import * as THREE from 'three';

class HexNutGeometry extends THREE.BufferGeometry {
    constructor(radius = 1, height = 0.5, holeRadius = 0.6) {
        super();

        this.parameters = {
            radius: radius,
            height: height,
            holeRadius: holeRadius
        };

        this.buildGeometry();
    }

    buildGeometry() {
        const radius = this.parameters.radius;
        const height = this.parameters.height;
        const holeRadius = this.parameters.holeRadius;

        const vertices = [];
        const indices = [];

        // 1. 定义六边形的顶点 (顶部和底部)
        for (let i = 0; i < 6; i++) {
            const angle = (Math.PI * 2 / 6) * i;
            const x = radius * Math.cos(angle);
            const y = radius * Math.sin(angle);

            // 顶部顶点
            vertices.push(x, y, height / 2);
            // 底部顶点
            vertices.push(x, y, -height / 2);
        }

        // 内部孔洞的顶点 (顶部和底部)
        for (let i = 0; i < 32; i++) { // 使用更多分段来近似圆形
            const angle = (Math.PI * 2 / 32) * i;
            const x = holeRadius * Math.cos(angle);
            const y = holeRadius * Math.sin(angle);

            // 顶部内侧顶点
            vertices.push(x, y, height / 2); // 索引从 12 开始
            // 底部内侧顶点
            vertices.push(x, y, -height / 2); // 索引从 12 + 32 开始
        }

        // 2. 定义侧面
        for (let i = 0; i < 6; i++) {
            const currentTop = i * 2;
            const nextTop = ((i + 1) % 6) * 2;
            const currentBottom = i * 2 + 1;
            const nextBottom = ((i + 1) % 6) * 2 + 1;

            // 两个三角形组成一个侧面
            indices.push(currentTop, nextTop, currentBottom);
            indices.push(nextTop, nextBottom, currentBottom);
        }

        // 3. 定义顶部和底部 (六边形扇面 - 注意避开中心孔洞)
        // 顶部
        for (let i = 0; i < 6; i++) {
            const current = i * 2;
            const next = ((i + 1) % 6) * 2;
            // 使用孔洞边缘的顶点来创建顶部面
            const holeIndex1 = 12 + i * 2;
            const holeIndex2 = 12 + ((i + 1) % 32) * 2; // 注意孔洞分段数

            indices.push(current, next, holeIndex1);
            indices.push(next, holeIndex2, holeIndex1);
        }

        // 底部
        for (let i = 0; i < 6; i++) {
            const current = i * 2 + 1;
            const next = ((i + 1) % 6) * 2 + 1;
            // 使用孔洞边缘的顶点来创建底面
            const holeIndex1 = 12 + 64 + i * 2;
            const holeIndex2 = 12 + 64 + ((i + 1) % 32) * 2; // 注意孔洞分段数

            indices.push(current, holeIndex1, next);
            indices.push(holeIndex1, holeIndex2, next);
        }

        // 4. 定义内部孔洞的侧面
        for (let i = 0; i < 32; i++) {
            const currentTop = 12 + i * 2;
            const nextTop = 12 + ((i + 1) % 32) * 2;
            const currentBottom = 12 + 64 + i * 2;
            const nextBottom = 12 + 64 + ((i + 1) % 32) * 2;

            indices.push(currentTop, nextTop, currentBottom);
            indices.push(nextTop, nextBottom, currentBottom);
        }

        this.setAttribute('position', new THREE.Float32BufferAttribute(vertices, 3));
        this.setIndex(indices);
        this.computeVertexNormals();
    }
}

export { HexNutGeometry };