// Copyright (C) 2013 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.lucene;

import com.google.gerrit.extensions.events.LifecycleListener;
import com.google.gerrit.lifecycle.LifecycleModule;
import com.google.gerrit.server.config.GerritServerConfig;
import com.google.gerrit.server.index.IndexConfig;
import com.google.gerrit.server.index.IndexModule;
import com.google.gerrit.server.index.Schema;
import com.google.gerrit.server.index.change.ChangeIndexCollection;
import com.google.gerrit.server.index.change.ChangeSchemas;
import com.google.gerrit.server.query.change.ChangeData;
import com.google.inject.Inject;
import com.google.inject.Provides;
import com.google.inject.Singleton;

import org.eclipse.jgit.lib.Config;

public class LuceneIndexModule extends LifecycleModule {
  private final Integer singleVersion;
  private final int threads;

  public LuceneIndexModule() {
    this(null, 0);
  }

  public LuceneIndexModule(Integer singleVersion, int threads) {
    this.singleVersion = singleVersion;
    this.threads = threads;
  }

  @Override
  protected void configure() {
    factory(LuceneChangeIndex.Factory.class);
    factory(OnlineReindexer.Factory.class);
    install(new IndexModule(threads));
    if (singleVersion == null) {
      install(new MultiVersionModule());
    } else {
      install(new SingleVersionModule());
    }
  }

  @Provides
  @Singleton
  IndexConfig getIndexConfig(@GerritServerConfig Config cfg) {
    return IndexConfig.fromConfig(cfg);
  }

  private static class MultiVersionModule extends LifecycleModule {
    @Override
    public void configure() {
      listener().to(LuceneVersionManager.class);
    }
  }

  private class SingleVersionModule extends LifecycleModule {
    @Override
    public void configure() {
      listener().to(SingleVersionListener.class);
    }

    @Provides
    @Singleton
    LuceneChangeIndex getIndex(LuceneChangeIndex.Factory factory) {
      Schema<ChangeData> schema = singleVersion != null
          ? ChangeSchemas.get(singleVersion)
          : ChangeSchemas.getLatest();
      return factory.create(schema);
    }
  }

  @Singleton
  static class SingleVersionListener implements LifecycleListener {
    private final ChangeIndexCollection indexes;
    private final LuceneChangeIndex index;

    @Inject
    SingleVersionListener(ChangeIndexCollection indexes,
        LuceneChangeIndex index) {
      this.indexes = indexes;
      this.index = index;
    }

    @Override
    public void start() {
      indexes.setSearchIndex(index);
      indexes.addWriteIndex(index);
    }

    @Override
    public void stop() {
      // Do nothing; indexes are closed by IndexCollection.
    }
  }
}