import { DataTexture } from "../textures/DataTexture.js";
import { FileLoader } from "./FileLoader.ts";
import { Loader } from "./Loader.ts";

interface ParseResult {
	data: Uint8ClampedArray;
	width: number;
	height: number;
}

/**
 * Base loader for raw data to DataTexture.
 * Subclasses override parse() to handle specific formats.
 */
export class DataTextureLoader extends Loader {
	override load(
		url: string,
		onLoad?: (texture: DataTexture) => void,
		onProgress?: (event: ProgressEvent) => void,
		onError?: (err: unknown) => void,
	): void {
		const fileLoader = new FileLoader(this.manager);
		fileLoader.setPath(this.path);
		fileLoader.setResponseType("arraybuffer");
		fileLoader.setRequestHeader(this.requestHeader);

		fileLoader.load(
			url,
			(buffer) => {
				const result = this.parse(buffer as ArrayBuffer);
				if (!result) return;
				const texture = new DataTexture(
					result.data,
					result.width,
					result.height,
				);
				texture.needsUpdate = true;
				onLoad?.(texture);
			},
			onProgress,
			onError,
		);
	}

	/** Abstract - subclasses override to decode buffer. */
	parse(_data: ArrayBuffer): ParseResult | undefined {
		return undefined;
	}
}