/*

 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 */

import com.oracle.java.testlibrary.Asserts;

import com.oracle.java.testlibrary.Platform;

import java.lang.reflect.InvocationTargetException;

import java.lang.reflect.Method;

import java.util.Arrays;

import java.util.Collections;

import java.util.EnumSet;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

/**

 * @test

 * @summary Verify that for each group of mutually exclusive predicates defined

 *          in com.oracle.java.testlibrary.Platform one and only one predicate

 *          evaluates to true.

 * @library /testlibrary

 * @run main TestMutuallyExclusivePlatformPredicates

 */

public class TestMutuallyExclusivePlatformPredicates {

    private static enum MethodGroup {

        ARCH("isARM", "isPPC", "isSparc", "isX86", "isX64"),

        BITNESS("is32bit", "is64bit"),

        OS("isLinux", "isSolaris", "isWindows", "isOSX"),

        VM_TYPE("isClient", "isServer", "isGraal", "isMinimal"),

        IGNORED("isEmbedded", "isDebugBuild");

        public final List<String> methodNames;

        private MethodGroup(String... methodNames) {

            this.methodNames = Collections.unmodifiableList(

                    Arrays.asList(methodNames));

        }

    }

    public static void main(String args[]) {

        EnumSet<MethodGroup> notIgnoredMethodGroups

                = EnumSet.complementOf(EnumSet.of(MethodGroup.IGNORED));

        notIgnoredMethodGroups.forEach(

                TestMutuallyExclusivePlatformPredicates::verifyPredicates);

        TestMutuallyExclusivePlatformPredicates.verifyCoverage();

    }

    /**

     * Verifies that one and only one predicate method defined in

     * {@link com.oracle.java.testlibrary.Platform}, whose name included into

     * methodGroup will return {@code true}.

     * @param methodGroup The group of methods that should be tested.

     */

    private static void verifyPredicates(MethodGroup methodGroup) {

        System.out.println("Verifying method group: " + methodGroup.name());

        long truePredicatesCount = methodGroup.methodNames.stream()

                .filter(TestMutuallyExclusivePlatformPredicates

                        ::evaluatePredicate)

                .count();

        Asserts.assertEQ(truePredicatesCount, 1L, String.format(

                "Only one predicate from group %s should be evaluated to true "

                        + "(Actually %d predicates were evaluated to true).",

                methodGroup.name(), truePredicatesCount));

    }

    /**

     * Verifies that all predicates defined in

     * {@link com.oracle.java.testlibrary.Platform} were either tested or

     * explicitly ignored.

     */

    private static void verifyCoverage() {

        Set<String> allMethods = new HashSet<>();

        for (MethodGroup group : MethodGroup.values()) {

            allMethods.addAll(group.methodNames);

        }

        for (Method m : Platform.class.getMethods()) {

            if (m.getParameterCount() == 0

                    && m.getReturnType() == boolean.class) {

                Asserts.assertTrue(allMethods.contains(m.getName()),

                        "All Platform's methods with signature '():Z' should "

                                + "be tested ");

            }

        }

    }

    /**

     * Evaluates predicate method with name {@code name} defined in

     * {@link com.oracle.java.testlibrary.Platform}.

     *

     * @param name The name of a predicate to be evaluated.

     * @return evaluated predicate's value.

     * @throws java.lang.Error if predicate is not defined or could not be

     *                         evaluated.

     */

    private static boolean evaluatePredicate(String name) {

        try {

            System.out.printf("Trying to evaluate predicate with name %s%n",

                    name);

            boolean value

                    = (Boolean) Platform.class.getMethod(name).invoke(null);

            System.out.printf("Predicate evaluated to: %s%n", value);

            return value;

        } catch (NoSuchMethodException e) {

            throw new Error("Predicate with name " + name

                    + " is not defined in " + Platform.class.getName(), e);

        } catch (IllegalAccessException | InvocationTargetException e) {

            throw new Error("Unable to evaluate predicate " + name, e);

        }

    }

}