import { Constants } from '../../constants.js';
import type {
	DataTrackerListChunk,
	DataTrackerListChunkData,
} from '../../models/data/data-tracker-list-chunk.js';
import type { DataTrackerChunk } from '../../models/index.js';
import { Decoders } from '../index.js';

export default (buffer: Uint8Array): DataTrackerListChunk => {
	const chunk = Decoders.Chunk(buffer);
	const trackers: DataTrackerChunk[] = [];

	// TODO(jwetzell): add error handling
	if (chunk.chunkData) {
		let offset = 0;
		while (offset < chunk.chunkData.length) {
			const trackerChunk = Decoders.DataTrackerChunk(
				chunk.chunkData.subarray(offset)
			);
			offset += Constants.CHUNK_HEADER_SIZE;
			if (trackerChunk.chunk.header.dataLen) {
				offset += trackerChunk.chunk.header.dataLen;
			}
			if (trackerChunk.chunk.header.id !== undefined) {
				trackers.push(trackerChunk);
			}
		}
	}

	const data: DataTrackerListChunkData = {
		trackers,
	};

	return {
		chunk,
		data,
	};
};