// 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.server.change;

import com.google.common.collect.ListMultimap;
import com.google.common.collect.MultimapBuilder;
import com.google.gerrit.entities.Project;
import com.google.gerrit.extensions.api.changes.IncludedInInfo;
import com.google.gerrit.extensions.config.ExternalIncludedIn;
import com.google.gerrit.extensions.restapi.BadRequestException;
import com.google.gerrit.extensions.restapi.ResourceConflictException;
import com.google.gerrit.extensions.restapi.RestApiException;
import com.google.gerrit.server.git.GitRepositoryManager;
import com.google.gerrit.server.plugincontext.PluginSetContext;
import com.google.inject.Inject;
import com.google.inject.Singleton;
import java.io.IOException;
import org.eclipse.jgit.errors.IncorrectObjectTypeException;
import org.eclipse.jgit.errors.MissingObjectException;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevCommit;
import org.eclipse.jgit.revwalk.RevWalk;

@Singleton
public class IncludedIn {
  private final GitRepositoryManager repoManager;
  private final PluginSetContext<ExternalIncludedIn> externalIncludedIn;

  @Inject
  IncludedIn(
      GitRepositoryManager repoManager, PluginSetContext<ExternalIncludedIn> externalIncludedIn) {
    this.repoManager = repoManager;
    this.externalIncludedIn = externalIncludedIn;
  }

  public IncludedInInfo apply(Project.NameKey project, String revisionId)
      throws RestApiException, IOException {
    try (Repository r = repoManager.openRepository(project);
        RevWalk rw = new RevWalk(r)) {
      rw.setRetainBody(false);
      RevCommit rev;
      try {
        rev = rw.parseCommit(ObjectId.fromString(revisionId));
      } catch (IncorrectObjectTypeException err) {
        throw new BadRequestException(err.getMessage());
      } catch (MissingObjectException err) {
        throw new ResourceConflictException(err.getMessage());
      }

      IncludedInResolver.Result d = IncludedInResolver.resolve(r, rw, rev);
      ListMultimap<String, String> external = MultimapBuilder.hashKeys().arrayListValues().build();
      externalIncludedIn.runEach(
          ext -> {
            ListMultimap<String, String> extIncludedIns =
                ext.getIncludedIn(project.get(), rev.name(), d.tags(), d.branches());
            if (extIncludedIns != null) {
              external.putAll(extIncludedIns);
            }
          });

      return new IncludedInInfo(
          d.branches(), d.tags(), (!external.isEmpty() ? external.asMap() : null));
    }
  }
}