/*
 * Copyright (c) 2010-2011 Lockheed Martin Corporation
 *
 * 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 org.eurekastreams.server.action.execution.notification.inapp;

import java.io.Serializable;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.List;

import org.eurekastreams.commons.actions.ExecutionStrategy;
import org.eurekastreams.commons.actions.context.ActionContext;
import org.eurekastreams.commons.logging.LogFactory;
import org.eurekastreams.server.domain.UnreadInAppNotificationCountDTO;
import org.eurekastreams.server.persistence.mappers.DomainMapper;
import org.eurekastreams.server.persistence.mappers.db.notification.DeleteInAppNotificationsByDate;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * Deletes application that are older (in days) than the configured ageInDays value.
 */
public class DeleteOldInAppNotificationsExecution implements ExecutionStrategy<ActionContext>
{
    /** Logger. */
    private final Logger log = LoggerFactory.getLogger(LogFactory.getClassName());

    /** Mapper to delete alerts. */
    private final DeleteInAppNotificationsByDate deleteMapper;

    /** Mapper to find user ids with old unread alerts. */
    private final DomainMapper<Date, List<Long>> unreadMapper;

    /** Mapper to sync database and cache unread alert count. */
    private final DomainMapper<Long, UnreadInAppNotificationCountDTO> syncMapper;

    /** Age at which alerts can be deleted. */
    private final int ageInDays;

    /**
     * Constructor.
     *
     * @param inDeleteMapper
     *            The mapper that performs the application alert deletion from the database.
     * @param inUnreadMapper
     *            The mapper that retrieves the ids of users that have old unread alerts.
     * @param inSyncMapper
     *            The mapper that syncs the unread alert count from the database with the value in cache.
     * @param inAgeInDays
     *            The age in days when an alert is considered "old".
     */
    public DeleteOldInAppNotificationsExecution(final DeleteInAppNotificationsByDate inDeleteMapper,
            final DomainMapper<Date, List<Long>> inUnreadMapper,
            final DomainMapper<Long, UnreadInAppNotificationCountDTO> inSyncMapper, final int inAgeInDays)
    {
        deleteMapper = inDeleteMapper;
        ageInDays = inAgeInDays;
        unreadMapper = inUnreadMapper;
        syncMapper = inSyncMapper;
    }

    /**
     * {@inheritDoc} This method calls the database mapper to delete application alerts that are older than ageInDays.
     * Before the delete, a mapper call is made to find which users had old unread alerts then after the actual
     * deletion, the cached count of unread alerts for these users is synced with the database.
     */
    @Override
    public Serializable execute(final ActionContext inActionContext)
    {
        log.debug("Deleting in-app notifications older than {} days.", ageInDays);

        GregorianCalendar calendar = new GregorianCalendar();
        calendar.add(GregorianCalendar.DATE, ageInDays * -1);
        Date oldDate = calendar.getTime();

        List<Long> userIdsToSync = unreadMapper.execute(oldDate);

        int count = (Integer) deleteMapper.execute(oldDate);

        log.info("Deleted {} in-app notifications older than {} (over {} days old).  Will sync {} users' counts.",
                new Object[] { count, oldDate, ageInDays, userIdsToSync.size() });

        for (long userId : userIdsToSync)
        {
            syncMapper.execute(userId);
        }

        return true;
    }
}