import { EPSILON, ICloneable, IEquatable } from '@chemistry/common';

export interface IVec3 {
  x: number;
  y: number;
  z: number;
}

export class Vec3 implements IVec3, ICloneable<Vec3>, IEquatable<Vec3> {
  public static add(v1: Vec3, v2: Vec3): Vec3 {
    return new Vec3(v1.x + v2.x, v1.y + v2.y, v1.z + v2.z);
  }

  public static sub(v1: Vec3, v2: Vec3): Vec3 {
    return new Vec3(v1.x - v2.x, v1.y - v2.y, v1.z - v2.z);
  }

  public static dot(v1: Vec3, v2: Vec3): number {
    return v1.x * v2.x + v1.y * v2.y + v1.z * v2.z;
  }

  public static cross(v1: Vec3, v2: Vec3): Vec3 {
    return new Vec3(
      v1.y * v2.z - v1.z * v2.y,
      v1.z * v2.x - v1.x * v2.z,
      v1.x * v2.y - v1.y * v2.x
    );
  }

  public static equals(v1: Vec3, v2: Vec3): boolean {
    return (
      Math.abs(v1.x - v2.x) < EPSILON &&
      Math.abs(v1.y - v2.y) < EPSILON &&
      Math.abs(v1.z - v2.z) < EPSILON
    );
  }

  public static getDecimal(v1: Vec3): Vec3 {
    const x: number = v1.x - Math.floor(v1.x);
    const y: number = v1.y - Math.floor(v1.y);
    const z: number = v1.z - Math.floor(v1.z);
    return new Vec3(x, y, z);
  }

  public x: number;
  public y: number;
  public z: number;

  constructor(x: number, y: number, z: number) {
    this.x = x;
    this.y = y;
    this.z = z;
  }

  public get length(): number {
    return Math.sqrt(this.x * this.x + this.y * this.y + this.z * this.z);
  }

  public get lengthPow2(): number {
    return this.x * this.x + this.y * this.y + this.z * this.z;
  }

  public get avg(): number {
    return (this.x + this.y + this.z) / 3;
  }

  public scale(num: number): Vec3 {
    return new Vec3(this.x * num, this.y * num, this.z * num);
  }

  public normalize(): Vec3 {
    const len = this.length;
    if (len === 0) {
      throw new Error('Can not normalize zero vector');
    } else {
      return new Vec3(this.x / len, this.y / len, this.z / len);
    }
  }

  public dot(vec: Vec3): number {
    return Vec3.dot(this, vec);
  }

  public sub(vec: Vec3): Vec3 {
    return Vec3.sub(this, vec);
  }

  public add(vector: Vec3): Vec3 {
    return Vec3.add(this, vector);
  }

  public equals(vec: Vec3): boolean {
    return Vec3.equals(this, vec);
  }

  public clone(): Vec3 {
    return new Vec3(this.x, this.y, this.z);
  }

  public toString(): string {
    return '(' + this.x.toFixed(3) + ',' + this.y.toFixed(3) + ',' + this.z.toFixed(3) + ')';
  }
}