/*
 * 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.exec;

import java.util.Locale;

/**
 * Condition that tests the OS type.
 *
 * Copied and adapted from Apache Ant 1.9.6 from org.apache.tools.ant.taskdefs.condition.OS.
 */
public final class OS {

    /**
     * OS family that can be tested for. {@value}
     */
    public static final String FAMILY_9X = "win9x";
    /**
     * OS family that can be tested for. {@value}
     */
    public static final String FAMILY_DOS = "dos";
    /**
     * OS family that can be tested for. {@value}
     */
    public static final String FAMILY_MAC = "mac";
    /**
     * OS family that can be tested for. {@value}
     */
    public static final String FAMILY_NETWARE = "netware";
    /**
     * OS family that can be tested for. {@value}
     */
    public static final String FAMILY_NT = "winnt";
    /**
     * OS family that can be tested for. {@value}
     */
    public static final String FAMILY_OS2 = "os/2";
    /**
     * OS family that can be tested for. {@value}
     */
    public static final String FAMILY_OS400 = "os/400";
    /**
     * OS family that can be tested for. {@value}
     */
    public static final String FAMILY_TANDEM = "tandem";
    /**
     * OS family that can be tested for. {@value}
     */
    public static final String FAMILY_UNIX = "unix";
    /**
     * OS family that can be tested for. {@value}
     */
    public static final String FAMILY_VMS = "openvms";
    /**
     * OS family that can be tested for. {@value}
     */
    public static final String FAMILY_WINDOWS = "windows";
    /**
     * OS family that can be tested for. {@value}
     */
    public static final String FAMILY_ZOS = "z/os";

    private static final String DARWIN = "darwin";

    private static final String OS_NAME = System.getProperty("os.name").toLowerCase(Locale.ENGLISH);
    private static final String OS_ARCH = System.getProperty("os.arch").toLowerCase(Locale.ENGLISH);
    private static final String OS_VERSION = System.getProperty("os.version").toLowerCase(Locale.ENGLISH);
    private static final String PATH_SEP = System.getProperty("path.separator");

    /**
     * Default constructor
     */
    private OS() {
    }

    /**
     * Determines if the OS on which commons-exec is executing matches the
     * given OS family.
     *
     * @param family the family to check for
     * @return true if the OS matches
     */
    private static boolean isFamily(final String family) {
        return isOs(family, null, null, null);
    }

    public static boolean isFamilyDOS() {
        return isFamily(FAMILY_DOS);
    }

    public static boolean isFamilyMac() {
        return isFamily(FAMILY_MAC);
    }

    public static boolean isFamilyNetware() {
        return isFamily(FAMILY_NETWARE);
    }

    public static boolean isFamilyOS2() {
        return isFamily(FAMILY_OS2);
    }

    public static boolean isFamilyTandem() {
        return isFamily(FAMILY_TANDEM);
    }

    public static boolean isFamilyUnix() {
        return isFamily(FAMILY_UNIX);
    }

    public static boolean isFamilyWindows() {
        return isFamily(FAMILY_WINDOWS);
    }

    public static boolean isFamilyWin9x() {
        return isFamily(FAMILY_9X);
    }

    public static boolean isFamilyWinNT() {
        return isFamily(FAMILY_NT);
    }

    public static boolean isFamilyZOS() {
        return isFamily(FAMILY_ZOS);
    }

    public static boolean isFamilyOS400() {
        return isFamily(FAMILY_OS400);
    }

    public static boolean isFamilyOpenVms() {
        return isFamily(FAMILY_VMS);
    }

    /**
     * Determines if the OS on which commons-exec is executing matches
     * the given OS name.
     *
     * @param name the OS name to check for
     * @return true if the OS matches
     */
    public static boolean isName(final String name) {
        return isOs(null, name, null, null);
    }

    /**
     * Determines if the OS on which commons-exec is executing matches
     * the given OS architecture.
     *
     * @param arch the OS architecture to check for
     * @return true if the OS matches
     */
    public static boolean isArch(final String arch) {
        return isOs(null, null, arch, null);
    }

    /**
     * Determines if the OS on which commonss-exec is executing matches
     * the given OS version.
     *
     * @param version the OS version to check for
     * @return true if the OS matches
     */
    public static boolean isVersion(final String version) {
        return isOs(null, null, null, version);
    }

    /**
     * Determines if the OS on which commons-exec is executing matches the
     * given OS family, name, architecture and version.
     *
     * @param family  The OS family
     * @param name    The OS name
     * @param arch    The OS architecture
     * @param version The OS version
     * @return true if the OS matches
     */
    public static boolean isOs(final String family, final String name,
                               final String arch, final String version) {
        boolean retValue = false;

        if (family != null || name != null || arch != null || version != null) {

            boolean isFamily = true;
            boolean isName = true;
            boolean isArch = true;
            boolean isVersion = true;

            if (family != null) {
                //windows probing logic relies on the word 'windows' in
                //the OS
                final boolean isWindows = OS_NAME.contains(FAMILY_WINDOWS);
                boolean is9x = false;
                boolean isNT = false;
                if (isWindows) {
                    //there are only four 9x platforms that we look for
                    is9x = (OS_NAME.contains("95")
                            || OS_NAME.contains("98")
                            || OS_NAME.contains("me")
                            //wince isn't really 9x, but crippled enough to
                            //be a muchness. Ant doesn't run on CE, anyway.
                            || OS_NAME.contains("ce"));
                    isNT = !is9x;
                }
                if (family.equals(FAMILY_WINDOWS)) {
                    isFamily = isWindows;
                } else if (family.equals(FAMILY_9X)) {
                    isFamily = isWindows && is9x;
                } else if (family.equals(FAMILY_NT)) {
                    isFamily = isWindows && isNT;
                } else if (family.equals(FAMILY_OS2)) {
                    isFamily = OS_NAME.contains(FAMILY_OS2);
                } else if (family.equals(FAMILY_NETWARE)) {
                    isFamily = OS_NAME.contains(FAMILY_NETWARE);
                } else if (family.equals(FAMILY_DOS)) {
                    isFamily = PATH_SEP.equals(";") && !isFamily(FAMILY_NETWARE);
                } else if (family.equals(FAMILY_MAC)) {
                    isFamily = OS_NAME.contains(FAMILY_MAC)
                            || OS_NAME.contains(DARWIN);
                } else if (family.equals(FAMILY_TANDEM)) {
                    isFamily = OS_NAME.contains("nonstop_kernel");
                } else if (family.equals(FAMILY_UNIX)) {
                    isFamily = PATH_SEP.equals(":")
                            && !isFamily(FAMILY_VMS)
                            && (!isFamily(FAMILY_MAC) || OS_NAME.endsWith("x")
                            || OS_NAME.contains(DARWIN));
                } else if (family.equals(FAMILY_ZOS)) {
                    isFamily = OS_NAME.contains(FAMILY_ZOS)
                            || OS_NAME.contains("os/390");
                } else if (family.equals(FAMILY_OS400)) {
                    isFamily = OS_NAME.contains(FAMILY_OS400);
                } else if (family.equals(FAMILY_VMS)) {
                    isFamily = OS_NAME.contains(FAMILY_VMS);
                } else {
                    throw new RuntimeException(
                            "Don\'t know how to detect os family \""
                                    + family + "\"");
                }
            }
            if (name != null) {
                isName = name.equals(OS_NAME);
            }
            if (arch != null) {
                isArch = arch.equals(OS_ARCH);
            }
            if (version != null) {
                isVersion = version.equals(OS_VERSION);
            }
            retValue = isFamily && isName && isArch && isVersion;
        }
        return retValue;
    }
}