/*

 * Copyright (c) 2011, 2012, 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * 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.

 */

/* @test

 * @summary unit tests for recursive method handles

 */

/*

 * @ignore The following test creates an unreasonable number of adapters in -Xcomp mode (7049122)

 * @run junit/othervm -DRicochetTest.MAX_ARITY=255 test.java.lang.invoke.RicochetTest

 */

package test.java.lang.invoke;

import java.lang.invoke.*;

import java.util.*;

import org.junit.*;

import static java.lang.invoke.MethodType.*;

import static java.lang.invoke.MethodHandles.*;

import static org.junit.Assert.*;

/**

 *

 * @author jrose

 */

public class RicochetTest {

    private static final Class<?> CLASS = RicochetTest.class;

    private static final int MAX_ARITY = Integer.getInteger(CLASS.getSimpleName()+".MAX_ARITY", 40);

    public static void main(String... av) throws Throwable {

        RicochetTest test = new RicochetTest();

        if (av.length > 0)  test.testOnly = Arrays.asList(av).toString();

        if (REPEAT == 1 || test.testOnly != null) {

            test.testAll();

            if (test.testOnlyTests == null)  throw new RuntimeException("no matching test: "+test.testOnly);

        } else if (REPEAT == 0) {

            org.junit.runner.JUnitCore.runClasses(RicochetTest.class);

        } else {

            verbose(1, "REPEAT="+REPEAT);

            for (int i = 0; i < REPEAT; i++) {

                test.testRepetition = (i+1);

                verbose(0, "[#"+test.testRepetition+"]");

                test.testAll();

            }

        }

    }

    int testRepetition;

    public void testAll() throws Throwable {

        testNull();

        testBoxInteger();

        testFilterReturnValue();

        testFilterObject();

        testBoxLong();

        testFilterInteger();

        testIntSpreads();

        testByteSpreads();

        testLongSpreads();

        testIntCollects();

        testReturns();

        testRecursion();

    }

    @Test

    public void testNull() throws Throwable {

        if (testRepetition > (1+REPEAT/100))  return;  // trivial test

        if (!startTest("testNull"))  return;

        assertEquals(opI(37), opI.invokeWithArguments(37));

        assertEqualFunction(opI, opI);

    }

    @Test

    public void testBoxInteger() throws Throwable {

        if (!startTest("testBoxInteger"))  return;

        assertEqualFunction(opI, opI.asType(opL_I.type()).asType(opI.type()));

    }

    @Test

    public void testFilterReturnValue() throws Throwable {

        if (!startTest("testFilterReturnValue"))  return;

        int[] ints = { 12, 23, 34, 45, 56, 67, 78, 89 };

        Object res = list8ints.invokeExact(ints[0], ints[1], ints[2], ints[3], ints[4], ints[5], ints[6], ints[7]);

        assertEquals(Arrays.toString(ints), res.toString());

        MethodHandle idreturn = filterReturnValue(list8ints, identity(Object.class));

        res = idreturn.invokeExact(ints[0], ints[1], ints[2], ints[3], ints[4], ints[5], ints[6], ints[7]);

        assertEquals(Arrays.toString(ints), res.toString());

        MethodHandle add0 = addL.bindTo(0);

        assertEqualFunction(filterReturnValue(opL2, add0), opL2);

    }

    @Test

    public void testFilterObject() throws Throwable {

        if (!startTest("testFilterObject"))  return;

        MethodHandle add0 = addL.bindTo(0);

        assertEqualFunction(sequence(opL2, add0), opL2);

        int bump13 = -13;  // value near 20 works as long as test values are near [-80..80]

        MethodHandle add13   = addL.bindTo(bump13);

        MethodHandle add13_0 = addL.bindTo(opI2(bump13, 0));

        MethodHandle add13_1 = addL.bindTo(opI2(0, bump13));

        assertEqualFunction(sequence(opL2, add13_0),

                            filterArguments(opL2, 0, add13));

        assertEqualFunction(sequence(opL2, add13_1),

                            filterArguments(opL2, 1, add13));

        System.out.println("[testFilterObject done]");

    }

    @Test

    public void testBoxLong() throws Throwable {

        if (!startTest("testBoxLong"))  return;

        assertEqualFunction(opJ, opJ.asType(opL_J.type()).asType(opJ.type()));

    }

    @Test

    public void testFilterInteger() throws Throwable {

        if (!startTest("testFilterInteger"))  return;

        assertEqualFunction(opI, sequence(convI_L, opL_I));

    }

    @Test

    public void testIntSpreads() throws Throwable {

        if (!startTest("testIntSpreads"))  return;

        MethodHandle id = identity(int[].class);

        final int MAX = MAX_ARITY-2;  // 253+1 would cause parameter overflow with 'this' added

        for (int nargs = 0; nargs <= MAX; nargs++) {

            if (nargs > 30 && nargs < MAX-20)  nargs += 10;

            int[] args = new int[nargs];

            for (int j = 0; j < args.length; j++)  args[j] = j + 11;

            //System.out.println("testIntSpreads "+Arrays.toString(args));

            int[] args1 = (int[]) id.invokeExact(args);

            assertArrayEquals(args, args1);

            MethodHandle coll = id.asCollector(int[].class, nargs);

            int[] args2 = args;

            switch (nargs) {

                case 0:  args2 = (int[]) coll.invokeExact(); break;

                case 1:  args2 = (int[]) coll.invokeExact(args[0]); break;

                case 2:  args2 = (int[]) coll.invokeExact(args[0], args[1]); break;

                case 3:  args2 = (int[]) coll.invokeExact(args[0], args[1], args[2]); break;

                case 4:  args2 = (int[]) coll.invokeExact(args[0], args[1], args[2], args[3]); break;

                case 5:  args2 = (int[]) coll.invokeExact(args[0], args[1], args[2], args[3], args[4]); break;

            }

            assertArrayEquals(args, args2);

            MethodHandle mh = coll.asSpreader(int[].class, nargs);

            int[] args3 = (int[]) mh.invokeExact(args);

            assertArrayEquals(args, args3);

        }

    }

    @Test

    public void testByteSpreads() throws Throwable {

        if (!startTest("testByteSpreads"))  return;

        MethodHandle id = identity(byte[].class);

        final int MAX = MAX_ARITY-2;  // 253+1 would cause parameter overflow with 'this' added

        for (int nargs = 0; nargs <= MAX; nargs++) {

            if (nargs > 30 && nargs < MAX-20)  nargs += 10;

            byte[] args = new byte[nargs];

            for (int j = 0; j < args.length; j++)  args[j] = (byte)(j + 11);

            //System.out.println("testByteSpreads "+Arrays.toString(args));

            byte[] args1 = (byte[]) id.invokeExact(args);

            assertArrayEquals(args, args1);

            MethodHandle coll = id.asCollector(byte[].class, nargs);

            byte[] args2 = args;

            switch (nargs) {

                case 0:  args2 = (byte[]) coll.invokeExact(); break;

                case 1:  args2 = (byte[]) coll.invokeExact(args[0]); break;

                case 2:  args2 = (byte[]) coll.invokeExact(args[0], args[1]); break;

                case 3:  args2 = (byte[]) coll.invokeExact(args[0], args[1], args[2]); break;

                case 4:  args2 = (byte[]) coll.invokeExact(args[0], args[1], args[2], args[3]); break;

                case 5:  args2 = (byte[]) coll.invokeExact(args[0], args[1], args[2], args[3], args[4]); break;

            }

            assertArrayEquals(args, args2);

            MethodHandle mh = coll.asSpreader(byte[].class, nargs);

            byte[] args3 = (byte[]) mh.invokeExact(args);

            assertArrayEquals(args, args3);

        }

    }

    @Test

    public void testLongSpreads() throws Throwable {

        if (!startTest("testLongSpreads"))  return;

        MethodHandle id = identity(long[].class);

        final int MAX = (MAX_ARITY - 2) / 2;  // 253/2+1 would cause parameter overflow with 'this' added

        for (int nargs = 0; nargs <= MAX; nargs++) {

            if (nargs > 30 && nargs < MAX-20)  nargs += 10;

            long[] args = new long[nargs];

            for (int j = 0; j < args.length; j++)  args[j] = (long)(j + 11);

            //System.out.println("testLongSpreads "+Arrays.toString(args));

            long[] args1 = (long[]) id.invokeExact(args);

            assertArrayEquals(args, args1);

            MethodHandle coll = id.asCollector(long[].class, nargs);

            long[] args2 = args;

            switch (nargs) {

                case 0:  args2 = (long[]) coll.invokeExact(); break;

                case 1:  args2 = (long[]) coll.invokeExact(args[0]); break;

                case 2:  args2 = (long[]) coll.invokeExact(args[0], args[1]); break;

                case 3:  args2 = (long[]) coll.invokeExact(args[0], args[1], args[2]); break;

                case 4:  args2 = (long[]) coll.invokeExact(args[0], args[1], args[2], args[3]); break;

                case 5:  args2 = (long[]) coll.invokeExact(args[0], args[1], args[2], args[3], args[4]); break;

            }

            assertArrayEquals(args, args2);

            MethodHandle mh = coll.asSpreader(long[].class, nargs);

            long[] args3 = (long[]) mh.invokeExact(args);

            assertArrayEquals(args, args3);

        }

    }

    @Test

    public void testIntCollects() throws Throwable {

        if (!startTest("testIntCollects"))  return;

        for (MethodHandle lister : INT_LISTERS) {

            int outputs = lister.type().parameterCount();

            for (int collects = 0; collects <= Math.min(outputs, INT_COLLECTORS.length-1); collects++) {

                int inputs = outputs - 1 + collects;

                if (inputs < 0)  continue;

                for (int pos = 0; pos + collects <= inputs; pos++) {

                    MethodHandle collector = INT_COLLECTORS[collects];

                    int[] args = new int[inputs];

                    int ap = 0, arg = 31;

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

                        args[ap++] = arg++ + 0;

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

                        args[ap++] = arg++ + 10;

                    while (ap < args.length)

                        args[ap++] = arg++ + 20;

                    // calculate piecemeal:

                    //System.out.println("testIntCollects "+Arrays.asList(lister, pos, collector)+" on "+Arrays.toString(args));

                    int[] collargs = Arrays.copyOfRange(args, pos, pos+collects);

                    int coll = (int) collector.asSpreader(int[].class, collargs.length).invokeExact(collargs);

                    int[] listargs = Arrays.copyOfRange(args, 0, outputs);

                    System.arraycopy(args, pos+collects, listargs, pos+1, outputs - (pos+1));

                    listargs[pos] = coll;

                    //System.out.println("  coll="+coll+" listargs="+Arrays.toString(listargs));

                    Object expect = lister.asSpreader(int[].class, listargs.length).invokeExact(listargs);

                    //System.out.println("  expect="+expect);

                    // now use the combined MH, and test the output:

                    MethodHandle mh = collectArguments(lister, pos, int[].class, INT_COLLECTORS[collects]);

                    if (mh == null)  continue;  // no infix collection, yet

                    assert(mh.type().parameterCount() == inputs);

                    Object observe = mh.asSpreader(int[].class, args.length).invokeExact(args);

                    assertEquals(expect, observe);

                }

            }

        }

    }

    @Test

    public void testByteCollects() throws Throwable {

        if (!startTest("testByteCollects"))  return;

        for (MethodHandle lister : BYTE_LISTERS) {

            int outputs = lister.type().parameterCount();

            for (int collects = 0; collects <= Math.min(outputs, BYTE_COLLECTORS.length-1); collects++) {

                int inputs = outputs - 1 + collects;

                if (inputs < 0)  continue;

                for (int pos = 0; pos + collects <= inputs; pos++) {

                    MethodHandle collector = BYTE_COLLECTORS[collects];

                    byte[] args = new byte[inputs];

                    int ap = 0, arg = 31;

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

                        args[ap++] = (byte)(arg++ + 0);

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

                        args[ap++] = (byte)(arg++ + 10);

                    while (ap < args.length)

                        args[ap++] = (byte)(arg++ + 20);

                    // calculate piecemeal:

                    //System.out.println("testIntCollects "+Arrays.asList(lister, pos, collector)+" on "+Arrays.toString(args));

                    byte[] collargs = Arrays.copyOfRange(args, pos, pos+collects);

                    byte coll = (byte) collector.asSpreader(byte[].class, collargs.length).invokeExact(collargs);

                    byte[] listargs = Arrays.copyOfRange(args, 0, outputs);

                    System.arraycopy(args, pos+collects, listargs, pos+1, outputs - (pos+1));

                    listargs[pos] = coll;

                    //System.out.println("  coll="+coll+" listargs="+Arrays.toString(listargs));

                    Object expect = lister.asSpreader(byte[].class, listargs.length).invokeExact(listargs);

                    //System.out.println("  expect="+expect);

                    // now use the combined MH, and test the output:

                    MethodHandle mh = collectArguments(lister, pos, byte[].class, BYTE_COLLECTORS[collects]);

                    if (mh == null)  continue;  // no infix collection, yet

                    assert(mh.type().parameterCount() == inputs);

                    Object observe = mh.asSpreader(byte[].class, args.length).invokeExact(args);

                    assertEquals(expect, observe);

                }

            }

        }

    }

    private static MethodHandle collectArguments(MethodHandle lister, int pos, Class<?> array, MethodHandle collector) {

        int collects = collector.type().parameterCount();

        int outputs = lister.type().parameterCount();

        if (pos == outputs - 1)

            return MethodHandles.filterArguments(lister, pos,

                        collector.asSpreader(array, collects))

                            .asCollector(array, collects);

        //return MethodHandles.collectArguments(lister, pos, collector); //no such animal

        return null;

    }

    private static final Class<?>[] RETURN_TYPES = {

        Object.class, String.class, Integer.class,

        int.class, long.class,

        boolean.class, byte.class, char.class, short.class,

        float.class, double.class,

        void.class,

    };

    @Test

    public void testReturns() throws Throwable {

        if (!startTest("testReturns"))  return;

        // fault injection:

        int faultCount = 0;  // total of 1296 tests

        faultCount = Integer.getInteger("testReturns.faultCount", 0);

        for (Class<?> ret : RETURN_TYPES) {

            // make a complicated identity function and pass something through it

            System.out.println(ret.getSimpleName());

            Class<?> vret = (ret == void.class) ? Void.class : ret;

            MethodHandle id = // (vret)->ret

                identity(vret).asType(methodType(ret, vret));

            final int LENGTH = 4;

            int[] index = {0};

            Object vals = java.lang.reflect.Array.newInstance(vret, LENGTH);

            MethodHandle indexGetter =  //()->int

                insertArguments(arrayElementGetter(index.getClass()), 0, index, 0);

            MethodHandle valSelector =  // (int)->vret

                arrayElementGetter(vals.getClass()).bindTo(vals);

            MethodHandle valGetter =  // ()->vret

                foldArguments(valSelector, indexGetter);

            if (ret != void.class) {

                for (int i = 0; i < LENGTH; i++) {

                    Object val = (i + 50);

                    if (ret == boolean.class)  val = (i % 3 == 0);

                    if (ret == String.class)   val = "#"+i;

                    if (ret == char.class)     val = (char)('a'+i);

                    if (ret == byte.class)     val = (byte)~i;

                    if (ret == short.class)    val = (short)(1<<i);

                    java.lang.reflect.Array.set(vals, i, val);

                }

            }

            for (int i = 0; i < LENGTH; i++) {

                Object val = java.lang.reflect.Array.get(vals, i);

                System.out.println(i+" => "+val);

                index[0] = i;

                if (--faultCount == 0)  index[0] ^= 1;

                Object x = valGetter.invokeWithArguments();

                assertEquals(val, x);

                // make a return-filter call:  x = id(valGetter())

                if (--faultCount == 0)  index[0] ^= 1;

                x = filterReturnValue(valGetter, id).invokeWithArguments();

                assertEquals(val, x);

                // make a filter call:  x = id(*,valGetter(),*)

                for (int len = 1; len <= 4; len++) {

                    for (int pos = 0; pos < len; pos++) {

                        MethodHandle proj = id;  // lambda(..., vret x,...){x}

                        for (int j = 0; j < len; j++) {

                            if (j == pos)  continue;

                            proj = dropArguments(proj, j, Object.class);

                        }

                        assert(proj.type().parameterCount() == len);

                        // proj: (Object*, pos: vret, Object*)->ret

                        assertEquals(vret, proj.type().parameterType(pos));

                        MethodHandle vgFilter = dropArguments(valGetter, 0, Object.class);

                        if (--faultCount == 0)  index[0] ^= 1;

                        x = filterArguments(proj, pos, vgFilter).invokeWithArguments(new Object[len]);

                        assertEquals(val, x);

                    }

                }

                // make a fold call:

                for (int len = 0; len <= 4; len++) {

                    for (int fold = 0; fold <= len; fold++) {

                        MethodHandle proj = id;  // lambda(ret x, ...){x}

                        if (ret == void.class)  proj = constant(Object.class, null);

                        int arg0 = (ret == void.class ? 0 : 1);

                        for (int j = 0; j < len; j++) {

                            proj = dropArguments(proj, arg0, Object.class);

                        }

                        assert(proj.type().parameterCount() == arg0 + len);

                        // proj: (Object*, pos: vret, Object*)->ret

                        if (arg0 != 0)  assertEquals(vret, proj.type().parameterType(0));

                        MethodHandle vgFilter = valGetter.asType(methodType(ret));

                        for (int j = 0; j < fold; j++) {

                            vgFilter = dropArguments(vgFilter, j, Object.class);

                        }

                        x = foldArguments(proj, vgFilter).invokeWithArguments(new Object[len]);

                        if (--faultCount == 0)  index[0] ^= 1;

                        assertEquals(val, x);

                    }

                }

            }

        }

        //System.out.println("faultCount="+faultCount);

    }

    @Test

    public void testRecursion() throws Throwable {

        if (!startTest("testRecursion"))  return;

        final int LIMIT = 10;

        for (int i = 0; i < LIMIT; i++) {

            RFCB rfcb = new RFCB(i);

            Object x = "x", y = "y";

            Object result = rfcb.recursiveFunction(x, y);

            verbose(1, result);

        }

    }

    /** Recursive Function Control Block */

    private static class RFCB {

        java.util.Random random;

        final MethodHandle[] fns;

        int depth;

        @SuppressWarnings("LeakingThisInConstructor")

        RFCB(int seed) throws Throwable {

            this.random = new java.util.Random(seed);

            this.fns = new MethodHandle[Math.max(29, (1 << MAX_DEPTH-2)/3)];

            java.util.Arrays.fill(fns, lookup().bind(this, "recursiveFunction", genericMethodType(2)));

            for (int i = 5; i < fns.length; i++) {

                switch (i % 4) {

                case 0: fns[i] = filterArguments(fns[i - 5], 0, insertArguments(fns[i - 4], 1, ".")); break;

                case 1: fns[i] = filterArguments(fns[i - 5], 1, insertArguments(fns[i - 3], 1, ".")); break;

                case 2: fns[i] = filterReturnValue(fns[i - 5], insertArguments(fns[i - 2], 1, ".")); break;

                }

            }

        }

        Object recursiveFunction(Object x, Object y) throws Throwable {

            depth++;

            try {

                final int ACTION_COUNT = 11;

                switch (random.nextInt(ACTION_COUNT)) {

                case 1:

                    Throwable ex = new RuntimeException();

                    ex.fillInStackTrace();

                    if (VERBOSITY >= 2) ex.printStackTrace(System.out);

                    x = "ST; " + x;

                    break;

                case 2:

                    System.gc();

                    x = "GC; " + x;

                    break;

                }

                boolean isLeaf = (depth >= MAX_DEPTH);

                if (isLeaf) {

                    return Arrays.asList(x, y).toString();

                }

                return fns[random.nextInt(fns.length)].invokeExact(x, y);

            } finally {

                depth--;

            }

        }

    }

    private static MethodHandle sequence(MethodHandle mh1, MethodHandle... mhs) {

        MethodHandle res = mh1;

        for (MethodHandle mh2 : mhs)

            res = filterReturnValue(res, mh2);

        return res;

    }

    private static void assertEqualFunction(MethodHandle x, MethodHandle y) throws Throwable {

        assertEquals(x.type(), y.type()); //??

        MethodType t = x.type();

        if (t.parameterCount() == 0) {

            assertEqualFunctionAt(null, x, y);

            return;

        }

        Class<?> ptype = t.parameterType(0);

        if (ptype == long.class || ptype == Long.class) {

            for (long i = -10; i <= 10; i++) {

                assertEqualFunctionAt(i, x, y);

            }

        } else {

            for (int i = -10; i <= 10; i++) {

                assertEqualFunctionAt(i, x, y);

            }

        }

    }

    private static void assertEqualFunctionAt(Object v, MethodHandle x, MethodHandle y) throws Throwable {

        Object[] args = new Object[x.type().parameterCount()];

        Arrays.fill(args, v);

        Object xval = invokeWithCatch(x, args);

        Object yval = invokeWithCatch(y, args);

        String msg = "ok";

        if (!Objects.equals(xval, yval)) {

            msg = ("applying "+x+" & "+y+" to "+v);

        }

        assertEquals(msg, xval, yval);

    }

    private static Object invokeWithCatch(MethodHandle mh, Object... args) throws Throwable {

        try {

            return mh.invokeWithArguments(args);

        } catch (Throwable ex) {

            System.out.println("threw: "+mh+Arrays.asList(args));

            ex.printStackTrace(System.out);

            return ex;

        }

    }

    private static final Lookup LOOKUP = lookup();

    private static MethodHandle findStatic(String name,

                                           Class<?> rtype,

                                           Class<?>... ptypes) {

        try {

            return LOOKUP.findStatic(LOOKUP.lookupClass(), name, methodType(rtype, ptypes));