/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.
 */
package org.apache.commons.lang3;

import org.apache.commons.lang3.math.NumberUtils;

/**
 * <p>
 * An enum representing all the versions of the Java specification. This is
 * intended to mirror available values from the
 * <em>java.specification.version</em> System property.
 * </p>
 *
 * @since 3.0
 */
public enum JavaVersion {

	/**
	 * The Java version reported by Android. This is not an official Java version
	 * number.
	 */
	JAVA_0_9(1.5f, "0.9"),

	/**
	 * Java 1.1.
	 */
	JAVA_1_1(1.1f, "1.1"),

	/**
	 * Java 1.2.
	 */
	JAVA_1_2(1.2f, "1.2"),

	/**
	 * Java 1.3.
	 */
	JAVA_1_3(1.3f, "1.3"),

	/**
	 * Java 1.4.
	 */
	JAVA_1_4(1.4f, "1.4"),

	/**
	 * Java 1.5.
	 */
	JAVA_1_5(1.5f, "1.5"),

	/**
	 * Java 1.6.
	 */
	JAVA_1_6(1.6f, "1.6"),

	/**
	 * Java 1.7.
	 */
	JAVA_1_7(1.7f, "1.7"),

	/**
	 * Java 1.8.
	 */
	JAVA_1_8(1.8f, "1.8"),

	/**
	 * Java 1.9.
	 *
	 * @deprecated As of release 3.5, replaced by {@link #JAVA_9}
	 */
	@Deprecated
	JAVA_1_9(9.0f, "9"),

	/**
	 * Java 9.
	 *
	 * @since 3.5
	 */
	JAVA_9(9.0f, "9"),

	/**
	 * Java 10.
	 *
	 * @since 3.7
	 */
	JAVA_10(10.0f, "10"),

	/**
	 * Java 11.
	 *
	 * @since 3.8
	 */
	JAVA_11(11.0f, "11"),

	/**
	 * Java 12.
	 *
	 * @since 3.9
	 */
	JAVA_12(12.0f, "12"),

	/**
	 * Java 13.
	 *
	 * @since 3.9
	 */
	JAVA_13(13.0f, "13"),

	/**
	 * Java 14.
	 *
	 * @since 3.11
	 */
	JAVA_14(14.0f, "14"),

	/**
	 * Java 15.
	 *
	 * @since 3.11
	 */
	JAVA_15(15.0f, "15"),

	/**
	 * Java 16.
	 *
	 * @since 3.11
	 */
	JAVA_16(16.0f, "16"),

	/**
	 * Java 17.
	 *
	 * @since 3.12.0
	 */
	JAVA_17(17.0f, "17"),

	/**
	 * The most recent java version. Mainly introduced to avoid to break when a new
	 * version of Java is used.
	 */
	JAVA_RECENT(maxVersion(), Float.toString(maxVersion()));

	/**
	 * The float value.
	 */
	private final float value;

	/**
	 * The standard name.
	 */
	private final String name;

	/**
	 * Constructor.
	 *
	 * @param value the float value
	 * @param name  the standard name, not null
	 */
	JavaVersion(final float value, final String name) {
		this.value = value;
		this.name = name;
	}

	// -----------------------------------------------------------------------
	/**
	 * <p>
	 * Whether this version of Java is at least the version of Java passed in.
	 * </p>
	 *
	 * <p>
	 * For example:<br>
	 * {@code myVersion.atLeast(JavaVersion.JAVA_1_4)}
	 * <p>
	 *
	 * @param requiredVersion the version to check against, not null
	 * @return true if this version is equal to or greater than the specified
	 *         version
	 */
	public boolean atLeast(final JavaVersion requiredVersion) {
		return this.value >= requiredVersion.value;
	}

	// -----------------------------------------------------------------------
	/**
	 * <p>
	 * Whether this version of Java is at most the version of Java passed in.
	 * </p>
	 *
	 * <p>
	 * For example:<br>
	 * {@code myVersion.atMost(JavaVersion.JAVA_1_4)}
	 * <p>
	 *
	 * @param requiredVersion the version to check against, not null
	 * @return true if this version is equal to or greater than the specified
	 *         version
	 * @since 3.9
	 */
	public boolean atMost(final JavaVersion requiredVersion) {
		return this.value <= requiredVersion.value;
	}

	/**
	 * Transforms the given string with a Java version number to the corresponding
	 * constant of this enumeration class. This method is used internally.
	 *
	 * @param nom the Java version as string
	 * @return the corresponding enumeration constant or <b>null</b> if the version
	 *         is unknown
	 */
	// helper for static importing
	static JavaVersion getJavaVersion(final String nom) {
		return get(nom);
	}

	/**
	 * Transforms the given string with a Java version number to the corresponding
	 * constant of this enumeration class. This method is used internally.
	 *
	 * @param versionStr the Java version as string
	 * @return the corresponding enumeration constant or <b>null</b> if the version
	 *         is unknown
	 */
	static JavaVersion get(final String versionStr) {
		if (versionStr == null) {
			return null;
		}
		switch (versionStr) {
		case "0.9":
			return JAVA_0_9;
		case "1.1":
			return JAVA_1_1;
		case "1.2":
			return JAVA_1_2;
		case "1.3":
			return JAVA_1_3;
		case "1.4":
			return JAVA_1_4;
		case "1.5":
			return JAVA_1_5;
		case "1.6":
			return JAVA_1_6;
		case "1.7":
			return JAVA_1_7;
		case "1.8":
			return JAVA_1_8;
		case "9":
			return JAVA_9;
		case "10":
			return JAVA_10;
		case "11":
			return JAVA_11;
		case "12":
			return JAVA_12;
		case "13":
			return JAVA_13;
		case "14":
			return JAVA_14;
		case "15":
			return JAVA_15;
		case "16":
			return JAVA_16;
		case "17":
			return JAVA_17;
		default:
			final float v = toFloatVersion(versionStr);
			if ((v - 1.) < 1.) { // then we need to check decimals > .9
				final int firstComma = Math.max(versionStr.indexOf('.'), versionStr.indexOf(','));
				final int end = Math.max(versionStr.length(), versionStr.indexOf(',', firstComma));
				if (Float.parseFloat(versionStr.substring(firstComma + 1, end)) > .9f) {
					return JAVA_RECENT;
				}
			} else if (v > 10) {
				return JAVA_RECENT;
			}
			return null;
		}
	}

	// -----------------------------------------------------------------------
	/**
	 * <p>
	 * The string value is overridden to return the standard name.
	 * </p>
	 *
	 * <p>
	 * For example, {@code "1.5"}.
	 * </p>
	 *
	 * @return the name, not null
	 */
	@Override
	public String toString() {
		return name;
	}

	/**
	 * Gets the Java Version from the system or 99.0 if the
	 * {@code java.specification.version} system property is not set.
	 *
	 * @return the value of {@code java.specification.version} system property or
	 *         99.0 if it is not set.
	 */
	private static float maxVersion() {
		final float v = toFloatVersion(System.getProperty("java.specification.version", "99.0"));
		if (v > 0) {
			return v;
		}
		return 99f;
	}

	/**
	 * Parses a float value from a String.
	 *
	 * @param value the String to parse.
	 * @return the float value represented by the string or -1 if the given String
	 *         can not be parsed.
	 */
	private static float toFloatVersion(final String value) {
		final int defaultReturnValue = -1;
		if (value.contains(".")) {
			final String[] toParse = value.split("\\.");
			if (toParse.length >= 2) {
				return NumberUtils.toFloat(toParse[0] + '.' + toParse[1], defaultReturnValue);
			}
		} else {
			return NumberUtils.toFloat(value, defaultReturnValue);
		}
		return defaultReturnValue;
	}
}