// 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.group;

import com.google.common.base.MoreObjects;
import com.google.common.base.Strings;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import com.google.common.collect.Sets;
import com.google.gerrit.common.data.GroupDescriptions;
import com.google.gerrit.common.data.GroupReference;
import com.google.gerrit.common.errors.NoSuchGroupException;
import com.google.gerrit.common.groups.ListGroupsOption;
import com.google.gerrit.extensions.restapi.RestReadView;
import com.google.gerrit.extensions.restapi.TopLevelResource;
import com.google.gerrit.extensions.restapi.Url;
import com.google.gerrit.reviewdb.client.Account;
import com.google.gerrit.reviewdb.client.AccountGroup;
import com.google.gerrit.server.IdentifiedUser;
import com.google.gerrit.server.OutputFormat;
import com.google.gerrit.server.account.AccountResource;
import com.google.gerrit.server.account.GetGroups;
import com.google.gerrit.server.account.GroupCache;
import com.google.gerrit.server.account.GroupComparator;
import com.google.gerrit.server.account.GroupControl;
import com.google.gerrit.server.group.GroupJson.GroupInfo;
import com.google.gerrit.server.project.ProjectControl;
import com.google.gson.reflect.TypeToken;
import com.google.gwtorm.server.OrmException;
import com.google.inject.Inject;
import com.google.inject.Provider;

import org.kohsuke.args4j.Option;

import java.util.ArrayList;
import java.util.Collections;
import java.util.EnumSet;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Set;

/** List groups visible to the calling user. */
public class ListGroups implements RestReadView<TopLevelResource> {

  protected final GroupCache groupCache;

  private final GroupControl.Factory groupControlFactory;
  private final GroupControl.GenericFactory genericGroupControlFactory;
  private final Provider<IdentifiedUser> identifiedUser;
  private final IdentifiedUser.GenericFactory userFactory;
  private final Provider<GetGroups> accountGetGroups;
  private final GroupJson json;
  private EnumSet<ListGroupsOption> options;

  @Option(name = "--project", aliases = {"-p"},
      usage = "projects for which the groups should be listed")
  private final List<ProjectControl> projects = new ArrayList<>();

  @Option(name = "--visible-to-all", usage = "to list only groups that are visible to all registered users")
  private boolean visibleToAll;

  @Option(name = "--user", aliases = {"-u"},
      usage = "user for which the groups should be listed")
  private Account.Id user;

  @Option(name = "--owned", usage = "to list only groups that are owned by the specified user"
      + " or by the calling user if no user was specifed")
  private boolean owned;

  private Set<AccountGroup.UUID> groupsToInspect = Sets.newHashSet();

  @Option(name = "-q", usage = "group to inspect")
  void addGroup(final AccountGroup.UUID id) {
    groupsToInspect.add(id);
  }

  @Option(name = "--limit", aliases = {"-n"}, metaVar = "CNT", usage = "maximum number of groups to list")
  private int limit;

  @Option(name = "--start", aliases = {"-S"}, metaVar = "CNT", usage = "number of groups to skip")
  private int start;

  @Option(name = "--match", aliases = {"-m"}, metaVar = "MATCH", usage = "match group substring")
  private String matchSubstring;

  @Option(name = "-o", usage = "Output options per group")
  public void addOption(ListGroupsOption o) {
    options.add(o);
  }

  @Option(name = "-O", usage = "Output option flags, in hex")
  void setOptionFlagsHex(String hex) {
    options.addAll(ListGroupsOption.fromBits(Integer.parseInt(hex, 16)));
  }

  @Inject
  protected ListGroups(final GroupCache groupCache,
      final GroupControl.Factory groupControlFactory,
      final GroupControl.GenericFactory genericGroupControlFactory,
      final Provider<IdentifiedUser> identifiedUser,
      final IdentifiedUser.GenericFactory userFactory,
      final Provider<GetGroups> accountGetGroups, GroupJson json) {
    this.groupCache = groupCache;
    this.groupControlFactory = groupControlFactory;
    this.genericGroupControlFactory = genericGroupControlFactory;
    this.identifiedUser = identifiedUser;
    this.userFactory = userFactory;
    this.accountGetGroups = accountGetGroups;
    this.json = json;
    this.options = EnumSet.noneOf(ListGroupsOption.class);
  }

  public Account.Id getUser() {
    return user;
  }

  public List<ProjectControl> getProjects() {
    return projects;
  }

  @Override
  public Object apply(TopLevelResource resource) throws OrmException {
    final Map<String, GroupInfo> output = Maps.newTreeMap();
    for (GroupInfo info : get()) {
      output.put(MoreObjects.firstNonNull(
          info.name,
          "Group " + Url.decode(info.id)), info);
      info.name = null;
    }
    return OutputFormat.JSON.newGson().toJsonTree(output,
        new TypeToken<Map<String, GroupInfo>>() {}.getType());
  }

  public List<GroupInfo> get() throws OrmException {
    List<GroupInfo> groupInfos;
    if (user != null) {
      if (owned) {
        groupInfos = getGroupsOwnedBy(userFactory.create(user));
      } else {
        groupInfos = accountGetGroups.get().apply(
            new AccountResource(userFactory.create(user)));
      }
    } else {
      if (owned) {
        groupInfos = getGroupsOwnedBy(identifiedUser.get());
      } else {
        List<AccountGroup> groupList;
        if (!projects.isEmpty()) {
          Map<AccountGroup.UUID, AccountGroup> groups = Maps.newHashMap();
          for (final ProjectControl projectControl : projects) {
            final Set<GroupReference> groupsRefs = projectControl.getAllGroups();
            for (final GroupReference groupRef : groupsRefs) {
              final AccountGroup group = groupCache.get(groupRef.getUUID());
              if (group != null) {
                groups.put(group.getGroupUUID(), group);
              }
            }
          }
          groupList = filterGroups(groups.values());
        } else {
          groupList = filterGroups(groupCache.all());
        }
        groupInfos = Lists.newArrayListWithCapacity(groupList.size());
        int found = 0;
        int foundIndex = 0;
        for (AccountGroup group : groupList) {
          if (foundIndex++ < start) {
            continue;
          }
          if (limit > 0 && ++found > limit) {
            break;
          }
          groupInfos.add(json.addOptions(options).format(
              GroupDescriptions.forAccountGroup(group)));
        }
      }
    }
    return groupInfos;
  }

  private List<GroupInfo> getGroupsOwnedBy(IdentifiedUser user)
      throws OrmException {
    List<GroupInfo> groups = Lists.newArrayList();
    int found = 0;
    int foundIndex = 0;
    for (AccountGroup g : filterGroups(groupCache.all())) {
      GroupControl ctl = groupControlFactory.controlFor(g);
      try {
        if (genericGroupControlFactory.controlFor(user, g.getGroupUUID())
            .isOwner()) {
          if (foundIndex++ < start) {
            continue;
          }
          if (limit > 0 && ++found > limit) {
            break;
          }
          groups.add(json.addOptions(options).format(ctl.getGroup()));
        }
      } catch (NoSuchGroupException e) {
        continue;
      }
    }
    return groups;
  }

  private List<AccountGroup> filterGroups(final Iterable<AccountGroup> groups) {
    final List<AccountGroup> filteredGroups = Lists.newArrayList();
    final boolean isAdmin =
        identifiedUser.get().getCapabilities().canAdministrateServer();
    for (final AccountGroup group : groups) {
      if (!Strings.isNullOrEmpty(matchSubstring)) {
        if (!group.getName().toLowerCase(Locale.US)
            .contains(matchSubstring.toLowerCase(Locale.US))) {
          continue;
        }
      }
      if (!isAdmin) {
        final GroupControl c = groupControlFactory.controlFor(group);
        if (!c.isVisible()) {
          continue;
        }
      }
      if (visibleToAll && !group.isVisibleToAll()) {
        continue;
      }
      if (!groupsToInspect.isEmpty()
          && !groupsToInspect.contains(group.getGroupUUID())) {
        continue;
      }
      filteredGroups.add(group);
    }
    Collections.sort(filteredGroups, new GroupComparator());
    return filteredGroups;
  }
}