/*
 * Copyright (c) 2011, 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
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */

/*
 * @test
 * @summary Basic test for Reducers SAM utils
 * @author  Mike Duigou
 */

import java.io.*;
import java.util.Objects;
import java.util.functions.*;

public class ReducersTest {

    private static void testNop() {
        String base = "base value";
        String result = Reducers.<Integer,String>nop().reduce(base,Integer.valueOf(1));
        check(base == result);
    }

    private static void testMin() {
        check(0 == Reducers.<Integer>min().reduce(0,Reducers.<Integer>min().reduce(1,Reducers.<Integer>min().reduce(Integer.valueOf(2),Integer.valueOf(3)))));
    }

    private static void testMax() {
        check(3 == Reducers.<Integer>max().reduce(0,Reducers.<Integer>max().reduce(1,Reducers.<Integer>max().reduce(Integer.valueOf(2),Integer.valueOf(3)))));
    }
    private static void testComposeMapper() {
        Mapper<Integer,String> truthMapper = #{ Integer x -> x != 0 ? "true" : "false" };
        Reducer<String,String> truth = #{ String b, String s -> b + " " + s};

        check("base false".equals(Reducers.compose(truth,truthMapper).reduce("base",Integer.valueOf(0))));
        check("base true".equals(Reducers.compose(truth,truthMapper).reduce("base",Integer.valueOf(1))));
    }

    public static void testComposePredicate() {
        Predicate<String> truthteller = #{ String s -> "true".equals(s) };
        Reducer<String,String> truth = #{ String b, String s -> if("true".equals(s)) return "truth"; else throw new IllegalArgumentException("only compatible with the truth");};

        check("base".equals(Reducers.compose(truth,truthteller).reduce("base","false")));
        check("truth".equals(Reducers.compose(truth,truthteller).reduce("base","true")));
    }

    public static void RealMain(String ... args) {
        testNop();
        testMin();
        testMax();
        testComposeMapper();
        testComposePredicate();
    }

    //--------------------- Infrastructure ---------------------------
    static volatile int passed = 0, failed = 0;
    static void pass() { passed++; }
    static void fail() { failed++; (new Exception("stack dump")).printStackTrace(System.err);}
    static void fail(String msg) { System.out.println(msg); fail(); }
    static void unexpected(Throwable t) { failed++; t.printStackTrace(System.err); }
    static void check(boolean cond) { if (cond) pass(); else fail(); }
    static void equal(Object x, Object y) {
        if (Objects.equals(x,y)) pass();
        else {System.out.println(x + " not equal to " + y); fail();}}
    static void equal2(Object x, Object y) {equal(x, y); equal(y, x);}
    public static void main(String[] args) throws Throwable {
        try { RealMain(args); } catch (Throwable t) { unexpected(t); }

        System.out.printf("%nPassed = %d, failed = %d%n%n", passed, failed);
        if (failed > 0) throw new Exception("Some tests failed");
    }
    private interface Fun {void f() throws Throwable;}
    static void THROWS(Class<? extends Throwable> k, Fun... fs) {
          for (Fun f : fs)
              try { f.f(); fail("Expected " + k.getName() + " not thrown"); }
              catch (Throwable t) {
                  if (k.isAssignableFrom(t.getClass())) pass();
                  else unexpected(t);}}
    static byte[] serializedForm(Object obj) {
        try {
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            new ObjectOutputStream(baos).writeObject(obj);
            return baos.toByteArray();
        } catch (IOException e) { throw new RuntimeException(e); }}
    static Object readObject(byte[] bytes)
        throws IOException, ClassNotFoundException {
        InputStream is = new ByteArrayInputStream(bytes);
        return new ObjectInputStream(is).readObject();}
    @SuppressWarnings("unchecked")
    static <T> T serialClone(T obj) {
        try { return (T) readObject(serializedForm(obj)); }
        catch (Exception e) { throw new RuntimeException(e); }}
}