import { FileLoader } from "./FileLoader.ts";
import { Loader } from "./Loader.ts";

/** Loads a JSON material definition and returns a material instance. */
export class MaterialLoader extends Loader {
	override load(
		url: string,
		onLoad?: ((material: Record<string, unknown>) => void) | undefined,
		onProgress?: ((event: ProgressEvent) => void) | undefined,
		onError?: ((err: unknown) => void) | undefined,
	): void {
		const fileLoader = new FileLoader(this.manager);
		fileLoader.setPath(this.path);
		fileLoader.setResponseType("json");
		fileLoader.setRequestHeader(this.requestHeader);

		fileLoader.load(
			url,
			(json) => {
				onLoad?.(this.parse(json as Record<string, unknown>));
			},
			onProgress,
			onError,
		);
	}

	parse(json: Record<string, unknown>): Record<string, unknown> {
		let material: Record<string, unknown>;

		switch (json["type"]) {
			case "BasicMaterial":
			case "LambertMaterial":
			case "PhongMaterial":
			case "StandardMaterial": {
				material = Object.assign(Object.create(null), {
					type: json["type"],
				});
				break;
			}
			default:
				console.warn(`MaterialLoader: unsupported type "${json["type"]}"`);
				material = Object.assign(Object.create(null), {
					type: json["type"] ?? "Material",
				});
				break;
		}

		const skip = new Set(["type"]);
		for (const [key, value] of Object.entries(json)) {
			if (!skip.has(key)) {
				material[key] = value;
			}
		}

		return material;
	}
}