// 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.schema;

import static com.google.common.base.Preconditions.checkArgument;
import static com.google.gerrit.entities.RefNames.REFS_SEQUENCES;
import static com.google.gerrit.server.group.SystemGroupBackend.ANONYMOUS_USERS;
import static com.google.gerrit.server.group.SystemGroupBackend.PROJECT_OWNERS;
import static com.google.gerrit.server.group.SystemGroupBackend.REGISTERED_USERS;
import static com.google.gerrit.server.schema.AclUtil.block;
import static com.google.gerrit.server.schema.AclUtil.grant;
import static com.google.gerrit.server.schema.AclUtil.rule;
import static com.google.gerrit.server.update.context.RefUpdateContext.RefUpdateType.INIT_REPO;
import static java.nio.charset.StandardCharsets.UTF_8;
import static org.eclipse.jgit.lib.Constants.OBJ_BLOB;

import com.google.gerrit.common.Version;
import com.google.gerrit.common.data.GlobalCapability;
import com.google.gerrit.entities.AccessSection;
import com.google.gerrit.entities.GroupReference;
import com.google.gerrit.entities.LabelType;
import com.google.gerrit.entities.Permission;
import com.google.gerrit.entities.PermissionRule.Action;
import com.google.gerrit.entities.RefNames;
import com.google.gerrit.entities.SubmitRequirement;
import com.google.gerrit.entities.SubmitRequirementExpression;
import com.google.gerrit.server.GerritPersonIdent;
import com.google.gerrit.server.Sequence;
import com.google.gerrit.server.config.AllProjectsName;
import com.google.gerrit.server.extensions.events.GitReferenceUpdated;
import com.google.gerrit.server.git.GitRepositoryManager;
import com.google.gerrit.server.git.meta.MetaDataUpdate;
import com.google.gerrit.server.group.SystemGroupBackend;
import com.google.gerrit.server.project.ProjectConfig;
import com.google.gerrit.server.update.context.RefUpdateContext;
import com.google.inject.Inject;
import java.io.IOException;
import java.util.Optional;
import org.eclipse.jgit.errors.ConfigInvalidException;
import org.eclipse.jgit.errors.RepositoryNotFoundException;
import org.eclipse.jgit.lib.BatchRefUpdate;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.NullProgressMonitor;
import org.eclipse.jgit.lib.ObjectId;
import org.eclipse.jgit.lib.ObjectInserter;
import org.eclipse.jgit.lib.PersonIdent;
import org.eclipse.jgit.lib.RefUpdate;
import org.eclipse.jgit.lib.Repository;
import org.eclipse.jgit.revwalk.RevWalk;
import org.eclipse.jgit.transport.ReceiveCommand;

/** Creates the {@code All-Projects} repository and initial ACLs. */
public class AllProjectsCreator {
  private final GitRepositoryManager repositoryManager;
  private final AllProjectsName allProjectsName;
  private final PersonIdent serverUser;
  private final NoteDbSchemaVersionManager versionManager;
  private final ProjectConfig.Factory projectConfigFactory;
  private final GroupReference anonymous;
  private final GroupReference registered;
  private final GroupReference owners;

  @Inject
  AllProjectsCreator(
      GitRepositoryManager repositoryManager,
      AllProjectsName allProjectsName,
      @GerritPersonIdent PersonIdent serverUser,
      NoteDbSchemaVersionManager versionManager,
      SystemGroupBackend systemGroupBackend,
      ProjectConfig.Factory projectConfigFactory) {
    this.repositoryManager = repositoryManager;
    this.allProjectsName = allProjectsName;
    this.serverUser = serverUser;
    this.versionManager = versionManager;
    this.projectConfigFactory = projectConfigFactory;

    this.anonymous = systemGroupBackend.getGroup(ANONYMOUS_USERS);
    this.registered = systemGroupBackend.getGroup(REGISTERED_USERS);
    this.owners = systemGroupBackend.getGroup(PROJECT_OWNERS);
  }

  public void create(AllProjectsInput input) throws IOException, ConfigInvalidException {
    try (RefUpdateContext updCtx = RefUpdateContext.open(INIT_REPO)) {
      try (Repository git = repositoryManager.openRepository(allProjectsName)) {
        initAllProjects(git, input);
      } catch (RepositoryNotFoundException notFound) {
        // A repository may be missing if this project existed only to store
        // inheritable permissions. For example 'All-Projects'.
        try (Repository git = repositoryManager.createRepository(allProjectsName)) {
          initAllProjects(git, input);
          RefUpdate u = git.updateRef(Constants.HEAD);
          u.link(RefNames.REFS_CONFIG);
        } catch (RepositoryNotFoundException err) {
          String name = allProjectsName.get();
          throw new IOException("Cannot create repository " + name, err);
        }
      }
    }
  }

  private void initAllProjects(Repository git, AllProjectsInput input)
      throws ConfigInvalidException, IOException {
    BatchRefUpdate bru = git.getRefDatabase().newBatchUpdate();
    try (MetaDataUpdate md =
        new MetaDataUpdate(GitReferenceUpdated.DISABLED, allProjectsName, git, bru)) {
      md.getCommitBuilder().setAuthor(serverUser);
      md.getCommitBuilder().setCommitter(serverUser);
      md.setMessage(
          input.commitMessage().isPresent()
              ? input.commitMessage().get()
              : "Initialized Gerrit Code Review " + Version.getVersion());

      // init basic project configs.
      ProjectConfig config = projectConfigFactory.read(md);
      config.updateProject(
          p -> {
            p.setDescription(
                input.projectDescription().orElse("Access inherited by all other projects."));
            // init boolean project configs.
            input.booleanProjectConfigs().forEach(p::setBooleanConfig);
          });

      // init labels.
      input.codeReviewLabel().ifPresent(codeReviewLabel -> config.upsertLabelType(codeReviewLabel));

      // init access sections.
      if (input.initDefaultAcls()) {
        initDefaultAcls(config, input);
      }

      // init submit requirement sections.
      input.codeReviewSubmitRequirement().ifPresent(config::upsertSubmitRequirement);
      if (input.initDefaultSubmitRequirements()) {
        initDefaultSubmitRequirements(config);
      }

      // commit all the above configs as a commit in "refs/meta/config" branch of the All-Projects.
      config.commitToNewRef(md, RefNames.REFS_CONFIG);

      // init sequence number.
      initSequences(git, bru, input.firstChangeIdForNoteDb());

      // init schema
      versionManager.init();

      execute(git, bru);
    }
  }

  private void initDefaultAcls(ProjectConfig config, AllProjectsInput input) {
    checkArgument(input.codeReviewLabel().isPresent());
    LabelType codeReviewLabel = input.codeReviewLabel().get();

    config.upsertAccessSection(
        AccessSection.HEADS,
        heads -> {
          initDefaultAclsForAnonymousUsers(heads, config);
          initDefaultAclsForRegisteredUsers(heads, codeReviewLabel, config);
        });

    config.upsertAccessSection(
        AccessSection.GLOBAL_CAPABILITIES,
        capabilities ->
            input
                .serviceUsersGroup()
                .ifPresent(
                    serviceUsersGroup ->
                        initDefaultAclsForServiceUsers(capabilities, config, serviceUsersGroup)));

    input
        .blockedUsersGroup()
        .ifPresent(blockedUsersGrouo -> initDefaultAclsForBlockedUsers(config, blockedUsersGrouo));

    input
        .administratorsGroup()
        .ifPresent(adminsGroup -> initDefaultAclsForAdmins(config, codeReviewLabel, adminsGroup));
  }

  private void initDefaultSubmitRequirements(ProjectConfig config) {
    config.upsertSubmitRequirement(
        SubmitRequirement.builder()
            .setName("No-Unresolved-Comments")
            .setDescription(
                Optional.of("Changes that have unresolved comments are not submittable."))
            .setApplicabilityExpression(SubmitRequirementExpression.of("has:unresolved"))
            .setSubmittabilityExpression(SubmitRequirementExpression.create("-has:unresolved"))
            .setAllowOverrideInChildProjects(false)
            .build());
  }

  private void initDefaultAclsForAnonymousUsers(AccessSection.Builder heads, ProjectConfig config) {
    grant(config, heads, Permission.READ, anonymous);

    config.upsertAccessSection(
        "refs/meta/version", version -> grant(config, version, Permission.READ, anonymous));
  }

  private void initDefaultAclsForRegisteredUsers(
      AccessSection.Builder heads, LabelType codeReviewLabel, ProjectConfig config) {
    grant(config, heads, codeReviewLabel, -1, 1, registered);
    grant(config, heads, Permission.FORGE_AUTHOR, registered);

    config.upsertAccessSection(
        "refs/for/*",
        refsFor -> {
          grant(config, refsFor, Permission.ADD_PATCH_SET, registered);
          grant(config, refsFor, Permission.PUSH, registered);
          grant(config, refsFor, Permission.PUSH_MERGE, registered);
        });
  }

  private void initDefaultAclsForServiceUsers(
      AccessSection.Builder capabilities, ProjectConfig config, GroupReference serviceUsersGroup) {
    Permission.Builder priority = capabilities.upsertPermission(GlobalCapability.PRIORITY);
    priority.add(rule(config, serviceUsersGroup).setAction(Action.BATCH));

    Permission.Builder stream = capabilities.upsertPermission(GlobalCapability.STREAM_EVENTS);
    stream.add(rule(config, serviceUsersGroup));
  }

  private void initDefaultAclsForBlockedUsers(
      ProjectConfig config, GroupReference blockedUsersGroup) {
    config.upsertAccessSection(
        AccessSection.ALL, all -> block(config, all, Permission.READ, blockedUsersGroup));
  }

  private void initDefaultAclsForAdmins(
      ProjectConfig config, LabelType codeReviewLabel, GroupReference adminsGroup) {
    config.upsertAccessSection(
        AccessSection.GLOBAL_CAPABILITIES,
        capabilities ->
            grant(config, capabilities, GlobalCapability.ADMINISTRATE_SERVER, adminsGroup));

    config.upsertAccessSection(
        AccessSection.ALL, all -> grant(config, all, Permission.READ, adminsGroup));

    config.upsertAccessSection(
        AccessSection.HEADS,
        heads -> {
          grant(config, heads, codeReviewLabel, -2, 2, adminsGroup, owners);
          grant(config, heads, Permission.CREATE, adminsGroup, owners);
          grant(config, heads, Permission.SUBMIT, adminsGroup, owners);
          grant(config, heads, Permission.FORGE_COMMITTER, adminsGroup, owners);
          grant(config, heads, Permission.EDIT_TOPIC_NAME, true, adminsGroup, owners);
          grant(config, heads, Permission.REVERT, adminsGroup, owners);
        });

    config.upsertAccessSection(
        "refs/tags/*",
        tags -> {
          grant(config, tags, Permission.CREATE, adminsGroup, owners);
          grant(config, tags, Permission.CREATE_TAG, adminsGroup, owners);
          grant(config, tags, Permission.CREATE_SIGNED_TAG, adminsGroup, owners);
        });

    config.upsertAccessSection(
        RefNames.REFS_CONFIG,
        meta -> {
          meta.upsertPermission(Permission.READ).setExclusiveGroup(true);
          grant(config, meta, Permission.READ, adminsGroup, owners);
          grant(config, meta, codeReviewLabel, -2, 2, adminsGroup, owners);
          grant(config, meta, Permission.CREATE, adminsGroup, owners);
          grant(config, meta, Permission.SUBMIT, adminsGroup, owners);
        });
  }

  private void initSequences(Repository git, BatchRefUpdate bru, int firstChangeId)
      throws IOException {
    if (git.exactRef(REFS_SEQUENCES + Sequence.NAME_CHANGES) == null) {
      // Can't easily reuse the inserter from MetaDataUpdate, but this shouldn't slow down site
      // initialization unduly.
      try (ObjectInserter ins = git.newObjectInserter()) {
        bru.addCommand(createNewChangeSequence(ins, firstChangeId));
        ins.flush();
      }
    }
  }

  private ReceiveCommand createNewChangeSequence(ObjectInserter ins, int val) throws IOException {
    ObjectId newId = ins.insert(OBJ_BLOB, Integer.toString(val).getBytes(UTF_8));
    return new ReceiveCommand(
        ObjectId.zeroId(), newId, RefNames.REFS_SEQUENCES + Sequence.NAME_CHANGES);
  }

  private void execute(Repository git, BatchRefUpdate bru) throws IOException {
    try (RevWalk rw = new RevWalk(git)) {
      bru.execute(rw, NullProgressMonitor.INSTANCE);
    }
    for (ReceiveCommand cmd : bru.getCommands()) {
      if (cmd.getResult() != ReceiveCommand.Result.OK) {
        throw new IOException("Failed to initialize " + allProjectsName + " refs:\n" + bru);
      }
    }
  }
}