/*
 * Copyright (c) 2003, 2021 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v. 2.0, which is available at
 * http://www.eclipse.org/legal/epl-2.0.
 *
 * This Source Code may also be made available under the following Secondary
 * Licenses when the conditions for such availability set forth in the
 * Eclipse Public License v. 2.0 are satisfied: GNU General Public License,
 * version 2 with the GNU Classpath Exception, which is available at
 * https://www.gnu.org/software/classpath/license.html.
 *
 * SPDX-License-Identifier: EPL-2.0 OR GPL-2.0 WITH Classpath-exception-2.0
 */

package com.sun.jndi.ldap.obj;

import java.util.Enumeration;
import java.util.Hashtable;

import javax.naming.Context;
import javax.naming.Name;
import javax.naming.NamingException;
import javax.naming.directory.Attribute;
import javax.naming.directory.Attributes;
import javax.naming.directory.DirContext;
import javax.naming.spi.DirObjectFactory;
import javax.naming.spi.DirStateFactory;

/**
 * A state factory and an object factory for handling LDAP groups.
 * The following group objects are supported:
 * <ul>
 * <li> {@link GroupOfNames}
 * <li> {@link GroupOfUniqueNames}
 * <li> {@link GroupOfURLs}
 * </ul>
 *
 * @author Vincent Ryan
 */
public class LdapGroupFactory implements DirStateFactory, DirObjectFactory {

    private static final boolean debug = false;

    public LdapGroupFactory() {
        if (debug) {
            System.out.println("[debug] constructing LdapGroupFactory object");
        }
    }

    /**
     * The method is not applicable to this class.
     *
     * @return null is always returned.
     */
    @Override
    public Object getStateToBind(Object obj, Name name, Context nameCtx, Hashtable environment) throws NamingException {
        return null;
    }

    /**
     * Extracts the attributes that represent the LDAP object.
     */
    @Override
    public DirStateFactory.Result getStateToBind(Object obj, Name name, Context nameCtx, Hashtable environment,
        Attributes inAttrs) throws NamingException {
        if (nameCtx instanceof DirContext) {

            // build the group's distinguished name
            String groupDN = getName(nameCtx, name);

            Attributes outAttrs = null;
            // interested only in group objects
            if (obj instanceof GroupOfURLs) {
                outAttrs = ((GroupOfURLs) obj).getAttributes();
                // set the group's LDAP context and name
                ((GroupOfURLs) obj).setName(groupDN, (DirContext) nameCtx, name);

            } else if (obj instanceof GroupOfUniqueNames) {
                outAttrs = ((GroupOfUniqueNames) obj).getAttributes();
                // set the group's LDAP context and name
                ((GroupOfUniqueNames) obj).setName(groupDN, (DirContext) nameCtx, name);

            } else if (obj instanceof GroupOfNames) {
                outAttrs = ((GroupOfNames) obj).getAttributes();
                // set the group's LDAP context and name
                ((GroupOfNames) obj).setName(groupDN, (DirContext) nameCtx, name);
            }

            // merge attribute sets (group's attributes may be overwritten)
            if (inAttrs != null) {
                for (Enumeration attrs = ((Attributes) inAttrs.clone()).getAll(); attrs.hasMoreElements();) {
                    outAttrs.put((Attribute) attrs.nextElement());
                }
            }
            return new DirStateFactory.Result(null, outAttrs);
        }
        return null;
    }


    /**
     * The method is not applicable to this class.
     *
     * @return null is always returned.
     */
    @Override
    public Object getObjectInstance(Object obj, Name name, Context ctx, Hashtable environment) throws Exception {
        return null;
    }

    /**
     * Creates an object that represents an LDAP object at directory context.
     * The LDAP objectClass attribute is examined to determine which object
     * to create.
     *
     * @return An LDAP object or null.
     */
    @Override
    public Object getObjectInstance(Object obj, Name name, Context ctx,
        Hashtable environment, Attributes attributes) throws Exception {

        if (obj instanceof DirContext && ctx instanceof DirContext) {
            // examine the objectClass attribute
            Attribute objectClass =
                (attributes != null ? attributes.get("objectClass") : null);
            if (objectClass != null) {
                // interested only in group objects
                if (GroupOfURLs.matches(objectClass)) {
                    return GroupOfURLs.getObjectInstance(
                        ((DirContext)obj).getNameInNamespace(), (DirContext)ctx,
                        name, environment, attributes);

                } else if (GroupOfUniqueNames.matches(objectClass)) {
                    return GroupOfUniqueNames.getObjectInstance(
                        ((DirContext)obj).getNameInNamespace(), (DirContext)ctx,
                        name, environment, attributes);

                } else if (GroupOfNames.matches(objectClass)) {
                    return GroupOfNames.getObjectInstance(
                        ((DirContext)obj).getNameInNamespace(), (DirContext)ctx,
                        name, environment, attributes);
                }
            }
        }
        return null;
    }

    /**
     * Builds a fully distinguished name from a context and relative name.
     */
    private String getName(Context ctx, Name name) throws NamingException {
        String suffix = ctx.getNameInNamespace();
        String prefix = name.toString();

        if (prefix.equals("")) {
            return suffix;
        } else if (suffix == null || suffix.equals("")) {
            return prefix;
        } else {
            StringBuffer buffer = new StringBuffer();
            return buffer.append(prefix).append(",").append(suffix).toString();
        }
    }
}