/* 
 * MHAP package
 * 
 * This  software is distributed "as is", without any warranty, including 
 * any implied warranty of merchantability or fitness for a particular
 * use. The authors assume no responsibility for, and shall not be liable
 * for, any special, indirect, or consequential damages, or any damages
 * whatsoever, arising out of or in connection with the use of this
 * software.
 * 
 * Copyright (c) 2014 by Konstantin Berlin and Sergey Koren
 * University Of Maryland
 * 
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 * 
 */
package edu.umd.marbl.mhap.sketch;

public abstract class AbstractBitSketch<T extends AbstractBitSketch<T>> implements Sketch<T>,
		Comparable<T>
{
	protected final long[] bits;
	/**
	 * 
	 */
	private static final long serialVersionUID = -3392030412388403092L;

	protected AbstractBitSketch(long[] bits)
	{
		this.bits = bits;
	}
	
	@Override
	public int compareTo(final T sim)
	{
		for (int bitIndex = 0; bitIndex < this.bits.length; bitIndex++)
		{
			if (this.bits[bitIndex] < sim.bits[bitIndex])
				return -1;
			if (this.bits[bitIndex] > sim.bits[bitIndex])
				return 1;
		}

		return 0;
	}

	public final boolean getBit(long index)
	{
		int arrayIndex = (int)(index/64L);
		int bitPos = (int)(index%64L);
		
		long mask = 0b1L<<bitPos;
		
		return (bits[arrayIndex] & mask) != 0L;		
	}
	
	public final long[] getBits()
	{
		return this.bits;
	}
	
	public final int getIntersectionCount(final T sh)
	{
		if (this.bits.length != sh.bits.length)
			throw new SketchRuntimeException("Size of bits in tables must match.");

		int count = 0;
		for (int longIndex = 0; longIndex < this.bits.length; longIndex++)
		{
			final long xor = this.bits[longIndex] ^ sh.bits[longIndex];

			count += Long.bitCount(xor);
		}

		return this.bits.length * 64 - count;
	}

	public long getWord(int index)
	{
		return this.bits[index];
	}
	
	public long numberOfBits()
	{
		return this.bits.length*64;
	}
	
	public int numberOfWords()
	{
		return this.bits.length;
	}

	@Override
	public final double similarity(T v)
	{
		int count = getIntersectionCount(v);
		
		return (double)count/(double) this.numberOfBits();
	}

	@Override
	public String toString()
	{
		StringBuilder s = new StringBuilder();
		for (int longIndex = 0; longIndex < this.bits.length; longIndex++)
		{
			long mask = 1L << 63;

			for (int bit = 63; bit >= 0; bit--)
			{
				if ((this.bits[longIndex] & mask) == 0)
					s.append("0");
				else
					s.append("1");

				mask = mask >>> 1;
			}
		}
		
		return s.toString();
	}
}