/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
 * or http://forgerock.org/license/CDDLv1.0.html.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at legal-notices/CDDLv1_0.txt.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information:
 *      Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 *
 *      Copyright 2015 ForgeRock AS
 */
package org.opends.server.replication.plugin;

import static org.assertj.core.api.Assertions.*;
import static org.forgerock.opendj.ldap.ModificationType.*;
import static org.mockito.Mockito.*;
import static org.testng.Assert.*;

import java.util.Iterator;
import java.util.List;

import org.forgerock.opendj.ldap.ByteString;
import org.forgerock.opendj.ldap.ModificationType;
import org.opends.server.replication.ReplicationTestCase;
import org.opends.server.replication.common.CSN;
import org.opends.server.replication.common.CSNGenerator;
import org.opends.server.types.Attribute;
import org.opends.server.types.Attributes;
import org.opends.server.types.Entry;
import org.opends.server.types.Modification;
import org.testng.annotations.AfterMethod;
import org.testng.annotations.BeforeMethod;
import org.testng.annotations.Test;

@SuppressWarnings("javadoc")
public class AttrHistoricalSingleTest extends ReplicationTestCase
{
  private static final boolean CONFLICT = true;
  private static final boolean NO_CONFLICT = false;
  private CSNGenerator csnGen = new CSNGenerator(1025, System.currentTimeMillis());
  private AttrHistoricalSingle attrHist;
  private CSN csn;
  private Entry entry;
  /** Avoids declaring the variable in the tests */
  private Modification mod;

  @BeforeMethod
  public void localSetUp() throws Exception
  {
    attrHist = new AttrHistoricalSingle();
    csn = csnGen.newCSN();
    entry = new Entry(null, null, null, null);
  }

  @AfterMethod
  public void localTearDown() throws Exception
  {
    attrHist = null;
    csn = null;
  }

  @Test
  public void replay_addDeleteSameTime() throws Exception
  {
    mod = newModification(ADD, "X");
    replayOperation(csn, entry, mod, NO_CONFLICT);

    mod = newModification(DELETE, "X");
    replayOperation(csn, entry, mod, NO_CONFLICT);
  }

  @Test
  public void replay_addThenDeleteThenOlderAdd() throws Exception
  {
    CSN[] t = newCSNs(3);

    mod = newModification(ADD, "X");
    replayOperation(t[0], entry, mod, NO_CONFLICT);

    mod = newModification(DELETE, "X");
    replayOperation(t[2], entry, mod, NO_CONFLICT);

    mod = newModification(ADD, "X");
    replayOperationSuppressMod(t[1], entry, mod, CONFLICT);
  }

  @Test
  public void replay_addThenDeleteThenAddThenOlderAdd() throws Exception
  {
    CSN[] t = newCSNs(4);

    mod = newModification(ADD, "X");
    replayOperation(t[0], entry, mod, NO_CONFLICT);

    mod = newModification(DELETE, "X");
    replayOperation(t[1], entry, mod, NO_CONFLICT);

    mod = newModification(ADD, "X");
    replayOperation(t[3], entry, mod, NO_CONFLICT);

    mod = newModification(ADD, "Y");
    replayOperation(t[2], entry, mod, CONFLICT);
  }

  @Test
  public void replay_addThenDeleteThenDelete() throws Exception
  {
    CSN[] t = newCSNs(3);

    mod = newModification(ADD, "X");
    replayOperation(t[0], entry, mod, NO_CONFLICT);

    mod = newModification(DELETE, "X");
    replayOperation(t[1], entry, mod, NO_CONFLICT);

    mod = newModification(DELETE, "X");
    replayOperationSuppressMod(t[2], entry, mod, CONFLICT);
  }

  @Test
  public void replay_addThenOlderDelete() throws Exception
  {
    CSN[] t = newCSNs(2);

    mod = newModification(ADD, "X");
    replayOperation(t[1], null, mod, NO_CONFLICT);

    mod = newModification(DELETE, "X");
    replayOperationSuppressMod(t[0], entry, mod, CONFLICT);
  }

  @Test
  public void replay_deleteMissingAttribute() throws Exception
  {
    mod = newModification(DELETE, "X");
    replayOperationSuppressMod(csn, entry, mod, CONFLICT);
  }

  @Test
  public void replay_deleteMissingAttributeValue() throws Exception
  {
    CSN[] t = newCSNs(2);

    mod = newModification(ADD, "X");
    replayOperation(t[0], entry, mod, NO_CONFLICT);

    mod = newModification(DELETE, "Y");
    replayOperationSuppressMod(t[1], entry, mod, CONFLICT);
  }

  /**
   * TODO JNR this looks dubious, is it ever possible in the server?
   * <p>
   * Could multi-threading make this scenario possible?
   * <p>
   * Or is it due to {@link AttrHistoricalSingle#assign(HistAttrModificationKey, ByteString, CSN)} ?
   */
  @Test
  public void replay_deleteValueThatDoesNotExistOnEntry() throws Exception
  {
    CSN[] t = newCSNs(2);

    mod = newModification(ADD, "X");
    entry.applyModification(mod);

    mod = newModification(DELETE, "Y");
    replayOperationSuppressMod(t[1], entry, mod, CONFLICT);
  }

  /**
   * TODO JNR this looks dubious, is it ever possible in the server?
   * <p>
   * Could multi-threading make this scenario possible?
   * <p>
   * Or is it due to {@link AttrHistoricalSingle#assign(HistAttrModificationKey, ByteString, CSN)} ?
   */
  @Test
  public void replay_deleteDubious() throws Exception
  {
    HistoricalAttributeValue histAttrVal = new HistoricalAttributeValue("display:" + csn + ":add:X");
    attrHist.assign(histAttrVal.getHistKey(), histAttrVal.getAttributeValue(), csn);
    mod = newModification(ADD, "X");
    entry.applyModification(mod);

    mod = newModification(DELETE, "Y");
    replayOperationSuppressMod(csn, entry, mod, CONFLICT);
  }

  @Test
  public void replay_replaceWithValue() throws Exception
  {
    mod = newModification(REPLACE, "X");
    replayOperation(csn, null, mod, NO_CONFLICT);
  }

  @Test
  public void replay_replaceNoValue() throws Exception
  {
    mod = newModification(REPLACE);
    replayOperation(csn, null, mod, NO_CONFLICT);
  }

  @Test
  public void replay_addThenDeleteThenOlderReplace() throws Exception
  {
    CSN[] t = newCSNs(3);

    mod = newModification(ADD, "X");
    replayOperation(t[0], entry, mod, NO_CONFLICT);

    mod = newModification(DELETE);
    replayOperation(t[2], entry, mod, NO_CONFLICT);

    mod = newModification(REPLACE);
    replayOperationSuppressMod(t[1], entry, mod, CONFLICT);
  }

  @Test
  public void replay_increment() throws Exception
  {
    mod = newModification(INCREMENT, "X");
    replayOperation(csn, null, mod, NO_CONFLICT);
  }


  private CSN[] newCSNs(int nb)
  {
    CSN[] results = new CSN[nb];
    for (int i = 0; i < nb; i++)
    {
      results[i] = csnGen.newCSN();
    }
    return results;
  }

  private Modification newModification(ModificationType modType, String attrValue)
  {
    return new Modification(modType, Attributes.create("display", attrValue));
  }

  private Modification newModification(ModificationType modType)
  {
    return new Modification(modType, Attributes.empty("display"));
  }

  private void replayOperation(CSN csn, Entry entry, Modification mod, boolean shouldConflict) throws Exception
  {
    replayOperation(null, csn, entry, mod, shouldConflict);
  }

  private void replayOperationSuppressMod(CSN csn, Entry entry, Modification mod, boolean shouldConflict)
      throws Exception
  {
    Iterator<Modification> itMod = mock(Iterator.class);
    replayOperation(itMod, csn, entry, mod, shouldConflict);
    verifyModNotReplayed(itMod);
  }

  private void replayOperation(Iterator<Modification> modsIterator, CSN csn, Entry entry, Modification mod,
      boolean shouldConflict) throws Exception
  {
    boolean result = attrHist.replayOperation(modsIterator, csn, entry, mod);
    assertEquals(result, shouldConflict,
        "Expected " + (shouldConflict ? "a" : "no") + " conflict when applying " + mod + " to " + entry);
    if (entry != null && !shouldConflict)
    {
      entry.applyModification(mod);
      assertAttributeValue(entry, mod);
    }
  }

  private void assertAttributeValue(Entry entry, Modification mod)
  {
    ByteString actualValue = getActualValue(entry, mod);
    switch (mod.getModificationType().asEnum())
    {
    case ADD:
    case REPLACE:
      ByteString expectedValue = uniqueValue(mod.getAttribute());
      assertEquals(actualValue, expectedValue);
      return;

    case DELETE:
      assertNull(actualValue);
      return;
    }
  }

  private ByteString getActualValue(Entry entry, Modification mod)
  {
    List<Attribute> attributes = entry.getAttribute(mod.getAttribute().getAttributeType());
    if (attributes != null)
    {
      assertThat(attributes).hasSize(1);
      return uniqueValue(attributes.get(0));
    }
    return null;
  }

  private ByteString uniqueValue(Attribute attribute)
  {
    assertThat(attribute).hasSize(1);
    ByteString attrValue = attribute.iterator().next();
    return attrValue;
  }

  private void verifyModNotReplayed(Iterator<Modification> it)
  {
    verify(it, times(1)).remove();
    verify(it, only()).remove();
  }
}