/*
 * 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.user

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.model.EventEntity
import im.vector.matrix.android.internal.database.model.EventEntityFields
import im.vector.matrix.android.internal.database.model.UserEntity
import im.vector.matrix.android.internal.database.query.types
import im.vector.matrix.android.internal.di.SessionDatabase
import im.vector.matrix.android.internal.task.TaskExecutor
import im.vector.matrix.android.internal.task.TaskThread
import im.vector.matrix.android.internal.task.configureWith
import im.vector.matrix.android.internal.util.tryTransactionAsync
import im.vector.matrix.android.internal.util.tryTransactionSync
import io.realm.OrderedCollectionChangeSet
import io.realm.RealmConfiguration
import io.realm.RealmResults
import io.realm.Sort
import javax.inject.Inject

internal class UserEntityUpdater @Inject constructor(@SessionDatabase realmConfiguration: RealmConfiguration,
                                                     private val monarchy: Monarchy,
                                                     private val updateUserTask: UpdateUserTask,
                                                     private val taskExecutor: TaskExecutor)
    : RealmLiveEntityObserver<EventEntity>(realmConfiguration) {

    override val query = Monarchy.Query<EventEntity> {
        EventEntity
                .types(it, listOf(EventType.STATE_ROOM_MEMBER))
                .sort(EventEntityFields.STATE_INDEX, Sort.DESCENDING)
                .distinct(EventEntityFields.STATE_KEY)
    }

    override fun onChange(results: RealmResults<EventEntity>, changeSet: OrderedCollectionChangeSet) {
        monarchy.tryTransactionSync { realm ->
            val userEntities = ArrayList<UserEntity>(changeSet.insertions.size)
            for (insertion in changeSet.insertions) {
                val roomMemberEvent = results[insertion] ?: continue
                val roomMemberTimelineEvent = roomMemberEvent.timelineEventEntity?.firstOrNull()
                                              ?: continue
                val userEntity = UserEntity(roomMemberEvent.stateKey
                                            ?: "", roomMemberTimelineEvent.senderName ?: "",
                                            roomMemberTimelineEvent.senderAvatar ?: "")
                userEntities.add(userEntity)
            }
            realm.insertOrUpdate(userEntities)
        }
    }

}