import { Matrix3D, Orientation3D, Vector3D, MathConsts } from '@awayjs/core';

import { ShaderBase, _Render_RenderableBase, AnimationRegisterData } from '@awayjs/renderer';

import { AnimationElements } from '../data/AnimationElements';
import { ParticleBillboardNode } from '../nodes/ParticleBillboardNode';

import { ParticleAnimator } from '../ParticleAnimator';

import { ParticleStateBase } from './ParticleStateBase';

/**
 * ...
 */
export class ParticleBillboardState extends ParticleStateBase {
	/** @private */
	public static MATRIX_INDEX: number = 0;

	private _matrix: Matrix3D = new Matrix3D;

	private _billboardAxis: Vector3D;

	/**
	 *
	 */
	constructor(animator: ParticleAnimator, particleNode: ParticleBillboardNode) {
		super(animator, particleNode);

		this._billboardAxis = particleNode._iBillboardAxis;
	}

	public setRenderState(shader: ShaderBase, renderable: _Render_RenderableBase, animationElements: AnimationElements, animationRegisterData: AnimationRegisterData): void {
		let comps: Array<Vector3D>;
		if (this._billboardAxis) {
			const pos: Vector3D = renderable.entity.node.getMatrix3D().position;
			let look: Vector3D = shader.view.projection.transform.matrix3D.position.subtract(pos);
			const right: Vector3D = look.crossProduct(this._billboardAxis);
			right.normalize();
			look = this.billboardAxis.crossProduct(right);
			look.normalize();

			//create a quick inverse projection matrix
			this._matrix.copyFrom(renderable.entity.node.getMatrix3D());
			comps = this._matrix.decompose(Orientation3D.AXIS_ANGLE);
			this._matrix.copyColumnFrom(0, right);
			this._matrix.copyColumnFrom(1, this.billboardAxis);
			this._matrix.copyColumnFrom(2, look);
			this._matrix.copyColumnFrom(3, pos);
			this._matrix.appendRotation(-comps[1].w * MathConsts.RADIANS_TO_DEGREES, comps[1]);
		} else {
			//create a quick inverse projection matrix
			this._matrix.copyFrom(renderable.entity.node.getMatrix3D());
			this._matrix.append(shader.view.projection.transform.inverseMatrix3D);

			//decompose using axis angle rotations
			comps = this._matrix.decompose(Orientation3D.AXIS_ANGLE);

			//recreate the matrix with just the rotation data
			this._matrix.identity();
			this._matrix.appendRotation(-comps[1].w * MathConsts.RADIANS_TO_DEGREES, comps[1]);
		}

		//set a new matrix transform constant
		shader.setVertexConstFromMatrix(animationRegisterData.getRegisterIndex(this._pAnimationNode, ParticleBillboardState.MATRIX_INDEX), this._matrix);
	}

	/**
	 * Defines the billboard axis.
	 */
	public get billboardAxis(): Vector3D {
		return this.billboardAxis;
	}

	public set billboardAxis(value: Vector3D) {
		this.billboardAxis = value ? value.clone() : null;
		if (this.billboardAxis)
			this.billboardAxis.normalize();
	}

}