import ndarray from 'ndarray';
import type { NdArray } from 'ndarray';

export function getPixelsInternal(
	buffer: Uint8Array,
	mimeType: string,
): Promise<NdArray<Uint8Array>> {
	// Warn for Data URIs, URLs, and file paths. Support removed in v3.
	if (!(buffer instanceof Uint8Array)) {
		throw new Error('[ndarray-pixels] Input must be Uint8Array or Buffer.');
	}

	const blob = new Blob([buffer], { type: mimeType });
	return createImageBitmap(blob, {
		premultiplyAlpha: 'none',
		colorSpaceConversion: 'none',
	}).then((img) => {
		const canvas = new OffscreenCanvas(img.width, img.height);
		const context = canvas.getContext('2d')!;
		context.drawImage(img, 0, 0);
		const pixels = context.getImageData(0, 0, img.width, img.height);
		return ndarray(
			new Uint8Array(pixels.data),
			[img.width, img.height, 4],
			[4, 4 * img.width, 1],
			0,
		);
	});
}