/*
 * Copyright 2023-2024 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 xyz.zhouxy.plusone.commons.base;

import xyz.zhouxy.plusone.commons.util.StringTools;

/**
 * JRE version
 */
public class JRE {

    private static final int JAVA_8 = 8;

    public static final int CURRENT_VERSION = getJre();

    public static boolean isJava8() {
        return CURRENT_VERSION == JAVA_8;
    }

    private static int getJre() {
        String version = System.getProperty("java.version");
        boolean isNotBlank = StringTools.isNotBlank(version);
        if (isNotBlank && version.startsWith("1.8")) {
            return JAVA_8;
        }
        // if JRE version is 9 or above, we can get version from
        // java.lang.Runtime.version()
        try {
            return getMajorVersion(version);
        } catch (Exception e) {
            // assuming that JRE version is 8.
        }
        // default java 8
        return JAVA_8;
    }

    private static int getMajorVersion(String version) {
        if (version.startsWith("1.")) {
            return Integer.parseInt(version.substring(2, 3));
        } else {
            int dotIndex = version.indexOf(".");
            return (dotIndex != -1) ? Integer.parseInt(version.substring(0, dotIndex)) : Integer.parseInt(version);
        }
    }

    private JRE() {
        throw new IllegalStateException("Utility class");
    }
}