NetatmoUnitSystem.java

/**
 * Copyright (c) 2010-2016 by the respective copyright holders.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 */
package org.openhab.binding.netatmo.internal.weather;

import java.math.BigDecimal;

import org.apache.commons.lang.StringUtils;

/**
 * @author Rob Nielsen
 * @since 1.8.0
 *
 *        This enum holds all the different unit systems for the Netatmo binding,
 *        along with conversion methods
 */
public enum NetatmoUnitSystem {
    M("Metric"),
    US("US");

    public static final NetatmoUnitSystem DEFAULT_UNIT_SYSTEM = NetatmoUnitSystem.M;

    private static final BigDecimal KPH_TO_MPH = new BigDecimal("0.6214");

    private static final double METERS_TO_FEET = 3.2808399;

    private static final BigDecimal MM_TO_INCHES = new BigDecimal("0.0394");

    private static final BigDecimal ONE_POINT_EIGHT = new BigDecimal("1.8");

    private static final BigDecimal THIRTY_TWO = new BigDecimal("32");

    String unitSystem;

    private NetatmoUnitSystem(String unitSystem) {
        this.unitSystem = unitSystem;
    }

    public String getunitSystem() {
        return unitSystem;
    }

    public static NetatmoUnitSystem fromString(String unitSystem) {
        if (!StringUtils.isEmpty(unitSystem)) {
            for (NetatmoUnitSystem unitSystemType : NetatmoUnitSystem.values()) {
                if (unitSystemType.toString().equalsIgnoreCase(unitSystem)) {
                    return unitSystemType;
                }
            }
        }
        throw new IllegalArgumentException("Invalid unitSystem: " + unitSystem);
    }

    /**
     * Convert to appropriate measurement.
     *
     * @param value
     *            altitude in Meters
     *
     * @return value in the proper measurement
     */
    public double convertAltitude(double value) {
        if (this == DEFAULT_UNIT_SYSTEM) {
            return value;
        }

        return value * METERS_TO_FEET;
    }

    /**
     * Convert to appropriate measurement.
     *
     * The Rain gauge is accurate to 1 mm/h or 0.04 in/h, and the range starts
     * at 0.2 mm/h or 0.01 in/h.
     *
     * @param value
     *            rain in Millimeters
     *
     * @return value in the proper measurement
     */
    public BigDecimal convertRain(BigDecimal value) {
        if (this == DEFAULT_UNIT_SYSTEM) {
            return value;
        }

        return value.multiply(MM_TO_INCHES);
    }

    /**
     * Convert to appropriate measurement.
     *
     * The Thermometer is accurate to +- 0.3°C or +- 0.54°F
     *
     * @param value
     *            temperature in Celsius
     *
     * @return value the in proper measurement
     */
    public BigDecimal convertTemp(BigDecimal value) {
        if (this == DEFAULT_UNIT_SYSTEM) {
            return value;
        }

        return value.multiply(ONE_POINT_EIGHT).add(THIRTY_TWO);
    }

    /**
     * Convert to appropriate measurement.
     *
     * The Wind gauge is accurate to 0.5 m/s (1.8 km/h, 1 mph)
     *
     * @param value
     *            wind in Kilometers per Hour
     *
     * @return value in the proper measurement
     */
    public BigDecimal convertWind(BigDecimal value) {
        if (this == DEFAULT_UNIT_SYSTEM) {
            return value;
        }

        return value.multiply(KPH_TO_MPH);
    }
}