/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
 *
 * 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 sample.contact;


import org.springframework.security.acls.domain.BasePermission;
import org.springframework.security.acls.domain.ObjectIdentityImpl;
import org.springframework.security.acls.domain.PrincipalSid;
import org.springframework.security.acls.model.AccessControlEntry;
import org.springframework.security.acls.model.MutableAcl;
import org.springframework.security.acls.model.MutableAclService;
import org.springframework.security.acls.model.NotFoundException;
import org.springframework.security.acls.model.ObjectIdentity;
import org.springframework.security.acls.model.Permission;
import org.springframework.security.acls.model.Sid;

import org.springframework.security.core.Authentication;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.security.core.userdetails.UserDetails;

import org.springframework.transaction.annotation.Transactional;

import org.springframework.beans.factory.InitializingBean;

import org.springframework.context.support.ApplicationObjectSupport;

import org.springframework.util.Assert;

import java.util.List;
import java.util.Random;


/**
 * Concrete implementation of {@link ContactManager}.
 *
 * @author Ben Alex
 */
@Transactional
public class ContactManagerBackend extends ApplicationObjectSupport implements ContactManager, InitializingBean {
    //~ Instance fields ================================================================================================

    private ContactDao contactDao;
    private MutableAclService mutableAclService;
    private int counter = 1000;

    //~ Methods ========================================================================================================

    public void afterPropertiesSet() throws Exception {
        Assert.notNull(contactDao, "contactDao required");
        Assert.notNull(mutableAclService, "mutableAclService required");
    }

    public void addPermission(Contact contact, Sid recipient, Permission permission) {
        MutableAcl acl;
        ObjectIdentity oid = new ObjectIdentityImpl(Contact.class, contact.getId());

        try {
            acl = (MutableAcl) mutableAclService.readAclById(oid);
        } catch (NotFoundException nfe) {
            acl = mutableAclService.createAcl(oid);
        }

        acl.insertAce(acl.getEntries().size(), permission, recipient, true);
        mutableAclService.updateAcl(acl);

        logger.debug("Added permission " + permission + " for Sid " + recipient + " contact " + contact);
    }

    public void create(Contact contact) {
        // Create the Contact itself
        contact.setId(new Long(counter++));
        contactDao.create(contact);

        // Grant the current principal administrative permission to the contact
        addPermission(contact, new PrincipalSid(getUsername()), BasePermission.ADMINISTRATION);

        if (logger.isDebugEnabled()) {
            logger.debug("Created contact " + contact + " and granted admin permission to recipient " + getUsername());
        }
    }

    public void delete(Contact contact) {
        contactDao.delete(contact.getId());

        // Delete the ACL information as well
        ObjectIdentity oid = new ObjectIdentityImpl(Contact.class, contact.getId());
        mutableAclService.deleteAcl(oid, false);

        if (logger.isDebugEnabled()) {
            logger.debug("Deleted contact " + contact + " including ACL permissions");
        }
    }

    public void deletePermission(Contact contact, Sid recipient, Permission permission) {
        ObjectIdentity oid = new ObjectIdentityImpl(Contact.class, contact.getId());
        MutableAcl acl = (MutableAcl) mutableAclService.readAclById(oid);

        // Remove all permissions associated with this particular recipient (string equality to KISS)
        List<AccessControlEntry> entries = acl.getEntries();

        for (int i = 0; i < entries.size(); i++) {
            if (entries.get(i).getSid().equals(recipient) && entries.get(i).getPermission().equals(permission)) {
                acl.deleteAce(i);
            }
        }

        mutableAclService.updateAcl(acl);

        if (logger.isDebugEnabled()) {
            logger.debug("Deleted contact " + contact + " ACL permissions for recipient " + recipient);
        }
    }

    @Transactional(readOnly=true)
    public List<Contact> getAll() {
        logger.debug("Returning all contacts");

        return contactDao.findAll();
    }

    @Transactional(readOnly=true)
    public List<String> getAllRecipients() {
        logger.debug("Returning all recipients");

        return contactDao.findAllPrincipals();
    }

    @Transactional(readOnly=true)
    public Contact getById(Long id) {
        if (logger.isDebugEnabled()) {
            logger.debug("Returning contact with id: " + id);
        }

        return contactDao.getById(id);
    }

    /**
     * This is a public method.
     */
    @Transactional(readOnly=true)
    public Contact getRandomContact() {
        logger.debug("Returning random contact");

        Random rnd = new Random();
        List<Contact> contacts = contactDao.findAll();
        int getNumber = rnd.nextInt(contacts.size());

        return contacts.get(getNumber);
    }

    protected String getUsername() {
        Authentication auth = SecurityContextHolder.getContext().getAuthentication();

        if (auth.getPrincipal() instanceof UserDetails) {
            return ((UserDetails) auth.getPrincipal()).getUsername();
        } else {
            return auth.getPrincipal().toString();
        }
    }

    public void setContactDao(ContactDao contactDao) {
        this.contactDao = contactDao;
    }

    public void setMutableAclService(MutableAclService mutableAclService) {
        this.mutableAclService = mutableAclService;
    }

    public void update(Contact contact) {
        contactDao.update(contact);

        logger.debug("Updated contact " + contact);
    }
}
