// Copyright (C) 2012 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.google.gerrit.server.extensions.events;

import com.google.gerrit.extensions.api.changes.NotifyHandling;
import com.google.gerrit.extensions.common.AccountInfo;
import com.google.gerrit.extensions.events.GitReferenceUpdatedListener;
import com.google.gerrit.extensions.registration.DynamicSet;
import com.google.gerrit.reviewdb.client.Account;
import com.google.gerrit.reviewdb.client.Project;
import com.google.inject.Inject;

import org.eclipse.jgit.lib.BatchRefUpdate;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.RefUpdate;
import org.eclipse.jgit.transport.ReceiveCommand;

public class GitReferenceUpdated {
  public static final GitReferenceUpdated DISABLED = new GitReferenceUpdated() {
    @Override
    public void fire(Project.NameKey project, RefUpdate refUpdate,
        ReceiveCommand.Type type, Account updater) {}

    @Override
    public void fire(Project.NameKey project, RefUpdate refUpdate,
        Account updater) {}

    @Override
    public void fire(Project.NameKey project, String ref, ObjectId oldObjectId,
        ObjectId newObjectId, Account updater) {}

    @Override
    public void fire(Project.NameKey project, ReceiveCommand cmd,
        Account updater) {}

    @Override
    public void fire(Project.NameKey project, BatchRefUpdate batchRefUpdate,
        Account updater) {}
  };

  private final DynamicSet<GitReferenceUpdatedListener> listeners;
  private final EventUtil util;

  @Inject
  GitReferenceUpdated(DynamicSet<GitReferenceUpdatedListener> listeners,
      EventUtil util) {
    this.listeners = listeners;
    this.util = util;
  }

  private GitReferenceUpdated() {
    this.listeners = null;
    this.util = null;
  }

  public void fire(Project.NameKey project, RefUpdate refUpdate,
      ReceiveCommand.Type type, Account updater) {
    fire(project, refUpdate.getName(), refUpdate.getOldObjectId(),
        refUpdate.getNewObjectId(), type, util.accountInfo(updater));
  }

  public void fire(Project.NameKey project, RefUpdate refUpdate,
      Account updater) {
    fire(project, refUpdate.getName(), refUpdate.getOldObjectId(),
        refUpdate.getNewObjectId(), ReceiveCommand.Type.UPDATE,
        util.accountInfo(updater));
  }

  public void fire(Project.NameKey project, String ref, ObjectId oldObjectId,
      ObjectId newObjectId, Account updater) {
    fire(project, ref, oldObjectId, newObjectId, ReceiveCommand.Type.UPDATE,
        util.accountInfo(updater));
  }

  public void fire(Project.NameKey project, ReceiveCommand cmd, Account updater) {
    fire(project, cmd.getRefName(), cmd.getOldId(), cmd.getNewId(), cmd.getType(),
        util.accountInfo(updater));
  }

  public void fire(Project.NameKey project, BatchRefUpdate batchRefUpdate,
      Account updater) {
    if (!listeners.iterator().hasNext()) {
      return;
    }
    for (ReceiveCommand cmd : batchRefUpdate.getCommands()) {
      if (cmd.getResult() == ReceiveCommand.Result.OK) {
        fire(project,
            cmd.getRefName(),
            cmd.getOldId(),
            cmd.getNewId(),
            cmd.getType(),
            util.accountInfo(updater));
      }
    }
  }

  private void fire(Project.NameKey project, String ref, ObjectId oldObjectId,
      ObjectId newObjectId, ReceiveCommand.Type type, AccountInfo updater) {
    if (!listeners.iterator().hasNext()) {
      return;
    }
    ObjectId o = oldObjectId != null ? oldObjectId : ObjectId.zeroId();
    ObjectId n = newObjectId != null ? newObjectId : ObjectId.zeroId();
    Event event = new Event(project, ref, o.name(), n.name(), type, updater);
    for (GitReferenceUpdatedListener l : listeners) {
      try {
        l.onGitReferenceUpdated(event);
      } catch (Exception e) {
        util.logEventListenerError(this, l, e);
      }
    }
  }

  private static class Event implements GitReferenceUpdatedListener.Event {
    private final String projectName;
    private final String ref;
    private final String oldObjectId;
    private final String newObjectId;
    private final ReceiveCommand.Type type;
    private final AccountInfo updater;

    Event(Project.NameKey project, String ref,
        String oldObjectId, String newObjectId,
        ReceiveCommand.Type type,
        AccountInfo updater) {
      this.projectName = project.get();
      this.ref = ref;
      this.oldObjectId = oldObjectId;
      this.newObjectId = newObjectId;
      this.type = type;
      this.updater = updater;
    }

    @Override
    public String getProjectName() {
      return projectName;
    }

    @Override
    public String getRefName() {
      return ref;
    }

    @Override
    public String getOldObjectId() {
      return oldObjectId;
    }

    @Override
    public String getNewObjectId() {
      return newObjectId;
    }

    @Override
    public boolean isCreate() {
      return type == ReceiveCommand.Type.CREATE;
    }

    @Override
    public boolean isDelete() {
      return type == ReceiveCommand.Type.DELETE;
    }

    @Override
    public boolean isNonFastForward() {
      return type == ReceiveCommand.Type.UPDATE_NONFASTFORWARD;
    }

    @Override
    public AccountInfo getUpdater() {
      return updater;
    }

    @Override
    public String toString() {
      return String.format("%s[%s,%s: %s -> %s]", getClass().getSimpleName(),
          projectName, ref, oldObjectId, newObjectId);
    }

    @Override
    public NotifyHandling getNotify() {
      return NotifyHandling.ALL;
    }
  }
}