import { LightShadow } from './LightShadow.js';
import { PerspectiveCamera } from '../cameras/PerspectiveCamera.js';
import { Matrix4 } from '../math/Matrix4.js';
import { Vector2 } from '../math/Vector2.js';
import { Vector3 } from '../math/Vector3.js';
import { Vector4 } from '../math/Vector4.js';

const _projScreenMatrix = /*@__PURE__*/ new Matrix4();
const _lightPositionWorld = /*@__PURE__*/ new Vector3();
const _lookTarget = /*@__PURE__*/ new Vector3();

class PointLightShadow extends LightShadow {
	constructor() {
		super(new PerspectiveCamera(90, 1, 0.5, 500));

		this._frameExtents = new Vector2(4, 2);

		this._viewportCount = 6;

		this._viewports = [
			// These viewports map a cube-map onto a 2D texture with the
			// following orientation:
			//
			//  xzXZ
			//   y Y
			//
			// X - Positive x direction
			// x - Negative x direction
			// Y - Positive y direction
			// y - Negative y direction
			// Z - Positive z direction
			// z - Negative z direction

			// positive X
			new Vector4(2, 1, 1, 1),
			// negative X
			new Vector4(0, 1, 1, 1),
			// positive Z
			new Vector4(3, 1, 1, 1),
			// negative Z
			new Vector4(1, 1, 1, 1),
			// positive Y
			new Vector4(3, 0, 1, 1),
			// negative Y
			new Vector4(1, 0, 1, 1),
		];

		this._cubeDirections = [
			new Vector3(1, 0, 0),
			new Vector3(-1, 0, 0),
			new Vector3(0, 0, 1),
			new Vector3(0, 0, -1),
			new Vector3(0, 1, 0),
			new Vector3(0, -1, 0),
		];

		this._cubeUps = [new Vector3(0, 1, 0), new Vector3(0, 1, 0), new Vector3(0, 1, 0), new Vector3(0, 1, 0), new Vector3(0, 0, 1), new Vector3(0, 0, -1)];
	}

	updateMatrices(light, viewportIndex = 0) {
		const camera = this.camera;
		const shadowMatrix = this.matrix;

		const far = light.distance || camera.far;

		if (far !== camera.far) {
			camera.far = far;
			camera.updateProjectionMatrix();
		}

		_lightPositionWorld.setFromMatrixPosition(light.matrixWorld);
		camera.position.copy(_lightPositionWorld);

		_lookTarget.copy(camera.position);
		_lookTarget.add(this._cubeDirections[viewportIndex]);
		camera.up.copy(this._cubeUps[viewportIndex]);
		camera.lookAt(_lookTarget);
		camera.updateMatrixWorld();

		shadowMatrix.makeTranslation(-_lightPositionWorld.x, -_lightPositionWorld.y, -_lightPositionWorld.z);

		_projScreenMatrix.multiplyMatrices(camera.projectionMatrix, camera.matrixWorldInverse);
		this._frustum.setFromProjectionMatrix(_projScreenMatrix);
	}
}

PointLightShadow.prototype.isPointLightShadow = true;

export { PointLightShadow };