// 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.change;

import com.google.gerrit.common.data.Capable;
import com.google.gerrit.extensions.api.changes.CherryPickInput;
import com.google.gerrit.extensions.common.ChangeInfo;
import com.google.gerrit.extensions.restapi.AuthException;
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.extensions.restapi.RestModifyView;
import com.google.gerrit.extensions.webui.UiAction;
import com.google.gerrit.reviewdb.client.Change;
import com.google.gerrit.reviewdb.client.RefNames;
import com.google.gerrit.reviewdb.server.ReviewDb;
import com.google.gerrit.server.git.IntegrationException;
import com.google.gerrit.server.git.UpdateException;
import com.google.gerrit.server.project.ChangeControl;
import com.google.gerrit.server.project.InvalidChangeOperationException;
import com.google.gerrit.server.project.NoSuchChangeException;
import com.google.gerrit.server.project.ProjectControl;
import com.google.gerrit.server.project.RefControl;
import com.google.gwtorm.server.OrmException;
import com.google.inject.Inject;
import com.google.inject.Provider;
import com.google.inject.Singleton;

import java.io.IOException;

@Singleton
public class CherryPick implements RestModifyView<RevisionResource, CherryPickInput>,
    UiAction<RevisionResource> {
  private final Provider<ReviewDb> dbProvider;
  private final CherryPickChange cherryPickChange;
  private final ChangeJson.Factory json;

  @Inject
  CherryPick(Provider<ReviewDb> dbProvider,
      CherryPickChange cherryPickChange,
      ChangeJson.Factory json) {
    this.dbProvider = dbProvider;
    this.cherryPickChange = cherryPickChange;
    this.json = json;
  }

  @Override
  public ChangeInfo apply(RevisionResource revision, CherryPickInput input)
      throws OrmException, IOException, UpdateException, RestApiException {
    final ChangeControl control = revision.getControl();
    int parent = input.parent == null ? 1 : input.parent;

    if (input.message == null || input.message.trim().isEmpty()) {
      throw new BadRequestException("message must be non-empty");
    } else if (input.destination == null
        || input.destination.trim().isEmpty()) {
      throw new BadRequestException("destination must be non-empty");
    }

    @SuppressWarnings("resource")
    ReviewDb db = dbProvider.get();
    if (!control.isVisible(db)) {
      throw new AuthException("Cherry pick not permitted");
    }

    ProjectControl projectControl = control.getProjectControl();
    Capable capable = projectControl.canPushToAtLeastOneRef();
    if (capable != Capable.OK) {
      throw new AuthException(capable.getMessage());
    }

    String refName = RefNames.fullName(input.destination);
    RefControl refControl = projectControl.controlForRef(refName);
    if (!refControl.canUpload()) {
      throw new AuthException("Not allowed to cherry pick "
          + revision.getChange().getId().toString() + " to "
          + input.destination);
    }

    try {
      Change.Id cherryPickedChangeId =
          cherryPickChange.cherryPick(revision.getChange(),
              revision.getPatchSet(), input.message, refName,
              refControl, parent);
      return json.create(ChangeJson.NO_OPTIONS).format(revision.getProject(),
          cherryPickedChangeId);
    } catch (InvalidChangeOperationException e) {
      throw new BadRequestException(e.getMessage());
    } catch (IntegrationException | NoSuchChangeException e) {
      throw new ResourceConflictException(e.getMessage());
    }
  }

  @Override
  public UiAction.Description getDescription(RevisionResource resource) {
    return new UiAction.Description()
      .setLabel("Cherry Pick")
      .setTitle("Cherry pick change to a different branch")
      .setVisible(resource.getControl().getProjectControl().canUpload()
          && resource.isCurrent());
  }
}