using System;
using System.Collections.Generic;
using System.Linq;

namespace Sunless.Architecture;

// Walls lining a hole, grown OUTSIDE the outline - grown inward they would narrow the hole they line. A shaft, a
// stairwell and a wrapped flight all stand one, so the ring is kernel geometry rather than any one module's.
public static class ArchCarveRing
{
	public static void Walls( ArchMesh canvas, IReadOnlyList<Vector2> outline, float thickness, float bottom, float top, ArchBrush brush )
	{
		if ( top - bottom < 0.05f )
		{
			return;
		}

		var carve = new ArchCarve();

		carve.Plus( ArchCarveVolume.Over( ArchFootprint.Grow( new List<List<Vector2>> { outline.ToList() }, thickness ).First(), bottom, top ) );
		carve.Less( ArchCarveVolume.Over( outline, bottom - 1f, top + 1f ) );

		// Per ring - a shaft is a stack of rings, two meeting end to end are two solids.
		using var welding = canvas.Welding();

		foreach ( var face in carve.Resolve().Faces )
		{
			canvas.Polygon( face.Points, brush );
		}
	}
}