MyFirstMAUI/MyFirstMauiApp/SharedResources/CustomTipPage.xaml.cs

namespace SharedResources;

public partial class CustomTipPage : ContentPage
{
	public CustomTipPage()
	{
		InitializeComponent();

        billInput.TextChanged += (s, e) => CalculateTip(false, false);
        roundDown.Clicked += (s, e) => CalculateTip(false, true);
        roundUp.Clicked += (s, e) => CalculateTip(true, false);

        tipPercentSlider.ValueChanged += (s, e) =>
        {
            double pct = Math.Round(e.NewValue);
            tipPercent.Text = $"{pct}%";
            CalculateTip(false, false);
        };
	}

    void CalculateTip(bool roundUp, bool roundDown)
    {
        double t;
        if (Double.TryParse(billInput.Text, out t) && t > 0)
        {
            double pct = Math.Round(tipPercentSlider.Value);
            double tip = Math.Round(t * (pct / 100.0), 2);

            double final = t + tip;

            if (roundUp)
            {
                final = Math.Ceiling(final);
                tip = final - t;
            }
            else if (roundDown)
            {
                final = Math.Floor(final);
                tip = final - t;
            }

            tipOutput.Text = tip.ToString("C");
            totalOutput.Text = final.ToString("C");
        }
    }

    private void OnNormalTip(object sender, EventArgs e)
    {
        tipPercentSlider.Value = 15;
    }

    private void OnGenerousTip(object sender, EventArgs e)
    {
        tipPercentSlider.Value = 20;
    }
}