okane/lib/ui/pages/account/breakdown_card.dart

import 'dart:math';

import 'package:fl_chart/fl_chart.dart';
import 'package:flutter/material.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:get_it/get_it.dart';
import 'package:okane/database/collections/transaction.dart';
import 'package:okane/database/database.dart';
import 'package:okane/ui/state/core.dart';
import 'package:okane/ui/utils.dart';

const CATEGORY_INCOME = "Income";
const CATEGORY_OTHER = "Other";

typedef LegendData =
    ({Map<String, double> expenses, Map<String, Color> colors, double usable});

class LegendItem extends StatelessWidget {
  final String text;
  final Color color;

  const LegendItem({required this.text, required this.color, super.key});

  @override
  Widget build(BuildContext context) {
    return Row(
      mainAxisAlignment: MainAxisAlignment.start,
      children: [
        DecoratedBox(
          decoration: BoxDecoration(
            color: color,
            borderRadius: BorderRadius.circular(5),
          ),
          child: SizedBox(width: 10, height: 10),
        ),
        Padding(padding: EdgeInsets.only(left: 8), child: Text(text)),
      ],
    );
  }
}

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

  LegendData _computeSections(List<Transaction> transactions) {
    Map<String, double> expenses = {};
    Map<String, Color> colors = {};
    double usableMoney = 0;
    transactions.forEach((t) {
      String category;
      if (t.amount > 0) {
        category = CATEGORY_INCOME;
        colors[CATEGORY_INCOME] = Colors.green;
      } else {
        if (t.expenseCategory.value?.name == null) {
          category = CATEGORY_OTHER;
          colors[category] = Colors.red;
        } else {
          category = t.expenseCategory.value!.name;
          colors[category] = colorHash(t.expenseCategory.value!.name);
        }
      }

      expenses.update(
        category,
        (value) => value + t.amount.abs(),
        ifAbsent: () => t.amount.abs(),
      );
      usableMoney += t.amount;
    });
    return (expenses: expenses, colors: colors, usable: usableMoney);
  }

  @override
  Widget build(BuildContext context) {
    final bloc = GetIt.I.get<CoreCubit>();
    return Card(
      child: Padding(
        padding: const EdgeInsets.all(8),
        child: BlocBuilder<CoreCubit, CoreState>(
          builder: (context, state) {
            if (bloc.activeAccount == null) {
              return Text("No active account");
            }

            return FutureBuilder(
              future: getLastTransactions(
                bloc.activeAccount!,
                DateTime.now(),
                30,
              ),
              builder: (context, snapshot) {
                final title = Padding(
                  padding: EdgeInsets.only(bottom: 16),
                  child: Text("Expense Breakdown"),
                );
                if (!snapshot.hasData) {
                  return Column(children: [title, CircularProgressIndicator()]);
                }

                if (snapshot.data!.isEmpty) {
                  return Column(children: [title, Text("No transactions")]);
                }

                final data = _computeSections(snapshot.data!);
                final sectionData =
                    data.expenses.entries
                        .map(
                          (entry) => PieChartSectionData(
                            value: entry.value,
                            title: formatCurrency(entry.value, precise: false),
                            titleStyle: TextStyle(fontWeight: FontWeight.bold),
                            radius: 40,
                            color: data.colors[entry.key]!,
                          ),
                        )
                        .toList();
                return Column(
                  children: [
                    title,
                    Row(
                      children: [
                        SizedBox(
                          width: 150,
                          height: 150,
                          child: AspectRatio(
                            aspectRatio: 1,
                            child: PieChart(
                              PieChartData(
                                borderData: FlBorderData(show: false),
                                sectionsSpace: 0,
                                centerSpaceRadius: 35,
                                sections: sectionData,
                              ),
                            ),
                          ),
                        ),

                        Padding(
                          padding: EdgeInsets.only(left: 16),
                          child: Column(
                            crossAxisAlignment: CrossAxisAlignment.start,
                            children:
                                data.expenses.keys
                                    .map(
                                      (key) => LegendItem(
                                        text: key,
                                        color: data.colors[key]!,
                                      ),
                                    )
                                    .toList(),
                          ),
                        ),
                      ],
                    ),

                    Padding(
                      padding: EdgeInsets.only(top: 16),
                      child: Text(
                        "Available money: ${formatCurrency(data.usable)}",
                      ),
                    ),
                  ],
                );
              },
            );
          },
        ),
      ),
    );
  }
}