/*
 * Copyright 2010-2020 the original author or authors.
 *
 * 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
 *
 *      https://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.springframework.data.geo;

import lombok.Value;

import java.io.Serializable;

import org.springframework.data.domain.Range;
import org.springframework.data.domain.Range.Bound;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

Value object to represent distances in a given metric.
Author:
Oliver Gierke, Thomas Darimont
Since:
1.8/**
 * Value object to represent distances in a given metric.
 *
 * @author Oliver Gierke
 * @author Thomas Darimont
 * @since 1.8
 */
@Value
public class Distance implements Serializable, Comparable<Distance> {

	private static final long serialVersionUID = 2460886201934027744L;

	
The distance value in the current Metric. /**
	 * The distance value in the current {@link Metric}.
	 */
	private final double value;

	
The Metric of the Distance. /**
	 * The {@link Metric} of the {@link Distance}.
	 */
	private final Metric metric;

	
Creates a new Distance with a neutral metric. This means the provided value needs to be in normalized form. 
Params:
value – /**
	 * Creates a new {@link Distance} with a neutral metric. This means the provided value needs to be in normalized form.
	 *
	 * @param value
	 */
	public Distance(double value) {
		this(value, Metrics.NEUTRAL);
	}

	
Creates a new Distance with the given Metric. 
Params:
value – 
metric – must not be null./**
	 * Creates a new {@link Distance} with the given {@link Metric}.
	 *
	 * @param value
	 * @param metric must not be {@literal null}.
	 */
	public Distance(double value, Metric metric) {

		Assert.notNull(metric, "Metric must not be null!");

		this.value = value;
		this.metric = metric;
	}

	
Creates a Range between the given Distance. 
Params:
min – can be null.
max – can be null.
Returns:
will never be null./**
	 * Creates a {@link Range} between the given {@link Distance}.
	 *
	 * @param min can be {@literal null}.
	 * @param max can be {@literal null}.
	 * @return will never be {@literal null}.
	 */
	public static Range<Distance> between(Distance min, Distance max) {
		return Range.from(Bound.inclusive(min)).to(Bound.inclusive(max));
	}

	
Creates a new Range by creating minimum and maximum Distance from the given values. 
Params:
minValue – 
minMetric – can be null.
maxValue – 
maxMetric – can be null.
Returns:
/**
	 * Creates a new {@link Range} by creating minimum and maximum {@link Distance} from the given values.
	 *
	 * @param minValue
	 * @param minMetric can be {@literal null}.
	 * @param maxValue
	 * @param maxMetric can be {@literal null}.
	 * @return
	 */
	public static Range<Distance> between(double minValue, Metric minMetric, double maxValue, Metric maxMetric) {
		return between(new Distance(minValue, minMetric), new Distance(maxValue, maxMetric));
	}

	
Returns the normalized value regarding the underlying Metric. 
Returns:
/**
	 * Returns the normalized value regarding the underlying {@link Metric}.
	 *
	 * @return
	 */
	public double getNormalizedValue() {
		return value / metric.getMultiplier();
	}

	
Returns a String representation of the unit the distance is in. 
See Also:
Metric.getAbbreviation()
Returns:
the unit/**
	 * Returns a {@link String} representation of the unit the distance is in.
	 *
	 * @return the unit
	 * @see Metric#getAbbreviation()
	 */
	public String getUnit() {
		return metric.getAbbreviation();
	}

	
Adds the given distance to the current one. The resulting Distance will be in the same metric as the current one. 
Params:
other – must not be null.
Returns:
/**
	 * Adds the given distance to the current one. The resulting {@link Distance} will be in the same metric as the
	 * current one.
	 *
	 * @param other must not be {@literal null}.
	 * @return
	 */
	public Distance add(Distance other) {

		Assert.notNull(other, "Distance to add must not be null!");

		double newNormalizedValue = getNormalizedValue() + other.getNormalizedValue();

		return new Distance(newNormalizedValue * metric.getMultiplier(), metric);
	}

	
Adds the given Distance to the current one and forces the result to be in a given Metric. 
Params:
other – must not be null.
metric – must not be null.
Returns:
/**
	 * Adds the given {@link Distance} to the current one and forces the result to be in a given {@link Metric}.
	 *
	 * @param other must not be {@literal null}.
	 * @param metric must not be {@literal null}.
	 * @return
	 */
	public Distance add(Distance other, Metric metric) {

		Assert.notNull(other, "Distance to must not be null!");
		Assert.notNull(metric, "Result metric must not be null!");

		double newLeft = getNormalizedValue() * metric.getMultiplier();
		double newRight = other.getNormalizedValue() * metric.getMultiplier();

		return new Distance(newLeft + newRight, metric);
	}

	
Returns a new Distance in the given Metric. This means that the returned instance will have the same normalized value as the original instance. 
Params:
metric – must not be null.
Returns:
/**
	 * Returns a new {@link Distance} in the given {@link Metric}. This means that the returned instance will have the
	 * same normalized value as the original instance.
	 *
	 * @param metric must not be {@literal null}.
	 * @return
	 */
	public Distance in(Metric metric) {

		Assert.notNull(metric, "Metric must not be null!");

		return this.metric.equals(metric) ? this : new Distance(getNormalizedValue() * metric.getMultiplier(), metric);
	}

	/*
	 * (non-Javadoc)
	 * @see java.lang.Comparable#compareTo(java.lang.Object)
	 */
	@Override
	public int compareTo(@Nullable Distance that) {

		if (that == null) {
			return 1;
		}

		double difference = this.getNormalizedValue() - that.getNormalizedValue();

		return difference == 0 ? 0 : difference > 0 ? 1 : -1;
	}

	/*
	 * (non-Javadoc)
	 * @see java.lang.Object#toString()
	 */
	@Override
	public String toString() {

		StringBuilder builder = new StringBuilder();
		builder.append(value);

		if (metric != Metrics.NEUTRAL) {
			builder.append(" ").append(metric.toString());
		}

		return builder.toString();
	}
}