/**
 * Copyright (C) 2011  JTalks.org Team
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

package org.jtalks.jcommune.service.security.acl.sids;

import org.jtalks.common.model.entity.Group;

import javax.annotation.Nonnegative;
import javax.annotation.Nonnull;
import javax.annotation.concurrent.Immutable;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Pattern;

/**
 * This class does the same as {@link org.springframework.security.acls.domain.PrincipalSid} does for users. More
 * precisely it contains some security ID that is used by Spring ACL to associate the owner to the permissions it owns.
 * Thus this class contains an ID that will be saved into database ({@code acl_sids#sid, acl_object_identity#owner_sid,
 * acl_entry#sid}).
 *
 * @author stanislav bashkirstev
 */
@Immutable
public class UserGroupSid implements UniversalSid {
    public static final String SID_PREFIX = "usergroup";
    private final String groupId;

    /**
     * @param sidId passes the direct sid id which should obey the format "usergroup:[group_id]"
     * @throws UniversalSid.WrongFormatException
     *          if the format of the passed string is wrong
     */
    public UserGroupSid(@Nonnull String sidId) {
        this.groupId = parseGroupId(sidId);
    }

    /**
     * Constructs SID by the group id. The {@link #getSidId()} will consist of word 'usrgroup:[specified id]'.
     *
     * @param groupId the id of the group that will own permissions for some actions on some objects
     * @see Group#getId()
     */
    public UserGroupSid(@Nonnegative long groupId) {
        this.groupId = String.valueOf(groupId);
    }

    /**
     * Constructs a SID by retrieving the group id from the {@link Group} object.
     *
     * @param group a group to take its database id
     * @see Group#getId()
     */
    public UserGroupSid(@Nonnull Group group) {
        this.groupId = String.valueOf(group.getId());
    }

    private String parseGroupId(String sidId) {
        String[] splitted = sidId.split(Pattern.quote(":"));
        if (splitted.length != 2) {
            throw new WrongFormatException(sidId);
        }
        return splitted[1];
    }

    /**
     * Gets the id of the {@link Group} which this SID is actually is.
     *
     * @return the id of the {@link Group} which this SID is actually is
     */
    public String getGroupId() {
        return groupId;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean isPrincipal() {
        return false;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String getSidId() {
        return SID_PREFIX + UniversalSid.SID_NAME_SEPARATOR + groupId;
    }

    /**
     * Creates a list of sids from the specified list of groups.
     *
     * @param groups the array of groups that should be turned into the list of sids, might be empty
     * @return the list of sids with the same size as it was specified
     * @see #UserGroupSid(Group)
     */
    public static List<UserGroupSid> create(@Nonnull Group... groups) {
        List<UserGroupSid> userGroupSids = new ArrayList<UserGroupSid>();
        for (Group group : groups) {
            userGroupSids.add(new UserGroupSid(group));
        }
        return userGroupSids;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        UserGroupSid that = (UserGroupSid) o;
        if (!groupId.equals(that.groupId)) {
            return false;
        }
        return true;
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public int hashCode() {
        return groupId.hashCode();
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public String toString() {
        return getSidId();
    }
}