/**
 * Represents an edge constraint between two vertices in the triangulation
 */
export class EdgeConstraint {
  /**
   * Index of the first end point of the constraint
   */
  v1: number;

  /**
   * Index of the second end point of the constraint
   */
  v2: number;

  /**
   * Index of the triangle prior to the edge crossing (v1 -> v2)
   */
  t1: number;

  /**
   * Index of the triangle after the edge crossing (v1 -> v2)
   */
  t2: number;

  /**
   * Index of the edge on the t1 side
   */
  t1Edge: number;

  /**
   * Creates a new edge constraint with the given end points
   */
  constructor(
    v1: number,
    v2: number,
    triangle1?: number,
    triangle2?: number,
    edge1?: number,
  ) {
    this.v1 = v1;
    this.v2 = v2;
    this.t1 = triangle1 ?? -1;
    this.t2 = triangle2 ?? -1;
    this.t1Edge = edge1 ?? 0;
  }

  /**
   * Determines whether the specified object is equal to the current object
   */
  equals(other: EdgeConstraint): boolean {
    return (
      (this.v1 === other.v1 && this.v2 === other.v2) ||
      (this.v1 === other.v2 && this.v2 === other.v1)
    );
  }

  /**
   * Creates a copy of this edge constraint
   */
  clone(): EdgeConstraint {
    return new EdgeConstraint(this.v1, this.v2, this.t1, this.t2, this.t1Edge);
  }

  /**
   * Returns a string that represents the current object
   */
  toString(): string {
    return `Edge: T${this.t1}->T${this.t2} (V${this.v1}->V${this.v2})`;
  }
}