/*
 * Java Genetic Algorithm Library (jenetics-8.0.0).
 * Copyright (c) 2007-2024 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.ext.moea;

import java.util.Comparator;
import java.util.List;

import io.jenetics.Optimize;

/**
 * This interface allows creating a vector object from a given array type
 * {@code T}. It is useful if you need some additional parametrization of the
 * created vectors.
 * <p>
 * As the following example shows, only one {@code VecFactory} instance should
 * be used for creating the vectors for a given multi-objective <em>problem</em>.
 * {@snippet lang="java":
 * private static final VecFactory<double[]> FACTORY = VecFactory.ofDoubleVec(
 *     Optimize.MAXIMUM,
 *     Optimize.MINIMUM,
 *     Optimize.MINIMUM,
 *     Optimize.MAXIMUM
 * );
 *
 * // The fitness function.
 * static Vec<double[]> fitness(final double[] x) {
 *     final double[] result = new double[4];
 *     // ...
 *     return FACTORY.newVec(result);
 * }
 * }
 * In the example above, the first dimension of the created vector is maximized,
 * the following two are minimized, and the last vector component is again
 * maximized.
 *
 * @see Vec
 *
 * @author <a href="mailto:franz.wilhelmstoetter@gmail.com">Franz Wilhelmstötter</a>
 * @version 6.0
 * @since 5.2
 */
@FunctionalInterface
public interface VecFactory<T> {

        /**
         * Create a new {@link Vec} object from the given {@code array}.
         *
         * @param array the array used in the created vector
         * @return a new {@link Vec} object from the given {@code array}
         * @throws NullPointerException if the given {@code array} is {@code null}
         * @throws IllegalArgumentException if the {@code array} length is zero or
         *         doesn't match the required length of the actual factory
         */
        Vec<T> newVec(final T array);

        /**
         * Create a new factory for {@code int[]} vectors. Additionally, you can
         * specify the optimization direction (maximization or minimization) for
         * each dimension. The dimensionality of the created vectors must be exactly
         * the same as the given length of the given {@code optimizes}. If the
         * lengths don't match, an {@link IllegalArgumentException} is thrown.
         *
         * @see #ofIntVec(Optimize...)
         *
         * @apiNote
         * Only one factory instance should be used for a given multi-objective
         * <em>problem</em>.
         *
         * @param optimizes the optimization <em>direction</em> for each dimension
         * @return a new factory for {@code int[]} vectors
         * @throws NullPointerException if the given {@code optimizes} is
         *         {@code null}
         * @throws IllegalArgumentException if the {@code optimizes} length is zero
         */
        static VecFactory<int[]> ofIntVec(final List<Optimize> optimizes) {
                return new GeneralIntVecFactory(optimizes);
        }

        /**
         * Create a new factory for {@code int[]} vectors. Additionally, you can
         * specify the optimization direction (maximization or minimization) for
         * each dimension. The dimensionality of the created vectors must be exactly
         * the same as the given length of the given {@code optimizes}. If the
         * lengths don't match, an {@link IllegalArgumentException} is thrown.
         *
         * @see #ofIntVec(List)
         *
         * @apiNote
         * Only one factory instance should be used for a given multi-objective
         * <em>problem</em>.
         *
         * @param optimizes the optimization <em>direction</em> for each dimension
         * @return a new factory for {@code int[]} vectors
         * @throws NullPointerException if the given {@code optimizes} is
         *         {@code null}
         * @throws IllegalArgumentException if the {@code optimizes} length is zero
         */
        static VecFactory<int[]> ofIntVec(final Optimize... optimizes) {
                return ofIntVec(List.of(optimizes));
        }

        /**
         * Create a new factory for {@code int[]} vectors, where all dimensions are
         * maximized.
         *
         * @see Vec#of(int...)
         *
         * @return a new factory for {@code int[]} vectors, where all dimensions are
         *             maximized
         */
        static VecFactory<int[]> ofIntVec() {
                return Vec::of;
        }

        /**
         * Create a new factory for {@code long[]} vectors. Additionally, you can
         * specify the optimization direction (maximization or minimization) for
         * each dimension. The dimensionality of the created vectors must be exactly
         * the same as the given length of the given {@code optimizes}. If the
         * lengths don't match, an {@link IllegalArgumentException} is thrown.
         *
         * @see #ofLongVec(Optimize...)
         *
         * @apiNote
         * Only one factory instance should be used for a given multi-objective
         * <em>problem</em>.
         *
         * @param optimizes the optimization <em>direction</em> for each dimension
         * @return a new factory for {@code long[]} vectors
         * @throws NullPointerException if the given {@code optimizes} is
         *         {@code null}
         * @throws IllegalArgumentException if the {@code optimizes} length is zero
         */
        static VecFactory<long[]> ofLongVec(final List<Optimize> optimizes) {
                return new GeneralLongVecFactory(optimizes);
        }

        /**
         * Create a new factory for {@code long[]} vectors. Additionally, you can
         * specify the optimization direction (maximization or minimization) for
         * each dimension. The dimensionality of the created vectors must be exactly
         * the same as the given length of the given {@code optimizes}. If the
         * lengths don't match, an {@link IllegalArgumentException} is thrown.
         *
         * @see #ofLongVec(List)
         *
         * @apiNote
         * Only one factory instance should be used for a given multi-objective
         * <em>problem</em>.
         *
         * @param optimizes the optimization <em>direction</em> for each dimension
         * @return a new factory for {@code long[]} vectors
         * @throws NullPointerException if the given {@code optimizes} is
         *         {@code null}
         * @throws IllegalArgumentException if the {@code optimizes} length is zero
         */
        static VecFactory<long[]> ofLongVec(final Optimize... optimizes) {
                return ofLongVec(List.of(optimizes));
        }

        /**
         * Create a new factory for {@code long[]} vectors, where all dimensions are
         * maximized.
         *
         * @see Vec#of(long...)
         *
         * @return a new factory for {@code long[]} vectors, where all dimensions are
         *             maximized
         */
        static VecFactory<long[]> ofLongVec() {
                return Vec::of;
        }

        /**
         * Create a new factory for {@code double[]} vectors. Additionally, you can
         * specify the optimization direction (maximization or minimization) for
         * each dimension. The dimensionality of the created vectors must be exactly
         * the same as the given length of the given {@code optimizes}. If the
         * lengths don't match, an {@link IllegalArgumentException} is thrown.
         *
         * @see #ofDoubleVec(Optimize...)
         *
         * @apiNote
         * Only one factory instance should be used for a given multi-objective
         * <em>problem</em>.
         *
         * @param optimizes the optimization <em>direction</em> for each dimension
         * @return a new factory for {@code double[]} vectors
         * @throws NullPointerException if the given {@code optimizes} is
         *         {@code null}
         * @throws IllegalArgumentException if the {@code optimizes} length is zero
         */
        static VecFactory<double[]> ofDoubleVec(final List<Optimize> optimizes) {
                return new GeneralDoubleVecFactory(optimizes);
        }

        /**
         * Create a new factory for {@code double[]} vectors. Additionally, you can
         * specify the optimization direction (maximization or minimization) for
         * each dimension. The dimensionality of the created vectors must be exactly
         * the same as the given length of the given {@code optimizes}. If the
         * lengths don't match, an {@link IllegalArgumentException} is thrown.
         *
         * @see #ofDoubleVec(List)
         *
         * @apiNote
         * Only one factory instance should be used for a given multi-objective
         * <em>problem</em>.
         *
         * @param optimizes the optimization <em>direction</em> for each dimension
         * @return a new factory for {@code double[]} vectors
         * @throws NullPointerException if the given {@code optimizes} is
         *         {@code null}
         * @throws IllegalArgumentException if the {@code optimizes} length is zero
         */
        static VecFactory<double[]> ofDoubleVec(final Optimize... optimizes) {
                return ofDoubleVec(List.of(optimizes));
        }

        /**
         * Create a new factory for {@code double[]} vectors, where all dimensions
         * are maximized.
         *
         * @see Vec#of(double...)
         *
         * @return a new factory for {@code double[]} vectors, where all dimensions
         *         are maximized
         */
        static VecFactory<double[]> ofDoubleVec() {
                return Vec::of;
        }

        /**
         * Create a new factory for {@code T[]} vectors. Additionally, you can
         * specify the optimization direction (maximization or minimization) for
         * each dimension. The dimensionality of the created vectors must be exactly
         * the same as the given length of the given {@code optimizes}. If the
         * lengths don't match, an {@link IllegalArgumentException} is thrown.
         *
         * @see #ofObjectVec(Comparator, ElementDistance, Optimize...)
         *
         * @param comparator the array element comparator
         * @param distance the element distance function
         * @param optimizes the optimization <em>direction</em> for each dimension
         * @param <T> the array element type
         * @return  a new factory for {@code T[]} vectors
         * @throws NullPointerException if one of the arguments is {@code null}
         * @throws IllegalArgumentException if the {@code optimizes} length is zero
         */
        static <T> VecFactory<T[]> ofObjectVec(
                final Comparator<? super T> comparator,
                final ElementDistance<T[]> distance,
                final List<Optimize> optimizes
        ) {
                return new GeneralObjectVecFactory<>(comparator, distance, optimizes);
        }

        /**
         * Create a new factory for {@code T[]} vectors. Additionally, you can
         * specify the optimization direction (maximization or minimization) for
         * each dimension. The dimensionality of the created vectors must be exactly
         * the same as the given length of the given {@code optimizes}. If the
         * lengths don't match, an {@link IllegalArgumentException} is thrown.
         *
         * @see #ofObjectVec(Comparator, ElementDistance, List)
         *
         * @param comparator the array element comparator
         * @param distance the element distance function
         * @param optimizes the optimization <em>direction</em> for each dimension
         * @param <T> the array element type
         * @return  a new factory for {@code T[]} vectors
         * @throws NullPointerException if one of the arguments is {@code null}
         * @throws IllegalArgumentException if the {@code optimizes} length is zero
         */
        static <T> VecFactory<T[]> ofObjectVec(
                final Comparator<? super T> comparator,
                final ElementDistance<T[]> distance,
                final Optimize... optimizes
        ) {
                return ofObjectVec(comparator, distance, List.of(optimizes));
        }

        /**
         * Create a new factory for {@code T[]} vectors with comparable element
         * types. Additionally, you can specify the optimization direction
         * (maximization or minimization) for each dimension. The dimensionality of
         * the created vectors must be exactly the same as the given length of the
         * given {@code optimizes}. If the lengths don't match, an
         * {@link IllegalArgumentException} is thrown.
         *
         * @since 6.0
         *
         * @see #ofObjectVec(Comparator, ElementDistance, List)
         *
         * @param distance the element distance function
         * @param optimizes the optimization <em>direction</em> for each dimension
         * @param <T> the array element type
         * @return a new factory for {@code T[]} vectors
         * @throws NullPointerException if one of the arguments is {@code null}
         * @throws IllegalArgumentException if the {@code optimizes} length is zero
         */
        static <T extends Comparable<? super T>> VecFactory<T[]> ofObjectVec(
                final ElementDistance<T[]> distance,
                final List<Optimize> optimizes
        ) {
                return ofObjectVec(
                        Comparator.naturalOrder(),
                        distance,
                        optimizes
                );
        }

        /**
         * Create a new factory for {@code T[]} vectors with comparable element
         * types. Additionally, you can specify the optimization direction
         * (maximization or minimization) for each dimension. The dimensionality of
         * the created vectors must be exactly the same as the given length of the
         * given {@code optimizes}. If the lengths don't match, an
         * {@link IllegalArgumentException} is thrown.
         *
         * @since 6.0
         *
         * @see #ofObjectVec(Comparator, ElementDistance, List)
         *
         * @param distance the element distance function
         * @param optimizes the optimization <em>direction</em> for each dimension
         * @param <T> the array element type
         * @return a new factory for {@code T[]} vectors
         * @throws NullPointerException if one of the arguments is {@code null}
         * @throws IllegalArgumentException if the {@code optimizes} length is zero
         */
        static <T extends Comparable<? super T>> VecFactory<T[]> ofObjectVec(
                final ElementDistance<T[]> distance,
                final Optimize... optimizes
        ) {
                return ofObjectVec(
                        Comparator.naturalOrder(),
                        distance,
                        optimizes
                );
        }

        /**
         * Create a new factory for {@code T[]} vectors with comparable element
         * types. Additionally, you can specify the optimization direction
         * (maximization or minimization) for each dimension. The dimensionality of
         * the created vectors must be exactly the same as the given length of the
         * given {@code optimizes}. If the lengths don't match, an
         * {@link IllegalArgumentException} is thrown.
         *
         * @since 6.0
         *
         * @see #ofObjectVec(Comparator, ElementDistance, List)
         *
         * @param optimizes the optimization <em>direction</em> for each dimension
         * @param <T> the array element type
         * @return a new factory for {@code T[]} vectors
         * @throws NullPointerException if one of the arguments is {@code null}
         * @throws IllegalArgumentException if the {@code optimizes} length is zero
         */
        static <T extends Comparable<? super T>> VecFactory<T[]>
        ofObjectVec(final List<Optimize> optimizes) {
                return ofObjectVec(VecFactory::dist, optimizes);
        }

        private static <T extends Comparable<? super T>>
        double dist(final T[] u, final T[] v, final int i) {
                return Integer.compare(u[i].compareTo(v[i]), 0);
        }

        /**
         * Create a new factory for {@code T[]} vectors with comparable element
         * types. Additionally, you can specify the optimization direction
         * (maximization or minimization) for each dimension. The dimensionality of
         * the created vectors must be exactly the same as the given length of the
         * given {@code optimizes}. If the lengths don't match, an
         * {@link IllegalArgumentException} is thrown.
         *
         * @since 6.0
         *
         * @see #ofObjectVec(Comparator, ElementDistance, List)
         *
         * @param optimizes the optimization <em>direction</em> for each dimension
         * @param <T> the array element type
         * @return a new factory for {@code T[]} vectors
         * @throws NullPointerException if one of the arguments is {@code null}
         * @throws IllegalArgumentException if the {@code optimizes} length is zero
         */
        static <T extends Comparable<? super T>> VecFactory<T[]>
        ofObjectVec(final Optimize... optimizes) {
                return ofObjectVec(VecFactory::dist, optimizes);
        }

        /**
         * Create a new factory for {@code T[]} vectors with comparable element
         * types. Additionally, you can specify the optimization direction
         * (maximization or minimization) for each dimension. The dimensionality of
         * the created vectors must be exactly the same as the given length of the
         * given {@code optimizes}. If the lengths don't match, an
         * {@link IllegalArgumentException} is thrown.
         *
         * @since 6.0
         *
         * @see Vec#of(Comparable[])
         *
         * @param <T> the array element type
         * @return a new factory for {@code T[]} vectors
         * @throws NullPointerException if one of the arguments is {@code null}
         * @throws IllegalArgumentException if the {@code optimizes} length is zero
         */
        static <T extends Comparable<? super T>> VecFactory<T[]> ofObjectVec() {
                return Vec::of;
        }

}