,
            ),
          ),
        ),
      ),
    );
  }
}