/*
    * Copyright 2017 LINE Corporation
    *
    * LINE Corporation licenses this file to you 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:
    *
    *   https://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.linecorp.centraldogma.server.internal.storage.repository.git;
  
  import static java.util.Objects.requireNonNull;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.concurrent.Executor;
  import java.util.concurrent.TimeUnit;
  import java.util.function.BiConsumer;
  import java.util.function.Supplier;
  
  import javax.annotation.Nullable;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import com.linecorp.armeria.common.util.TextFormatter;
  import com.linecorp.centraldogma.common.Author;
  import com.linecorp.centraldogma.common.CentralDogmaException;
  import com.linecorp.centraldogma.common.RepositoryExistsException;
  import com.linecorp.centraldogma.common.RepositoryNotFoundException;
  import com.linecorp.centraldogma.internal.Util;
  import com.linecorp.centraldogma.server.internal.storage.DirectoryBasedStorageManager;
  import com.linecorp.centraldogma.server.internal.storage.repository.RepositoryCache;
  import com.linecorp.centraldogma.server.storage.project.Project;
  import com.linecorp.centraldogma.server.storage.repository.Repository;
  import com.linecorp.centraldogma.server.storage.repository.RepositoryManager;
  
  public class GitRepositoryManager extends DirectoryBasedStorageManager<Repository>
          implements RepositoryManager {
  
      private static final Logger logger = LoggerFactory.getLogger(GitRepositoryManager.class);
  
      private final Project parent;
      private final Executor repositoryWorker;
  
      @Nullable
      private final RepositoryCache cache;
  
      public GitRepositoryManager(Project parent, File rootDir, Executor repositoryWorker,
                                  Executor purgeWorker, @Nullable RepositoryCache cache) {
          super(rootDir, Repository.class, purgeWorker);
          this.parent = requireNonNull(parent, "parent");
          this.repositoryWorker = requireNonNull(repositoryWorker, "repositoryWorker");
          this.cache = cache;
          init();
      }
  
      @Override
      public Project parent() {
          return parent;
      }
  
      @Override
      protected Repository openChild(File childDir) throws Exception {
          return new GitRepository(parent, childDir, repositoryWorker, cache);
      }
  
      private static void deleteCruft(File dir) throws IOException {
          logger.info("Deleting the cruft from previous migration: {}", dir);
          Util.deleteFileTree(dir);
          logger.info("Deleted the cruft from previous migration: {}", dir);
      }
  
      @Override
      protected Repository createChild(File childDir, Author author, long creationTimeMillis) throws Exception {
          return new GitRepository(parent, childDir, repositoryWorker,
                                   creationTimeMillis, author, cache);
      }
  
      @Override
      protected void closeChild(File childDir, Repository child,
                                Supplier<CentralDogmaException> failureCauseSupplier) {
          ((GitRepository) child).close(failureCauseSupplier);
      }
  
      @Override
      protected CentralDogmaException newStorageExistsException(String name) {
          return new RepositoryExistsException(parent().name() + '/' + name);
      }
  
      @Override
      protected CentralDogmaException newStorageNotFoundException(String name) {
         return new RepositoryNotFoundException(parent().name() + '/' + name);
     }
 
     /**
      * Logs the migration progress periodically.
      */
     private static class MigrationProgressLogger implements BiConsumer<Integer, Integer> {
 
         private static final long REPORT_INTERVAL_NANOS = TimeUnit.SECONDS.toNanos(10);
 
         private final String name;
         private final long startTimeNanos;
         private long lastReportTimeNanos;
 
         MigrationProgressLogger(Repository repo) {
             name = repo.parent().name() + '/' + repo.name();
             startTimeNanos = lastReportTimeNanos = System.nanoTime();
         }
 
         @Override
         public void accept(Integer current, Integer total) {
             final long currentTimeNanos = System.nanoTime();
             final long elapsedTimeNanos = currentTimeNanos - startTimeNanos;
             if (currentTimeNanos - lastReportTimeNanos > REPORT_INTERVAL_NANOS) {
                 logger.info("{}: {}% ({}/{}) - took {}",
                             name, (int) ((double) current / total * 100),
                             current, total, TextFormatter.elapsed(elapsedTimeNanos));
                 lastReportTimeNanos = currentTimeNanos;
             } else if (current.equals(total)) {
                 logger.info("{}: 100% ({}/{}) - took {}",
                             name, current, total,
                             TextFormatter.elapsed(elapsedTimeNanos));
             }
         }
     }
 }