// Copyright (C) 2019 The Android Open Source Project
//
// 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.
// Copyright (C) 2018 The Android Open Source Project
//
// 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 com.googlesource.gerrit.plugins.multisite.validation;

import com.google.common.flogger.FluentLogger;
import com.google.inject.Inject;
import com.google.inject.assistedinject.Assisted;
import com.googlesource.gerrit.plugins.multisite.validation.dfsrefdb.SharedRefDatabase;
import java.io.IOException;
import org.eclipse.jgit.lib.AnyObjectId;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.PersonIdent;
import org.eclipse.jgit.lib.Ref;
import org.eclipse.jgit.lib.RefDatabase;
import org.eclipse.jgit.lib.RefUpdate;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.transport.PushCertificate;

public class MultiSiteRefUpdate extends RefUpdate {

  private static final FluentLogger logger = FluentLogger.forEnclosingClass();

  protected final RefUpdate refUpdateBase;

  private final SharedRefDatabase sharedDb;
  private final String projectName;

  public interface Factory {
    MultiSiteRefUpdate create(String projectName, RefUpdate refUpdate);
  }

  @Inject
  public MultiSiteRefUpdate(
      SharedRefDatabase db, @Assisted String projectName, @Assisted RefUpdate refUpdate) {
    super(refUpdate.getRef());
    refUpdateBase = refUpdate;
    this.sharedDb = db;
    this.projectName = projectName;
  }

  private void checkSharedDBForRefUpdate() throws IOException {
    try {
      Ref newRef = sharedDb.newRef(refUpdateBase.getName(), refUpdateBase.getNewObjectId());

      if (!sharedDb.compareAndPut(projectName, refUpdateBase.getRef(), newRef)) {
        throw new IOException(
            String.format(
                "Unable to update ref '%s', the local objectId '%s' is not equal to the one "
                    + "in the shared ref datasuper",
                newRef.getName(), refUpdateBase.getName()));
      }
    } catch (IOException ioe) {
      logger.atSevere().withCause(ioe).log(
          "Local status inconsistent with shared ref datasuper for ref %s. "
              + "Trying to update it cannot extract the existing one on DB",
          refUpdateBase.getName());

      throw new IOException(
          String.format(
              "Unable to update ref '%s', cannot open the local ref on the local DB",
              refUpdateBase.getName()),
          ioe);
    }
  }

  private void checkSharedDbForRefDelete() throws IOException {
    Ref oldRef = this.getRef();
    try {
      if (!sharedDb.compareAndRemove(projectName, oldRef)) {
        throw new IOException(
            String.format(
                "Unable to delete ref '%s', the local ObjectId '%s' is not equal to the one "
                    + "in the shared ref database",
                oldRef.getName(), oldRef.getName()));
      }
    } catch (IOException ioe) {
      logger.atSevere().withCause(ioe).log(
          "Local status inconsistent with shared ref database for ref %s. "
              + "Trying to delete it but it is not in the DB",
          oldRef.getName());

      throw new IOException(
          String.format(
              "Unable to delete ref '%s', cannot find it in the shared ref database",
              oldRef.getName()),
          ioe);
    }
  }

  @Override
  protected RefDatabase getRefDatabase() {
    return notImplementedException();
  }

  private <T> T notImplementedException() {
    throw new IllegalStateException("This method should have never been invoked");
  }

  @Override
  protected Repository getRepository() {
    return notImplementedException();
  }

  @Override
  protected boolean tryLock(boolean deref) throws IOException {
    return notImplementedException();
  }

  @Override
  protected void unlock() {
    notImplementedException();
  }

  @Override
  protected Result doUpdate(Result result) throws IOException {
    return notImplementedException();
  }

  @Override
  protected Result doDelete(Result result) throws IOException {
    return notImplementedException();
  }

  @Override
  protected Result doLink(String target) throws IOException {
    return notImplementedException();
  }

  @Override
  public Result update() throws IOException {
    checkSharedDBForRefUpdate();
    return refUpdateBase.update();
  }

  @Override
  public Result update(RevWalk rev) throws IOException {
    checkSharedDBForRefUpdate();
    return refUpdateBase.update(rev);
  }

  @Override
  public Result delete() throws IOException {
    checkSharedDbForRefDelete();
    return refUpdateBase.delete();
  }

  @Override
  public Result delete(RevWalk walk) throws IOException {
    checkSharedDbForRefDelete();
    return refUpdateBase.delete(walk);
  }

  @Override
  public int hashCode() {
    return refUpdateBase.hashCode();
  }

  @Override
  public boolean equals(Object obj) {
    return refUpdateBase.equals(obj);
  }

  @Override
  public String toString() {
    return refUpdateBase.toString();
  }

  @Override
  public String getName() {
    return refUpdateBase.getName();
  }

  @Override
  public Ref getRef() {
    return refUpdateBase.getRef();
  }

  @Override
  public ObjectId getNewObjectId() {
    return refUpdateBase.getNewObjectId();
  }

  @Override
  public void setDetachingSymbolicRef() {
    refUpdateBase.setDetachingSymbolicRef();
  }

  @Override
  public boolean isDetachingSymbolicRef() {
    return refUpdateBase.isDetachingSymbolicRef();
  }

  @Override
  public void setNewObjectId(AnyObjectId id) {
    refUpdateBase.setNewObjectId(id);
  }

  @Override
  public ObjectId getExpectedOldObjectId() {
    return refUpdateBase.getExpectedOldObjectId();
  }

  @Override
  public void setExpectedOldObjectId(AnyObjectId id) {
    refUpdateBase.setExpectedOldObjectId(id);
  }

  @Override
  public boolean isForceUpdate() {
    return refUpdateBase.isForceUpdate();
  }

  @Override
  public void setForceUpdate(boolean b) {
    refUpdateBase.setForceUpdate(b);
  }

  @Override
  public PersonIdent getRefLogIdent() {
    return refUpdateBase.getRefLogIdent();
  }

  @Override
  public void setRefLogIdent(PersonIdent pi) {
    refUpdateBase.setRefLogIdent(pi);
  }

  @Override
  public String getRefLogMessage() {
    return refUpdateBase.getRefLogMessage();
  }

  @Override
  public void setRefLogMessage(String msg, boolean appendStatus) {
    refUpdateBase.setRefLogMessage(msg, appendStatus);
  }

  @Override
  public void disableRefLog() {
    refUpdateBase.disableRefLog();
  }

  @Override
  public void setForceRefLog(boolean force) {
    refUpdateBase.setForceRefLog(force);
  }

  @Override
  public ObjectId getOldObjectId() {
    return refUpdateBase.getOldObjectId();
  }

  @Override
  public void setPushCertificate(PushCertificate cert) {
    refUpdateBase.setPushCertificate(cert);
  }

  @Override
  public Result getResult() {
    return refUpdateBase.getResult();
  }

  @Override
  public Result forceUpdate() throws IOException {
    return refUpdateBase.forceUpdate();
  }

  @Override
  public Result link(String target) throws IOException {
    return refUpdateBase.link(target);
  }

  @Override
  public void setCheckConflicting(boolean check) {
    refUpdateBase.setCheckConflicting(check);
  }
}