// 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.project;

import com.google.common.base.MoreObjects;
import com.google.common.base.Strings;
import com.google.gerrit.common.ChangeHooks;
import com.google.gerrit.extensions.api.projects.PutDescriptionInput;
import com.google.gerrit.extensions.restapi.AuthException;
import com.google.gerrit.extensions.restapi.ResourceConflictException;
import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
import com.google.gerrit.extensions.restapi.Response;
import com.google.gerrit.extensions.restapi.RestModifyView;
import com.google.gerrit.reviewdb.client.Branch;
import com.google.gerrit.reviewdb.client.Project;
import com.google.gerrit.reviewdb.client.RefNames;
import com.google.gerrit.server.IdentifiedUser;
import com.google.gerrit.server.git.GitRepositoryManager;
import com.google.gerrit.server.git.MetaDataUpdate;
import com.google.gerrit.server.git.ProjectConfig;
import com.google.inject.Inject;
import com.google.inject.Singleton;

import org.eclipse.jgit.errors.ConfigInvalidException;
import org.eclipse.jgit.errors.RepositoryNotFoundException;
import org.eclipse.jgit.lib.ObjectId;

import java.io.IOException;
import java.util.Objects;

@Singleton
public class PutDescription implements RestModifyView<ProjectResource, PutDescriptionInput> {
  private final ProjectCache cache;
  private final MetaDataUpdate.Server updateFactory;
  private final GitRepositoryManager gitMgr;
  private final ChangeHooks hooks;

  @Inject
  PutDescription(ProjectCache cache,
      MetaDataUpdate.Server updateFactory,
      ChangeHooks hooks,
      GitRepositoryManager gitMgr) {
    this.cache = cache;
    this.updateFactory = updateFactory;
    this.hooks = hooks;
    this.gitMgr = gitMgr;
  }

  @Override
  public Response<String> apply(ProjectResource resource,
      PutDescriptionInput input) throws AuthException,
      ResourceConflictException, ResourceNotFoundException, IOException {
    if (input == null) {
      input = new PutDescriptionInput(); // Delete would set description to null.
    }

    ProjectControl ctl = resource.getControl();
    IdentifiedUser user = ctl.getUser().asIdentifiedUser();
    if (!ctl.isOwner()) {
      throw new AuthException("not project owner");
    }

    try {
      MetaDataUpdate md = updateFactory.create(resource.getNameKey());
      try {
        ProjectConfig config = ProjectConfig.read(md);
        Project project = config.getProject();
        project.setDescription(Strings.emptyToNull(input.description));

        String msg = MoreObjects.firstNonNull(
          Strings.emptyToNull(input.commitMessage),
          "Updated description.\n");
        if (!msg.endsWith("\n")) {
          msg += "\n";
        }
        md.setAuthor(user);
        md.setMessage(msg);
        ObjectId baseRev = config.getRevision();
        ObjectId commitRev = config.commit(md);
        // Only fire hook if project was actually changed.
        if (!Objects.equals(baseRev, commitRev)) {
          hooks.doRefUpdatedHook(
            new Branch.NameKey(resource.getNameKey(), RefNames.REFS_CONFIG),
            baseRev, commitRev, user.getAccount());
        }
        cache.evict(ctl.getProject());
        gitMgr.setProjectDescription(
            resource.getNameKey(),
            project.getDescription());

        return Strings.isNullOrEmpty(project.getDescription())
            ? Response.<String>none()
            : Response.ok(project.getDescription());
      } finally {
        md.close();
      }
    } catch (RepositoryNotFoundException notFound) {
      throw new ResourceNotFoundException(resource.getName());
    } catch (ConfigInvalidException e) {
      throw new ResourceConflictException(String.format(
          "invalid project.config: %s", e.getMessage()));
    }
  }
}