/*
 * Copyright 2010-2013 Ning, Inc.
 * Copyright 2014-2015 Groupon, Inc
 * Copyright 2014-2015 The Billing Project, LLC
 *
 * The Billing Project 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:
 *
 *    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.killbill.billing.subscription.engine.dao;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.Collections;
import java.util.Comparator;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;
import java.util.UUID;

import javax.annotation.Nullable;
import javax.inject.Inject;

import org.joda.time.DateTime;
import org.killbill.billing.ErrorCode;
import org.killbill.billing.callcontext.InternalCallContext;
import org.killbill.billing.callcontext.InternalTenantContext;
import org.killbill.billing.catalog.api.Catalog;
import org.killbill.billing.catalog.api.CatalogApiException;
import org.killbill.billing.catalog.api.CatalogService;
import org.killbill.billing.catalog.api.Plan;
import org.killbill.billing.catalog.api.ProductCategory;
import org.killbill.billing.entitlement.api.SubscriptionApiException;
import org.killbill.billing.entity.EntityPersistenceException;
import org.killbill.billing.subscription.api.SubscriptionBase;
import org.killbill.billing.subscription.api.SubscriptionBaseTransitionType;
import org.killbill.billing.subscription.api.migration.AccountMigrationData;
import org.killbill.billing.subscription.api.migration.AccountMigrationData.BundleMigrationData;
import org.killbill.billing.subscription.api.migration.AccountMigrationData.SubscriptionMigrationData;
import org.killbill.billing.subscription.api.transfer.TransferCancelData;
import org.killbill.billing.subscription.api.user.DefaultEffectiveSubscriptionEvent;
import org.killbill.billing.subscription.api.user.DefaultRequestedSubscriptionEvent;
import org.killbill.billing.subscription.api.user.DefaultSubscriptionBase;
import org.killbill.billing.subscription.api.user.DefaultSubscriptionBaseBundle;
import org.killbill.billing.subscription.api.user.SubscriptionBaseBundle;
import org.killbill.billing.subscription.api.user.SubscriptionBaseTransitionData;
import org.killbill.billing.subscription.api.user.SubscriptionBuilder;
import org.killbill.billing.subscription.engine.addon.AddonUtils;
import org.killbill.billing.subscription.engine.core.DefaultSubscriptionBaseService;
import org.killbill.billing.subscription.engine.core.SubscriptionNotificationKey;
import org.killbill.billing.subscription.engine.dao.model.SubscriptionBundleModelDao;
import org.killbill.billing.subscription.engine.dao.model.SubscriptionEventModelDao;
import org.killbill.billing.subscription.engine.dao.model.SubscriptionModelDao;
import org.killbill.billing.subscription.events.EventBaseBuilder;
import org.killbill.billing.subscription.events.SubscriptionBaseEvent;
import org.killbill.billing.subscription.events.SubscriptionBaseEvent.EventType;
import org.killbill.billing.subscription.events.phase.PhaseEvent;
import org.killbill.billing.subscription.events.phase.PhaseEventBuilder;
import org.killbill.billing.subscription.events.user.ApiEvent;
import org.killbill.billing.subscription.events.user.ApiEventBuilder;
import org.killbill.billing.subscription.events.user.ApiEventCancel;
import org.killbill.billing.subscription.events.user.ApiEventChange;
import org.killbill.billing.subscription.events.user.ApiEventMigrateBilling;
import org.killbill.billing.subscription.events.user.ApiEventType;
import org.killbill.billing.subscription.exceptions.SubscriptionBaseError;
import org.killbill.billing.util.UUIDs;
import org.killbill.billing.util.cache.CacheControllerDispatcher;
import org.killbill.billing.util.dao.NonEntityDao;
import org.killbill.billing.util.entity.Pagination;
import org.killbill.billing.util.entity.dao.DefaultPaginationSqlDaoHelper.PaginationIteratorBuilder;
import org.killbill.billing.util.entity.dao.EntityDaoBase;
import org.killbill.billing.util.entity.dao.EntitySqlDaoTransactionWrapper;
import org.killbill.billing.util.entity.dao.EntitySqlDaoTransactionalJdbiWrapper;
import org.killbill.billing.util.entity.dao.EntitySqlDaoWrapperFactory;
import org.killbill.bus.api.BusEvent;
import org.killbill.bus.api.PersistentBus;
import org.killbill.bus.api.PersistentBus.EventBusException;
import org.killbill.clock.Clock;
import org.killbill.notificationq.api.NotificationEvent;
import org.killbill.notificationq.api.NotificationQueue;
import org.killbill.notificationq.api.NotificationQueueService;
import org.killbill.notificationq.api.NotificationQueueService.NoSuchNotificationQueue;
import org.skife.jdbi.v2.IDBI;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import com.google.common.base.Function;
import com.google.common.base.Predicate;
import com.google.common.collect.ArrayListMultimap;
import com.google.common.collect.Collections2;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;
import com.google.common.collect.Multimap;

public class DefaultSubscriptionDao extends EntityDaoBase<SubscriptionBundleModelDao, SubscriptionBaseBundle, SubscriptionApiException> implements SubscriptionDao {

    private static final Logger log = LoggerFactory.getLogger(DefaultSubscriptionDao.class);

    private final Clock clock;
    private final NotificationQueueService notificationQueueService;
    private final AddonUtils addonUtils;
    private final PersistentBus eventBus;
    private final CatalogService catalogService;

    @Inject
    public DefaultSubscriptionDao(final IDBI dbi, final Clock clock, final AddonUtils addonUtils,
                                  final NotificationQueueService notificationQueueService, final PersistentBus eventBus, final CatalogService catalogService,
                                  final CacheControllerDispatcher cacheControllerDispatcher, final NonEntityDao nonEntityDao) {
        super(new EntitySqlDaoTransactionalJdbiWrapper(dbi, clock, cacheControllerDispatcher, nonEntityDao), BundleSqlDao.class);
        this.clock = clock;
        this.notificationQueueService = notificationQueueService;
        this.addonUtils = addonUtils;
        this.eventBus = eventBus;
        this.catalogService = catalogService;
    }

    @Override
    protected SubscriptionApiException generateAlreadyExistsException(final SubscriptionBundleModelDao entity, final InternalCallContext context) {
        return new SubscriptionApiException(ErrorCode.SUB_CREATE_ACTIVE_BUNDLE_KEY_EXISTS, entity.getExternalKey());
    }

    @Override
    public List<SubscriptionBaseBundle> getSubscriptionBundlesForAccountAndKey(final UUID accountId, final String bundleKey, final InternalTenantContext context) {
        return transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<List<SubscriptionBaseBundle>>() {
            @Override
            public List<SubscriptionBaseBundle> inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final List<SubscriptionBundleModelDao> models = entitySqlDaoWrapperFactory.become(BundleSqlDao.class).getBundlesFromAccountAndKey(accountId.toString(), bundleKey, context);
                return new ArrayList<SubscriptionBaseBundle>(Collections2.transform(models, new Function<SubscriptionBundleModelDao, SubscriptionBaseBundle>() {
                    @Override
                    public SubscriptionBaseBundle apply(@Nullable final SubscriptionBundleModelDao input) {
                        return SubscriptionBundleModelDao.toSubscriptionbundle(input);
                    }
                }));
            }
        });
    }

    @Override
    public List<SubscriptionBaseBundle> getSubscriptionBundleForAccount(final UUID accountId, final InternalTenantContext context) {
        return transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<List<SubscriptionBaseBundle>>() {
            @Override
            public List<SubscriptionBaseBundle> inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final List<SubscriptionBundleModelDao> models = entitySqlDaoWrapperFactory.become(BundleSqlDao.class).getBundleFromAccount(accountId.toString(), context);

                return new ArrayList<SubscriptionBaseBundle>(Collections2.transform(models, new Function<SubscriptionBundleModelDao, SubscriptionBaseBundle>() {
                    @Override
                    public SubscriptionBaseBundle apply(@Nullable final SubscriptionBundleModelDao input) {
                        return SubscriptionBundleModelDao.toSubscriptionbundle(input);
                    }
                }));
            }
        });
    }

    @Override
    public SubscriptionBaseBundle getSubscriptionBundleFromId(final UUID bundleId, final InternalTenantContext context) {
        return transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<SubscriptionBaseBundle>() {
            @Override
            public SubscriptionBaseBundle inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final SubscriptionBundleModelDao model = entitySqlDaoWrapperFactory.become(BundleSqlDao.class).getById(bundleId.toString(), context);
                return SubscriptionBundleModelDao.toSubscriptionbundle(model);
            }
        });
    }

    @Override
    public List<SubscriptionBaseBundle> getSubscriptionBundlesForKey(final String bundleKey, final InternalTenantContext context) {
        return transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<List<SubscriptionBaseBundle>>() {
            @Override
            public List<SubscriptionBaseBundle> inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final List<SubscriptionBundleModelDao> models = entitySqlDaoWrapperFactory.become(BundleSqlDao.class).getBundlesForKey(bundleKey, context);
                return new ArrayList<SubscriptionBaseBundle>(Collections2.transform(models, new Function<SubscriptionBundleModelDao, SubscriptionBaseBundle>() {
                    @Override
                    public SubscriptionBaseBundle apply(@Nullable final SubscriptionBundleModelDao input) {
                        return SubscriptionBundleModelDao.toSubscriptionbundle(input);
                    }
                }));
            }
        });
    }

    @Override
    public Pagination<SubscriptionBundleModelDao> searchSubscriptionBundles(final String searchKey, final Long offset, final Long limit, final InternalTenantContext context) {
        return paginationHelper.getPagination(BundleSqlDao.class,
                                              new PaginationIteratorBuilder<SubscriptionBundleModelDao, SubscriptionBaseBundle, BundleSqlDao>() {
                                                  @Override
                                                  public Long getCount(final BundleSqlDao bundleSqlDao, final InternalTenantContext context) {
                                                      return bundleSqlDao.getSearchCount(searchKey, String.format("%%%s%%", searchKey), context);
                                                  }

                                                  @Override
                                                  public Iterator<SubscriptionBundleModelDao> build(final BundleSqlDao bundleSqlDao, final Long limit, final InternalTenantContext context) {
                                                      return bundleSqlDao.search(searchKey, String.format("%%%s%%", searchKey), offset, limit, context);
                                                  }
                                              },
                                              offset,
                                              limit,
                                              context);
    }

    @Override
    public Iterable<UUID> getNonAOSubscriptionIdsForKey(final String bundleKey, final InternalTenantContext context) {
        return transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<Iterable<UUID>>() {
            @Override
            public Iterable<UUID> inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {

                final BundleSqlDao bundleSqlDao = entitySqlDaoWrapperFactory.become(BundleSqlDao.class);

                final List<SubscriptionBundleModelDao> bundles = bundleSqlDao.getBundlesForKey(bundleKey, context);

                final Collection<UUID> nonAOSubscriptionIdsForKey = new LinkedList<UUID>();
                final SubscriptionSqlDao subscriptionSqlDao = entitySqlDaoWrapperFactory.become(SubscriptionSqlDao.class);
                for (final SubscriptionBundleModelDao bundle : bundles) {
                    final List<SubscriptionModelDao> subscriptions = subscriptionSqlDao.getSubscriptionsFromBundleId(bundle.getId().toString(), context);

                    final Collection<SubscriptionModelDao> nonAddonSubscriptions = Collections2.filter(subscriptions,
                                                                                                       new Predicate<SubscriptionModelDao>() {
                                                                                                           @Override
                                                                                                           public boolean apply(final SubscriptionModelDao input) {
                                                                                                               return input.getCategory() != ProductCategory.ADD_ON;
                                                                                                           }
                                                                                                       });

                    nonAOSubscriptionIdsForKey.addAll(Collections2.transform(nonAddonSubscriptions,
                                                                             new Function<SubscriptionModelDao, UUID>() {
                                                                                 @Override
                                                                                 public UUID apply(final SubscriptionModelDao input) {
                                                                                     return input.getId();
                                                                                 }
                                                                             }));

                }

                return nonAOSubscriptionIdsForKey;
            }
        });
    }

    @Override
    public SubscriptionBaseBundle createSubscriptionBundle(final DefaultSubscriptionBaseBundle bundle, final InternalCallContext context) {
        return transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<SubscriptionBaseBundle>() {
            @Override
            public SubscriptionBaseBundle inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws EntityPersistenceException {

                final SubscriptionBundleModelDao model = new SubscriptionBundleModelDao(bundle);
                entitySqlDaoWrapperFactory.become(BundleSqlDao.class).create(model, context);
                final SubscriptionBundleModelDao result = entitySqlDaoWrapperFactory.become(BundleSqlDao.class).getById(bundle.getId().toString(), context);
                return SubscriptionBundleModelDao.toSubscriptionbundle(result);
            }
        });
    }

    @Override
    public UUID getAccountIdFromSubscriptionId(final UUID subscriptionId, final InternalTenantContext context) {

        return transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<UUID>() {
            @Override
            public UUID inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final SubscriptionModelDao subscriptionModel = entitySqlDaoWrapperFactory.become(SubscriptionSqlDao.class).getById(subscriptionId.toString(), context);
                if (subscriptionModel == null) {
                    log.error(String.format(ErrorCode.SUB_INVALID_SUBSCRIPTION_ID.getFormat(), subscriptionId.toString()));
                    return null;
                }

                final UUID bundleId = subscriptionModel.getBundleId();
                if (bundleId == null) {
                    log.error(String.format(ErrorCode.SUB_GET_NO_BUNDLE_FOR_SUBSCRIPTION.getFormat(), subscriptionId.toString()));
                    return null;
                }

                final SubscriptionBundleModelDao bundleModel = entitySqlDaoWrapperFactory.become(BundleSqlDao.class).getById(bundleId.toString(), context);
                if (bundleModel == null) {
                    log.error(String.format(ErrorCode.SUB_GET_INVALID_BUNDLE_ID.getFormat(), bundleId.toString()));
                    return null;
                }
                return bundleModel.getAccountId();
            }
        });
    }

    @Override
    public SubscriptionBase getBaseSubscription(final UUID bundleId, final InternalTenantContext context) throws CatalogApiException {
        return getBaseSubscription(bundleId, true, context);
    }

    @Override
    public SubscriptionBase getSubscriptionFromId(final UUID subscriptionId, final InternalTenantContext context) throws CatalogApiException {
        final SubscriptionBase shellSubscription = transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<SubscriptionBase>() {
            @Override
            public SubscriptionBase inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final SubscriptionModelDao model = entitySqlDaoWrapperFactory.become(SubscriptionSqlDao.class).getById(subscriptionId.toString(), context);
                return SubscriptionModelDao.toSubscription(model);
            }
        });
        return buildSubscription(shellSubscription, context);
    }

    @Override
    public List<SubscriptionBase> getSubscriptions(final UUID bundleId, final List<SubscriptionBaseEvent> dryRunEvents, final InternalTenantContext context) throws CatalogApiException {
        return buildBundleSubscriptions(getSubscriptionFromBundleId(bundleId, context), null, dryRunEvents, context);
    }

    private List<SubscriptionBase> getSubscriptionFromBundleId(final UUID bundleId, final InternalTenantContext context) {
        return transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<List<SubscriptionBase>>() {
            @Override
            public List<SubscriptionBase> inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final List<SubscriptionModelDao> models = entitySqlDaoWrapperFactory.become(SubscriptionSqlDao.class).getSubscriptionsFromBundleId(bundleId.toString(), context);
                return new ArrayList<SubscriptionBase>(Collections2.transform(models, new Function<SubscriptionModelDao, SubscriptionBase>() {
                    @Override
                    public SubscriptionBase apply(@Nullable final SubscriptionModelDao input) {
                        return SubscriptionModelDao.toSubscription(input);
                    }
                }));
            }
        });
    }

    @Override
    public Map<UUID, List<SubscriptionBase>> getSubscriptionsForAccount(final InternalTenantContext context) throws CatalogApiException {
        final Map<UUID, List<SubscriptionBase>> subscriptionsFromAccountId = getSubscriptionsFromAccountId(context);

        final List<SubscriptionBaseEvent> eventsForAccount = getEventsForAccountId(context);

        final Map<UUID, List<SubscriptionBase>> result = new HashMap<UUID, List<SubscriptionBase>>();
        for (final UUID bundleId : subscriptionsFromAccountId.keySet()) {

            final List<SubscriptionBase> subscriptionsForBundle = subscriptionsFromAccountId.get(bundleId);
            final Collection<UUID> subscriptionIdsForBundle = Collections2.transform(subscriptionsForBundle, new Function<SubscriptionBase, UUID>() {
                @Override
                public UUID apply(final SubscriptionBase input) {
                    return input.getId();
                }
            });
            final Multimap<UUID, SubscriptionBaseEvent> eventsForSubscriptions = ArrayListMultimap.create();

            for (final SubscriptionBase cur : subscriptionsForBundle) {
                final Collection<SubscriptionBaseEvent> events = Collections2.filter(eventsForAccount, new Predicate<SubscriptionBaseEvent>() {
                    @Override
                    public boolean apply(final SubscriptionBaseEvent input) {
                        return input.getSubscriptionId().equals(cur.getId());

                    }
                });
                eventsForSubscriptions.putAll(cur.getId(), ImmutableList.copyOf(events));
            }

            result.put(bundleId, buildBundleSubscriptions(subscriptionsForBundle, eventsForSubscriptions, null, context));
        }
        return result;
    }

    private Map<UUID, List<SubscriptionBase>> getSubscriptionsFromAccountId(final InternalTenantContext context) {
        final List<SubscriptionBase> allSubscriptions = transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<List<SubscriptionBase>>() {
            @Override
            public List<SubscriptionBase> inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final List<SubscriptionModelDao> models = entitySqlDaoWrapperFactory.become(SubscriptionSqlDao.class).getByAccountRecordId(context);
                return new ArrayList<SubscriptionBase>(Collections2.transform(models, new Function<SubscriptionModelDao, SubscriptionBase>() {
                    @Override
                    public SubscriptionBase apply(final SubscriptionModelDao input) {
                        return SubscriptionModelDao.toSubscription(input);
                    }
                }));
            }
        });

        final Map<UUID, List<SubscriptionBase>> result = new HashMap<UUID, List<SubscriptionBase>>();
        for (final SubscriptionBase subscriptionBase : allSubscriptions) {
            if (result.get(subscriptionBase.getBundleId()) == null) {
                result.put(subscriptionBase.getBundleId(), new LinkedList<SubscriptionBase>());
            }
            result.get(subscriptionBase.getBundleId()).add(subscriptionBase);
        }
        return result;
    }

    @Override
    public void updateChargedThroughDate(final DefaultSubscriptionBase subscription, final InternalCallContext context) {
        final Date ctd = (subscription.getChargedThroughDate() != null) ? subscription.getChargedThroughDate().toDate() : null;

        transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<Void>() {
            @Override
            public Void inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final SubscriptionSqlDao transactionalDao = entitySqlDaoWrapperFactory.become(SubscriptionSqlDao.class);
                transactionalDao.updateChargedThroughDate(subscription.getId().toString(), ctd, context);

                final BundleSqlDao bundleSqlDao = entitySqlDaoWrapperFactory.become(BundleSqlDao.class);
                final String bundleId = subscription.getBundleId().toString();
                bundleSqlDao.updateBundleLastSysTime(bundleId, clock.getUTCNow().toDate(), context);
                return null;
            }
        });
    }

    @Override
    public void createNextPhaseEvent(final DefaultSubscriptionBase subscription, final SubscriptionBaseEvent readyPhaseEvent, final SubscriptionBaseEvent nextPhaseEvent, final InternalCallContext context) {
        transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<Void>() {
            @Override
            public Void inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final SubscriptionEventSqlDao transactional = entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class);
                final UUID subscriptionId = subscription.getId();
                cancelNextPhaseEventFromTransaction(subscriptionId, entitySqlDaoWrapperFactory, context);
                transactional.create(new SubscriptionEventModelDao(nextPhaseEvent), context);
                recordFutureNotificationFromTransaction(entitySqlDaoWrapperFactory,
                                                        nextPhaseEvent.getEffectiveDate(),
                                                        new SubscriptionNotificationKey(nextPhaseEvent.getId()), context);

                // Notify the Bus
                notifyBusOfRequestedChange(entitySqlDaoWrapperFactory, subscription, nextPhaseEvent, SubscriptionBaseTransitionType.PHASE, context);
                notifyBusOfEffectiveImmediateChange(entitySqlDaoWrapperFactory, subscription, readyPhaseEvent, 0, context);

                return null;
            }
        });
    }

    @Override
    public SubscriptionBaseEvent getEventById(final UUID eventId, final InternalTenantContext context) {
        return transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<SubscriptionBaseEvent>() {
            @Override
            public SubscriptionBaseEvent inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                SubscriptionEventModelDao model = entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class).getById(eventId.toString(), context);
                return SubscriptionEventModelDao.toSubscriptionEvent(model);
            }
        });
    }

    @Override
    public List<SubscriptionBaseEvent> getEventsForSubscription(final UUID subscriptionId, final InternalTenantContext context) {
        return transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<List<SubscriptionBaseEvent>>() {
            @Override
            public List<SubscriptionBaseEvent> inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final List<SubscriptionEventModelDao> models = entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class).getEventsForSubscription(subscriptionId.toString(), context);
                return filterSubscriptionBaseEvents(models);
            }
        });
    }

    @Override
    public Iterable<SubscriptionBaseEvent> getFutureEventsForAccount(final InternalTenantContext context) {
        return transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<Iterable<SubscriptionBaseEvent>>() {
            @Override
            public Iterable<SubscriptionBaseEvent> inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final SubscriptionEventSqlDao transactional = entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class);
                final List<SubscriptionEventModelDao> activeEvents = transactional.getFutureActiveEventsForAccount(clock.getUTCNow().toDate(), context);
                return Iterables.transform(activeEvents, new Function<SubscriptionEventModelDao, SubscriptionBaseEvent>() {

                    @Override
                    public SubscriptionBaseEvent apply(final SubscriptionEventModelDao input) {
                        return SubscriptionEventModelDao.toSubscriptionEvent(input);
                    }
                });
            }
        });
    }

    @Override
    public List<SubscriptionBaseEvent> getPendingEventsForSubscription(final UUID subscriptionId, final InternalTenantContext context) {
        final Date now = clock.getUTCNow().toDate();

        return transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<List<SubscriptionBaseEvent>>() {
            @Override
            public List<SubscriptionBaseEvent> inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final List<SubscriptionEventModelDao> eventModels = entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class).getFutureActiveEventForSubscription(subscriptionId.toString(), now, context);
                final List<SubscriptionBaseEvent> events = new ArrayList<SubscriptionBaseEvent>(Collections2.transform(eventModels, new Function<SubscriptionEventModelDao, SubscriptionBaseEvent>() {
                    @Override
                    public SubscriptionBaseEvent apply(@Nullable final SubscriptionEventModelDao input) {
                        return SubscriptionEventModelDao.toSubscriptionEvent(input);
                    }
                }));
                return events;
            }
        });
    }

    @Override
    public void createSubscription(final DefaultSubscriptionBase subscription, final List<SubscriptionBaseEvent> initialEvents, final InternalCallContext context) {
        transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<Void>() {
            @Override
            public Void inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final SubscriptionSqlDao transactional = entitySqlDaoWrapperFactory.become(SubscriptionSqlDao.class);
                transactional.create(new SubscriptionModelDao(subscription), context);

                final SubscriptionEventSqlDao eventsDaoFromSameTransaction = entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class);
                for (final SubscriptionBaseEvent cur : initialEvents) {
                    eventsDaoFromSameTransaction.create(new SubscriptionEventModelDao(cur), context);

                    final boolean isBusEvent = cur.getEffectiveDate().compareTo(clock.getUTCNow()) <= 0 && (cur.getType() == EventType.API_USER);
                    recordBusOrFutureNotificationFromTransaction(subscription, cur, entitySqlDaoWrapperFactory, isBusEvent, 0, context);

                }
                // Notify the Bus of the latest requested change, if needed
                if (initialEvents.size() > 0) {
                    notifyBusOfRequestedChange(entitySqlDaoWrapperFactory, subscription, initialEvents.get(initialEvents.size() - 1), SubscriptionBaseTransitionType.CREATE, context);
                }
                return null;
            }
        });
    }

    @Override
    public void createSubscriptionWithAddOns(final List<DefaultSubscriptionBase> subscriptions, final Map<UUID, List<SubscriptionBaseEvent>> initialEventsMap, final InternalCallContext context) {
        transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<Void>() {
            @Override
            public Void inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final SubscriptionSqlDao transactional = entitySqlDaoWrapperFactory.become(SubscriptionSqlDao.class);
                final SubscriptionEventSqlDao eventsDaoFromSameTransaction = entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class);

                for (DefaultSubscriptionBase subscription : subscriptions) {
                    transactional.create(new SubscriptionModelDao(subscription), context);

                    final List<SubscriptionBaseEvent> initialEvents = initialEventsMap.get(subscription.getId());
                    for (final SubscriptionBaseEvent cur : initialEvents) {
                        eventsDaoFromSameTransaction.create(new SubscriptionEventModelDao(cur), context);

                        final boolean isBusEvent = cur.getEffectiveDate().compareTo(clock.getUTCNow()) <= 0 && (cur.getType() == EventType.API_USER);
                        recordBusOrFutureNotificationFromTransaction(subscription, cur, entitySqlDaoWrapperFactory, isBusEvent, 0, context);

                    }
                    // Notify the Bus of the latest requested change, if needed
                    if (initialEvents.size() > 0) {
                        notifyBusOfRequestedChange(entitySqlDaoWrapperFactory, subscription, initialEvents.get(initialEvents.size() - 1), SubscriptionBaseTransitionType.CREATE, context);
                    }
                }
                return null;
            }
        });
    }

    @Override
    public void recreateSubscription(final DefaultSubscriptionBase subscription, final List<SubscriptionBaseEvent> recreateEvents, final InternalCallContext context) {
        transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<Void>() {
            @Override
            public Void inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final SubscriptionEventSqlDao transactional = entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class);

                for (final SubscriptionBaseEvent cur : recreateEvents) {
                    transactional.create(new SubscriptionEventModelDao(cur), context);

                    final boolean isBusEvent = cur.getEffectiveDate().compareTo(clock.getUTCNow()) <= 0 && (cur.getType() == EventType.API_USER);
                    recordBusOrFutureNotificationFromTransaction(subscription, cur, entitySqlDaoWrapperFactory, isBusEvent, 0, context);
                }

                // Notify the Bus of the latest requested change
                notifyBusOfRequestedChange(entitySqlDaoWrapperFactory, subscription, recreateEvents.get(recreateEvents.size() - 1), SubscriptionBaseTransitionType.RE_CREATE, context);

                return null;
            }
        });
    }

    @Override
    public void cancelSubscriptionsOnBasePlanEvent(final DefaultSubscriptionBase subscription, final SubscriptionBaseEvent event, final List<DefaultSubscriptionBase> subscriptions, final List<SubscriptionBaseEvent> cancelEvents, final InternalCallContext context) {
        transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<Void>() {
            @Override
            public Void inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                cancelSubscriptionsFromTransaction(entitySqlDaoWrapperFactory, subscriptions, cancelEvents, context);
                // Make sure to always send the event, even if there were no subscriptions to cancel
                notifyBusOfEffectiveImmediateChange(entitySqlDaoWrapperFactory, subscription, event, subscriptions.size(), context);
                return null;
            }
        });
    }

    @Override
    public void cancelSubscriptions(final List<DefaultSubscriptionBase> subscriptions, final List<SubscriptionBaseEvent> cancelEvents, final InternalCallContext context) {
        transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<Void>() {
            @Override
            public Void inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                cancelSubscriptionsFromTransaction(entitySqlDaoWrapperFactory, subscriptions, cancelEvents, context);
                return null;
            }
        });
    }

    private void cancelSubscriptionsFromTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory, final List<DefaultSubscriptionBase> subscriptions, final List<SubscriptionBaseEvent> cancelEvents, final InternalCallContext context) throws EntityPersistenceException {
        for (int i = 0; i < subscriptions.size(); i++) {
            final DefaultSubscriptionBase subscription = subscriptions.get(i);
            final SubscriptionBaseEvent cancelEvent = cancelEvents.get(i);
            cancelSubscriptionFromTransaction(subscription, cancelEvent, entitySqlDaoWrapperFactory, context, subscriptions.size() - i - 1);
        }
    }

    @Override
    public void uncancelSubscription(final DefaultSubscriptionBase subscription, final List<SubscriptionBaseEvent> uncancelEvents, final InternalCallContext context) {
        transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<Void>() {
            @Override
            public Void inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final SubscriptionEventSqlDao transactional = entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class);

                final UUID subscriptionId = subscription.getId();
                SubscriptionEventModelDao cancelledEvent = null;
                final Date now = clock.getUTCNow().toDate();
                final List<SubscriptionEventModelDao> eventModels = transactional.getFutureActiveEventForSubscription(subscriptionId.toString(), now, context);

                for (final SubscriptionEventModelDao cur : eventModels) {
                    if (cur.getUserType() == ApiEventType.CANCEL) {
                        if (cancelledEvent != null) {
                            throw new SubscriptionBaseError(String.format("Found multiple cancelWithRequestedDate active events for subscriptions %s", subscriptionId.toString()));
                        }
                        cancelledEvent = cur;
                    }
                }

                if (cancelledEvent != null) {
                    final String cancelledEventId = cancelledEvent.getId().toString();
                    transactional.unactiveEvent(cancelledEventId, context);
                    for (final SubscriptionBaseEvent cur : uncancelEvents) {
                        transactional.create(new SubscriptionEventModelDao(cur), context);
                        recordFutureNotificationFromTransaction(entitySqlDaoWrapperFactory,
                                                                cur.getEffectiveDate(),
                                                                new SubscriptionNotificationKey(cur.getId()),
                                                                context);
                    }

                    // Notify the Bus of the latest requested change
                    notifyBusOfRequestedChange(entitySqlDaoWrapperFactory, subscription, uncancelEvents.get(uncancelEvents.size() - 1), SubscriptionBaseTransitionType.UNCANCEL, context);
                }

                return null;
            }
        });
    }

    @Override
    public void changePlan(final DefaultSubscriptionBase subscription, final List<SubscriptionBaseEvent> changeEvents, final List<DefaultSubscriptionBase> subscriptionsToBeCancelled, final List<SubscriptionBaseEvent> cancelEvents, final InternalCallContext context) {
        transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<Void>() {
            @Override
            public Void inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final SubscriptionEventSqlDao transactional = entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class);
                final UUID subscriptionId = subscription.getId();

                final List<SubscriptionBaseEvent> changeEventsTweakedWithMigrateBilling = reinsertFutureMigrateBillingEventOnChangeFromTransaction(subscriptionId,
                                                                                                                                                   changeEvents,
                                                                                                                                                   entitySqlDaoWrapperFactory,
                                                                                                                                                   context);
                cancelFutureEventsFromTransaction(subscriptionId, changeEvents.get(0).getEffectiveDate(), entitySqlDaoWrapperFactory, context);

                for (final SubscriptionBaseEvent cur : changeEventsTweakedWithMigrateBilling) {
                    transactional.create(new SubscriptionEventModelDao(cur), context);

                    final boolean isBusEvent = cur.getEffectiveDate().compareTo(clock.getUTCNow()) <= 0 && (cur.getType() == EventType.API_USER);
                    recordBusOrFutureNotificationFromTransaction(subscription, cur, entitySqlDaoWrapperFactory, isBusEvent, 0, context);
                }

                // Notify the Bus of the latest requested change
                final SubscriptionBaseEvent finalEvent = changeEventsTweakedWithMigrateBilling.get(changeEvents.size() - 1);
                notifyBusOfRequestedChange(entitySqlDaoWrapperFactory, subscription, finalEvent, SubscriptionBaseTransitionType.CHANGE, context);

                // Cancel associated add-ons
                cancelSubscriptionsFromTransaction(entitySqlDaoWrapperFactory, subscriptionsToBeCancelled, cancelEvents, context);

                return null;
            }
        });
    }

    //
    // This piece of code has been isolated in its own method in order to allow for migrated subscriptions to have their plan to changed prior
    // to MIGRATE_BILLING; the effect will be to reflect the change from an subscription point of view while ignoring the change until we hit
    // the begining of the billing, that is when we hit the MIGRATE_BILLING event. If we had a clear separation between subscription and
    // billing that would not be needed.
    //
    // If there is a change of plan prior to a future MIGRATE_BILLING, we want to modify the existing MIGRATE_BILLING so it reflects
    // the new plan, phase, pricelist; Invoice will only see the MIGRATE_BILLING as things prior to that will be ignored, so we need to make sure
    // that event reflects the correct subscription information.
    //
    //
    final List<SubscriptionBaseEvent> reinsertFutureMigrateBillingEventOnChangeFromTransaction(final UUID subscriptionId, final List<SubscriptionBaseEvent> changeEvents, final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory, final InternalCallContext context) {
        final SubscriptionEventModelDao migrateBillingEvent = findFutureEventFromTransaction(subscriptionId, entitySqlDaoWrapperFactory, EventType.API_USER, ApiEventType.MIGRATE_BILLING, context);
        if (migrateBillingEvent == null) {
            // No future migrate billing : returns same list
            return changeEvents;
        }

        String prevPlan = null;
        String prevPhase = null;
        String prevPriceList = null;
        String curPlan = null;
        String curPhase = null;
        String curPriceList = null;
        for (SubscriptionBaseEvent cur : changeEvents) {
            switch (cur.getType()) {
                case API_USER:
                    final ApiEvent apiEvent = (ApiEvent) cur;
                    curPlan = apiEvent.getEventPlan();
                    curPhase = apiEvent.getEventPlanPhase();
                    curPriceList = apiEvent.getPriceList();
                    break;

                case PHASE:
                    final PhaseEvent phaseEvent = (PhaseEvent) cur;
                    curPhase = phaseEvent.getPhase();
                    break;

                default:
                    throw new SubscriptionBaseError("Unknown event type " + cur.getType());
            }

            if (cur.getEffectiveDate().compareTo(migrateBillingEvent.getEffectiveDate()) > 0) {
                if (cur.getType() == EventType.API_USER && ((ApiEvent) cur).getApiEventType() == ApiEventType.CHANGE) {
                    // This is an EOT change that is occurring after the MigrateBilling : returns same list
                    return changeEvents;
                }
                // We found the first event after the migrate billing
                break;
            }
            prevPlan = curPlan;
            prevPhase = curPhase;
            prevPriceList = curPriceList;
        }

        if (prevPlan != null) {
            // Create the new MIGRATE_BILLING with same effectiveDate but new plan information
            final DateTime now = clock.getUTCNow();
            final ApiEventBuilder builder = new ApiEventBuilder()
                    .setActive(true)
                    .setApiEventType(ApiEventType.MIGRATE_BILLING)
                    .setFromDisk(true)
                    .setTotalOrdering(migrateBillingEvent.getTotalOrdering())
                    .setUuid(UUIDs.randomUUID())
                    .setSubscriptionId(migrateBillingEvent.getSubscriptionId())
                    .setCreatedDate(now)
                    .setUpdatedDate(now)
                    .setEffectiveDate(migrateBillingEvent.getEffectiveDate())
                    .setActiveVersion(migrateBillingEvent.getCurrentVersion())
                    .setEventPlan(prevPlan)
                    .setEventPlanPhase(prevPhase)
                    .setEventPriceList(prevPriceList);

            final SubscriptionBaseEvent newMigrateBillingEvent = new ApiEventMigrateBilling(builder);
            changeEvents.add(newMigrateBillingEvent);

            Collections.sort(changeEvents, new Comparator<SubscriptionBaseEvent>() {
                @Override
                public int compare(final SubscriptionBaseEvent o1, final SubscriptionBaseEvent o2) {
                    return o1.getEffectiveDate().compareTo(o2.getEffectiveDate());
                }
            });
        }

        return changeEvents;
    }

    private List<SubscriptionBaseEvent> filterSubscriptionBaseEvents(final List<SubscriptionEventModelDao> models) {
        final Collection<SubscriptionEventModelDao> filteredModels = Collections2.filter(models, new Predicate<SubscriptionEventModelDao>() {
            @Override
            public boolean apply(@Nullable final SubscriptionEventModelDao input) {
                return input.getUserType() != ApiEventType.UNCANCEL;
            }
        });
        return new ArrayList<SubscriptionBaseEvent>(Collections2.transform(filteredModels, new Function<SubscriptionEventModelDao, SubscriptionBaseEvent>() {
            @Override
            public SubscriptionBaseEvent apply(@Nullable final SubscriptionEventModelDao input) {
                return SubscriptionEventModelDao.toSubscriptionEvent(input);
            }
        }));
    }

    private List<SubscriptionBaseEvent> getEventsForAccountId(final InternalTenantContext context) {
        return transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<List<SubscriptionBaseEvent>>() {
            @Override
            public List<SubscriptionBaseEvent> inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final List<SubscriptionEventModelDao> models = entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class).getByAccountRecordId(context);
                return filterSubscriptionBaseEvents(models);
            }
        });
    }

    private void cancelSubscriptionFromTransaction(final DefaultSubscriptionBase subscription, final SubscriptionBaseEvent cancelEvent, final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory, final InternalCallContext context, final int seqId)
            throws EntityPersistenceException {
        final UUID subscriptionId = subscription.getId();
        cancelFutureEventsFromTransaction(subscriptionId, cancelEvent.getEffectiveDate(), entitySqlDaoWrapperFactory, context);
        entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class).create(new SubscriptionEventModelDao(cancelEvent), context);

        final boolean isBusEvent = cancelEvent.getEffectiveDate().compareTo(clock.getUTCNow()) <= 0;
        recordBusOrFutureNotificationFromTransaction(subscription, cancelEvent, entitySqlDaoWrapperFactory, isBusEvent, seqId, context);

        // Notify the Bus of the requested change
        notifyBusOfRequestedChange(entitySqlDaoWrapperFactory, subscription, cancelEvent, SubscriptionBaseTransitionType.CANCEL, context);
    }

    private void cancelNextPhaseEventFromTransaction(final UUID subscriptionId, final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory, final InternalCallContext context) {
        cancelFutureEventFromTransaction(subscriptionId, entitySqlDaoWrapperFactory, EventType.PHASE, null, context);
    }

    private void cancelFutureEventsFromTransaction(final UUID subscriptionId, final DateTime effectiveDate, final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory, final InternalCallContext context) {
        final List<SubscriptionEventModelDao> eventModels = entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class).getFutureActiveEventForSubscription(subscriptionId.toString(), effectiveDate.toDate(), context);
        for (final SubscriptionEventModelDao cur : eventModels) {
            unactivateEventFromTransaction(cur, entitySqlDaoWrapperFactory, context);
        }
    }

    private void cancelFutureEventFromTransaction(final UUID subscriptionId, final EntitySqlDaoWrapperFactory dao, final EventType type,
                                                  @Nullable final ApiEventType apiType, final InternalCallContext context) {
        final SubscriptionEventModelDao futureEvent = findFutureEventFromTransaction(subscriptionId, dao, type, apiType, context);
        unactivateEventFromTransaction(futureEvent, dao, context);
    }

    private SubscriptionEventModelDao findFutureEventFromTransaction(final UUID subscriptionId, final EntitySqlDaoWrapperFactory dao, final EventType type,
                                                                     @Nullable final ApiEventType apiType, final InternalCallContext context) {

        SubscriptionEventModelDao futureEvent = null;
        final Date now = clock.getUTCNow().toDate();
        final List<SubscriptionEventModelDao> eventModels = dao.become(SubscriptionEventSqlDao.class).getFutureActiveEventForSubscription(subscriptionId.toString(), now, context);
        for (final SubscriptionEventModelDao cur : eventModels) {
            if (cur.getEventType() == type &&
                (apiType == null || apiType == cur.getUserType())) {
                if (futureEvent != null) {
                    throw new SubscriptionBaseError(String.format("Found multiple future events for type %s for subscriptions %s",
                                                                  type, subscriptionId.toString()));
                }
                futureEvent = cur;
                // To check that there is only one such event
                //break;
            }
        }
        return futureEvent;
    }

    private void unactivateEventFromTransaction(final SubscriptionEventModelDao event, final EntitySqlDaoWrapperFactory dao, final InternalCallContext context) {
        if (event != null) {
            final String eventId = event.getId().toString();
            dao.become(SubscriptionEventSqlDao.class).unactiveEvent(eventId, context);
        }
    }

    private SubscriptionBase buildSubscription(final SubscriptionBase input, final InternalTenantContext context) throws CatalogApiException {

        if (input == null) {
            return null;
        }
        final List<SubscriptionBase> bundleInput = new ArrayList<SubscriptionBase>();
        if (input.getCategory() == ProductCategory.ADD_ON) {
            final SubscriptionBase baseSubscription = getBaseSubscription(input.getBundleId(), false, context);
            if (baseSubscription == null) {
                return null;
            }

            bundleInput.add(baseSubscription);
            bundleInput.add(input);
        } else {
            bundleInput.add(input);
        }

        final List<SubscriptionBase> reloadedSubscriptions = buildBundleSubscriptions(bundleInput, null, null, context);
        for (final SubscriptionBase cur : reloadedSubscriptions) {
            if (cur.getId().equals(input.getId())) {
                return cur;
            }
        }

        throw new SubscriptionBaseError("Unexpected code path in buildSubscription");
    }

    private List<SubscriptionBase> buildBundleSubscriptions(final List<SubscriptionBase> input, @Nullable final Multimap<UUID, SubscriptionBaseEvent> eventsForSubscription,
                                                            @Nullable List<SubscriptionBaseEvent> dryRunEvents, final InternalTenantContext context) throws CatalogApiException {
        if (input == null || input.size() == 0) {
            return Collections.emptyList();
        }

        // Make sure BasePlan -- if exists-- is first
        Collections.sort(input, new Comparator<SubscriptionBase>() {
            @Override
            public int compare(final SubscriptionBase o1, final SubscriptionBase o2) {
                if (o1.getCategory() == ProductCategory.BASE) {
                    return -1;
                } else if (o2.getCategory() == ProductCategory.BASE) {
                    return 1;
                } else {
                    return ((DefaultSubscriptionBase) o1).getAlignStartDate().compareTo(((DefaultSubscriptionBase) o2).getAlignStartDate());
                }
            }
        });

        final List<ApiEventChange> baseChangeEvents = new LinkedList<ApiEventChange>();
        ApiEventCancel baseCancellationEvent = null;
        final List<SubscriptionBase> result = new ArrayList<SubscriptionBase>(input.size());
        for (final SubscriptionBase cur : input) {
            final List<SubscriptionBaseEvent> events = eventsForSubscription != null ?
                                                       (List<SubscriptionBaseEvent>) eventsForSubscription.get(cur.getId()) :
                                                       getEventsForSubscription(cur.getId(), context);
            mergeDryRunEvents(cur.getId(), events, dryRunEvents);

            SubscriptionBase reloaded = createSubscriptionForInternalUse(cur, events, context);

            switch (cur.getCategory()) {
                case BASE:
                    for (final SubscriptionBaseEvent event : events) {
                        if (!event.isActive()) {
                            continue;
                        } else if (event instanceof ApiEventCancel) {
                            baseCancellationEvent = (ApiEventCancel) event;
                            break;
                        } else if (event instanceof ApiEventChange) {
                            // Need to track all changes, see https://github.com/killbill/killbill/issues/268
                            baseChangeEvents.add((ApiEventChange) event);
                        }
                    }
                    break;
                case ADD_ON:
                    final Plan targetAddOnPlan = reloaded.getCurrentPlan();
                    if (targetAddOnPlan == null || reloaded.getFutureEndDate() != null) {
                        // TODO What if reloaded.getFutureEndDate() is not null but a base plan change
                        // triggers another cancellation before?
                        break;
                    }

                    SubscriptionBaseEvent baseTriggerEventForAddOnCancellation = baseCancellationEvent;
                    for (final ApiEventChange baseChangeEvent : baseChangeEvents) {
                        final String baseProductName = baseChangeEvent.getEventPlan();

                        if ((!addonUtils.isAddonAvailableFromPlanName(baseProductName, targetAddOnPlan, baseChangeEvent.getEffectiveDate(), context)) ||
                            (addonUtils.isAddonIncludedFromPlanName(baseProductName, targetAddOnPlan, baseChangeEvent.getEffectiveDate(), context))) {
                            if (baseTriggerEventForAddOnCancellation != null) {
                                if (baseTriggerEventForAddOnCancellation.getEffectiveDate().isAfter(baseChangeEvent.getEffectiveDate())) {
                                    baseTriggerEventForAddOnCancellation = baseChangeEvent;
                                }
                            } else {
                                baseTriggerEventForAddOnCancellation = baseChangeEvent;
                            }
                        }
                    }

                    if (baseTriggerEventForAddOnCancellation != null) {
                        final DateTime now = clock.getUTCNow();
                        final SubscriptionBaseEvent addOnCancelEvent = new ApiEventCancel(new ApiEventBuilder()
                                                                                                  .setSubscriptionId(reloaded.getId())
                                                                                                  .setActiveVersion(((DefaultSubscriptionBase) reloaded).getActiveVersion())
                                                                                                  .setEffectiveDate(baseTriggerEventForAddOnCancellation.getEffectiveDate())
                                                                                                  .setCreatedDate(baseTriggerEventForAddOnCancellation.getCreatedDate())
                                                                                                  // This event is only there to indicate the ADD_ON is future canceled, but it is not there
                                                                                                  // on disk until the base plan cancellation becomes effective
                                                                                                  .setFromDisk(false));

                        events.add(addOnCancelEvent);
                        // Finally reload subscription with full set of events
                        reloaded = createSubscriptionForInternalUse(cur, events, context);
                    }
                    break;
                default:
                    break;
            }

            result.add(reloaded);
        }

        return result;
    }

    private void mergeDryRunEvents(final UUID subscriptionId, final List<SubscriptionBaseEvent> events, @Nullable List<SubscriptionBaseEvent> dryRunEvents) {
        if (dryRunEvents == null || dryRunEvents.isEmpty()) {
            return;
        }
        for (SubscriptionBaseEvent curDryRun : dryRunEvents) {
            if (curDryRun.getSubscriptionId() != null && curDryRun.getSubscriptionId().equals(subscriptionId)) {

                //boolean inserted = false;
                final Iterator<SubscriptionBaseEvent> it = events.iterator();
                while (it.hasNext()) {
                    final SubscriptionBaseEvent event = it.next();
                    if (event.getEffectiveDate().isAfter(curDryRun.getEffectiveDate())) {
                        it.remove();
                    }
                }
                // Set total ordering value of the fake dryRun event to make sure billing events are correctly ordered
                final SubscriptionBaseEvent curAdjustedDryRun;
                if (!events.isEmpty()) {
                    final EventBaseBuilder eventBuilder = (curDryRun.getType() == EventType.API_USER) ?
                                                          new ApiEventBuilder((ApiEvent) curDryRun) :
                                                          new PhaseEventBuilder((PhaseEvent) curDryRun);
                    eventBuilder.setTotalOrdering(events.get(events.size() - 1).getTotalOrdering() + 1);

                    curAdjustedDryRun = eventBuilder.build();
                } else {
                    curAdjustedDryRun = curDryRun;
                }
                events.add(curAdjustedDryRun);
            }
        }
    }

    @Override
    public void migrate(final UUID accountId, final AccountMigrationData accountData, final InternalCallContext context) {
        transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<Void>() {
            @Override
            public Void inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final SubscriptionEventSqlDao transactional = entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class);

                for (final BundleMigrationData curBundle : accountData.getData()) {
                    migrateBundleDataFromTransaction(curBundle, transactional, entitySqlDaoWrapperFactory, context);
                }
                return null;
            }
        });
    }

    @Override
    public void transfer(final UUID srcAccountId, final UUID destAccountId, final BundleMigrationData bundleTransferData,
                         final List<TransferCancelData> transferCancelData, final InternalCallContext fromContext, final InternalCallContext toContext) {

        transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<Void>() {
            @Override
            public Void inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {
                final SubscriptionEventSqlDao transactional = entitySqlDaoWrapperFactory.become(SubscriptionEventSqlDao.class);

                // Cancel the subscriptions for the old bundle
                for (final TransferCancelData cancel : transferCancelData) {
                    cancelSubscriptionFromTransaction(cancel.getSubscription(), cancel.getCancelEvent(), entitySqlDaoWrapperFactory, fromContext, 0);
                }

                migrateBundleDataFromTransaction(bundleTransferData, transactional, entitySqlDaoWrapperFactory, toContext);
                return null;
            }
        });
    }

    @Override
    public void updateBundleExternalKey(final UUID bundleId, final String externalKey, final InternalCallContext context) {
        transactionalSqlDao.execute(new EntitySqlDaoTransactionWrapper<Void>() {
            @Override
            public Void inTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory) throws Exception {

                final BundleSqlDao bundleSqlDao = entitySqlDaoWrapperFactory.become(BundleSqlDao.class);
                bundleSqlDao.updateBundleExternalKey(bundleId.toString(), externalKey, context);
                return null;
            }
        });
    }

    private DefaultSubscriptionBase createSubscriptionForInternalUse(final SubscriptionBase shellSubscription, final List<SubscriptionBaseEvent> events, final InternalTenantContext context) throws CatalogApiException {
        final DefaultSubscriptionBase result = new DefaultSubscriptionBase(new SubscriptionBuilder(((DefaultSubscriptionBase) shellSubscription)), null, clock);
        if (events.size() > 0) {
            final Catalog fullCatalog = catalogService.getFullCatalog(context);
            result.rebuildTransitions(events, fullCatalog);
        }
        return result;
    }

    private SubscriptionBase getBaseSubscription(final UUID bundleId, final boolean rebuildSubscription, final InternalTenantContext context) throws CatalogApiException {
        final List<SubscriptionBase> subscriptions = getSubscriptionFromBundleId(bundleId, context);
        for (final SubscriptionBase cur : subscriptions) {
            if (cur.getCategory() == ProductCategory.BASE) {
                return rebuildSubscription ? buildSubscription(cur, context) : cur;
            }
        }
        return null;
    }

    //
    // Either records a notification or sends a bus event if operation is immediate
    //
    private void recordBusOrFutureNotificationFromTransaction(final DefaultSubscriptionBase subscription, final SubscriptionBaseEvent event, final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory, final boolean busEvent,
                                                              final int seqId, final InternalCallContext context) {
        if (busEvent) {
            rebuildSubscriptionAndNotifyBusOfEffectiveImmediateChange(entitySqlDaoWrapperFactory, subscription, event, seqId, context);
        } else {
            recordFutureNotificationFromTransaction(entitySqlDaoWrapperFactory,
                                                    event.getEffectiveDate(),
                                                    new SubscriptionNotificationKey(event.getId()),
                                                    context);
        }
    }

    // Sends bus notification for event on effective date -- only used for operation that happen immediately
    private void rebuildSubscriptionAndNotifyBusOfEffectiveImmediateChange(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory, final DefaultSubscriptionBase subscription,
                                                                           final SubscriptionBaseEvent immediateEvent, final int seqId, final InternalCallContext context) {
        try {
            final DefaultSubscriptionBase upToDateSubscription = createSubscriptionWithNewEvent(subscription, immediateEvent, context);
            notifyBusOfEffectiveImmediateChange(entitySqlDaoWrapperFactory, upToDateSubscription, immediateEvent, seqId, context);
        } catch (final CatalogApiException e) {
            log.warn("Failed to post effective event for subscription " + subscription.getId(), e);
        }
    }

    private void notifyBusOfEffectiveImmediateChange(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory, final DefaultSubscriptionBase subscription,
                                                     final SubscriptionBaseEvent immediateEvent, final int seqId, final InternalCallContext context) {
        try {
            final SubscriptionBaseTransitionData transition = subscription.getTransitionFromEvent(immediateEvent, seqId);
            final BusEvent busEvent = new DefaultEffectiveSubscriptionEvent(transition,
                                                                            subscription.getAlignStartDate(),
                                                                            context.getUserToken(),
                                                                            context.getAccountRecordId(),
                                                                            context.getTenantRecordId());

            eventBus.postFromTransaction(busEvent, entitySqlDaoWrapperFactory.getHandle().getConnection());
        } catch (final EventBusException e) {
            log.warn("Failed to post effective event for subscription " + subscription.getId(), e);
        }
    }

    private void notifyBusOfRequestedChange(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory, final DefaultSubscriptionBase subscription,
                                            final SubscriptionBaseEvent nextEvent, final SubscriptionBaseTransitionType transitionType, final InternalCallContext context) {
        try {
            eventBus.postFromTransaction(new DefaultRequestedSubscriptionEvent(subscription, nextEvent, transitionType, context.getAccountRecordId(), context.getTenantRecordId(), context.getUserToken()), entitySqlDaoWrapperFactory.getHandle().getConnection());
        } catch (final EventBusException e) {
            log.warn("Failed to post requested change event for subscription " + subscription.getId(), e);
        }
    }

    private void recordFutureNotificationFromTransaction(final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory, final DateTime effectiveDate,
                                                         final NotificationEvent notificationKey, final InternalCallContext context) {
        try {
            final NotificationQueue subscriptionEventQueue = notificationQueueService.getNotificationQueue(DefaultSubscriptionBaseService.SUBSCRIPTION_SERVICE_NAME,
                                                                                                           DefaultSubscriptionBaseService.NOTIFICATION_QUEUE_NAME);
            subscriptionEventQueue.recordFutureNotificationFromTransaction(entitySqlDaoWrapperFactory.getHandle().getConnection(), effectiveDate, notificationKey, context.getUserToken(), context.getAccountRecordId(), context.getTenantRecordId());
        } catch (NoSuchNotificationQueue e) {
            throw new RuntimeException(e);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    private void migrateBundleDataFromTransaction(final BundleMigrationData bundleTransferData, final SubscriptionEventSqlDao transactional,
                                                  final EntitySqlDaoWrapperFactory entitySqlDaoWrapperFactory, final InternalCallContext context) throws EntityPersistenceException {

        final SubscriptionSqlDao transSubDao = entitySqlDaoWrapperFactory.become(SubscriptionSqlDao.class);
        final BundleSqlDao transBundleDao = entitySqlDaoWrapperFactory.become(BundleSqlDao.class);

        final DefaultSubscriptionBaseBundle bundleData = bundleTransferData.getData();

        final List<SubscriptionBundleModelDao> existingBundleModels = transBundleDao.getBundlesFromAccountAndKey(bundleData.getAccountId().toString(), bundleData.getExternalKey(), context);
        if (existingBundleModels.size() != 0) {
            log.error(String.format("Attempted to create a bundle for account %s and key %s that already existed, skip...", bundleData.getAccountId().toString(), bundleData.getExternalKey()));
            return;
        }

        for (final SubscriptionMigrationData curSubscription : bundleTransferData.getSubscriptions()) {
            final DefaultSubscriptionBase subData = curSubscription.getData();
            for (final SubscriptionBaseEvent curEvent : curSubscription.getInitialEvents()) {
                transactional.create(new SubscriptionEventModelDao(curEvent), context);
                recordFutureNotificationFromTransaction(entitySqlDaoWrapperFactory,
                                                        curEvent.getEffectiveDate(),
                                                        new SubscriptionNotificationKey(curEvent.getId()),
                                                        context);
            }
            transSubDao.create(new SubscriptionModelDao(subData), context);

            // Notify the Bus of the latest requested change
            final SubscriptionBaseEvent finalEvent = curSubscription.getInitialEvents().get(curSubscription.getInitialEvents().size() - 1);
            notifyBusOfRequestedChange(entitySqlDaoWrapperFactory, subData, finalEvent, SubscriptionBaseTransitionType.MIGRATE_BILLING, context);
        }

        transBundleDao.create(new SubscriptionBundleModelDao(bundleData), context);
    }

    //
    // Creates a copy of the existing subscriptions whose 'transitions' will reflect the new event
    //
    private DefaultSubscriptionBase createSubscriptionWithNewEvent(final DefaultSubscriptionBase subscription, SubscriptionBaseEvent newEvent, final InternalTenantContext context) throws CatalogApiException {

        final DefaultSubscriptionBase subscriptionWithNewEvent = new DefaultSubscriptionBase(subscription, null, clock);
        final List<SubscriptionBaseEvent> allEvents = new LinkedList<SubscriptionBaseEvent>();
        if (subscriptionWithNewEvent.getEvents() != null) {
            allEvents.addAll(subscriptionWithNewEvent.getEvents());
        }
        allEvents.add(newEvent);
        subscriptionWithNewEvent.rebuildTransitions(allEvents, catalogService.getFullCatalog(context));
        return subscriptionWithNewEvent;
    }

}
