using System;
using Microsoft.Maui.Graphics;
 
namespace Microsoft.Maui.Layouts
{
	public class VerticalStackLayoutManager : StackLayoutManager
	{
		public VerticalStackLayoutManager(IStackLayout stackLayout) : base(stackLayout)
		{
		}
 
		public override Size Measure(double widthConstraint, double heightConstraint)
		{
			var padding = Stack.Padding;
 
			double measuredHeight = 0;
			double measuredWidth = 0;
			double childWidthConstraint = widthConstraint - padding.HorizontalThickness;
			int spacingCount = 0;
 
			for (int n = 0; n < Stack.Count; n++)
			{
				var child = Stack[n];
 
				if (child.Visibility == Visibility.Collapsed)
				{
					continue;
				}
 
				spacingCount += 1;
				var measure = child.Measure(childWidthConstraint, double.PositiveInfinity);
				measuredHeight += measure.Height;
				measuredWidth = Math.Max(measuredWidth, measure.Width);
			}
 
			measuredHeight += MeasureSpacing(Stack.Spacing, spacingCount);
			measuredHeight += padding.VerticalThickness;
			measuredWidth += padding.HorizontalThickness;
 
			var finalHeight = ResolveConstraints(heightConstraint, Stack.Height, measuredHeight, Stack.MinimumHeight, Stack.MaximumHeight);
			var finalWidth = ResolveConstraints(widthConstraint, Stack.Width, measuredWidth, Stack.MinimumWidth, Stack.MaximumWidth);
 
			return new Size(finalWidth, finalHeight);
		}
 
		public override Size ArrangeChildren(Rect bounds)
		{
			var padding = Stack.Padding;
 
			double stackHeight = padding.Top + bounds.Y;
			double left = padding.Left + bounds.X;
			double width = bounds.Width - padding.HorizontalThickness;
 
			for (int n = 0; n < Stack.Count; n++)
			{
				var child = Stack[n];
 
				if (child.Visibility == Visibility.Collapsed)
				{
					continue;
				}
 
				var destination = new Rect(left, stackHeight, width, child.DesiredSize.Height);
				child.Arrange(destination);
				stackHeight += destination.Height + Stack.Spacing;
			}
 
			var actual = new Size(width, stackHeight);
 
			return actual.AdjustForFill(bounds, Stack);
		}
	}
}