package org.warp.jcwdb.ann;

import org.warp.jcwdb.FileIndexManager;

import java.io.IOError;
import java.io.IOException;

public class DBObjectIndicesManager {
	private final FileIndexManager indices;

	DBObjectIndicesManager(FileIndexManager indices) {
		this.indices = indices;
	}

	public long allocate(int fieldsCount, int propertiesCount) {
		long uid = indices.add(calculateObjectSize(fieldsCount, propertiesCount));
		//System.err.println("ALLOCATED UID " + uid);
		return uid;
	}

	public void setNull(long uid) throws IOException {
		indices.set(uid, 0, (w) -> w.write(new byte[0]));
	}

	public void set(long uid, long[] fields, long[] properties) throws IOException {
		indices.set(uid, calculateObjectSize(fields, properties), (w) -> {
			w.writeInt(fields.length);
			w.writeInt(properties.length);
			for (int i = 0; i < fields.length; i++) {
				w.writeLong(fields[i]);
			}
			for (int i = 0; i < properties.length; i++) {
				w.writeLong(properties[i]);
			}
		});
	}

	public DBObjectInfo get(long uid) throws IOException {
		return indices.get(uid, (i, size) -> {
			if (size < Integer.BYTES * 2) {
				return null;
			}
			long[] indices = new long[i.readInt()];
			long[] properties = new long[i.readInt()];
			if (size != calculateObjectSize(indices, properties)) {
				throw new IOError(new IOException("The size of the object is different!"));
			}
			for (int indicesI = 0; indicesI < indices.length; indicesI++) {
				indices[indicesI] = i.readLong();
			}
			for (int propertiesI = 0; propertiesI < properties.length; propertiesI++) {
				properties[propertiesI] = i.readLong();
			}
			return new DBObjectInfo(indices, properties);
		});
	}

	public boolean has(long uid) {
		return indices.has(uid);
	}

	private int calculateObjectSize(long[] fields, long[] properties) {
		return calculateObjectSize(fields.length, properties.length);
	}

	private int calculateObjectSize(int fieldsCount, int propertiesCount) {
		return Integer.BYTES * 2 + (fieldsCount + propertiesCount) * Long.BYTES;
	}

	public class DBObjectInfo {
		private final long[] fields;
		private final long[] properties;

		public DBObjectInfo(long[] fields, long[] properties) {
			this.fields = fields;
			this.properties = properties;
		}

		public long[] getFields() {
			return fields;
		}

		public long[] getProperties() {
			return properties;
		}
	}
}