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 = ExpenseInputForm();
      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!');
    }

    Widget newExpense() {
      return AlertDialog(title: Text("Add New Value"), content: dialog);
    }

    Widget? floatingButton;
    if (dialog != null) {
      floatingButton = IconButton(
        onPressed: newExpense,
        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: [
        ExpenseInputForm(),
        ListTile(
          title: Text("Fake Item 1"),
          subtitle: Text("30.00 / month"),
        ),
        ListTile(
          title: Text("Fake Item 2"),
          subtitle: Text("180.00 / year"),
        ),
      ],
    );
  }
}

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

  @override
  State<ExpenseInputForm> createState() => _ExpenseInputFormState();
}

class _ExpenseInputFormState extends State<ExpenseInputForm> {
  @override
  Widget build(BuildContext context) {
    const inputWidth = 300.0;
    const inputHeight = 50.0;

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

    return Center(
      child: Column(mainAxisSize: MainAxisSize.min, spacing: 10, children: [
        Text('New Expense'),
        SizedBox(
            width: inputWidth,
            height: inputHeight,
            child: TextField(
              keyboardType: TextInputType.text,
              decoration: InputDecoration(
                labelText: "Name",
                hintText: "Example: Red Pocket Phone Bill",
              ),
              // https://docs.flutter.dev/cookbook/forms/retrieve-input
              //controller: nameFieldController,
            )),
        SizedBox(
          width: inputWidth,
          height: inputHeight,
          child: TextField(
            keyboardType: TextInputType.numberWithOptions(decimal: true),
            decoration:
                InputDecoration(labelText: "Cost", hintText: "Example: 10.00"),
          ),
        ),
        DropdownMenu(
          dropdownMenuEntries: recurrenceValues,
          width: inputWidth,
          label: Text("Recurrence"),
          hintText: "Example: Monthly",
        ),
        SizedBox(
            width: inputWidth,
            height: inputHeight,
            child: TextField(
              keyboardType: TextInputType.text,
              decoration: InputDecoration(
                  labelText: "Description",
                  hintText: "Example: 1GB data with unlimited talk & text."),
            )),
        SizedBox(
            width: inputWidth,
            height: inputHeight,
            child: Row(
              mainAxisAlignment: MainAxisAlignment.spaceEvenly,
              children: [
                ElevatedButton.icon(
                  onPressed: () {
                    print("TODO: Clear fields!");
                  },
                  icon: Icon(Icons.cancel),
                  label: Text('Cancel'),
                ),
                ElevatedButton.icon(
                  onPressed: () {
                    print("TODO: Save expense!");
                  },
                  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();
  }
}