package it.cavallium.strangedb.database;

import it.cavallium.strangedb.BlockInfo;

import java.io.IOException;
import java.nio.ByteBuffer;

import static it.cavallium.strangedb.database.IBlocksMetadata.EMPTY_BLOCK_ID;

public class DatabaseBlocksIO implements IBlocksIO {

	private final DatabaseFileIO fileIO;
	private final IBlocksMetadata blocksMetadata;

	public DatabaseBlocksIO(DatabaseFileIO fileIO, IBlocksMetadata blocksMetadata) {
		this.fileIO = fileIO;
		this.blocksMetadata = blocksMetadata;
	}

	@Override
	public long newBlock(int size, ByteBuffer data) throws IOException {
		if (size == 0) {
			return EMPTY_BLOCK_ID;
		}
		long index = fileIO.writeAtEnd(size, data);
		return blocksMetadata.newBlock(index, size);
	}

	@Override
	public ByteBuffer readBlock(long blockId) throws IOException {
		if (blockId == EMPTY_BLOCK_ID) {
			return ByteBuffer.wrap(new byte[0]);
		}
		BlockInfo blockInfo = blocksMetadata.getBlockInfo(blockId);
		return fileIO.readAt(blockInfo.getIndex(), blockInfo.getSize());
	}

	@Override
	public void close() {

	}
}