// Copyright (C) 2019 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.acceptance.git;

import static com.google.common.truth.Truth.assertThat;
import static com.google.gerrit.acceptance.GitUtil.deleteRef;
import static com.google.gerrit.acceptance.testsuite.project.TestProjectUpdate.allow;
import static com.google.gerrit.server.group.SystemGroupBackend.REGISTERED_USERS;
import static com.google.gerrit.testing.GerritJUnit.assertThrows;
import static org.eclipse.jgit.lib.Constants.HEAD;
import static org.eclipse.jgit.transport.ReceiveCommand.Type.CREATE;
import static org.eclipse.jgit.transport.ReceiveCommand.Type.DELETE;
import static org.eclipse.jgit.transport.ReceiveCommand.Type.UPDATE;
import static org.eclipse.jgit.transport.ReceiveCommand.Type.UPDATE_NONFASTFORWARD;

import com.google.gerrit.acceptance.AbstractDaemonTest;
import com.google.gerrit.acceptance.ExtensionRegistry;
import com.google.gerrit.acceptance.ExtensionRegistry.Registration;
import com.google.gerrit.acceptance.PushOneCommit;
import com.google.gerrit.acceptance.config.GerritConfig;
import com.google.gerrit.acceptance.testsuite.project.ProjectOperations;
import com.google.gerrit.entities.Permission;
import com.google.gerrit.extensions.api.projects.BranchInput;
import com.google.gerrit.extensions.restapi.RestApiException;
import com.google.gerrit.server.events.RefReceivedEvent;
import com.google.gerrit.server.git.validators.RefOperationValidationListener;
import com.google.gerrit.server.git.validators.ValidationMessage;
import com.google.gerrit.server.validators.ValidationException;
import com.google.inject.Inject;
import java.util.Collections;
import java.util.List;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.RefUpdate;
import org.eclipse.jgit.transport.PushResult;
import org.eclipse.jgit.transport.ReceiveCommand;
import org.eclipse.jgit.transport.RemoteRefUpdate;
import org.junit.Test;

public class RefOperationValidationIT extends AbstractDaemonTest {
  private static final String TEST_REF = "refs/heads/protected";

  @Inject private ProjectOperations projectOperations;
  @Inject private ExtensionRegistry extensionRegistry;

  private static class TestRefValidator implements RefOperationValidationListener {
    private final ReceiveCommand.Type rejectType;
    private final String rejectRef;

    public TestRefValidator(ReceiveCommand.Type rejectType) {
      this.rejectType = rejectType;
      this.rejectRef = TEST_REF;
    }

    @Override
    public List<ValidationMessage> onRefOperation(RefReceivedEvent refEvent)
        throws ValidationException {
      if (refEvent.getRefName().equals(rejectRef)
          && refEvent.command.getType().equals(rejectType)) {
        throw new ValidationException(rejectType.name());
      }
      return Collections.emptyList();
    }
  }

  private Registration testValidator(ReceiveCommand.Type rejectType) {
    return extensionRegistry.newRegistration().add(new TestRefValidator(rejectType));
  }

  @Test
  public void rejectRefCreation() throws Exception {
    try (Registration registration = testValidator(CREATE)) {
      RestApiException expected =
          assertThrows(
              RestApiException.class,
              () -> gApi.projects().name(project.get()).branch(TEST_REF).create(new BranchInput()));
      assertThat(expected).hasMessageThat().contains(CREATE.name());
    }
  }

  private void grant(String permission) {
    projectOperations
        .project(project)
        .forUpdate()
        .add(allow(permission).ref("refs/*").group(REGISTERED_USERS).force(true))
        .update();
  }

  @Test
  public void rejectRefCreationByPush() throws Exception {
    try (Registration registration = testValidator(CREATE)) {
      grant(Permission.PUSH);
      PushOneCommit push1 =
          pushFactory.create(admin.newIdent(), testRepo, "change1", "a.txt", "content");
      PushOneCommit.Result r1 = push1.to("refs/heads/master");
      r1.assertOkStatus();
      PushOneCommit.Result r2 = push1.to(TEST_REF);
      r2.assertErrorStatus(CREATE.name());
    }
  }

  @Test
  public void rejectRefDeletion() throws Exception {
    gApi.projects().name(project.get()).branch(TEST_REF).create(new BranchInput());
    try (Registration registration = testValidator(DELETE)) {
      RestApiException expected =
          assertThrows(
              RestApiException.class,
              () -> gApi.projects().name(project.get()).branch(TEST_REF).delete());
      assertThat(expected).hasMessageThat().contains(DELETE.name());
    }
  }

  @Test
  public void rejectRefDeletionByPush() throws Exception {
    gApi.projects().name(project.get()).branch(TEST_REF).create(new BranchInput());
    grant(Permission.DELETE);
    try (Registration registration = testValidator(DELETE)) {
      PushResult result = deleteRef(testRepo, TEST_REF);
      RemoteRefUpdate refUpdate = result.getRemoteUpdate(TEST_REF);
      assertThat(refUpdate.getMessage()).contains(DELETE.name());
    }
  }

  @Test
  public void rejectRefUpdateFastForward() throws Exception {
    gApi.projects().name(project.get()).branch(TEST_REF).create(new BranchInput());
    try (Registration registration = testValidator(UPDATE)) {
      grant(Permission.PUSH);
      PushOneCommit push1 =
          pushFactory.create(admin.newIdent(), testRepo, "change1", "a.txt", "content");
      PushOneCommit.Result r1 = push1.to(TEST_REF);
      r1.assertErrorStatus(UPDATE.name());
    }
  }

  @Test
  public void rejectRefUpdateNonFastForward() throws Exception {
    gApi.projects().name(project.get()).branch(TEST_REF).create(new BranchInput());
    try (Registration registration = testValidator(UPDATE_NONFASTFORWARD)) {
      ObjectId initial = repo().exactRef(HEAD).getLeaf().getObjectId();
      grant(Permission.PUSH);
      PushOneCommit push1 =
          pushFactory.create(admin.newIdent(), testRepo, "change1", "a.txt", "content");
      PushOneCommit.Result r1 = push1.to(TEST_REF);
      r1.assertOkStatus();

      // Reset HEAD to initial so the new change is a non-fast forward
      RefUpdate ru = repo().updateRef(HEAD);
      ru.setNewObjectId(initial);
      assertThat(ru.forceUpdate()).isEqualTo(RefUpdate.Result.FORCED);

      PushOneCommit push2 =
          pushFactory.create(admin.newIdent(), testRepo, "change2", "b.txt", "content");
      push2.setForce(true);
      PushOneCommit.Result r2 = push2.to(TEST_REF);
      r2.assertErrorStatus(UPDATE_NONFASTFORWARD.name());
    }
  }

  @Test
  public void rejectRefUpdateNonFastForwardToExistingCommit() throws Exception {
    gApi.projects().name(project.get()).branch(TEST_REF).create(new BranchInput());

    try (Registration registration = testValidator(UPDATE_NONFASTFORWARD)) {
      grant(Permission.PUSH);
      PushOneCommit push1 =
          pushFactory.create(admin.newIdent(), testRepo, "change1", "a.txt", "content");
      PushOneCommit.Result r1 = push1.to("refs/heads/master");
      r1.assertOkStatus();
      ObjectId push1Id = r1.getCommit();

      PushOneCommit push2 =
          pushFactory.create(admin.newIdent(), testRepo, "change2", "b.txt", "content");
      PushOneCommit.Result r2 = push2.to("refs/heads/master");
      r2.assertOkStatus();
      ObjectId push2Id = r2.getCommit();

      RefUpdate ru = repo().updateRef(HEAD);
      ru.setNewObjectId(push1Id);
      assertThat(ru.forceUpdate()).isEqualTo(RefUpdate.Result.FORCED);

      PushOneCommit push3 =
          pushFactory.create(admin.newIdent(), testRepo, "change3", "c.txt", "content");
      PushOneCommit.Result r3 = push3.to(TEST_REF);
      r3.assertOkStatus();

      ru = repo().updateRef(HEAD);
      ru.setNewObjectId(push2Id);
      assertThat(ru.forceUpdate()).isEqualTo(RefUpdate.Result.FORCED);

      PushOneCommit push4 =
          pushFactory.create(admin.newIdent(), testRepo, "change4", "d.txt", "content");
      push4.setForce(true);
      PushOneCommit.Result r4 = push4.to(TEST_REF);
      r4.assertErrorStatus(UPDATE_NONFASTFORWARD.name());
    }
  }

  @Test
  @GerritConfig(name = "change.maxFiles", value = "0")
  public void dontEnforceFileCountForDirectPushes() throws Exception {
    PushOneCommit push =
        pushFactory.create(admin.newIdent(), testRepo, "change", "c.txt", "content");
    PushOneCommit.Result result = push.to("refs/heads/master");
    result.assertOkStatus();
  }

  @Test
  @GerritConfig(name = "change.maxFiles", value = "0")
  public void enforceFileCountLimitOnPushesForReview() throws Exception {
    PushOneCommit push =
        pushFactory.create(admin.newIdent(), testRepo, "change", "c.txt", "content");
    PushOneCommit.Result result = push.to("refs/for/master");
    result.assertErrorStatus("Exceeding maximum number of files per change");
  }
}