/*
 * 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 org.apache.sysds.runtime.meta;

import org.apache.sysds.runtime.util.UtilFunctions;

import java.util.Arrays;


public class TensorCharacteristics extends DataCharacteristics
{
	private static final long serialVersionUID = 8300479822915546000L;

	// TODO move block size to `ConfigurationManager`
	public static final int[] DEFAULT_BLOCK_SIZE = {1024, 128, 32, 16, 8, 8};
	private long[] _dims;
	private long _nnz = -1;
	
	public TensorCharacteristics() {}
	
	public TensorCharacteristics(long[] dims, long nnz) {
		set(dims, DEFAULT_BLOCK_SIZE[dims.length - 2], nnz);
	}
	
	public TensorCharacteristics(long[] dims, int blocksize) {
		set(dims, blocksize, -1);
	}

	public TensorCharacteristics(long[] dims, int blocksize, long nnz) {
		set(dims, blocksize, nnz);
	}

	public TensorCharacteristics(DataCharacteristics that) {
		set(that);
	}

	@Override
	public DataCharacteristics set(long[] dims, int blocksize) {
		set(dims, blocksize, -1);
		return this;
	}

	@Override
	public DataCharacteristics set(long[] dims, int blocksize, long nnz) {
		_dims = dims;
		_blocksize = blocksize;
		return this;
	}

	@Override
	public DataCharacteristics set(DataCharacteristics that) {
		long[] dims = that.getDims().clone();
		set(dims, that.getBlocksize(), that.getNonZeros());
		return this;
	}

	@Override
	public DataCharacteristics setNonZeros(long nnz) {
		_nnz = nnz;
		return this;
	}

	@Override
	public boolean dimsKnown() {
		for (long dim : _dims) {
			if (dim < 0)
				return false;
		}
		return true;
	}

	@Override
	public boolean dimsKnown(boolean includeNnz) {
		return dimsKnown() && (!includeNnz || nnzKnown());
	}

	@Override
	public boolean nnzKnown() {
		return _nnz >= 0;
	}

	@Override
	public int getNumDims() {
		return _dims.length;
	}

	@Override
	public long getDim(int i) {
		return _dims[i];
	}

	@Override
	public long[] getLongDims() {
		return _dims;
	}

	@Override
	public int[] getIntDims() {
		return Arrays.stream(getLongDims()).mapToInt(i -> (int) i).toArray();
	}

	@Override
	public DataCharacteristics setDim(int i, long dim) {
		_dims[i] = dim;
		return this;
	}

	@Override
	public DataCharacteristics setDims(long[] dims) {
		_dims = dims;
		return this;
	}

	@Override
	public long getLength() {
		return UtilFunctions.prod(_dims);
	}

	@Override
	public long getNumBlocks() {
		long ret = 1;
		for( int i=0; i<getNumDims(); i++ )
			ret *= getNumBlocks(i);
		return ret;
	}

	@Override
	public long getNumBlocks(int i) {
		return Math.max((long) Math.ceil((double)getDim(i) / getBlocksize()), 1);
	}

	@Override
	public long getNonZeros() {
		return _nnz;
	}

	@Override
	public String toString() {
		return "["+Arrays.toString(_dims)+", nnz="+_nnz + ", blocksize= "+_blocksize+"]";
	}
	
	@Override
	public boolean equalDims(Object anObject) {
		if( !(anObject instanceof TensorCharacteristics) )
			return false;
		TensorCharacteristics tc = (TensorCharacteristics) anObject;
		return dimsKnown() && tc.dimsKnown()
			&& Arrays.equals(_dims, tc._dims);
	}
	
	@Override
	public boolean equals (Object anObject) {
		if( !(anObject instanceof TensorCharacteristics) )
			return false;
		TensorCharacteristics tc = (TensorCharacteristics) anObject;
		return Arrays.equals(_dims, tc._dims)
			&& _blocksize == tc._blocksize
			&& _nnz == tc._nnz;
	}
	
	@Override
	public int hashCode() {
		return UtilFunctions.intHashCode(UtilFunctions.intHashCode(
			Arrays.hashCode(_dims), _blocksize), Long.hashCode(_nnz));
	}
}
