Investerings Guiden - Det bedste projekt af dem alle

App.xaml

<Application xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             xmlns:local="clr-namespace:InvesteringsGuiden"
             x:Class="InvesteringsGuiden.App">
    <Application.Resources>
        <ResourceDictionary>
            <local:AlternatingRowConverter x:Key="AlternatingRowConverter" />
        </ResourceDictionary>
    </Application.Resources>
</Application>

App.xaml.cs

namespace InvesteringsGuiden;

public partial class App : Application
{
    public App()
    {
        InitializeComponent();

        MainPage = new AppShell();
    }
}

AppShell.xaml

<?xml version="1.0" encoding="UTF-8" ?>
<Shell
    x:Class="InvesteringsGuiden.AppShell"
    xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
    xmlns:local="clr-namespace:InvesteringsGuiden"
    Shell.FlyoutBehavior="Disabled"
    Title="InvesteringsGuiden">

    <ShellContent
        Title="Home"
        ContentTemplate="{DataTemplate local:MainPage}"
        Route="MainPage" />

</Shell>

AppShell.xaml.cs

namespace InvesteringsGuiden;

public partial class AppShell : Shell
{
    public AppShell()
    {
        InitializeComponent();
    }
}

MainPage.xaml

<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="InvesteringsGuiden.MainPage"
             Title="Investerings guiden til din aktiesparekonto!">
    <ScrollView>
        <StackLayout Padding="20" Spacing="15">
            <Label Text="Månedlig indbetaling:" />
            <Entry x:Name="MonthlyDepositEntry" Keyboard="Numeric" Placeholder="Indtast beløb" />

            <Label Text="Antal år frem:" />
            <Entry x:Name="YearsEntry" Keyboard="Numeric" Placeholder="Indtast antal år" />

            <Label Text="Årlig stigning (%):" />
            <Entry x:Name="AnnualIncreaseEntry" Keyboard="Numeric" Placeholder="Indtast procent" />

            <Button Text="Beregn" BackgroundColor="Bisque" Clicked="OnCalculateClicked" />

            <Label x:Name="ResultLabel" Text="Resultatet vises her." TextColor="Blue" />

            <!-- Excel-stil tabel -->
            <CollectionView ItemsSource="{Binding MonthlyDataCollection}" SelectionMode="None">
                <CollectionView.Header>
                    <Grid BackgroundColor="#f0f0f0" Padding="5">
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="150" />
                            <ColumnDefinition Width="200" />
                            <ColumnDefinition Width="200" />
                            <ColumnDefinition Width="200" />
                            <ColumnDefinition Width="200" />
                        </Grid.ColumnDefinitions>
                        <Label Text="Måned" Grid.Column="0" FontAttributes="Bold" />
                        <Label Text="Saldo" Grid.Column="1" FontAttributes="Bold" />
                        <Label Text="Månedlig Profit" Grid.Column="2" FontAttributes="Bold" />
                        <Label Text="Total Profit" Grid.Column="3" FontAttributes="Bold" />
                        <Label Text="Betalt Skat" Grid.Column="4" FontAttributes="Bold" />
                    </Grid>
                </CollectionView.Header>

                <CollectionView.ItemTemplate>
                    <DataTemplate>
                        <Grid Padding="5" RowSpacing="2"
                              BackgroundColor="{Binding Month, Converter={StaticResource AlternatingRowConverter}}">
                            <Grid.ColumnDefinitions>
                                <ColumnDefinition Width="150" />
                                <ColumnDefinition Width="200" />
                                <ColumnDefinition Width="200" />
                                <ColumnDefinition Width="200" />
                                <ColumnDefinition Width="200" />
                            </Grid.ColumnDefinitions>

                            <BoxView BackgroundColor="#e0e0e0" HeightRequest="1" Grid.ColumnSpan="5" />
                            <Label Text="{Binding Month}" Grid.Column="0" />
                            <Label Text="{Binding Balance, StringFormat='{0:C}'}" Grid.Column="1" />
                            <Label Text="{Binding MonthlyProfit, StringFormat='{0:C}'}" Grid.Column="2" />
                            <Label Text="{Binding TotalProfit, StringFormat='{0:C}'}" Grid.Column="3" />
                            <Label Text="{Binding TaxPaid, StringFormat='{0:C}'}" Grid.Column="4" />
                        </Grid>
                    </DataTemplate>
                </CollectionView.ItemTemplate>
            </CollectionView>
        </StackLayout>
    </ScrollView>
</ContentPage>

MainPage.xaml.cs

using System;
using System.Collections.ObjectModel;

namespace InvesteringsGuiden;

public partial class MainPage : ContentPage
{
    public ObservableCollection<MonthlyData> MonthlyDataCollection { get; set; }

    public MainPage()
    {
        InitializeComponent();
        MonthlyDataCollection = new ObservableCollection<MonthlyData>();
        BindingContext = this;
    }

    private void OnCalculateClicked(object sender, EventArgs e)
    {
        MonthlyDataCollection.Clear();

        if (!decimal.TryParse(MonthlyDepositEntry.Text, out var monthlyDeposit) ||
            !int.TryParse(YearsEntry.Text, out var years) ||
            !double.TryParse(AnnualIncreaseEntry.Text, out var annualIncrease))
        {
            ResultLabel.Text = "Ugyldigt input. Prøv igen.";
            return;
        }

        const decimal maxDepositLimit = 135900m;
        const double taxRate = 0.17;

        // Konverter årlig stigning til månedlig stigning
        var monthlyRate = Math.Pow(1 + annualIncrease / 100, 1.0 / 12) - 1;

        decimal totalSavings = 0;
        decimal totalTaxPaid = 0;
        decimal totalProfit = 0;

        for (var year = 1; year <= years; year++)
        {
            // Beregn hvor meget man må indbetale dette år
            var maxAllowedDeposit = Math.Max(0, maxDepositLimit - totalSavings);
            var actualMonthlyDeposit = Math.Min(monthlyDeposit, maxAllowedDeposit / 12);

            decimal annualProfit = 0;

            for (var month = 1; month <= 12; month++)
            {
                var monthlyProfit = totalSavings * (decimal)monthlyRate;
                annualProfit += monthlyProfit;
                totalProfit += monthlyProfit;

                totalSavings += monthlyProfit + actualMonthlyDeposit;

                MonthlyDataCollection.Add(new MonthlyData
                {
                    Month = (year - 1) * 12 + month,
                    Balance = totalSavings,
                    MonthlyProfit = monthlyProfit,
                    TotalProfit = totalProfit,
                    TaxPaid = totalTaxPaid
                });
            }

            decimal taxForYear = annualProfit * (decimal)taxRate;
            totalTaxPaid += taxForYear;
            totalSavings -= taxForYear;
        }

        ResultLabel.Text = $"Beregningen er færdig! Se resultaterne nedenfor.";
    }
}

public class MonthlyData
{
    public int Month { get; set; }
    public decimal Balance { get; set; }
    public decimal MonthlyProfit { get; set; }
    public decimal TotalProfit { get; set; }
    public decimal TaxPaid { get; set; }
}

MauiProgram.cs

using Microsoft.Extensions.Logging;

namespace InvesteringsGuiden;

public static class MauiProgram
{
    public static MauiApp CreateMauiApp()
    {
        var builder = MauiApp.CreateBuilder();
        builder
            .UseMauiApp<App>()
            .ConfigureFonts(fonts =>
            {
                fonts.AddFont("OpenSans-Regular.ttf", "OpenSansRegular");
                fonts.AddFont("OpenSans-Semibold.ttf", "OpenSansSemibold");
            });

#if DEBUG
        builder.Logging.AddDebug();
#endif

        return builder.Build();
    }
}