SubwayTooter-Android-App/app/src/main/java/jp/juggler/subwaytooter/streaming/StreamGroupAcct.kt

package jp.juggler.subwaytooter.streaming

import jp.juggler.subwaytooter.api.TootParser
import jp.juggler.subwaytooter.api.entity.TootInstance
import jp.juggler.subwaytooter.table.SavedAccount
import jp.juggler.util.log.LogCategory
import java.util.concurrent.ConcurrentHashMap

// ストリーミング接続をacct単位でグルーピングする
class StreamGroupAcct(
    private val manager: StreamManager,
    val account: SavedAccount,
    var ti: TootInstance,
) {
    companion object {
        private val log = LogCategory("StreamGroupAcct")
    }

    val parser: TootParser = TootParser(manager.appState.context, linkHelper = account)

    val keyGroups = ConcurrentHashMap<StreamSpec, StreamGroup>()

    // 接続を束ねない場合に使われる
    private val connections = ConcurrentHashMap<StreamSpec, StreamConnection>()

    // 接続を束ねる場合に使われる
    private var mergedConnection: StreamConnection? = null

    // カラムIDから出力先へのマップ
    @Volatile
    private var destinations = ConcurrentHashMap<Int, StreamRelation>()

    fun addSpec(dst: StreamRelation) {
        val spec = dst.spec
        var group = keyGroups[spec]
        if (group == null) {
            group = StreamGroup(spec)
            keyGroups[spec] = group
        }
        group.destinations[dst.columnInternalId] = dst
    }

    private fun updateDestinations() {
        destinations = ConcurrentHashMap<Int, StreamRelation>().apply {
            keyGroups.values.forEach { group ->
                group.destinations.values.forEach { relation ->
                    put(relation.columnInternalId, relation)
                }
            }
        }
    }

    // マージではなく、作られてデータを追加された直後に呼ばれる
    fun initialize() {
        updateDestinations()
    }

    fun merge(newServer: StreamGroupAcct) {

        // 新スペックの値をコピー
        this.ti = newServer.ti

        newServer.keyGroups.entries.forEach {
            keyGroups[it.key] = it.value
        }

        // 新グループにないグループを削除
        keyGroups.entries.toList().forEach {
            if (!newServer.keyGroups.containsKey(it.key)) keyGroups.remove(it.key)
        }

        // グループにない接続を破棄
        connections.entries.toList().forEach {
            if (!keyGroups.containsKey(it.key)) {
                it.value.dispose()
                connections.remove(it.key)
            }
        }

        updateDestinations()
    }

    // このオブジェクトはもう使われなくなる
    fun dispose() {
        connections.values.forEach { it.dispose() }
        connections.clear()

        mergedConnection?.dispose()
        mergedConnection = null

        keyGroups.clear()
    }

    private fun findConnection(spec: StreamSpec): StreamConnection? =
        when (val mergedConnection = this.mergedConnection) {
            null -> when (val conn = connections[spec]) {
                null -> {
                    log.w("findConnection: missing connection for ${spec.name}")
                    null
                }
                else -> conn
            }
            else -> mergedConnection
        }

    // ストリーミング接続インジケータ
    fun getStreamStatus(columnInternalId: Int): StreamStatus =
        when (val spec = destinations[columnInternalId]?.spec) {
            null -> {
                log.w("getStreamStatus: missing destination for ${account.acct.pretty}")
                StreamStatus.Missing
            }
            else -> findConnection(spec)?.getStreamStatus(spec) ?: StreamStatus.Missing
        }

    suspend fun updateConnection() {

        val multiplex = if (account.isMastodon) {
            ti.versionGE(TootInstance.VERSION_3_3_0_rc1)
        } else {
            account.misskeyVersion >= 11
        }

        if (multiplex) {
            connections.values.forEach { it.dispose() }
            connections.clear()

            if (destinations.isEmpty()) {
                mergedConnection?.dispose()
                mergedConnection = null
            } else {
                if (mergedConnection == null) {
                    mergedConnection = StreamConnection(
                        manager,
                        this,
                        spec = null,
                        name = "[${account.acct.pretty}:multiplex]",
                    )
                }
                mergedConnection?.updateConnection()
            }
        } else {
            mergedConnection?.dispose()
            mergedConnection = null

            keyGroups.entries.forEach { pair ->
                val (streamKey, group) = pair
                var conn = connections[streamKey]
                if (conn == null) {
                    conn = StreamConnection(
                        manager,
                        this,
                        spec = group.spec,
                        "[${account.acct.pretty}:${group.spec.name}]",
                    )
                    connections[streamKey] = conn
                }
                conn.updateConnection()
            }
        }
    }

    fun getConnection(internalId: Int) =
        mergedConnection ?: destinations[internalId]?.spec?.let { connections[it] }
}