import {combineUint8Arrays} from '../../combine-uint8-arrays';
import type {SpsAndPps} from '../../state/parser-state';
import {truthy} from '../../truthy';

function serializeUint16(value: number): Uint8Array {
	const buffer = new ArrayBuffer(2);

	const view = new DataView(buffer);

	view.setUint16(0, value);

	return new Uint8Array(buffer);
}

export const createSpsPpsData = (avc1Profile: SpsAndPps) => {
	return combineUint8Arrays(
		[
			new Uint8Array([
				// https://gist.github.com/uupaa/8493378ec15f644a3d2b
				1, // version
				avc1Profile.sps.spsData.profile,
				avc1Profile.sps.spsData.compatibility,
				avc1Profile.sps.spsData.level,
				0xff,
				0xe1,
			]),
			// sequence parameter set length
			serializeUint16(avc1Profile.sps.sps.length),
			// sequence parameter set
			avc1Profile.sps.sps,
			// num of PPS
			new Uint8Array([0x01]),
			// picture parameter set length
			serializeUint16(avc1Profile.pps.pps.length),
			// PPS
			avc1Profile.pps.pps,
			// if AVCProfileIndication != 66 && AVCProfileIndication != 77 && AVCProfileIndication != 88
			[66, 77, 88].some((b) => avc1Profile.sps.spsData.profile === b)
				? null
				: /**
				 *  reserved	63 (0x3F)
						chroma_format	1, '4:2:0'
						reserved	31 (0x1F)
						bit_depth_luma_minus8	0
						reserved	31 (0x1F)
						bit_depth_chroma_minus8	0
						numOfSequenceParameterSetExt	0
				 */
					new Uint8Array([0xfd, 0xf8, 0xf8, 0]),
		].filter(truthy),
	);
};