/*
 * Copyright 2019 New Vector Ltd
 *
 * 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 im.vector.matrix.android.internal.session.room.prune

import com.zhuinden.monarchy.Monarchy
import im.vector.matrix.android.api.session.events.model.EventType
import im.vector.matrix.android.internal.database.RealmLiveEntityObserver
import im.vector.matrix.android.internal.database.mapper.asDomain
import im.vector.matrix.android.internal.database.model.EventEntity
import im.vector.matrix.android.internal.database.query.whereTypes
import im.vector.matrix.android.internal.di.SessionDatabase
import io.realm.OrderedCollectionChangeSet
import io.realm.RealmConfiguration
import io.realm.RealmResults
import kotlinx.coroutines.launch
import timber.log.Timber
import javax.inject.Inject

/**
 * Listens to the database for the insertion of any redaction event.
 * As it will actually delete the content, it should be called last in the list of listener.
 */
internal class EventsPruner @Inject constructor(@SessionDatabase realmConfiguration: RealmConfiguration,
                                                private val pruneEventTask: PruneEventTask) :
        RealmLiveEntityObserver<EventEntity>(realmConfiguration) {

    override val query = Monarchy.Query<EventEntity> { EventEntity.whereTypes(it, listOf(EventType.REDACTION)) }

    override fun onChange(results: RealmResults<EventEntity>, changeSet: OrderedCollectionChangeSet) {
        Timber.v("Event pruner called with ${changeSet.insertions.size} insertions")

        val insertedDomains = changeSet.insertions
                .asSequence()
                .mapNotNull { results[it]?.asDomain() }
                .toList()

        observerScope.launch {
            val params = PruneEventTask.Params(insertedDomains)
            pruneEventTask.execute(params)
        }
    }
}
