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package org.openide.util;

import java.util.ArrayList;

import java.util.Arrays;

import java.util.Collection;

import java.util.Collections;

import java.util.Enumeration;

import java.util.Iterator;

import java.util.List;

import java.util.Map;

import java.util.NoSuchElementException;

import java.util.Set;

import org.netbeans.junit.NbTestCase;

/** This is the base test for new and old enumerations. It contains

 * factory methods for various kinds of enumerations and set of tests

 * that use them. Factory methods are overriden in OldEnumerationsTest

 *

 * @author Jaroslav Tulach

 */

public class EnumerationsTest extends NbTestCase {

    /** Creates a new instance of EnumerationsTest */

    public EnumerationsTest(String testName) {

        super(testName);

    }

    //

    // Factory methods

    //

    protected <T> Enumeration<T> singleton(T obj) {

        return Enumerations.singleton(obj);

    }

    protected <T> Enumeration<T> concat(Enumeration<T> en1, Enumeration<T> en2) {

        return Enumerations.concat(en1, en2);

    }

    protected <T> Enumeration<T> concat(Enumeration<Enumeration<T>> enumOfEnums) {

        return Enumerations.concat(enumOfEnums);

    }

    protected <T> Enumeration<T> removeDuplicates(Enumeration<T> en) {

        return Enumerations.removeDuplicates(en);

    }

    protected <T> Enumeration<T> empty() {

        return Enumerations.empty();

    }

    protected <T> Enumeration<T> array(T[] arr) {

        return Enumerations.array(arr);

    }

    protected <T,R> Enumeration<R> convert(Enumeration<T> en, final Map<T,R> map) {

        class P implements Enumerations.Processor<T,R> {

            public R process(T obj, Collection<T> nothing) {

                return map.get(obj);

            }

        }

        return Enumerations.convert(en, new P());

    }

    protected <T> Enumeration<T> removeNulls(Enumeration<T> en) {

        return Enumerations.removeNulls(en);

    }

    protected <T> Enumeration<T> filter(Enumeration<T> en, final Set<T> filter) {

        class P implements Enumerations.Processor<T,T> {

            public T process(T obj, Collection<T> nothing) {

                return filter.contains(obj) ? obj : null;

            }

        }

        return Enumerations.filter(en, new P());

    }

    protected <T,R> Enumeration<R> filter(Enumeration<T> en, final QueueProcess<T,R> filter) {

        class P implements Enumerations.Processor<T,R> {

            public R process(T obj, Collection<T> nothing) {

                return filter.process(obj, nothing);

            }

        }

        return Enumerations.filter(en, new P());

    }

    /**

     * @param filter the set.contains (...) is called before each object is produced

     * @return Enumeration

     */

    protected <T,R> Enumeration<R> queue(Collection<T> initContent, final QueueProcess<T,R> process) {

        class C implements Enumerations.Processor<T,R> {

            public R process(T object, Collection<T> toAdd) {

                return process.process(object, toAdd);

            }

        }

        return Enumerations.queue(

                Collections.enumeration(initContent),

                new C()

                );

    }

    /** Processor interface.

     */

    public static interface QueueProcess<T,R> {

        public R process(T object, Collection<T> toAdd);

    }

    //

    // The tests

    //

    public void testEmptyIsEmpty() {

        Enumeration e = empty();

        assertFalse(e.hasMoreElements());

        try {

            e.nextElement();

            fail("No elements");

        } catch (NoSuchElementException ex) {

            // ok

        }

    }

    public void testSingleIsSingle() {

        Enumeration e = singleton(this);

        assertTrue(e.hasMoreElements());

        assertEquals("Returns me", this, e.nextElement());

        assertFalse("Now it is empty", e.hasMoreElements());

        try {

            e.nextElement();

            fail("No elements");

        } catch (NoSuchElementException ex) {

            // ok

        }

    }

    public void testConcatTwoAndArray() {

        Object[] one = { 1, 2, 3 };

        Object[] two = { "1", "2", "3" };

        List<Object> list = new ArrayList<Object>(Arrays.asList(one));

        list.addAll(Arrays.asList(two));

        assertEnums(

                concat(array(one), array(two)),

                Collections.enumeration(list)

                );

    }

    public void testConcatTwoAndArrayAndTakeOnlyStrings() {

        Object[] one = { 1, 2, 3 };

        Object[] two = { "1", "2", "3" };

        Object[] three = { 1L };

        Object[] four = { "Kuk" };

        List<Object> list = new ArrayList<Object>(Arrays.asList(two));

        list.addAll(Arrays.asList(four));

        @SuppressWarnings("unchecked")

        Enumeration<Object>[] alls = (Enumeration<Object>[]) new Enumeration<?>[] {

            array(one), array(two), array(three), array(four)

        };

        assertEnums(

                filter(concat(array(alls)), new OnlyStrings()),

                Collections.enumeration(list)

                );

    }

    public void testRemoveDuplicates() {

        Object[] one = { 1, 2, 3 };

        Object[] two = { "1", "2", "3" };

        Object[] three = { 1 };

        Object[] four = { "2", "3", "4" };

        @SuppressWarnings("unchecked")

        Enumeration<Object>[] alls = (Enumeration<Object>[]) new Enumeration<?>[] {

            array(one), array(two), array(three), array(four)

        };

        assertEnums(

                removeDuplicates(concat(array(alls))),

                array(new Object[] { 1, 2, 3, "1", "2", "3", "4" })

                );

    }

    public void testRemoveDuplicatesAndGCWorks() {

        /*** Return { i1, "", "", "", i2 } */

        class WeakEnum implements Enumeration<Object> {

            public Object i1 = new Integer(1);

            public Object i2 = new Integer(1);

            private int state;

            public boolean hasMoreElements() {

                return state < 5;

            }

            public Object nextElement() {

                switch (state++) {

                    case 0: return i1;

                    case 1: case 2: case 3: return "";

                    default: return i2;

                }

            }

        }

        WeakEnum weak = new WeakEnum();

        Enumeration en = removeDuplicates(weak);

        assertTrue("Has some elements", en.hasMoreElements());

        assertEquals("And the first one is get", weak.i1, en.nextElement());

        /*

        try {

            Reference<?> ref = new WeakReference<Object>(weak.i1);

         */

            weak.i1 = null;

        /*

            assertGC("Try hard to GC the first integer", ref);

            // does not matter whether it GCs or not

        } catch (Throwable tw) {

            // not GCed, but does not matter

        }

         */

        assertTrue("Next object will be string", en.hasMoreElements());

        assertEquals("is empty string", "", en.nextElement());

        assertFalse("The second integer is however equal to the original i1 and thus" +

                " the enum should not be there", en.hasMoreElements());

    }

    public void testQueueEnum() {

        class Pr implements QueueProcess<Integer,Integer> {

            public Integer process(Integer i, Collection<Integer> c) {

                int plus = i + 1;

                if (plus < 10) {

                    c.add(plus);

                }

                return i;

            }

        }

        Pr p = new Pr();

        Enumeration en = queue(

                Collections.nCopies(1, 0), p

                );

        for (int i = 0; i < 10; i++) {

            assertTrue("has next", en.hasMoreElements());

            en.nextElement();

        }

        assertFalse("No next element", en.hasMoreElements());

    }

    public void testFilteringAlsoDoesConvertions() throws Exception {

        class Pr implements QueueProcess<Integer,Integer> {

            public Integer process(Integer i, Collection<Integer> ignore) {

                return i + 1;

            }

        }

        Pr p = new Pr();

        Enumeration<Integer> onetwo = array(new Integer[] { 1, 2 });

        Enumeration<Integer> twothree = array(new Integer[] { 2, 3 });

        assertEnums(

                filter(onetwo, p), twothree

                );

    }

    private static <T> void assertEnums(Enumeration<T> e1, Enumeration<T> e2) {

        int indx = 0;

        while (e1.hasMoreElements() && e2.hasMoreElements()) {

            T i1 = e1.nextElement();

            T i2 = e2.nextElement();

            assertEquals(indx++ + "th: ", i1, i2);

        }

        if (e1.hasMoreElements()) {

            fail("first one contains another element: " + e1.nextElement());

        }

        if (e2.hasMoreElements()) {

            fail("second one contains another element: " + e2.nextElement());

        }

        try {

            e1.nextElement();

            fail("First one should throw exception, but nothing happend");

        } catch (NoSuchElementException ex) {

            // ok

        }

        try {

            e2.nextElement();

            fail("Second one should throw exception, but nothing happend");

        } catch (NoSuchElementException ex) {

            // ok

        }

    }

    public void testConvertIntegersToStringRemoveNulls() {

        Object[] garbage = { 1, "kuk", "hle", 5 };

        assertEnums(

                removeNulls(convert(array(garbage), new MapIntegers())),

                array(new Object[] { "1", "5" })

                );

    }

    public void testQueueEnumerationCanReturnNulls() {

        Object[] nuls = { null, "NULL" };

        class P implements QueueProcess<Object,Object> {

            public Object process(Object toRet, Collection<Object> toAdd) {

                if (toRet == null) return null;

                if ("NULL".equals(toRet)) {

                    toAdd.add(null);

                    return null;

                }

                return null;

            }

        }

        assertEnums(

                array(new Object[] { null, null, null }),

                queue(Arrays.asList(nuls), new P())

                );

    }

    /** Filters only strings.

     */

    private static final class OnlyStrings implements Set<Object> {

        public boolean add(Object o) {

            fail("Should not be every called");

            return false;

        }

        public boolean addAll(Collection c) {

            fail("Should not be every called");

            return false;

        }

        public void clear() {

            fail("Should not be every called");

        }

        public boolean contains(Object o) {

            return o instanceof String;

        }

        public boolean containsAll(Collection c) {

            fail("Should not be every called");

            return false;

        }

        public boolean isEmpty() {

            fail("Should not be every called");

            return false;

        }

        public Iterator<Object> iterator() {

            fail("Should not be every called");

            return null;

        }

        public boolean remove(Object o) {

            fail("Should not be every called");

            return false;

        }

        public boolean removeAll(Collection c) {

            fail("Should not be every called");

            return false;

        }

        public boolean retainAll(Collection c) {

            fail("Should not be every called");

            return false;

        }

        public int size() {

            fail("Should not be every called");

            return 1;

        }

        public Object[] toArray() {

            fail("Should not be every called");

            return null;

        }

        public <T> T[] toArray(T[] a) {

            fail("Should not be every called");

            return null;

        }

    }

    /** Filters only strings.

     */

    private static final class MapIntegers implements Map<Object,Object> {

        public boolean containsKey(Object key) {

            fail("Should not be every called");

            return false;

        }

        public boolean containsValue(Object value) {

            fail("Should not be every called");

            return false;

        }

        public Set<Map.Entry<Object,Object>> entrySet() {

            fail("Should not be every called");

            return null;

        }

        public Object get(Object key) {

            if (key instanceof Integer) {

                return key.toString();

            }

            return null;

        }

        public Set<Object> keySet() {

            fail("Should not be every called");

            return null;

        }

        public Object put(Object key, Object value) {

            fail("Should not be every called");

            return null;

        }

        public void putAll(Map t) {

            fail("Should not be every called");

        }

        public Collection<Object> values() {

            fail("Should not be every called");

            return null;

        }

        public void clear() {

            fail("Should not be every called");

        }

        public boolean isEmpty() {

            fail("Should not be every called");

            return false;

        }

        public Object remove(Object key) {

            fail("Should not be every called");

            return null;

        }

        public int size() {

            fail("Should not be every called");

            return 1;

        }

    }

}