/*
 * Java Genetic Algorithm Library (jenetics-7.1.0).
 * Copyright (c) 2007-2022 Franz Wilhelmstötter
 *
 * 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.
 *
 * Author:
 *    Franz Wilhelmstötter (franz.wilhelmstoetter@gmail.com)
 */
package io.jenetics;

import static java.util.Objects.requireNonNull;
import static io.jenetics.internal.util.SerialIO.readInt;
import static io.jenetics.internal.util.SerialIO.writeInt;

import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serial;
import java.io.Serializable;
import java.util.function.Function;
import java.util.stream.IntStream;
import java.util.stream.Stream;

import io.jenetics.util.ISeq;
import io.jenetics.util.IntRange;
import io.jenetics.util.MSeq;

/**
 * Numeric chromosome implementation which holds 32-bit integer numbers.
 *
 * @see IntegerGene
 *
 * @implNote
 * This class is immutable and thread-safe.
 *
 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz  Wilhelmstötter</a>
 * @since 2.0
 * @version 7.0
 */
public class IntegerChromosome
        extends AbstractBoundedChromosome<Integer, IntegerGene>
        implements
                NumericChromosome<Integer, IntegerGene>,
                Serializable
{
        @Serial
        private static final long serialVersionUID = 3L;

        /**
         * Create a new chromosome from the given {@code genes} and the allowed
         * length range of the chromosome.
         *
         * @since 4.0
         *
         * @param genes the genes that form the chromosome.
         * @param lengthRange the allowed length range of the chromosome
         * @throws NullPointerException if one of the arguments is {@code null}.
         * @throws IllegalArgumentException if the length of the gene sequence is
         *         empty, doesn't match with the allowed length range, the minimum
         *         or maximum of the range is smaller or equal zero or the given
         *         range size is zero.
         */
        protected IntegerChromosome(
                final ISeq<IntegerGene> genes,
                final IntRange lengthRange
        ) {
                super(genes, lengthRange);
        }

        @Override
        public IntegerChromosome newInstance(final ISeq<IntegerGene> genes) {
                return new IntegerChromosome(genes, lengthRange());
        }

        @Override
        public IntegerChromosome newInstance() {
                return of(_min, _max, lengthRange());
        }

        /**
         * Maps the gene alleles of this chromosome, given as {@code int[]} array,
         * by applying the given mapper function {@code f}. The mapped gene values
         * are then wrapped into a newly created chromosome.
         *
         * <pre>{@code
         * final IntegerChromosome chromosome = ...;
         * final IntegerChromosome halved = chromosome.map(Main::half);
         *
         * static int[] half(final int[] values) {
         *     for (int i = 0; i < values.length; ++i) {
         *         values[i] /= 2;
         *     }
         *     return values;
         * }
         * }</pre>
         *
         * @since 6.1
         *
         * @param f the mapper function
         * @return a newly created chromosome with the mapped gene values
         * @throws NullPointerException if the mapper function is {@code null}.
         * @throws IllegalArgumentException if the length of the mapped
         *         {@code int[]} array is empty or doesn't match with the allowed
         *         length range
         */
        public IntegerChromosome map(final Function<? super int[], int[]> f) {
                requireNonNull(f);

                final var range = IntRange.of(_min, _max);
                final var genes = IntStream.of(f.apply(toArray()))
                        .mapToObj(v -> IntegerGene.of(v, range))
                        .collect(ISeq.toISeq());

                return newInstance(genes);
        }

        /**
         * Returns a sequential stream of the alleles with this chromosome as its
         * source.
         *
         * @since 4.3
         *
         * @return a sequential stream of alleles
         */
        public IntStream intStream() {
                return IntStream.range(0, length()).map(this::intValue);
        }

        /**
         * Returns an int array containing all the elements in this chromosome in
         * proper sequence.  If the chromosome fits in the specified array, it is
         * returned therein. Otherwise, a new array is allocated with the length of
         * this chromosome.
         *
         * @since 3.0
         *
         * @param array the array into which the elements of these chromosomes are
         *        to be stored, if it is big enough; otherwise, a new array is
         *        allocated for this purpose.
         * @return an array containing the elements of this chromosome
         * @throws NullPointerException if the given {@code array} is {@code null}
         */
        public int[] toArray(final int[] array) {
                final int[] a = array.length >= length() ? array : new int[length()];
                for (int i = length(); --i >= 0;) {
                        a[i] = intValue(i);
                }

                return a;
        }

        /**
         * Returns an int array containing all the elements in this chromosome in
         * proper sequence.
         *
         * @since 3.0
         *
         * @return an array containing the elements of this chromosome
         */
        public int[] toArray() {
                return toArray(new int[length()]);
        }


        /* *************************************************************************
         * Static factory methods.
         * ************************************************************************/

        /**
         * Create a new {@code IntegerChromosome} with the given genes.
         *
         * @param genes the genes of the chromosome.
         * @return a new chromosome with the given genes.
         * @throws IllegalArgumentException if the length of the genes array is
         *         empty or the given {@code genes} doesn't have the same range.
         */
        public static IntegerChromosome of(final IntegerGene... genes) {
                checkGeneRange(Stream.of(genes).map(IntegerGene::range));
                return new IntegerChromosome(ISeq.of(genes), IntRange.of(genes.length));
        }

        /**
         * Create a new {@code IntegerChromosome} with the given genes.
         *
         * @since 4.3
         *
         * @param genes the genes of the chromosome.
         * @return a new chromosome with the given genes.
         * @throws NullPointerException if the given {@code genes} are {@code null}
         * @throws IllegalArgumentException if the of the genes iterable is empty or
         *         the given {@code genes} doesn't have the same range.
         */
        public static IntegerChromosome of(final Iterable<IntegerGene> genes) {
                final ISeq<IntegerGene> values = ISeq.of(genes);
                checkGeneRange(values.stream().map(IntegerGene::range));
                return new IntegerChromosome(values, IntRange.of(values.length()));
        }

        /**
         * Create a new random chromosome.
         *
         * @since 4.0
         *
         * @param min the min value of the {@link IntegerGene}s (inclusively).
         * @param max the max value of the {@link IntegerGene}s (exclusively).
         * @param lengthRange the allowed length range of the chromosome.
         * @return a new {@code IntegerChromosome} with the given parameter
         * @throws IllegalArgumentException if the length of the gene sequence is
         *         empty, doesn't match with the allowed length range, the minimum
         *         or maximum of the range is smaller or equal zero or the given
         *         range size is zero.
         * @throws IllegalArgumentException if {@code max} is greater than
         *         or equal to {@code min}
         * @throws NullPointerException if the given {@code lengthRange} is
         *         {@code null}
         */
        public static IntegerChromosome of(
                final int min,
                final int max,
                final IntRange lengthRange
        ) {
                final ISeq<IntegerGene> values = IntegerGene.seq(min, max, lengthRange);
                return new IntegerChromosome(values, lengthRange);
        }

        /**
         * Create a new random {@code IntegerChromosome}.
         *
         * @param min the min value of the {@link IntegerGene}s (inclusively).
         * @param max the max value of the {@link IntegerGene}s (exclusively).
         * @param length the length of the chromosome.
         * @return a new random {@code IntegerChromosome}
         * @throws IllegalArgumentException if the length is smaller than one
         * @throws IllegalArgumentException if {@code max} is greater than
         *         or equal to {@code min}
         */
        public static IntegerChromosome of(
                final int min,
                final int max,
                final int length
        ) {
                return of(min, max, IntRange.of(length));
        }

        /**
         * Create a new random chromosome.
         *
         * @since 4.0
         *
         * @param range the integer range of the chromosome.
         * @param lengthRange the allowed length range of the chromosome.
         * @return a new {@code IntegerChromosome} with the given parameter
         * @throws IllegalArgumentException if the length of the gene sequence is
         *         empty, doesn't match with the allowed length range, the minimum
         *         or maximum of the range is smaller or equal zero or the given
         *         range size is zero.
         * @throws NullPointerException if the given {@code lengthRange} is
         *         {@code null}
         * @throws IllegalArgumentException if {@code max} is greater than
         *         or equal to {@code min}
         */
        public static IntegerChromosome of(
                final IntRange range,
                final IntRange lengthRange
        ) {
                return of(range.min(), range.max(), lengthRange);
        }

        /**
         * Create a new random {@code IntegerChromosome}.
         *
         * @since 3.2
         *
         * @param range the integer range of the chromosome.
         * @param length the length of the chromosome.
         * @return a new random {@code IntegerChromosome}
         * @throws NullPointerException if the given {@code range} is {@code null}
         * @throws IllegalArgumentException if the length is smaller than one
         * @throws IllegalArgumentException if {@code max} is greater than
         *         or equal to {@code min}
         */
        public static IntegerChromosome of(final IntRange range, final int length) {
                return of(range.min(), range.max(), length);
        }

        /**
         * Create a new random {@code IntegerChromosome} of length one.
         *
         * @param min the minimal value of this chromosome (inclusively).
         * @param max the maximal value of this chromosome (exclusively).
         * @return a new random {@code IntegerChromosome} of length one
         * @throws IllegalArgumentException if {@code max} is greater than
         *         or equal to {@code min}
         */
        public static IntegerChromosome of(final int min, final int max) {
                return of(min, max, 1);
        }

        /**
         * Create a new random {@code IntegerChromosome} of length one.
         *
         * @since 3.2
         *
         * @param range the integer range of the chromosome.
         * @return a new random {@code IntegerChromosome} of length one
         * @throws NullPointerException if the given {@code range} is {@code null}
         * @throws IllegalArgumentException if {@code max} is greater than
         *         or equal to {@code min}
         */
        public static IntegerChromosome of(final IntRange range) {
                return of(range.min(), range.max(), 1);
        }



        /* *************************************************************************
         *  Java object serialization
         * ************************************************************************/

        @Serial
        private Object writeReplace() {
                return new SerialProxy(SerialProxy.INTEGER_CHROMOSOME, this);
        }

        @Serial
        private void readObject(final ObjectInputStream stream)
                throws InvalidObjectException
        {
                throw new InvalidObjectException("Serialization proxy required.");
        }

        void write(final DataOutput out) throws IOException {
                writeInt(length(), out);
                writeInt(lengthRange().min(), out);
                writeInt(lengthRange().max(), out);
                writeInt(_min, out);
                writeInt(_max, out);

                for (int i = 0, n = length(); i < n; ++i) {
                        writeInt(intValue(i), out);
                }
        }

        static IntegerChromosome read(final DataInput in) throws IOException {
                final var length = readInt(in);
                final var lengthRange = IntRange.of(readInt(in), readInt(in));
                final var min = readInt(in);
                final var max = readInt(in);

                final MSeq<IntegerGene> values = MSeq.ofLength(length);
                for (int i = 0; i < length; ++i) {
                        values.set(i, IntegerGene.of(readInt(in), min, max));
                }

                return new IntegerChromosome(values.toISeq(), lengthRange);
        }

}