import { math } from '../../math/math.js';

import { AnimBlendTree } from './anim-blend-tree.js';

/**

* @private

* @class

* @name AnimBlendTree1D

* @classdesc An AnimBlendTree that calculates its weights using a 1D algorithm

* based on the thesis http://runevision.com/thesis/rune_skovbo_johansen_thesis.pdf Chapter 6.

* @description Create a new BlendTree1D.

*/

class AnimBlendTree1D extends AnimBlendTree {

constructor(state, parent, name, point, parameters, children, syncAnimations, createTree, findParameter) {

children.sort((a, b) => a.point - b.point);

super(state, parent, name, point, parameters, children, syncAnimations, createTree, findParameter);

}

calculateWeights() {

if (this.updateParameterValues()) return;

var i;

var weightedDurationSum = 0.0;

this._children[0].weight = 0.0;

for (i = 0; i < this._children.length; i++) {

var c1 = this._children[i];

if (i !== this._children.length - 1) {

var c2 = this._children[i + 1];

if (c1.point === c2.point) {

c1.weight = 0.5;

c2.weight = 0.5;

} else if (math.between(this._parameterValues[0], c1.point, c2.point, true)) {

var child2Distance = Math.abs(c1.point - c2.point);

var parameterDistance = Math.abs(c1.point - this._parameterValues[0]);

var weight = (child2Distance - parameterDistance) / child2Distance;

c1.weight = weight;

c2.weight = (1.0 - weight);

} else {

c2.weight = 0.0;

}

}

if (this._syncAnimations) {

weightedDurationSum += c1.animTrack.duration / c1.absoluteSpeed * c1.weight;

}

}

if (this._syncAnimations) {

for (i = 0; i < this._children.length; i++) {

const child = this._children[i];

child.weightedSpeed = child.animTrack.duration / child.absoluteSpeed / weightedDurationSum;

}

}

}

}

export { AnimBlendTree1D };