import { Nullable } from "types";
import { GeometryBufferRenderer } from "Rendering";
import { Scene } from "scene";
import { ISceneComponent, SceneComponentConstants } from "sceneComponent";
import { SmartArrayNoDuplicate } from "Tools";
import { RenderTargetTexture } from "Materials";

    export interface Scene {
        /** @hidden (Backing field) */
        _geometryBufferRenderer: Nullable<GeometryBufferRenderer>;

        /**
         * Gets or Sets the current geometry buffer associated to the scene.
         */
        geometryBufferRenderer: Nullable<GeometryBufferRenderer>;

        /**
         * Enables a GeometryBufferRender and associates it with the scene
         * @param ratio defines the scaling ratio to apply to the renderer (1 by default which means same resolution)
         * @returns the GeometryBufferRenderer
         */
        enableGeometryBufferRenderer(ratio?: number): Nullable<GeometryBufferRenderer>;

        /**
         * Disables the GeometryBufferRender associated with the scene
         */
        disableGeometryBufferRenderer(): void;
    }

    Object.defineProperty(Scene.prototype, "geometryBufferRenderer", {
        get: function(this: Scene) {
            this._geometryBufferRenderer;
        },
        set: function(this: Scene, value: Nullable<GeometryBufferRenderer>) {
            if (value && value.isSupported) {
                this._geometryBufferRenderer = value;
            }
        },
        enumerable: true,
        configurable: true
    });

    Scene.prototype.enableGeometryBufferRenderer = function(ratio: number = 1): Nullable<GeometryBufferRenderer> {
        if (this._geometryBufferRenderer) {
            return this._geometryBufferRenderer;
        }

        this._geometryBufferRenderer = new GeometryBufferRenderer(this, ratio);
        if (!this._geometryBufferRenderer.isSupported) {
            this._geometryBufferRenderer = null;
        }

        return this._geometryBufferRenderer;
    };

    Scene.prototype.disableGeometryBufferRenderer = function(): void {
        if (!this._geometryBufferRenderer) {
            return;
        }

        this._geometryBufferRenderer.dispose();
        this._geometryBufferRenderer = null;
    };

    /**
     * Defines the Geometry Buffer scene component responsible to manage a G-Buffer useful
     * in several rendering techniques.
     */
    export class GeometryBufferRendererSceneComponent implements ISceneComponent {
        /**
         * The component name helpful to identify the component in the list of scene components.
         */
        public readonly name = SceneComponentConstants.NAME_GEOMETRYBUFFERRENDERER;

        /**
         * The scene the component belongs to.
         */
        public scene: Scene;

        /**
         * Creates a new instance of the component for the given scene
         * @param scene Defines the scene to register the component in
         */
        constructor(scene: Scene) {
            this.scene = scene;
        }

        /**
         * Registers the component in a given scene
         */
        public register(): void {
            this.scene._gatherRenderTargetsStage.registerStep(SceneComponentConstants.STEP_GATHERRENDERTARGETS_GEOMETRYBUFFERRENDERER, this, this._gatherRenderTargets);
        }

        /**
         * Rebuilds the elements related to this component in case of
         * context lost for instance.
         */
        public rebuild(): void {
            // Nothing to do for this component
        }

        /**
         * Disposes the component and the associated ressources
         */
        public dispose(): void {
            // Nothing to do for this component
        }

        private _gatherRenderTargets(renderTargets: SmartArrayNoDuplicate<RenderTargetTexture>): void {
            if (this.scene._geometryBufferRenderer) {
                renderTargets.push(this.scene._geometryBufferRenderer.getGBuffer());
            }
        }
    }