namespace Lumi.Companion.Overlay;

public readonly record struct PhysicalRect(int X, int Y, int Width, int Height);

public static class AnchorLayout
{
    public static void ClampPadding(OverlayContainerSettings settings)
    {
        var top = settings.Anchor is OverlayAnchor.TopLeft or OverlayAnchor.Top or OverlayAnchor.TopRight or OverlayAnchor.Left or OverlayAnchor.Right;
        var bottom = settings.Anchor is OverlayAnchor.BottomLeft or OverlayAnchor.Bottom or OverlayAnchor.BottomRight or OverlayAnchor.Left or OverlayAnchor.Right;
        var left = settings.Anchor is OverlayAnchor.TopLeft or OverlayAnchor.Left or OverlayAnchor.BottomLeft or OverlayAnchor.Top or OverlayAnchor.Bottom;
        var right = settings.Anchor is OverlayAnchor.TopRight or OverlayAnchor.Right or OverlayAnchor.BottomRight or OverlayAnchor.Top or OverlayAnchor.Bottom;
        if (!top) settings.PaddingTop = 0;
        if (!right) settings.PaddingRight = 0;
        if (!bottom) settings.PaddingBottom = 0;
        if (!left) settings.PaddingLeft = 0;
    }

    public static PhysicalRect Calculate(OverlayContainerSettings value, int monitorWidth, int monitorHeight)
    {
        ClampPadding(value);
        var availableWidth = Math.Max(1, monitorWidth - value.PaddingLeft - value.PaddingRight);
        var availableHeight = Math.Max(1, monitorHeight - value.PaddingTop - value.PaddingBottom);
        var width = Math.Clamp(value.Width, 1, availableWidth);
        var height = Math.Clamp(value.Height, 1, availableHeight);
        var x = value.Anchor switch
        {
            OverlayAnchor.TopRight or OverlayAnchor.Right or OverlayAnchor.BottomRight => monitorWidth - value.PaddingRight - width,
            OverlayAnchor.Top or OverlayAnchor.Bottom => value.PaddingLeft + (availableWidth - width) / 2,
            _ => value.PaddingLeft
        };
        var y = value.Anchor switch
        {
            OverlayAnchor.BottomLeft or OverlayAnchor.Bottom or OverlayAnchor.BottomRight => monitorHeight - value.PaddingBottom - height,
            OverlayAnchor.Left or OverlayAnchor.Right => value.PaddingTop + (availableHeight - height) / 2,
            _ => value.PaddingTop
        };
        return new(x, y, width, height);
    }
}