import { Constants } from '../../constants.js';
import type {
	DataPacketChunk,
	DataPacketChunkData,
} from '../../models/data/data-packet-chunk.js';
import { Decoders } from '../index.js';

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

	const data: DataPacketChunkData = {};

	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:
					data.packetHeader = Decoders.PacketHeaderChunk(
						chunk.chunkData.subarray(offset)
					);
					offset += Constants.CHUNK_HEADER_SIZE;
					if (data.packetHeader.chunk.header.dataLen) {
						offset += data.packetHeader.chunk.header.dataLen;
					}
					break;
				case 0x0001:
					data.trackerList = Decoders.DataTrackerListChunk(
						chunk.chunkData.subarray(offset)
					);
					offset += Constants.CHUNK_HEADER_SIZE;
					if (data.trackerList.chunk.header.dataLen) {
						offset += data.trackerList.chunk.header.dataLen;
					}
					break;
				default:
					break;
			}
		}
	}

	return {
		chunk,
		data,
	};
};