expense-tracker/lib/widgets/chart.dart

import 'package:expense_planner/widgets/chart_bar.dart';
import 'package:flutter/material.dart';
import 'package:intl/intl.dart';

import '../models/transaction.dart';

class Chart extends StatelessWidget {
  const Chart({Key? key, required this.transactions}) : super(key: key);

  final List<Transaction> transactions;

  List<Map<String, Object>> get groupedTransactions {
    return List.generate(7, (index) {
      final weekDay = DateTime.now().subtract(Duration(days: index));
      double totalSum = 0;

      for (var transaction in transactions) {
        if (transaction.date.day == weekDay.day &&
            transaction.date.month == weekDay.month &&
            transaction.date.year == weekDay.year) {
          totalSum += transaction.amount;
        }
      }

      return {
        'day': DateFormat.E().format(weekDay).substring(0, 1).toUpperCase(),
        'amount': totalSum,
      };
    }).reversed.toList();
  }

  double get maxSpending {
    return groupedTransactions.fold(
        0.0, (sum, transaction) => sum + (transaction['amount'] as double));
  }

  @override
  Widget build(BuildContext context) {
    return Card(
      elevation: 1,
      margin: EdgeInsets.all(10),
      child: Padding(
        padding: EdgeInsets.all(5),
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceAround,
          children: groupedTransactions.map((data) {
            return Flexible(
              fit: FlexFit.tight,
              child: ChartBar(
                label: (data['day'] as String),
                amount: (data['amount'] as double),
                spendingPercentTotal: maxSpending == 0.0
                    ? 0.0
                    : (data['amount'] as double) / maxSpending,
              ),
            );
          }).toList(),
        ),
      ),
    );
  }
}