import { Vector2 } from '../../math/Vector2.js';
import { Curve } from '../core/Curve.js';

class LineCurve extends Curve {

	constructor( v1 = new Vector2(), v2 = new Vector2() ) {

		super();

		this.type = 'LineCurve';

		this.v1 = v1;
		this.v2 = v2;

	}

	getPoint( t, optionalTarget = new Vector2() ) {

		const point = optionalTarget;

		if ( t === 1 ) {

			point.copy( this.v2 );

		} else {

			point.copy( this.v2 ).sub( this.v1 );
			point.multiplyScalar( t ).add( this.v1 );

		}

		return point;

	}

	// Line curve is linear, so we can overwrite default getPointAt
	getPointAt( u, optionalTarget ) {

		return this.getPoint( u, optionalTarget );

	}

	getTangent( t, optionalTarget ) {

		const tangent = optionalTarget || new Vector2();

		tangent.copy( this.v2 ).sub( this.v1 ).normalize();

		return tangent;

	}

	copy( source ) {

		super.copy( source );

		this.v1.copy( source.v1 );
		this.v2.copy( source.v2 );

		return this;

	}

	toJSON() {

		const data = super.toJSON();

		data.v1 = this.v1.toArray();
		data.v2 = this.v2.toArray();

		return data;

	}

	fromJSON( json ) {

		super.fromJSON( json );

		this.v1.fromArray( json.v1 );
		this.v2.fromArray( json.v2 );

		return this;

	}

}

LineCurve.prototype.isLineCurve = true;

export { LineCurve };