/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.jackrabbit.oak.spi.security.principal;

import java.security.Principal;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import java.util.Set;
import java.util.TreeSet;

import com.google.common.base.Predicate;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableSet;
import com.google.common.collect.Iterables;

import org.apache.jackrabbit.api.security.principal.GroupPrincipal;
import org.apache.jackrabbit.api.security.principal.ItemBasedPrincipal;
import org.apache.jackrabbit.api.security.principal.PrincipalManager;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;
import org.junit.Test;

import static org.junit.Assert.assertArrayEquals;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNotSame;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertSame;
import static org.junit.Assert.assertTrue;
import static org.mockito.ArgumentMatchers.anyString;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.when;

public class CompositePrincipalProviderTest {

    private final TestPrincipalProvider pp1 = new TestPrincipalProvider();
    private final TestPrincipalProvider pp2 = new TestPrincipalProvider("p1", "p2");
    private final PrincipalProvider cpp = CompositePrincipalProvider.of(ImmutableList.<PrincipalProvider>of(pp1, pp2));

    private Iterable<Principal> testPrincipals() {
        return Iterables.concat(pp1.getTestPrincipals(), pp2.getTestPrincipals());
    }

    private static void assertIterator(@NotNull Iterable<? extends Principal> expected, @NotNull Iterator<? extends Principal> result) {
        assertEquals(ImmutableSet.copyOf(expected), ImmutableSet.copyOf(result));
    }

    @Test
    public void testOfEmptyList() {
        assertSame(EmptyPrincipalProvider.INSTANCE, CompositePrincipalProvider.of(ImmutableList.<PrincipalProvider>of()));
    }

    @Test
    public void testOfSingletonList() {
        PrincipalProvider pp = new TestPrincipalProvider(true);
        assertSame(pp, CompositePrincipalProvider.of(ImmutableList.of(pp)));
    }

    @Test
    public void testOfList() {
        assertNotSame(pp1, cpp);
        assertNotSame(pp2, cpp);
        assertTrue(cpp instanceof CompositePrincipalProvider);
    }

    @Test
    public void getPrincipalUnknown() {
        assertNull(cpp.getPrincipal(TestPrincipalProvider.UNKNOWN.getName()));
    }

    @Test
    public void getPrincipal() {
        for (Principal principal : testPrincipals()) {
            assertEquals(principal, cpp.getPrincipal(principal.getName()));
        }
    }

    @Test
    public void testGetItemBasedPrincipalDefault() throws Exception {
        for (Principal p : testPrincipals()) {
            if (p instanceof ItemBasedPrincipal) {
                assertNull(cpp.getItemBasedPrincipal(((ItemBasedPrincipal) p).getPath()));
            }
         }
    }

    @Test
    public void testGetItemBasedPrincipal() throws Exception {
        ItemBasedPrincipal p = mock(ItemBasedPrincipal.class);
        PrincipalProvider pp = when(mock(PrincipalProvider.class).getItemBasedPrincipal(anyString())).thenReturn(p).getMock();

        assertEquals(p, CompositePrincipalProvider.of(ImmutableList.of(pp, pp2)).getItemBasedPrincipal("/any/path"));
    }

    @Test
    public void testGetGroupMembership() {
        for (Principal principal : testPrincipals()) {
            assertTrue(cpp.getGroupMembership(principal).isEmpty());
        }
    }

    @Test
    public void testGetMembershipPrincipals() {
        for (Principal principal : testPrincipals()) {
            boolean atleastEveryone = cpp.getMembershipPrincipals(principal).contains(EveryonePrincipal.getInstance());
            assertTrue("All principals (except everyone) must be member of the everyone group. Violation: "+principal.getName(), atleastEveryone);
        }
    }

    @Test
    public void testGetMembershipPrincipalsUnknown() {
        assertTrue(cpp.getMembershipPrincipals(TestPrincipalProvider.UNKNOWN).isEmpty());
    }

    @Test
    public void testGetPrincipalsByUnknownId() {
        assertTrue(cpp.getPrincipals(TestPrincipalProvider.getIDFromPrincipal(TestPrincipalProvider.UNKNOWN)).isEmpty());
    }

    @Test
    public void findPrincipalsUnknown() {
        assertFalse(cpp.findPrincipals(TestPrincipalProvider.UNKNOWN.getName(), PrincipalManager.SEARCH_TYPE_ALL).hasNext());
        assertFalse(cpp.findPrincipals(TestPrincipalProvider.UNKNOWN.getName(), PrincipalManager.SEARCH_TYPE_NOT_GROUP).hasNext());
        assertFalse(cpp.findPrincipals(TestPrincipalProvider.UNKNOWN.getName(), PrincipalManager.SEARCH_TYPE_GROUP).hasNext());
    }

    @Test
    public void findPrincipalsByTypeGroup() {
        Iterable<? extends Principal> expected = Iterables.concat(ImmutableSet.of(EveryonePrincipal.getInstance()), Iterables.filter(testPrincipals(), new Predicate<Principal>() {
            @Override
            public boolean apply(Principal input) {
                return input instanceof GroupPrincipal;
            }
        }));

        Iterator<? extends Principal> result = cpp.findPrincipals(PrincipalManager.SEARCH_TYPE_GROUP);
        assertIterator(expected, result);
    }

    @Test
    public void findPrincipalsByTypeNotGroup() {
        Iterable<? extends Principal> expected = Iterables.filter(testPrincipals(), input -> !(input instanceof GroupPrincipal));

        Iterator<? extends Principal> result = cpp.findPrincipals(PrincipalManager.SEARCH_TYPE_NOT_GROUP);
        assertIterator(expected, result);
    }

    @Test
    public void findPrincipalsByTypeAll() {
        Iterator<? extends Principal> result = cpp.findPrincipals(PrincipalManager.SEARCH_TYPE_ALL);
        assertIterator(Iterables.concat(ImmutableSet.of(EveryonePrincipal.getInstance()), testPrincipals()), result);
    }

    /**
     * Tests that the default implementation of range based
     * {@code findPrincipals} methods of PrincipalProvider work properly. See
     * OAK-7994
     */
    @Test
    public void testRangeDefault() {
        List<? extends Principal> pps = ImmutableList.of(new PrincipalImpl("p0"), new PrincipalImpl("p1"),
                new PrincipalImpl("p2"));

        PrincipalProvider pp = new PrincipalProvider() {
            @Override
            @NotNull
            public Set<? extends Principal> getPrincipals(@NotNull String userID) {
                return Collections.emptySet();
            }
            @Override
            @Nullable
            public Principal getPrincipal(@NotNull String principalName) {
                return null;
            }
            @Override
            @NotNull
            public Iterator<? extends Principal> findPrincipals(int searchType) {
                return pps.iterator();
            }
            @Override
            @NotNull
            public Iterator<? extends Principal> findPrincipals(@Nullable String nameHint, int searchType) {
                return pps.iterator();
            }
        };

        List<String> expected = getNames(pps.iterator());
        for (int offset = 0; offset < expected.size() + 1; offset++) {
            for (int limit = -1; limit < expected.size() + 2; limit++) {
                int to = expected.size();
                if (limit >= 0) {
                    to = Math.min(offset + limit, to);
                }
                List<String> sub = expected.subList(offset, to);
                Iterator<? extends Principal> i0 = pp.findPrincipals(null, false, PrincipalManager.SEARCH_TYPE_ALL, offset, limit);
                assertEquals(sub, getNames(i0));
                Iterator<? extends Principal> i1 = pp.findPrincipals("", false, PrincipalManager.SEARCH_TYPE_ALL, offset,
                        limit);
                assertEquals(sub, getNames(i1));
            }
        }
    }

    private static List<String> getNames(Iterator<? extends Principal> i) {
        List<String> l = new ArrayList<>();
        while (i.hasNext()) {
            l.add(i.next().getName());
        }
        return l;
    }

    @Test
    public void testFindPrincipalsRandom() {
        long seed = System.currentTimeMillis();
        int bound = 10;
        int inputSize = 3;
        Random r = new Random(seed);

        List<String> expected = new ArrayList<>();
        Collection<Collection<String>> input = new ArrayList<>();
        for (int i = 0; i < inputSize; i++) {
            Set<String> l = new TreeSet<>();
            int size = r.nextInt(bound);
            while (size > 0) {
                int v = r.nextInt(bound);
                String n = "p" + v;
                if (l.add(n)) {
                    expected.add(n);
                    size--;
                }
            }
            input.add(l);
        }
        input.add(Collections.emptyList());
        String pb = "p" + bound;
        expected.add(pb);
        input.add(Collections.singleton(pb));

        List<PrincipalProvider> in = new ArrayList<>();
        for (Collection<String> i : input) {
            TestPrincipalProvider t = new TestPrincipalProvider(i.toArray(new String[0]));
            in.add(t);
        }
        PrincipalProvider cpp = CompositePrincipalProvider.of(in);

        List<String> out = getNames(cpp.findPrincipals("p", true, PrincipalManager.SEARCH_TYPE_ALL, 0, -1));
        Collections.sort(expected);
        assertEquals(expected, out);
    }

    @Test
    public void testFindPrincipalsRange() {
        TestPrincipalProvider t0 = new TestPrincipalProvider("p2", "p3", "p4");
        TestPrincipalProvider t1 = new TestPrincipalProvider("p1");
        PrincipalProvider cpp = CompositePrincipalProvider.of(Arrays.asList(t0, t1));
        List<String> out = getNames(cpp.findPrincipals("p", false, PrincipalManager.SEARCH_TYPE_ALL, 3, 1));
        assertArrayEquals(new String[] {"p4"}, out.toArray(new String[0]));
    }

    @Test
    public void testFindWithOffsetLimit() {
        Iterator principals = new TestPrincipalProvider("p1", "p2", "p3", "p4").getTestPrincipals().iterator();
        PrincipalProvider pp = mock(PrincipalProvider.class);
        // NOTE: CompositePrincipalProvider passes 0 offset to the aggregated provider!
        when(pp.findPrincipals("p", false, PrincipalManager.SEARCH_TYPE_ALL, 0, 3)).thenReturn(principals);

        PrincipalProvider cpp = CompositePrincipalProvider.of(ImmutableList.of(pp, EmptyPrincipalProvider.INSTANCE));

        Iterator<? extends Principal> it = cpp.findPrincipals("p", false, PrincipalManager.SEARCH_TYPE_ALL, 2, 1);
        assertTrue(it.hasNext());
        Principal p = it.next();
        assertEquals("p3", p.getName());
        assertFalse(it.hasNext());
    }
}
