#pragma once

#include "CoreMinimal.h"

class UProceduralMeshComponent;
class UMaterialInterface;

/**
 * The geometry builder of the carrier blockout (DESIGN_UE.md section 3.2). Pure data (no UObject), so the automation tests can
 * build every room and check the result without a world. Everything is in carrier-local METRES; Commit() converts to Unreal units.
 * Triangle winding is derived from the face normal you give, so no caller has to think about Unreal's clockwise convention.
 */
namespace Descent::Carrier
{
	/** Blockout materials: instances /Game/Carrier/Materials/MI_Carrier_<Name> made by Tools/ue/assets_35_carrier_materials.py. */
	enum class EMat : uint8
	{
		Wall, Wall2, Floor, Ceiling, Hazard, Wood, Fabric, White, Rust, Olive, Hull, DarkMetal, RustMetal, Shaft,
		LampWhite, LampCyan, LampAmber, LampRed, ScreenCyan, ScreenTeal, ScreenAmber, Core, Furnace,
		NavRed, NavGreen, NavWhite, WindowGlow, PoolWater, Count
	};
	THEDESCENT_API const TCHAR* MatName(EMat M);
	/** Loads the material (cached); a missing asset logs one error naming the script and returns the engine's grid material. */
	THEDESCENT_API UMaterialInterface* LoadCarrierMaterial(EMat M);

	struct FSectionData
	{
		EMat Mat = EMat::Wall;
		TArray<FVector> V, N;
		TArray<FVector2D> UV;
		TArray<int32> Tri;
	};

	class THEDESCENT_API FMeshBuilder
	{
	public:
		TArray<FSectionData> Sections;
		/** Convex collision hulls as point sets, metres. */
		TArray<TArray<FVector>> Convex;

		void Reset() { Sections.Reset(); Convex.Reset(); }
		FSectionData& Section(EMat M);

		/** A planar quad given counter-clockwise seen from the side the normal points to (right-handed). */
		void Quad(EMat M, const FVector& A, const FVector& B, const FVector& C, const FVector& D, const FVector& N);
		void Tri(EMat M, const FVector& A, const FVector& B, const FVector& C, const FVector& N);

		/** Axis-aligned box (optionally rotated about its centre). bCollide adds one convex hull. */
		void Box(EMat M, const FVector& Centre, const FVector& Size, bool bCollide = true, const FQuat& Rot = FQuat::Identity);
		void BoxMinMax(EMat M, const FVector& Min, const FVector& Max, bool bCollide = true) { Box(M, 0.5 * (Min + Max), Max - Min, bCollide); }
		/** Cylinder with the axis along Axis (0 = X, 1 = Y, 2 = Z), capped. */
		void Cylinder(EMat M, const FVector& Centre, double Radius, double Length, int32 Segs, int32 Axis, bool bCollide, bool bCaps = true);
		/** Convex polygon in the X-Z plane (counter-clockwise seen from +Y... any order is fixed up) extruded along Y. */
		void ExtrudeY(EMat M, const TArray<FVector2D>& PolyXZ, double Y0, double Y1, bool bCollide);
		/** Torus about the X axis (major radius R, tube radius r). */
		void TorusX(EMat M, const FVector& Centre, double R, double Tube, int32 SegsMajor, int32 SegsMinor);
		/** Collision only. */
		void ColBox(const FVector& Min, const FVector& Max);
		void AddConvexPoints(const TArray<FVector>& PointsM) { Convex.Add(PointsM); }

		int32 NumTriangles() const;
		void Append(const FMeshBuilder& Other);

		/** Replaces the sections, materials and simple collision of the component. bCollision false: render only. */
		void Commit(UProceduralMeshComponent* Comp, bool bCollision) const;
	};
}