using System;
using System.Collections.Generic;
using Sandbox;

namespace Sunless.Architecture;

// Edge barrier for wall-hung fixtures; delegates to the barrier engine.
public static class ArchFixtureGuard {
	// Bays are edge-by-edge so stations land on straight stretches, not across corners.
	public static ArchBarrierSpec Spec( ArchKit kit, float height, IReadOnlyList<Vector3> path, BarrierGround ground, BarrierStyle style = BarrierStyle.Picket ) {
		var spec = new ArchBarrierSpec {
			Style = style,
			Top = PicketTop.Flat,
			Ground = ground,
			Height = MathF.Max( 12f, height ),
			PanelLength = ArchGuardStyles.Bay( style, kit ),
			PostSize = MathF.Max( 1f, kit.NewelSize ),
			PanelThickness = kit.SolidGuardThickness,
			Rails = 2
		};

		for ( var edge = 0; edge + 1 < (path?.Count ?? 0); edge++ ) {
			var division = ArchDivide.AtMost( (path[edge + 1] - path[edge]).Length, spec.PanelLength );

			for ( var bay = 0; bay < division.Count; bay++ ) {
				spec.Bays.Add( new ArchBarrierBay { Span = division.Step } );
			}
		}

		return spec;
	}

	// One resolve for the generator and the ghost: the posts drawn are the posts built.
	public static ArchBarrierShape Resolve( IReadOnlyList<Vector3> path, ArchBarrierSpec spec ) {
		if ( path is not { Count: >= 2 } ) {
			return new ArchBarrierShape();
		}

		return ArchBarrierShape.Resolve( ArchCurve.Polyline( path ), spec );
	}

	public static void Build( ArchMesh canvas, IReadOnlyList<Vector3> path, ArchKit kit, float height, BarrierGround ground, ArchBarrierBrushes brushes,
		BarrierStyle style = BarrierStyle.Picket ) {
		var spec = Spec( kit, height, path, ground, style );

		ArchBarrierGen.Build( canvas, Resolve( path, spec ), spec, kit, brushes );
	}

	public static void Ghost( IReadOnlyList<Vector3> path, ArchKit kit, float height, BarrierGround ground, BarrierStyle style = BarrierStyle.Picket ) {
		var spec = Spec( kit, height, path, ground, style );

		ArchGhost.Barrier( Resolve( path, spec ), spec );
	}
}