import { Constants } from '../../constants.js';
import type {
	InfoTrackerChunk,
	InfoTrackerChunkData,
} from '../../models/info/info-tracker-chunk.js';
import { Decoders } from '../index.js';

export default (buffer: Uint8Array): InfoTrackerChunk => {
	const chunk = Decoders.Chunk(buffer);

	if (chunk.header.hasSubchunks && chunk.chunkData && chunk.header.dataLen) {
		let offset = 0;
		while (offset < chunk.header.dataLen) {
			const chunkId =
				(chunk.chunkData.subarray(offset)[1] << 8) +
				chunk.chunkData.subarray(offset)[0];
			switch (chunkId) {
				case 0x0000: {
					const data: InfoTrackerChunkData = {
						trackerName: Decoders.InfoTrackerNameChunk(
							chunk.chunkData.subarray(offset)
						),
					};
					offset += Constants.CHUNK_HEADER_SIZE;
					if (data.trackerName.chunk.header.dataLen) {
						offset += data.trackerName.chunk.header.dataLen;
					}
					return {
						chunk,
						data,
					};
				}
				default:
					break;
			}
		}
	}

	return {
		chunk,
	};
};