/*
 * Licensed to Jasig under one or more contributor license
 * agreements. See the NOTICE file distributed with this work
 * for additional information regarding copyright ownership.
 * Jasig licenses this file to you 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 the following location:
 *
 *   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 org.jasig.cas.ticket.registry;

import java.io.IOException;
import java.util.Arrays;
import java.util.Collection;
import javax.validation.constraints.Min;
import javax.validation.constraints.NotNull;

import net.spy.memcached.AddrUtil;
import net.spy.memcached.MemcachedClient;
import org.jasig.cas.ticket.ServiceTicket;
import org.jasig.cas.ticket.Ticket;
import org.jasig.cas.ticket.TicketGrantingTicket;
import org.springframework.beans.factory.DisposableBean;

/**
 * Key-value ticket registry implementation that stores tickets in memcached keyed on the ticket ID.
 *
 * @author Scott Battaglia
 * @author Marvin S. Addison
 * @version $Revision: 1.1 $ $Date: 2005/08/19 18:27:17 $
 * @since 3.3
 */
public final class MemCacheTicketRegistry extends AbstractDistributedTicketRegistry implements DisposableBean {

    /** Memcached client */
    @NotNull
    private final MemcachedClient client;

    /**
     * TGT cache entry timeout in seconds.
     */
    @Min(0)
    private final int tgtTimeout;

    /**
     * ST cache entry timeout in seconds.
     */
    @Min(0)
    private final int stTimeout;


    /**
     * Creates a new instance that stores tickets in the given memcached hosts.
     *
     * @param hostnames                   Array of memcached hosts where each element is of the form host:port.
     * @param ticketGrantingTicketTimeOut TGT timeout in seconds.
     * @param serviceTicketTimeOut        ST timeout in seconds.
     */
    public MemCacheTicketRegistry(final String[] hostnames, final int ticketGrantingTicketTimeOut, final int serviceTicketTimeOut) {
        try {
            this.client = new MemcachedClient(AddrUtil.getAddresses(Arrays.asList(hostnames)));
        } catch (final IOException e) {
            throw new IllegalArgumentException("Invalid memcached host specification.", e);
        }
        this.tgtTimeout = ticketGrantingTicketTimeOut;
        this.stTimeout = serviceTicketTimeOut;
    }

    /**
     * This alternative constructor takes time in milliseconds.
     * It has the timeout parameters in order to create a unique method signature.
     *
     * @param ticketGrantingTicketTimeOut TGT timeout in milliseconds.
     * @param serviceTicketTimeOut ST timeout in milliseconds.
     * @param hostnames  Array of memcached hosts where each element is of the form host:port.
     * @see MemCacheTicketRegistry#MemCacheTicketRegistry(String[], int, int)
     */
    @Deprecated
    public MemCacheTicketRegistry(final long ticketGrantingTicketTimeOut, final long serviceTicketTimeOut, final String[] hostnames) {
        this(hostnames, (int) (ticketGrantingTicketTimeOut / 1000), (int) (serviceTicketTimeOut / 1000));
    }

    /**
     * Creates a new instance using the given memcached client instance, which is presumably configured via
     * <code>net.spy.memcached.spring.MemcachedClientFactoryBean</code>.
     *
     * @param client                      Memcached client.
     * @param ticketGrantingTicketTimeOut TGT timeout in seconds.
     * @param serviceTicketTimeOut        ST timeout in seconds.
     */
    public MemCacheTicketRegistry(final MemcachedClient client, final int ticketGrantingTicketTimeOut, final int serviceTicketTimeOut) {
        this.tgtTimeout = ticketGrantingTicketTimeOut;
        this.stTimeout = serviceTicketTimeOut;
        this.client = client;
    }

    protected void updateTicket(final Ticket ticket) {
        log.debug("Updating ticket {}", ticket);
        try {
            if (!this.client.replace(ticket.getId(), getTimeout(ticket), ticket).get()) {
                log.error("Failed updating {}", ticket);
            }
        } catch (final InterruptedException e) {
            log.warn("Interrupted while waiting for response to async replace operation for ticket {}. " +
                    "Cannot determine whether update was successful.", ticket);
        } catch (final Exception e) {
            log.error("Failed updating {}", ticket, e);
        }
    }

    public void addTicket(final Ticket ticket) {
        log.debug("Adding ticket {}", ticket);
        try {
            if (!this.client.add(ticket.getId(), getTimeout(ticket), ticket).get()) {
                log.error("Failed adding {}", ticket);
            }
        } catch (final InterruptedException e) {
            log.warn("Interrupted while waiting for response to async add operation for ticket {}. " +
                    "Cannot determine whether add was successful.", ticket);
        } catch (final Exception e) {
            log.error("Failed adding {}", ticket, e);
        }
    }

    public boolean deleteTicket(final String ticketId) {
        log.debug("Deleting ticket {}", ticketId);
        try {
            return this.client.delete(ticketId).get();
        } catch (final Exception e) {
            log.error("Failed deleting {}", ticketId, e);
        }
        return false;
    }

    public Ticket getTicket(final String ticketId) {
        try {
            final Ticket t = (Ticket) this.client.get(ticketId);
            if (t != null) {
                return getProxiedTicketInstance(t);
            }
        } catch (final Exception e) {
            log.error("Failed fetching {} ", ticketId, e);
        }
        return null;
    }

    /**
     * This operation is not supported.
     *
     * @throws UnsupportedOperationException if you try and call this operation.
     */
    public Collection<Ticket> getTickets() {
        throw new UnsupportedOperationException("GetTickets not supported.");
    }

    public void destroy() throws Exception {
        this.client.shutdown();
    }

    /**
     * As of version 3.5, this operation has no effect since async writes can cause registry consistency issues.
     */
    @Deprecated
    public void setSynchronizeUpdatesToRegistry(final boolean b) { /* NOOP */ }

    @Override
    protected boolean needsCallback() {
        return true;
    }

    private int getTimeout(final Ticket t) {
        if (t instanceof TicketGrantingTicket) {
            return this.tgtTimeout;
        } else if (t instanceof ServiceTicket) {
            return this.stTimeout;
        }
        throw new IllegalArgumentException("Invalid ticket type");
    }
}
