/*
 * Units of Measurement Reference Implementation
 * Copyright (c) 2005-2021, Jean-Marie Dautelle, Werner Keil, Otavio Santana.
 *
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice, this list of conditions
 *    and the following disclaimer in the documentation and/or other materials provided with the distribution.
 *
 * 3. Neither the name of JSR-385, Indriya nor the names of their contributors may be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
 * EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package tech.units.indriya.unit;

import javax.measure.Dimension;
import javax.measure.Quantity;
import javax.measure.Unit;

import tech.units.indriya.AbstractUnit;
import java.io.Serializable;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;
import java.util.logging.Level;
import java.util.logging.Logger;

/**
 * <p>
 * This class represents a dimension of a unit of measurement.
 * </p>
 *
 * <p>
 * The dimension associated to any given quantity are given by the published
 * {@link Dimension} instances. For convenience, a static method
 * <code>UnitDimension.of(Class)</code> aggregating the results of all
 * 
 * {@link Dimension} instances is provided.<br>
 * <br>
 * <code>
 *        Dimension speedDimension
 *            = UnitDimension.of(Speed.class);
 *     </code>
 * </p>
 *
 * @author <a href="mailto:jean-marie@dautelle.com">Jean-Marie Dautelle</a>
 * @author <a href="mailto:werner@units.tech">Werner Keil</a>
 * @author  Martin Desruisseaux (Geomatys)
 * @author  Andi Huber
 * @version 2.1, $Date: 2021-03-13 $
 * @since 2.0
 */
public class UnitDimension implements Dimension, Serializable {
    /** */
        private static final long serialVersionUID = 7806787530512644696L;

        private static final Logger LOGGER = Logger.getLogger(UnitDimension.class.getName());

        /**
         * Holds dimensionless.
         * 
         * @since 1.0
         */
        public static final Dimension NONE = new UnitDimension(AbstractUnit.ONE);

        /**
         * Holds length dimension (L).
         * 
         * @since 1.0
         */
        public static final Dimension LENGTH = new UnitDimension('L');

        /**
         * Holds mass dimension (M).
         * 
         * @since 1.0
         */
        public static final Dimension MASS = new UnitDimension('M');

        /**
         * Holds time dimension (T).
         * 
         * @since 1.0
         */
        public static final Dimension TIME = new UnitDimension('T');

        /**
         * Holds electric current dimension (I).
         * 
         * @since 1.0
         */
        public static final Dimension ELECTRIC_CURRENT = new UnitDimension('I');

        /**
         * Holds temperature dimension (Θ).
         * 
         * @since 1.0
         */
        public static final Dimension TEMPERATURE = new UnitDimension('\u0398');

        /**
         * Holds amount of substance dimension (N).
         * 
         * @since 1.0
         */
        public static final Dimension AMOUNT_OF_SUBSTANCE = new UnitDimension('N');

        /**
         * Holds luminous intensity dimension (J).
         */
        public static final Dimension LUMINOUS_INTENSITY = new UnitDimension('J');

        /**
         * Holds the pseudo unit associated to this dimension.
         */
        private final Unit<?> pseudoUnit;

        /**
         * Returns the dimension for the specified quantity type by aggregating the
         * results from the default {@link javax.measure.spi.SystemOfUnits SystemOfUnits} or <code>null</code> if the specified
         * quantity is unknown.
         *
         * @param quantityType the quantity type.
         * @return the dimension for the quantity type or <code>null</code>.
         * @since 1.1
         */
        public static <Q extends Quantity<Q>> Dimension of(Class<Q> quantityType) {
                // TODO: Track services and aggregate results (register custom types)
                Unit<Q> siUnit = Units.getInstance().getUnit(quantityType);
                if (siUnit == null && LOGGER.isLoggable(Level.FINE)) {
                        LOGGER.log(Level.FINE, "Quantity type: " + quantityType + " unknown");
                }
                return (siUnit != null) ? siUnit.getDimension() : null;
        }

        /**
         * Returns the dimension for the specified symbol.
         *
         * @param sambol the quantity symbol.
         * @return the dimension for the given symbol.
         * @since 1.0.1
         */
        public static Dimension parse(char symbol) {
                return new UnitDimension(symbol);
        }

        /**
         * Returns the unit dimension having the specified symbol.
         *
         * @param symbol the associated symbol.
         */
        @SuppressWarnings("rawtypes")
        private UnitDimension(char symbol) {
                pseudoUnit = new BaseUnit("[" + symbol + ']', NONE);
        }

        /**
         * Constructor from pseudo-unit (not visible).
         *
         * @param pseudoUnit the pseudo-unit.
         */
        private UnitDimension(Unit<?> pseudoUnit) {
                this.pseudoUnit = pseudoUnit;
        }
        
        /**
         * Default Constructor (not visible).
         *
         */
        protected UnitDimension() {
                this(AbstractUnit.ONE);
        }
        

        /**
         * Returns the product of this dimension with the one specified. 
         * If the specified dimension is not a <code>UnitDimension</code>, then
         * <code>that.multiply(this)</code> is returned.
         *
         * @param that the dimension multiplicand.
         * @return <code>this * that</code>
         * @since 1.0
         */
        public Dimension multiply(Dimension that) {
                return that instanceof UnitDimension
                        ? this.multiply((UnitDimension) that)
                : that.multiply(this);
        }

        /**
         * Returns the product of this dimension with the one specified.
         *
         * @param that the dimension multiplicand.
         * @return <code>this * that</code>
         * @since 1.0
         */
        private UnitDimension multiply(UnitDimension that) {
                return new UnitDimension(this.pseudoUnit.multiply(that.pseudoUnit));
        }

        /**
         * Returns the quotient of this dimension with the one specified.
         * If the specified dimension is not a <code>UnitDimension</code>, then
     * <code>that.divide(this).pow(-1)</code> is returned.
         *
         * @param that the dimension divisor.
         * @return <code>this / that</code>
         * @since 1.0
         */
        public Dimension divide(Dimension that) {
                return that instanceof UnitDimension
                        ? this.divide((UnitDimension) that)
                : that.divide(this).pow(-1);
        }

        /**
         * Returns the quotient of this dimension with the one specified.
         *
         * @param that the dimension divisor.
         * @return <code>this / that</code>
         * @since 1.0
         */
        private UnitDimension divide(UnitDimension that) {
                return new UnitDimension(ProductUnit.ofQuotient(pseudoUnit, that.pseudoUnit));
        }

        /**
         * Returns this dimension raised to an exponent.
         *
         * @param n the exponent.
         * @return the result of raising this dimension to the exponent.
         * @since 1.0
         */
        public UnitDimension pow(int n) {
                return new UnitDimension(this.pseudoUnit.pow(n));
        }

        /**
         * Returns the given root of this dimension.
         *
         * @param n the root's order.
         * @return the result of taking the given root of this dimension.
         * @throws ArithmeticException if <code>n == 0</code>.
         * @since 1.0
         */
        public UnitDimension root(int n) {
                return new UnitDimension(this.pseudoUnit.root(n));
        }

        /**
         * Returns the fundamental (base) dimensions and their exponent whose product is
         * this dimension or <code>null</code> if this dimension is a fundamental
         * dimension.
         *
         * @return the mapping between the base dimensions and their exponent.
         * @since 1.0
         */
        @SuppressWarnings("rawtypes")
        public Map<? extends Dimension, Integer> getBaseDimensions() {
                Map<? extends Unit, Integer> pseudoUnits = pseudoUnit.getBaseUnits();
                if (pseudoUnits == null) {
                        return null;
                }
                final Map<UnitDimension, Integer> baseDimensions = new HashMap<>();
                for (Map.Entry<? extends Unit, Integer> entry : pseudoUnits.entrySet()) {
                        baseDimensions.put(new UnitDimension(entry.getKey()), entry.getValue());
                }
                return baseDimensions;
        }

        @Override
        public String toString() {
                return pseudoUnit.toString();
        }

        @Override
        public boolean equals(Object obj) {
                if (this == obj) {
                        return true;
                }
                if (obj instanceof UnitDimension) {
                        UnitDimension other = (UnitDimension) obj;
                        return Objects.equals(pseudoUnit, other.pseudoUnit);
                }
                return false;
        }

        @Override
        public int hashCode() {
                return Objects.hashCode(pseudoUnit);
        }
}