/*-
 *
 *  * Copyright 2015 Skymind,Inc.
 *  *
 *  *    Licensed 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.nd4j.linalg.util;

import org.nd4j.linalg.api.ndarray.INDArray;
import org.nd4j.linalg.exception.ND4JIllegalStateException;

import java.util.Arrays;

/**
 * Linear algebra exceptions
 *
 * @author Adam Gibson
 */
public class LinAlgExceptions {
    /**
     * Asserts both arrays be the same length
     * @param n
     * @param n2
     */
    public static void assertSameLength(INDArray n, INDArray n2) {
        if (n.length() != n2.length() && n.length() != 1 && n2.length() != 1)
            throw new IllegalStateException("Mis matched lengths: [" + n.length() + "] != [" + n2.length() + "] - " +
                    "Array 1 shape: " + Arrays.toString(n.shape()) + ", array 2 shape: " + Arrays.toString(n2.shape()));
    }

    public static void assertSameShape(INDArray n, INDArray n2) {
        if (!Arrays.equals(n.shape(), n2.shape()))
            throw new IllegalStateException("Mis matched shapes: " + Arrays.toString(n.shape()) + ", "
                    + Arrays.toString(n2.shape()));
    }

    public static void assertRows(INDArray n, INDArray n2) {
        if (n.rows() != n2.rows())
            throw new IllegalStateException("Mis matched rows: " + n.rows() + " != " + n2.rows());
    }


    public static void assertVector(INDArray... arr) {
        for (INDArray a1 : arr)
            assertVector(a1);
    }

    public static void assertMatrix(INDArray... arr) {
        for (INDArray a1 : arr)
            assertMatrix(a1);
    }

    public static void assertVector(INDArray arr) {
        if (!arr.isVector())
            throw new IllegalArgumentException("Array must be a vector. Array has shape: " + Arrays.toString(arr.shape()));
    }

    public static void assertMatrix(INDArray arr) {
        if (arr.shape().length > 2)
            throw new IllegalArgumentException("Array must be a matrix. Array has shape: " + Arrays.toString(arr.shape()));
    }



    /**
     * Asserts matrix multiply rules (columns of left == rows of right or rows of left == columns of right)
     *
     * @param nd1 the left ndarray
     * @param nd2 the right ndarray
     */
    public static void assertMultiplies(INDArray nd1, INDArray nd2) {
        if (nd1.rank() == 2 && nd2.rank() == 2 && nd1.columns() == nd2.rows()) {
            return;
        }

        // 1D edge case
        if (nd1.rank() == 2 && nd2.rank() == 1 && nd1.columns() == nd2.length())
            return;

        throw new ND4JIllegalStateException("Cannot execute matrix multiplication: " + Arrays.toString(nd1.shape())
                        + "x" + Arrays.toString(nd2.shape())
                        + (nd1.rank() != 2 || nd2.rank() != 2 ? ": inputs are not matrices"
                                        : ": Column of left array " + nd1.columns() + " != rows of right "
                                                        + nd2.rows()));
    }


    public static void assertColumns(INDArray n, INDArray n2) {
        if (n.columns() != n2.columns())
            throw new IllegalStateException("Mis matched columns: " + n.columns() + " != " + n2.columns());
    }

    public static void assertValidNum(INDArray n) {
        INDArray linear = n.linearView();
        for (int i = 0; i < linear.length(); i++) {
            double d = linear.getDouble(i);
            if (Double.isNaN(d) || Double.isInfinite(d))
                throw new IllegalStateException("Found infinite or nan");

        }
    }

}
