import * as THREE from 'three';
import { ConvexHull } from 'three/addons/math/ConvexHull.js';

const {BufferGeometry, Float32BufferAttribute, Vector3} = THREE;

export class ConvexGeometry extends BufferGeometry {

	constructor( points = [] ) {
      super();
      this.convexHull = new ConvexHull();
      this.setFromPoints(points);
    }

    setFromPoints(points) {
        const {convexHull} = this;

        convexHull.setFromPoints(points);
		// buffers

		const vertices = [];
		const normals = [];

		// generate vertices and normals

		const faces = convexHull.faces;

		for ( let i = 0; i < faces.length; i ++ ) {

			const face = faces[ i ];
			let edge = face.edge;

			// we move along a doubly-connected edge list to access all face points (see HalfEdge docs)

			do {

				const point = edge.head().point;

				vertices.push( point.x, point.y, point.z );
				normals.push( face.normal.x, face.normal.y, face.normal.z );

				edge = edge.next;

			} while ( edge !== face.edge );

		}

		// build geometry

		this.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );
		this.setAttribute( 'normal', new Float32BufferAttribute( normals, 3 ) );

	}

}

export class WireframeGeometry extends BufferGeometry {

	constructor( geometry = null ) {

		super();

		this.type = 'WireframeGeometry';

		this.parameters = {
			geometry: geometry
		};

      this.update();
    }

    update() {
        const {geometry} = this.parameters;

		if ( geometry !== null ) {

			// buffer

			const vertices = [];
			const edges = new Set();

			// helper variables

			const start = new Vector3();
			const end = new Vector3();

			if ( geometry.index !== null ) {

				// indexed BufferGeometry

				const position = geometry.attributes.position;
				const indices = geometry.index;
				let groups = geometry.groups;

				if ( groups.length === 0 ) {

					groups = [ { start: 0, count: indices.count, materialIndex: 0 } ];

				}

				// create a data structure that contains all edges without duplicates

				for ( let o = 0, ol = groups.length; o < ol; ++ o ) {

					const group = groups[ o ];

					const groupStart = group.start;
					const groupCount = group.count;

					for ( let i = groupStart, l = ( groupStart + groupCount ); i < l; i += 3 ) {

						for ( let j = 0; j < 3; j ++ ) {

							const index1 = indices.getX( i + j );
							const index2 = indices.getX( i + ( j + 1 ) % 3 );

							start.fromBufferAttribute( position, index1 );
							end.fromBufferAttribute( position, index2 );

							if ( isUniqueEdge( start, end, edges ) === true ) {

								vertices.push( start.x, start.y, start.z );
								vertices.push( end.x, end.y, end.z );

							}

						}

					}

				}

			} else {

				// non-indexed BufferGeometry

				const position = geometry.attributes.position;

				for ( let i = 0, l = ( position.count / 3 ); i < l; i ++ ) {

					for ( let j = 0; j < 3; j ++ ) {

						// three edges per triangle, an edge is represented as (index1, index2)
						// e.g. the first triangle has the following edges: (0,1),(1,2),(2,0)

						const index1 = 3 * i + j;
						const index2 = 3 * i + ( ( j + 1 ) % 3 );

						start.fromBufferAttribute( position, index1 );
						end.fromBufferAttribute( position, index2 );

						if ( isUniqueEdge( start, end, edges ) === true ) {

							vertices.push( start.x, start.y, start.z );
							vertices.push( end.x, end.y, end.z );

						}

					}

				}

			}

			// build geometry

			this.setAttribute( 'position', new Float32BufferAttribute( vertices, 3 ) );

		}

	}

	copy( source ) {

		super.copy( source );

		this.parameters = Object.assign( {}, source.parameters );

		return this;

	}

}

export function isUniqueEdge( start, end, edges ) {

	const hash1 = `${start.x},${start.y},${start.z}-${end.x},${end.y},${end.z}`;
	const hash2 = `${end.x},${end.y},${end.z}-${start.x},${start.y},${start.z}`; // coincident edge

	if ( edges.has( hash1 ) === true || edges.has( hash2 ) === true ) {

		return false;

	} else {

		edges.add( hash1 );
		edges.add( hash2 );
		return true;

	}

}