/*

 * 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

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

/*

 * This file is available under and governed by the GNU General Public

 * License version 2 only, as published by the Free Software Foundation.

 * However, the following notice accompanied the original version of this

 * file:

 *

 * Written by Doug Lea with assistance from members of JCP JSR-166

 * Expert Group and released to the public domain, as explained at

 * http://creativecommons.org/publicdomain/zero/1.0/

 */

import java.util.Arrays;

import java.util.List;

import java.util.SplittableRandom;

import java.util.concurrent.atomic.AtomicInteger;

import java.util.concurrent.atomic.LongAdder;

import java.lang.reflect.Method;

import java.util.function.Predicate;

import java.util.stream.Collectors;

import junit.framework.Test;

import junit.framework.TestSuite;

public class SplittableRandomTest extends JSR166TestCase {

    public static void main(String[] args) {

        main(suite(), args);

    }

    public static Test suite() {

        return new TestSuite(SplittableRandomTest.class);

    }

    /*

     * Testing coverage notes:

     *

     * 1. Many of the test methods are adapted from ThreadLocalRandomTest.

     *

     * 2. These tests do not check for random number generator quality.

     * But we check for minimal API compliance by requiring that

     * repeated calls to nextX methods, up to NCALLS tries, produce at

     * least two distinct results. (In some possible universe, a

     * "correct" implementation might fail, but the odds are vastly

     * less than that of encountering a hardware failure while running

     * the test.) For bounded nextX methods, we sample various

     * intervals across multiples of primes. In other tests, we repeat

     * under REPS different values.

     */

    // max numbers of calls to detect getting stuck on one value

    static final int NCALLS = 10000;

    // max sampled int bound

    static final int MAX_INT_BOUND = (1 << 26);

    // max sampled long bound

    static final long MAX_LONG_BOUND = (1L << 40);

    // Number of replications for other checks

    static final int REPS =

        Integer.getInteger("SplittableRandomTest.reps", 4);

    /**

     * Repeated calls to nextInt produce at least two distinct results

     */

    public void testNextInt() {

        SplittableRandom sr = new SplittableRandom();

        int f = sr.nextInt();

        int i = 0;

        while (i < NCALLS && sr.nextInt() == f)

            ++i;

        assertTrue(i < NCALLS);

    }

    /**

     * Repeated calls to nextLong produce at least two distinct results

     */

    public void testNextLong() {

        SplittableRandom sr = new SplittableRandom();

        long f = sr.nextLong();

        int i = 0;

        while (i < NCALLS && sr.nextLong() == f)

            ++i;

        assertTrue(i < NCALLS);

    }

    /**

     * Repeated calls to nextDouble produce at least two distinct results

     */

    public void testNextDouble() {

        SplittableRandom sr = new SplittableRandom();

        double f = sr.nextDouble();

        int i = 0;

        while (i < NCALLS && sr.nextDouble() == f)

            ++i;

        assertTrue(i < NCALLS);

    }

    /**

     * Two SplittableRandoms created with the same seed produce the

     * same values for nextLong.

     */

    public void testSeedConstructor() {

        for (long seed = 2; seed < MAX_LONG_BOUND; seed += 15485863) {

            SplittableRandom sr1 = new SplittableRandom(seed);

            SplittableRandom sr2 = new SplittableRandom(seed);

            for (int i = 0; i < REPS; ++i)

                assertEquals(sr1.nextLong(), sr2.nextLong());

        }

    }

    /**

     * A SplittableRandom produced by split() of a default-constructed

     * SplittableRandom generates a different sequence

     */

    public void testSplit1() {

        SplittableRandom sr = new SplittableRandom();

        for (int reps = 0; reps < REPS; ++reps) {

            SplittableRandom sc = sr.split();

            int i = 0;

            while (i < NCALLS && sr.nextLong() == sc.nextLong())

                ++i;

            assertTrue(i < NCALLS);

        }

    }

    /**

     * A SplittableRandom produced by split() of a seeded-constructed

     * SplittableRandom generates a different sequence

     */

    public void testSplit2() {

        SplittableRandom sr = new SplittableRandom(12345);

        for (int reps = 0; reps < REPS; ++reps) {

            SplittableRandom sc = sr.split();

            int i = 0;

            while (i < NCALLS && sr.nextLong() == sc.nextLong())

                ++i;

            assertTrue(i < NCALLS);

        }

    }

    /**

     * nextInt(non-positive) throws IllegalArgumentException

     */

    public void testNextIntBoundNonPositive() {

        SplittableRandom sr = new SplittableRandom();

        assertThrows(

            IllegalArgumentException.class,

            () -> sr.nextInt(-17),

            () -> sr.nextInt(0),

            () -> sr.nextInt(Integer.MIN_VALUE));

    }

    /**

     * nextInt(least >= bound) throws IllegalArgumentException

     */

    public void testNextIntBadBounds() {

        SplittableRandom sr = new SplittableRandom();

        assertThrows(

            IllegalArgumentException.class,

            () -> sr.nextInt(17, 2),

            () -> sr.nextInt(-42, -42),

            () -> sr.nextInt(Integer.MAX_VALUE, Integer.MIN_VALUE));

    }

    /**

     * nextInt(bound) returns 0 <= value < bound;

     * repeated calls produce at least two distinct results

     */

    public void testNextIntBounded() {

        SplittableRandom sr = new SplittableRandom();

        for (int i = 0; i < 2; i++) assertEquals(0, sr.nextInt(1));

        // sample bound space across prime number increments

        for (int bound = 2; bound < MAX_INT_BOUND; bound += 524959) {

            int f = sr.nextInt(bound);

            assertTrue(0 <= f && f < bound);

            int i = 0;

            int j;

            while (i < NCALLS &&

                   (j = sr.nextInt(bound)) == f) {

                assertTrue(0 <= j && j < bound);

                ++i;

            }

            assertTrue(i < NCALLS);

        }

    }

    /**

     * nextInt(least, bound) returns least <= value < bound;

     * repeated calls produce at least two distinct results

     */

    public void testNextIntBounded2() {

        SplittableRandom sr = new SplittableRandom();

        for (int least = -15485863; least < MAX_INT_BOUND; least += 524959) {

            for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 49979687) {

                int f = sr.nextInt(least, bound);

                assertTrue(least <= f && f < bound);

                int i = 0;

                int j;

                while (i < NCALLS &&

                       (j = sr.nextInt(least, bound)) == f) {

                    assertTrue(least <= j && j < bound);

                    ++i;

                }

                assertTrue(i < NCALLS);

            }

        }

    }

    /**

     * nextLong(non-positive) throws IllegalArgumentException

     */

    public void testNextLongBoundNonPositive() {

        SplittableRandom sr = new SplittableRandom();

        assertThrows(

            IllegalArgumentException.class,

            () -> sr.nextLong(-17L),

            () -> sr.nextLong(0L),

            () -> sr.nextLong(Long.MIN_VALUE));

    }

    /**

     * nextLong(least >= bound) throws IllegalArgumentException

     */

    public void testNextLongBadBounds() {

        SplittableRandom sr = new SplittableRandom();

        assertThrows(

            IllegalArgumentException.class,

            () -> sr.nextLong(17L, 2L),

            () -> sr.nextLong(-42L, -42L),

            () -> sr.nextLong(Long.MAX_VALUE, Long.MIN_VALUE));

    }

    /**

     * nextLong(bound) returns 0 <= value < bound;

     * repeated calls produce at least two distinct results

     */

    public void testNextLongBounded() {

        SplittableRandom sr = new SplittableRandom();

        for (int i = 0; i < 2; i++) assertEquals(0L, sr.nextLong(1L));

        for (long bound = 2; bound < MAX_LONG_BOUND; bound += 15485863) {

            long f = sr.nextLong(bound);

            assertTrue(0 <= f && f < bound);

            int i = 0;

            long j;

            while (i < NCALLS &&

                   (j = sr.nextLong(bound)) == f) {

                assertTrue(0 <= j && j < bound);

                ++i;

            }

            assertTrue(i < NCALLS);

        }

    }

    /**

     * nextLong(least, bound) returns least <= value < bound;

     * repeated calls produce at least two distinct results

     */

    public void testNextLongBounded2() {

        SplittableRandom sr = new SplittableRandom();

        for (long least = -86028121; least < MAX_LONG_BOUND; least += 982451653L) {

            for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {

                long f = sr.nextLong(least, bound);

                assertTrue(least <= f && f < bound);

                int i = 0;

                long j;

                while (i < NCALLS &&

                       (j = sr.nextLong(least, bound)) == f) {

                    assertTrue(least <= j && j < bound);

                    ++i;

                }

                assertTrue(i < NCALLS);

            }

        }

    }

    /**

     * nextDouble(non-positive) throws IllegalArgumentException

     */

    public void testNextDoubleBoundNonPositive() {

        SplittableRandom sr = new SplittableRandom();

        assertThrows(

            IllegalArgumentException.class,

            () -> sr.nextDouble(-17.0d),

            () -> sr.nextDouble(0.0d),

            () -> sr.nextDouble(-Double.MIN_VALUE),

            () -> sr.nextDouble(Double.NEGATIVE_INFINITY),

            () -> sr.nextDouble(Double.NaN));

    }

    /**

     * nextDouble(! (least < bound)) throws IllegalArgumentException

     */

    public void testNextDoubleBadBounds() {

        SplittableRandom sr = new SplittableRandom();

        assertThrows(

            IllegalArgumentException.class,

            () -> sr.nextDouble(17.0d, 2.0d),

            () -> sr.nextDouble(-42.0d, -42.0d),

            () -> sr.nextDouble(Double.MAX_VALUE, Double.MIN_VALUE),

            () -> sr.nextDouble(Double.NaN, 0.0d),

            () -> sr.nextDouble(0.0d, Double.NaN));

    }

    // TODO: Test infinite bounds!

    //() -> sr.nextDouble(Double.NEGATIVE_INFINITY, 0.0d),

    //() -> sr.nextDouble(0.0d, Double.POSITIVE_INFINITY),

    /**

     * nextDouble(least, bound) returns least <= value < bound;

     * repeated calls produce at least two distinct results

     */

    public void testNextDoubleBounded2() {

        SplittableRandom sr = new SplittableRandom();

        for (double least = 0.0001; least < 1.0e20; least *= 8) {

            for (double bound = least * 1.001; bound < 1.0e20; bound *= 16) {

                double f = sr.nextDouble(least, bound);

                assertTrue(least <= f && f < bound);

                int i = 0;

                double j;

                while (i < NCALLS &&

                       (j = sr.nextDouble(least, bound)) == f) {

                    assertTrue(least <= j && j < bound);

                    ++i;

                }

                assertTrue(i < NCALLS);

            }

        }

    }

    /**

     * Invoking sized ints, long, doubles, with negative sizes throws

     * IllegalArgumentException

     */

    public void testBadStreamSize() {

        SplittableRandom r = new SplittableRandom();

        assertThrows(

            IllegalArgumentException.class,

            () -> { java.util.stream.IntStream x = r.ints(-1L); },

            () -> { java.util.stream.IntStream x = r.ints(-1L, 2, 3); },

            () -> { java.util.stream.LongStream x = r.longs(-1L); },

            () -> { java.util.stream.LongStream x = r.longs(-1L, -1L, 1L); },

            () -> { java.util.stream.DoubleStream x = r.doubles(-1L); },

            () -> { java.util.stream.DoubleStream x = r.doubles(-1L, .5, .6); });

    }

    /**

     * Invoking bounded ints, long, doubles, with illegal bounds throws

     * IllegalArgumentException

     */

    public void testBadStreamBounds() {

        SplittableRandom r = new SplittableRandom();

        assertThrows(

            IllegalArgumentException.class,

            () -> { java.util.stream.IntStream x = r.ints(2, 1); },

            () -> { java.util.stream.IntStream x = r.ints(10, 42, 42); },

            () -> { java.util.stream.LongStream x = r.longs(-1L, -1L); },

            () -> { java.util.stream.LongStream x = r.longs(10, 1L, -2L); },

            () -> { java.util.stream.DoubleStream x = r.doubles(0.0, 0.0); },

            () -> { java.util.stream.DoubleStream x = r.doubles(10, .5, .4); });

    }

    /**

     * A parallel sized stream of ints generates the given number of values

     */

    public void testIntsCount() {

        LongAdder counter = new LongAdder();

        SplittableRandom r = new SplittableRandom();

        long size = 0;

        for (int reps = 0; reps < REPS; ++reps) {

            counter.reset();

            r.ints(size).parallel().forEach(x -> counter.increment());

            assertEquals(size, counter.sum());

            size += 524959;

        }

    }

    /**

     * A parallel sized stream of longs generates the given number of values

     */

    public void testLongsCount() {

        LongAdder counter = new LongAdder();

        SplittableRandom r = new SplittableRandom();

        long size = 0;

        for (int reps = 0; reps < REPS; ++reps) {

            counter.reset();

            r.longs(size).parallel().forEach(x -> counter.increment());

            assertEquals(size, counter.sum());

            size += 524959;

        }

    }

    /**

     * A parallel sized stream of doubles generates the given number of values

     */

    public void testDoublesCount() {

        LongAdder counter = new LongAdder();

        SplittableRandom r = new SplittableRandom();

        long size = 0;

        for (int reps = 0; reps < REPS; ++reps) {

            counter.reset();

            r.doubles(size).parallel().forEach(x -> counter.increment());

            assertEquals(size, counter.sum());

            size += 524959;

        }

    }

    /**

     * Each of a parallel sized stream of bounded ints is within bounds

     */

    public void testBoundedInts() {

        AtomicInteger fails = new AtomicInteger(0);

        SplittableRandom r = new SplittableRandom();

        long size = 12345L;

        for (int least = -15485867; least < MAX_INT_BOUND; least += 524959) {

            for (int bound = least + 2; bound > least && bound < MAX_INT_BOUND; bound += 67867967) {

                final int lo = least, hi = bound;

                r.ints(size, lo, hi).parallel().forEach(

                    x -> {

                        if (x < lo || x >= hi)

                            fails.getAndIncrement(); });

            }

        }

        assertEquals(0, fails.get());

    }

    /**

     * Each of a parallel sized stream of bounded longs is within bounds

     */

    public void testBoundedLongs() {

        AtomicInteger fails = new AtomicInteger(0);

        SplittableRandom r = new SplittableRandom();

        long size = 123L;

        for (long least = -86028121; least < MAX_LONG_BOUND; least += 1982451653L) {

            for (long bound = least + 2; bound > least && bound < MAX_LONG_BOUND; bound += Math.abs(bound * 7919)) {

                final long lo = least, hi = bound;

                r.longs(size, lo, hi).parallel().forEach(

                    x -> {

                        if (x < lo || x >= hi)

                            fails.getAndIncrement(); });

            }

        }

        assertEquals(0, fails.get());

    }

    /**

     * Each of a parallel sized stream of bounded doubles is within bounds

     */

    public void testBoundedDoubles() {

        AtomicInteger fails = new AtomicInteger(0);

        SplittableRandom r = new SplittableRandom();

        long size = 456;

        for (double least = 0.00011; least < 1.0e20; least *= 9) {

            for (double bound = least * 1.0011; bound < 1.0e20; bound *= 17) {

                final double lo = least, hi = bound;

                r.doubles(size, lo, hi).parallel().forEach(

                    x -> {

                        if (x < lo || x >= hi)

                            fails.getAndIncrement(); });

            }

        }

        assertEquals(0, fails.get());

    }

    /**

     * A parallel unsized stream of ints generates at least 100 values

     */

    public void testUnsizedIntsCount() {

        LongAdder counter = new LongAdder();

        SplittableRandom r = new SplittableRandom();

        long size = 100;

        r.ints().limit(size).parallel().forEach(x -> counter.increment());

        assertEquals(size, counter.sum());

    }

    /**

     * A parallel unsized stream of longs generates at least 100 values

     */

    public void testUnsizedLongsCount() {

        LongAdder counter = new LongAdder();

        SplittableRandom r = new SplittableRandom();

        long size = 100;

        r.longs().limit(size).parallel().forEach(x -> counter.increment());

        assertEquals(size, counter.sum());

    }

    /**

     * A parallel unsized stream of doubles generates at least 100 values

     */

    public void testUnsizedDoublesCount() {

        LongAdder counter = new LongAdder();

        SplittableRandom r = new SplittableRandom();

        long size = 100;

        r.doubles().limit(size).parallel().forEach(x -> counter.increment());

        assertEquals(size, counter.sum());

    }

    /**

     * A sequential unsized stream of ints generates at least 100 values

     */

    public void testUnsizedIntsCountSeq() {

        LongAdder counter = new LongAdder();

        SplittableRandom r = new SplittableRandom();