/*
 * Copyright 2000-2018 JetBrains s.r.o.
 *
 * Licensed 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 jetbrains.buildServer.buildTriggers.vcs.clearcase;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import jetbrains.buildServer.serverSide.TeamCityProperties;
import jetbrains.buildServer.util.Dates;
import jetbrains.buildServer.vcs.VcsException;
import jetbrains.buildServer.vcs.clearcase.Constants;
import jetbrains.buildServer.vcs.clearcase.Util;
import org.apache.log4j.Logger;
import org.jetbrains.annotations.NonNls;
import org.jetbrains.annotations.NotNull;
import org.jetbrains.annotations.Nullable;


public class CCParseUtil {
  @NotNull private static final Logger LOG = Logger.getLogger(CCParseUtil.class);

  @NonNls public static final String CC_VERSION_SEPARATOR = "@@";
  @NonNls private static final String DIRECTORY_ELEMENT = "directory element";
  @NonNls private static final String FILE_ELEMENT = "file element";
  @NonNls private static final String NOT_LOADED = "[not loaded]";

  private CCParseUtil() {}

  @NotNull
  public static List<DirectoryChildElement> readDirectoryVersionContent(@NotNull final ClearCaseConnection connection, @NotNull final String dirPathWithVersion) throws VcsException {
    final List<SimpleDirectoryChildElement> simpleChildren = connection.getChildren(dirPathWithVersion);
    final List<DirectoryChildElement> children = new ArrayList<DirectoryChildElement>(simpleChildren.size());
    for (SimpleDirectoryChildElement simpleChild : simpleChildren) {
      final DirectoryChildElement child = simpleChild.createFullElement(connection);
      if (child != null) {
        children.add(child);
      }
    }
    return children;
  }

  public static void processChangedFiles(final ClearCaseConnection connection,
                                         @NotNull final Revision fromVersion,
                                         @Nullable final Revision toVersion,
                                         @Nullable final ChangedFilesProcessor fileProcessor) throws IOException, VcsException {
    LOG.debug(String.format("Processing changes: fromVersion = [%s], toVersion = [%s]", fromVersion, toVersion));

    final int pastMinutes = getLookForTheChangesInThePastMinutes();
    if (pastMinutes == 0) {
      LOG.debug("Look for the changes in the past: false");
    }
    else {
      LOG.debug(String.format("Look for the changes in the past: true, %d minute(s)", pastMinutes));
    }

    final HistoryElementIterator iterator = getChangesIterator(connection, fromVersion.shiftToPast(pastMinutes));

    final ChangesInverter actualChangesProcessor = fileProcessor == null ? null : new ChangesInverter(fileProcessor),
                          ignoringChangesProcessor = toVersion == null ? null : new ChangesInverter(connection.createIgnoringChangesProcessor());

    try {
      while (iterator.hasNext()) {
        final HistoryElement element = iterator.next();
        final Revision version = Revision.fromChange(element.getChangeInfo());
        if (version.beforeOrEquals(fromVersion)) continue;
        LOG.debug("Processing event: " + element.getLogRepresentation());
        if (CCPathElement.isInsideView(element.getObjectName(), connection.getViewWholePath())) {
          if (toVersion == null || version.beforeOrEquals(toVersion)) {
            if (actualChangesProcessor != null) {
              LOG.debug("Actual change");
              processHistoryElement(element, connection, actualChangesProcessor);
            }
          }
          else {
            LOG.debug("Change to ignore");
            processHistoryElement(element, connection, ignoringChangesProcessor);
          }
        }
      }
    }
    finally {
      iterator.close();
    }

    if (ignoringChangesProcessor != null) {
      ignoringChangesProcessor.processCollectedChangesInInvertedOrder();
    }
    if (actualChangesProcessor != null) {
      actualChangesProcessor.processCollectedChangesInInvertedOrder();
    }
  }

  public static int getLookForTheChangesInThePastMinutes() {
    return TeamCityProperties.getInteger("clearcase.look.for.the.changes.in.the.past.minutes", 0);
  }

  private static void processHistoryElement(@NotNull final HistoryElement element,
                                            @NotNull final ClearCaseConnection connection,
                                            @NotNull final ChangedFilesProcessor processor) throws IOException, VcsException {
    if ("checkin".equals(element.getOperation())) {
      if ("create directory version".equals(element.getEvent())) {
        if (element.versionIsInsideView(connection, false) && connection.fileExistsInParents(element, false)) {
          processor.processChangedDirectory(element);
        }
      } else if ("create version".equals(element.getEvent())) {
        if (element.versionIsInsideView(connection, true) && connection.fileExistsInParents(element, true)) {
          processor.processChangedFile(element);
        }
      }
    } else if ("rmver".equals(element.getOperation())) {
      if ("destroy version on branch".equals(element.getEvent()) && connection.fileExistsInParents(element, true)) {
        processor.processDestroyedFileVersion(element);
      }
    }
  }

  // see http://devnet.jetbrains.net/message/5273615
  private static HistoryElementIterator getChangesIterator(final ClearCaseConnection connection, final Revision fromVersion) throws IOException, VcsException {
    final HistoryElementIterator iterator = connection.getChangesIterator(fromVersion);
    if (!connection.isUCM()) {
      return iterator;
    }
    final long delay = TeamCityProperties.getInteger(Constants.TEAMCITY_PROPERTY_LSHISTORY_UCM_DELAY, 5) * Dates.ONE_SECOND;
    final Revision thresholdRevision = connection.getCurrentRevision();
    int eventCount_1, eventCount_2 = getEventCount(iterator, thresholdRevision);
    do {
      try {
        Util.sleep("HistoryElementIterator: UCM events synchronizer", delay);
      } catch (final InterruptedException ignore) {}
      eventCount_1 = eventCount_2;
      eventCount_2 = getEventCount(connection.getChangesIterator(fromVersion), thresholdRevision);
    } while (eventCount_1 != eventCount_2);
    return connection.getChangesIterator(fromVersion);
  }

  private static int getEventCount(final HistoryElementIterator iterator, final Revision thresholdRevision) throws IOException {
    try {
      int count = 0;
      while (iterator.hasNext()) {
        if (Revision.fromChange(iterator.next().getChangeInfo()).beforeOrEquals(thresholdRevision)) {
          count++;
        }
      }
      return count;
    }
    finally {
      iterator.close();
    }
  }

  public static void processChangedDirectory(final HistoryElement element,
                                             final ClearCaseConnection connection,
                                             ChangedStructureProcessor processor) throws IOException, VcsException {

    if (element.getObjectVersionInt() > 0) {
      final String before = element.getObjectName() + CC_VERSION_SEPARATOR + element.getPreviousVersion(connection, true);
      final String after = element.getObjectName() + CC_VERSION_SEPARATOR + element.getObjectVersion();

      final List<SimpleDirectoryChildElement> elementsBefore = connection.getChildren(before);
      final List<SimpleDirectoryChildElement> elementsAfter = connection.getChildren(after);

      final Map<String, SimpleDirectoryChildElement> filesBefore = collectMap(elementsBefore);
      final Map<String, SimpleDirectoryChildElement> filesAfter = collectMap(elementsAfter);

      for (final String fileName : filesBefore.keySet()) {
        if (!filesAfter.containsKey(fileName)) {
          final SimpleDirectoryChildElement sourceElement = filesBefore.get(fileName);
          switch (sourceElement.getType()) {
            case DIRECTORY:
              processor.directoryDeleted(sourceElement);
              break;
            case FILE:
              processor.fileDeleted(sourceElement);
              break;
          }
        }
      }

      for (final String fileName : filesAfter.keySet()) {
        if (!filesBefore.containsKey(fileName)) {
          final SimpleDirectoryChildElement targetElement = filesAfter.get(fileName);
          switch (targetElement.getType()) {
            case DIRECTORY:
              processor.directoryAdded(targetElement);
              break;
            case FILE:
              processor.fileAdded(targetElement);
              break;
          }
        }
      }

    }
  }

  @NotNull
  private static Map<String, SimpleDirectoryChildElement> collectMap(@NotNull final List<SimpleDirectoryChildElement> elementsBefore) {
    final HashMap<String, SimpleDirectoryChildElement> result = new HashMap<String, SimpleDirectoryChildElement>();
    for (final SimpleDirectoryChildElement element : elementsBefore) {
      result.put(element.getName(), element);
    }
    return result;
  }

  public static String getFileName(final String subdirectory) {
    return new File(subdirectory).getName();
  }

  public static int getVersionInt(final String wholeVersion) {
    final int versSeparator = wholeVersion.lastIndexOf(File.separator);
    return Integer.parseInt(wholeVersion.substring(versSeparator + 1));
  }

  public static String getLastBranch(final String wholeVersion) {
    final int lastSeparatorPos = wholeVersion.lastIndexOf(File.separator);
    final int preLastSeparatorPos = wholeVersion.lastIndexOf(File.separator, lastSeparatorPos - 1);
    return wholeVersion.substring(preLastSeparatorPos + 1, lastSeparatorPos);
  }

  @Nullable
  public static SimpleDirectoryChildElement readChildFromLSFormat(@NotNull final String line) {
    final DirectoryChildElement.Type type;
    String currentPath = line;
    if (currentPath.startsWith(DIRECTORY_ELEMENT)) {
      currentPath = currentPath.substring(DIRECTORY_ELEMENT.length()).trim();
      type = DirectoryChildElement.Type.DIRECTORY;
    }
    else if (currentPath.startsWith(FILE_ELEMENT)){
      type = DirectoryChildElement.Type.FILE;
      currentPath = currentPath.substring(FILE_ELEMENT.length()).trim();
    }
    else {
      type = null;
    }

    if (currentPath.endsWith(NOT_LOADED)) {
      currentPath = currentPath.substring(0, currentPath.length() - NOT_LOADED.length()).trim();
    }

    if (currentPath.endsWith(CC_VERSION_SEPARATOR)) {
      currentPath = currentPath.substring(0, currentPath.length() - CC_VERSION_SEPARATOR.length()).trim();
    }

    if (currentPath.startsWith("\"") && currentPath.endsWith("\"")) {
      currentPath = currentPath.substring(1, currentPath.length() - 1);
    }

    if (type != null) {
      return new SimpleDirectoryChildElement(currentPath, type);
    }

    return null;
  }
}