flutter-expense-tracker/lib/main.dart

// Helpful guides:
// - https://flutter.dev/docs/cookbook/forms/validation

import 'package:flutter/material.dart';

void main() {
  runApp(const MainApp());
}

// https://www.tutorialspoint.com/dart_programming/dart_programming_enumeration.htm
enum Recurrence { daily, weekly, biweekly, montly, yearly }

class Expense {
  String name;
  double cost;
  Recurrence recurrence;
  String description;

  Expense(this.name, this.cost, this.recurrence, this.description);
}

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

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Recurring Expense Tracker',
      theme: ThemeData(
        useMaterial3: true,
        colorScheme: ColorScheme.fromSeed(seedColor: Colors.green),
      ),
      home: HomePage(),
    );
  }
}

class HomePage extends StatefulWidget {
  const HomePage({
    super.key,
  });

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  var pageSelected = 0;

  @override
  Widget build(BuildContext context) {
    Widget page;
    Widget? dialog;
    switch (pageSelected) {
      case 0:
        page = ExpensePage();
        dialog = ExpenseInputDialog();
      case 1:
        page = IncomePage();
      case 2:
        page = AssetPage();
      case 3:
        page = ProjectionPage();
      case 4:
        page = SettingsPage();
      default:
        throw UnimplementedError('No widget for page $pageSelected yet!');
    }

    Future<void> addNewValue(BuildContext context) {
      return showDialog(
          context: context, builder: (_) => AlertDialog(content: dialog));
    }

    Widget? floatingButton;
    if (dialog != null) {
      floatingButton = IconButton(
        onPressed: () {
          addNewValue(context);
        },
        icon: Icon(Icons.add),
        color: Theme.of(context).colorScheme.onSurface,
      );
    }

    return LayoutBuilder(builder: (context, constraints) {
      return Scaffold(
        body: Row(
          children: [
            SafeArea(
              child: NavigationRail(
                extended: constraints.maxWidth >= 800,
                destinations: [
                  NavigationRailDestination(
                    icon: Icon(Icons.payment),
                    label: Text('Expenses'),
                  ),
                  NavigationRailDestination(
                    icon: Icon(Icons.account_balance),
                    label: Text('Income'),
                  ),
                  NavigationRailDestination(
                    icon: Icon(Icons.attach_money),
                    label: Text('Liquid Assets'),
                  ),
                  NavigationRailDestination(
                    icon: Icon(Icons.bar_chart),
                    label: Text('Projections'),
                  ),
                  NavigationRailDestination(
                    icon: Icon(Icons.settings),
                    label: Text('Settings'),
                  ),
                ],
                selectedIndex: pageSelected,
                onDestinationSelected: (value) {
                  setState(() {
                    pageSelected = value;
                  });
                },
              ),
            ),
            Expanded(
              child: Container(
                color: Theme.of(context).colorScheme.primaryContainer,
                child: page,
              ),
            ),
          ],
        ),
        floatingActionButton: floatingButton,
      );
    });
  }
}

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

  @override
  Widget build(BuildContext context) {
    return ListView(
      children: [
        ListTile(
          title: Text("Fake Item 1"),
          subtitle: Text("30.00 / month"),
        ),
        ListTile(
          title: Text("Fake Item 2"),
          subtitle: Text("180.00 / year"),
        ),
      ],
    );
  }
}

class ExpenseInputDialog extends StatefulWidget {
  const ExpenseInputDialog({
    super.key,
  });

  @override
  State<ExpenseInputDialog> createState() => _ExpenseInputDialogState();
}

class _ExpenseInputDialogState extends State<ExpenseInputDialog> {
  final _expenseFormKey = GlobalKey<FormState>();

  @override
  Widget build(BuildContext context) {
    const inputWidth = 300.0;
    const inputHeight = 50.0;

    const recurrenceValues = <DropdownMenuItem>[
      DropdownMenuItem(value: Recurrence.daily, child: Text("Daily")),
      DropdownMenuItem(value: Recurrence.weekly, child: Text("Weekly")),
      DropdownMenuItem(value: Recurrence.biweekly, child: Text("Biweekly")),
      DropdownMenuItem(value: Recurrence.montly, child: Text("Monthly")),
      DropdownMenuItem(
          value: Recurrence.yearly,
          child: Text(
            "Yearly",
          )),
    ];

    return AlertDialog(
      title: Center(child: Text("Add New Expense")),
      content: Form(
        key: _expenseFormKey,
        autovalidateMode: AutovalidateMode.onUserInteraction,
        child: Column(mainAxisSize: MainAxisSize.min, spacing: 10, children: [
          SizedBox(
              width: inputWidth,
              height: inputHeight,
              child: TextFormField(
                keyboardType: TextInputType.text,
                decoration: InputDecoration(
                  labelText: "Name",
                  hintText: "Example: Red Pocket Phone Bill",
                ),
                validator: (value) {
                  if (value!.isEmpty) {
                    return "Name must be provided.";
                  }
                  return null;
                },
                onChanged: (newValue) {
                  // _expenseFormKey.currentState!.reset();
                },
              )),
          SizedBox(
            width: inputWidth,
            height: inputHeight,
            child: TextFormField(
              keyboardType: TextInputType.numberWithOptions(decimal: true),
              decoration: InputDecoration(
                  labelText: "Cost", hintText: "Example: 10.00"),
              validator: (value) {
                if (value!.isEmpty) {
                  return "Cost must be provided.";
                }
                if (double.tryParse(value!) == null) {
                  return "Cost must be a valid number.";
                }
                return null;
              },
              onChanged: (newValue) {
                //_expenseFormKey.currentState!.reset();
              },
            ),
          ),
          SizedBox(
            width: inputWidth,
            height: inputHeight,
            child: DropdownButtonFormField(
              items: recurrenceValues,
              decoration: InputDecoration(
                  labelText: "Recurrence", hintText: "Example: Monthly"),
              validator: (value) {
                if (value == null) {
                  return "Recurrence must be provided.";
                }
                return null;
              },
              onChanged: (newValue) {
                //_expenseFormKey.currentState!.reset();
              },
            ),
          ),
          SizedBox(
              width: inputWidth,
              height: inputHeight,
              child: TextFormField(
                keyboardType: TextInputType.text,
                decoration: InputDecoration(
                    labelText: "Description",
                    hintText: "Example: 1GB data with unlimited talk & text."),
                validator: (value) {
                  return null;
                },
                onChanged: (newValue) {
                  //_expenseFormKey.currentState!.reset();
                },
              )),
        ]),
      ),
      actions: [
        SizedBox(
            width: inputWidth,
            height: inputHeight,
            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              crossAxisAlignment: CrossAxisAlignment.center,
              children: [
                ElevatedButton.icon(
                  onPressed: () {
                    print("TODO: Clear fields!");
                    Navigator.of(context).pop();
                  },
                  icon: Icon(Icons.cancel),
                  label: Text('Cancel'),
                ),
                ElevatedButton.icon(
                  onPressed: () {
                    print("TODO: Save expense!");
                    if (_expenseFormKey.currentState!.validate()) {
                      _expenseFormKey.currentState!.save();
                      Navigator.of(context).pop();
                    }
                  },
                  icon: Icon(Icons.save),
                  label: Text('Submit'),
                ),
              ],
            ))
      ],
    );
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Center(
        child: Column(
      children: [
        Text("TBD"),
        Placeholder(),
      ],
    ));
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Placeholder();
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Placeholder();
  }
}

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

  @override
  Widget build(BuildContext context) {
    return Placeholder();
  }
}