import 'package:fl_chart/fl_chart.dart';
import 'package:flutter/material.dart';
import 'package:intl/intl.dart' as intl;
import 'dart:math';

import '../model/reading.dart';

class ReadingGraph extends StatelessWidget {
  const ReadingGraph({super.key, required List<Reading> readings})
      : _readings = readings;
  final List<Reading> _readings;

  @override
  Widget build(BuildContext context) {
    final spots = _readings
        .map<FlSpot>(
          (e) => FlSpot(
              e.dateTime.millisecondsSinceEpoch.toDouble() / 1000 / 60,
              e.value),
        )
        .toList();

    return LineChart(
      LineChartData(
        maxY: _readings.map<double>((e) => e.value).reduce(max) + 0.05,
        minY: _readings.map<double>((e) => e.value).reduce(min) - 0.05,
        lineBarsData: [
          LineChartBarData(
            isCurved: true,
            color: Colors.cyan,
            barWidth: 2,
            isStrokeCapRound: true,
            dotData: const FlDotData(show: false),
            spots: _readings
                .map<FlSpot>(
                  (e) => FlSpot(
                      e.dateTime.millisecondsSinceEpoch.toDouble() / 1000 / 60,
                      e.value),
                )
                .toList(),
          )
        ],
        titlesData: FlTitlesData(
          bottomTitles: getBottomTitles(spots),
          leftTitles: getLeftTitles(spots),
          topTitles: const AxisTitles(sideTitles: SideTitles()),
          rightTitles: const AxisTitles(sideTitles: SideTitles()),
        ),
      ),
    );
  }

  AxisTitles getBottomTitles(List<FlSpot> spots) {
    return AxisTitles(
      sideTitles: SideTitles(
        interval: 90,
        reservedSize: 40,
        showTitles: true,
        maxIncluded: false,
        getTitlesWidget: (value, meta) => SideTitleWidget(
          meta: meta,
          child: Text(getDate(value)),
        ),
      ),
    );
  }

  AxisTitles getLeftTitles(List<FlSpot> spots) {
    return AxisTitles(
      sideTitles: SideTitles(
        reservedSize: 50,
        showTitles: true,
        maxIncluded: false,
        minIncluded: false,
        getTitlesWidget: (value, meta) => SideTitleWidget(
          meta: meta,
          child: Text(value.toStringAsFixed(2)),
        ),
      ),
    );
  }

  String getDate(double value) {
    intl.DateFormat hmFormat = intl.DateFormat('Hm');
    return hmFormat.format(
        DateTime.fromMillisecondsSinceEpoch((value * 1000 * 60).toInt()));
  }
}