// 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.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 com.google.common.base.MoreObjects;
import com.google.common.base.Strings;
import com.google.common.collect.ImmutableList;
import com.google.gerrit.common.Version;
import com.google.gerrit.common.data.AccessSection;
import com.google.gerrit.common.data.GlobalCapability;
import com.google.gerrit.common.data.GroupReference;
import com.google.gerrit.common.data.LabelType;
import com.google.gerrit.common.data.LabelValue;
import com.google.gerrit.common.data.Permission;
import com.google.gerrit.common.data.PermissionRule;
import com.google.gerrit.common.data.PermissionRule.Action;
import com.google.gerrit.extensions.client.InheritableBoolean;
import com.google.gerrit.reviewdb.client.Project;
import com.google.gerrit.reviewdb.client.RefNames;
import com.google.gerrit.server.GerritPersonIdent;
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.MetaDataUpdate;
import com.google.gerrit.server.git.ProjectConfig;
import com.google.gerrit.server.group.SystemGroupBackend;
import com.google.inject.Inject;

import org.eclipse.jgit.errors.ConfigInvalidException;
import org.eclipse.jgit.errors.RepositoryNotFoundException;
import org.eclipse.jgit.lib.Constants;
import org.eclipse.jgit.lib.PersonIdent;
import org.eclipse.jgit.lib.RefUpdate;
import org.eclipse.jgit.lib.Repository;

import java.io.IOException;

/** Creates the {@code All-Projects} repository and initial ACLs. */
public class AllProjectsCreator {
  private final GitRepositoryManager mgr;
  private final AllProjectsName allProjectsName;
  private final PersonIdent serverUser;
  private String message;

  private GroupReference admin;
  private GroupReference batch;
  private GroupReference anonymous;
  private GroupReference registered;
  private GroupReference owners;

  @Inject
  AllProjectsCreator(
      GitRepositoryManager mgr,
      AllProjectsName allProjectsName,
      @GerritPersonIdent PersonIdent serverUser) {
    this.mgr = mgr;
    this.allProjectsName = allProjectsName;
    this.serverUser = serverUser;

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

  public AllProjectsCreator setAdministrators(GroupReference admin) {
    this.admin = admin;
    return this;
  }

  public AllProjectsCreator setBatchUsers(GroupReference batch) {
    this.batch = batch;
    return this;
  }

  public AllProjectsCreator setCommitMessage(String message) {
    this.message = message;
    return this;
  }

  public void create() throws IOException, ConfigInvalidException {
    Repository git = null;
    try {
      git = mgr.openRepository(allProjectsName);
      initAllProjects(git);
    } catch (RepositoryNotFoundException notFound) {
      // A repository may be missing if this project existed only to store
      // inheritable permissions. For example 'All-Projects'.
      try {
        git = mgr.createRepository(allProjectsName);
        initAllProjects(git);

        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);
      }
    } finally {
      if (git != null) {
        git.close();
      }
    }
  }

  private void initAllProjects(Repository git)
      throws IOException, ConfigInvalidException {
    MetaDataUpdate md = new MetaDataUpdate(
        GitReferenceUpdated.DISABLED,
        allProjectsName,
        git);
    md.getCommitBuilder().setAuthor(serverUser);
    md.getCommitBuilder().setCommitter(serverUser);
    md.setMessage(MoreObjects.firstNonNull(
        Strings.emptyToNull(message),
        "Initialized Gerrit Code Review " + Version.getVersion()));

    ProjectConfig config = ProjectConfig.read(md);
    Project p = config.getProject();
    p.setDescription("Access inherited by all other projects.");
    p.setRequireChangeID(InheritableBoolean.TRUE);
    p.setUseContentMerge(InheritableBoolean.TRUE);
    p.setUseContributorAgreements(InheritableBoolean.FALSE);
    p.setUseSignedOffBy(InheritableBoolean.FALSE);

    AccessSection cap = config.getAccessSection(AccessSection.GLOBAL_CAPABILITIES, true);
    AccessSection all = config.getAccessSection(AccessSection.ALL, true);
    AccessSection heads = config.getAccessSection(AccessSection.HEADS, true);
    AccessSection tags = config.getAccessSection("refs/tags/*", true);
    AccessSection meta = config.getAccessSection(RefNames.REFS_CONFIG, true);
    AccessSection magic = config.getAccessSection("refs/for/" + AccessSection.ALL, true);

    grant(config, cap, GlobalCapability.ADMINISTRATE_SERVER, admin);
    grant(config, all, Permission.READ, admin, anonymous);

    if (batch != null) {
      Permission priority = cap.getPermission(GlobalCapability.PRIORITY, true);
      PermissionRule r = rule(config, batch);
      r.setAction(Action.BATCH);
      priority.add(r);

      Permission stream = cap.getPermission(GlobalCapability.STREAM_EVENTS, true);
      stream.add(rule(config, batch));
    }

    LabelType cr = initCodeReviewLabel(config);
    grant(config, heads, cr, -1, 1, registered);
    grant(config, heads, cr, -2, 2, admin, owners);
    grant(config, heads, Permission.CREATE, admin, owners);
    grant(config, heads, Permission.PUSH, admin, owners);
    grant(config, heads, Permission.SUBMIT, admin, owners);
    grant(config, heads, Permission.FORGE_AUTHOR, registered);
    grant(config, heads, Permission.FORGE_COMMITTER, admin, owners);
    grant(config, heads, Permission.EDIT_TOPIC_NAME, true, admin, owners);

    grant(config, tags, Permission.PUSH_TAG, admin, owners);
    grant(config, tags, Permission.PUSH_SIGNED_TAG, admin, owners);

    grant(config, magic, Permission.PUSH, registered);
    grant(config, magic, Permission.PUSH_MERGE, registered);

    meta.getPermission(Permission.READ, true).setExclusiveGroup(true);
    grant(config, meta, Permission.READ, admin, owners);
    grant(config, meta, cr, -2, 2, admin, owners);
    grant(config, meta, Permission.PUSH, admin, owners);
    grant(config, meta, Permission.SUBMIT, admin, owners);

    config.commitToNewRef(md, RefNames.REFS_CONFIG);
  }

  private void grant(ProjectConfig config, AccessSection section,
      String permission, GroupReference... groupList) {
    grant(config, section, permission, false, groupList);
  }

  private void grant(ProjectConfig config, AccessSection section,
      String permission, boolean force, GroupReference... groupList) {
    Permission p = section.getPermission(permission, true);
    for (GroupReference group : groupList) {
      if (group != null) {
        PermissionRule r = rule(config, group);
        r.setForce(force);
        p.add(r);
      }
    }
  }

  private void grant(ProjectConfig config,
      AccessSection section, LabelType type,
      int min, int max, GroupReference... groupList) {
    String name = Permission.LABEL + type.getName();
    Permission p = section.getPermission(name, true);
    for (GroupReference group : groupList) {
      if (group != null) {
        PermissionRule r = rule(config, group);
        r.setRange(min, max);
        p.add(r);
      }
    }
  }

  private PermissionRule rule(ProjectConfig config, GroupReference group) {
    return new PermissionRule(config.resolve(group));
  }

  public static LabelType initCodeReviewLabel(ProjectConfig c) {
    LabelType type = new LabelType("Code-Review", ImmutableList.of(
        new LabelValue((short) 2, "Looks good to me, approved"),
        new LabelValue((short) 1, "Looks good to me, but someone else must approve"),
        new LabelValue((short) 0, "No score"),
        new LabelValue((short) -1, "I would prefer this is not merged as is"),
        new LabelValue((short) -2, "This shall not be merged")));
    type.setCopyMinScore(true);
    c.getLabelSections().put(type.getName(), type);
    return type;
  }
}