/*
 * Units of Measurement Reference Implementation
 * Copyright (c) 2005-2023, 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 javax.measure.UnitConverter;

import tech.units.indriya.AbstractUnit;
import tech.units.indriya.function.AbstractConverter;
import tech.units.indriya.unit.UnitDimension;

import java.util.Map;
import java.util.Objects;

/**
 * <p>
 * This class represents the building blocks on top of which all others physical
 * units are created. Base units are always unscaled SI units.
 * </p>
 * 
 * <p>
 * When using the {@link tech.units.indriya.spi.StandardModel standard model},
 * all seven <b>SI</b> base units are dimensionally independent.
 * </p>
 *
 * @see <a href="http://en.wikipedia.org/wiki/SI_base_unit"> Wikipedia: SI base
 *      unit</a>
 *
 * @author <a href="mailto:jean-marie@dautelle.com">Jean-Marie Dautelle</a>
 * @author <a href="mailto:werner@units.tech">Werner Keil</a>
 * @version 2.0, February 7, 2020
 * @since 1.0
 */
public final class BaseUnit<Q extends Quantity<Q>> extends AbstractUnit<Q> {

        /**
         * 
         */
        private static final long serialVersionUID = 1721629233768215930L;

        /**
         * Holds the base unit dimension.
         */
        private final Dimension dimension;

        /**
         * Creates a base unit having the specified symbol and dimension.
         *
         * @param symbol the symbol of this base unit.
         */
        public BaseUnit(String symbol, Dimension dimension) {
                super(symbol);
                this.dimension = dimension;
        }

        /**
         * Creates a base unit having the specified symbol.
         *
         * @param symbol the symbol of this base unit.
         */
        public BaseUnit(String symbol) {
                super(symbol);
                this.dimension = UnitDimension.NONE;
        }

        /**
         * Creates a base unit having the specified symbol and name.
         *
         * @param symbol the symbol of this base unit.
         * @param name   the name of this base unit.
         * @throws IllegalArgumentException if the specified symbol is associated to a
         *                                  different unit.
         */
        public BaseUnit(String symbol, String name) {
                this(symbol);
                this.name = name;
        }

        /**
         * Creates a base unit having the specified symbol, name and dimension.
         *
         * @param symbol the symbol of this base unit.
         * @param name   the name of this base unit.
         * @throws IllegalArgumentException if the specified symbol is associated to a
         *                                  different unit.
         * @since 2.0
         */
        public BaseUnit(String symbol, String name, Dimension dimension) {
                super(symbol);
                this.name = name;
                this.dimension = dimension;
        }

        @Override
        public Unit<Q> toSystemUnit() {
                return this;
        }

        @Override
        public UnitConverter getSystemConverter() throws UnsupportedOperationException {
                return AbstractConverter.IDENTITY;
        }

        @Override
        public Dimension getDimension() {
                return dimension;
        }

        @Override
        public int hashCode() {
                final int prime = 31;
                int result = 1;
                result = prime * result + ((getSymbol() == null) ? 0 : getSymbol().hashCode());
                // result = result + prime * result + ((name == null) ? 0 : name.hashCode());
                result = result + prime * result + ((dimension == null) ? 0 : dimension.hashCode());
                return result;
        }

        @Override
        public boolean equals(Object obj) {
                if (this == obj)
                        return true;
                if (obj == null)
                        return false;
                if (getClass() != obj.getClass())
                        return false;
                @SuppressWarnings("rawtypes")
                BaseUnit other = (BaseUnit) obj;
                return Objects.equals(dimension, other.dimension) && Objects.equals(getSymbol(), other.getSymbol());
        }

        @Override
        public Map<? extends AbstractUnit<Q>, Integer> getBaseUnits() {
                // TODO Shall we return null, empty list or what (e.g. Optional from Java 8)?
                return null;
        }
}