import { DataTextureLoader,EquirectangularReflectionMapping, Object3D, PerspectiveCamera, Scene, Vector3 } from "three";
import { OrbitControls } from "three/examples/jsm/controls/OrbitControls.js";

import { AssetReference } from "./engine_addressables.js";
import { getBoundingBox } from "./engine_three_utils.js";

declare type ComparisonSceneOptions = {
    /**
     * An array of model urls to load
     */
    files: string[];
    /**
     * Optional dom element to attach the orbit controls to. By default this should be the WebGLRenderer.domElement
     */
    domElement?: HTMLElement;
    /**
     * Can be a .hdr or .exr file url
     */
    environment?: string;
}

/**
 * A collection of utility methods for quickly spinning up test environments
 */
export class TestSceneUtils {

    /**
     * Use this method to quickly setup a scene to compare multiple models.  
     * @example
     * ```ts
     * const files = [
     *    "https://threejs.org/examples/models/gltf/RobotExpressive/RobotExpressive.glb",
     *   "https://threejs.org/examples/models/gltf/Lantern/glTF-Binary/Lantern.glb",
     * ];
     * const { scene, camera } = await TestUtils.createComparisonScene({ files });
     * // this could now be assigned to the Needle Engine Context
     * context.scene = scene;
     * context.mainCamera = camera;
     * ```
     */
    static async createComparisonScene(opts: ComparisonSceneOptions) {

        const { files } = opts;

        const promises = Promise.all(files.map(file => new AssetReference(file).loadAssetAsync()));
        const results = await promises;
        const scene = new Scene();

        let offset = 0;
        for (const result of results) {
            if (result instanceof Object3D) {
                result.position.y = offset;
                scene.add(result);
                const box = getBoundingBox([result]);
                offset += box.getSize(new Vector3()).y;
                offset += .1;
            }
        }
        const camera = new PerspectiveCamera(20);
        scene.add(camera);

        // Load an environment map
        const environmentUrl = opts.environment || "https://dl.polyhaven.org/file/ph-assets/HDRIs/exr/1k/studio_small_09_1k.exr";
        if (environmentUrl) {
            let loader: DataTextureLoader | null = null;
            if (environmentUrl.endsWith(".hdr")) {
                const RGBELoader = (await import("three/examples/jsm/loaders/RGBELoader.js")).RGBELoader;
                loader = new RGBELoader();
            }
            else if (environmentUrl.endsWith(".exr")) {
                const EXRLoader = (await import("three/examples/jsm/loaders/EXRLoader.js")).EXRLoader;
                loader = new EXRLoader();
            }
            if (loader) {
                const envmap = await loader.loadAsync(environmentUrl).catch((e) => { console.error(e); return null; });
                if (envmap) {
                    envmap.mapping = EquirectangularReflectionMapping;
                    envmap.needsUpdate = true;
                    scene.background = envmap;
                    scene.environment = envmap;
                    scene.backgroundBlurriness = .75;
                }
            }
            else console.warn("Unsupported environment map format", environmentUrl);
        }

        const box = getBoundingBox(scene.children);
        const center = box.getCenter(new Vector3());
        const size = box.getSize(new Vector3());
        const max = Math.max(size.x, size.y, size.z);
        const distance = max / (2 * Math.tan(Math.PI * camera.fov / 360));
        camera.position.set(center.x, center.y, distance);
        camera.lookAt(center);

        const orbit = new OrbitControls(camera, opts.domElement || document.body);
        orbit.target = center;
        orbit.update();


        const element = (opts.domElement || document.body).getBoundingClientRect();
        camera.aspect = element.width / element.height;
        camera.updateProjectionMatrix();

        return {
            scene,
            camera
        }
    }
}