tgbotapi/TelegramBotAPI-extensions-api/src/commonMain/kotlin/com/github/insanusmokrassar/TelegramBotAPI/extensions/api/utils/UpdatesHandling.kt

package com.github.insanusmokrassar.TelegramBotAPI.extensions.api.utils

import com.github.insanusmokrassar.TelegramBotAPI.extensions.api.InternalUtils.convertWithMediaGroupUpdates
import com.github.insanusmokrassar.TelegramBotAPI.types.message.abstracts.MediaGroupMessage
import com.github.insanusmokrassar.TelegramBotAPI.types.update.abstracts.*
import com.github.insanusmokrassar.TelegramBotAPI.updateshandlers.UpdateReceiver
import com.github.insanusmokrassar.TelegramBotAPI.utils.extensions.accumulateByKey
import kotlinx.coroutines.CoroutineScope
import kotlinx.coroutines.channels.Channel
import kotlinx.coroutines.launch

/**
 * Create [UpdateReceiver] object which will correctly accumulate updates and send into output updates which INCLUDE
 * [com.github.insanusmokrassar.TelegramBotAPI.types.update.MediaGroupUpdates.MediaGroupUpdate]s.
 *
 * @see UpdateReceiver
 */
fun CoroutineScope.updateHandlerWithMediaGroupsAdaptation(
    output: UpdateReceiver<Update>
): UpdateReceiver<Update> {
    val updatesChannel = Channel<Update>(Channel.UNLIMITED)
    val mediaGroupChannel = Channel<Pair<String, BaseMessageUpdate>>(Channel.UNLIMITED)
    val mediaGroupAccumulatedChannel = mediaGroupChannel.accumulateByKey(
        1000L,
        scope = this
    )

    launch {
        launch {
            for (update in updatesChannel) {
                when (val data = update.data) {
                    is MediaGroupMessage -> mediaGroupChannel.send("${data.mediaGroupId}${update::class.simpleName}" to update as BaseMessageUpdate)
                    else -> output(update)
                }
            }
        }
        launch {
            for ((_, mediaGroup) in mediaGroupAccumulatedChannel) {
                mediaGroup.convertWithMediaGroupUpdates().forEach {
                    output(it)
                }
            }
        }
    }

    return { updatesChannel.send(it) }
}