/
SyncController.kt
328 lines (280 loc) · 9.5 KB
/
SyncController.kt
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package com.techyourchance.synccontroller
import java.util.concurrent.locks.ReentrantLock
import kotlin.concurrent.withLock
/**
* This class orchestrates the data sync flows between the client and the server.
* IMPLEMENTATION NOTE: this class (i.e. all its methods) must be fully thread-safe
*/
class SyncController(
private val loginStateDelegate: LoginStateDelegate,
private val syncPreferencesDelegate: SyncPreferencesDelegate,
private val realtimeSyncDelegate: RealtimeSyncDelegate,
private val httpSyncDelegate: HttpSyncDelegate,
private val longSyncDelegate: LongSyncDelegate,
private val appForegroundStateDelegate: AppForegroundStateDelegate,
private val loggerDelegate: LoggerDelegate,
) {
private val lock = ReentrantLock(true)
private var syncState: SyncState = SyncState.IDLE
private var isFallbackSyncInProgress = false
private val httpListener = object : HttpSyncDelegate.Listener {
override fun onHttpSyncCompleted() {
this@SyncController.onHttpSyncCompleted()
}
override fun onHttpResponseUnsuccessful() {
this@SyncController.onHttpResponseUnsuccessful()
}
override fun onHttpSyncTimedOut() {
this@SyncController.onHttpSyncTimedOut()
}
}
private val realtimeListener = object : RealtimeSyncDelegate.Listener {
override fun onRealtimeInitSucceeded() {
lock.withLock {
log("onRealtimeInitSucceeded()")
setState(SyncState.REALTIME)
}
}
override fun onRealtimeInitFailed() {
lock.withLock {
log("onRealtimeInitFailed()")
setState(SyncState.FALLBACK)
}
}
override fun onRealtimeResponseUnsuccessful() {
lock.withLock {
log("onRealtimeResponseUnsuccessful()")
startRecoverySync()
}
}
override fun onRealtimeSyncTimedOut() {
lock.withLock {
log("onRealtimeSyncTimedOut()")
realtimeSyncDelegate.shutDownRealtimeSync()
startPostTimeoutSync()
}
}
override fun onRealtimeShutDown() {
lock.withLock {
log("onRealtimeShutDown()")
if (syncState == SyncState.REALTIME) {
setState(SyncState.FALLBACK)
}
}
}
}
private val longSyncListener = object : LongSyncDelegate.Listener {
override fun onLongSyncCompleted() {
this@SyncController.onLongSyncCompleted()
}
}
private val appForegroundListener = object : AppForegroundStateDelegate.Listener {
override fun onAppTransitionToForeground() {
lock.withLock {
log("onAppTransitionToForeground()")
startSync()
}
}
override fun onAppTransitionToBackground() {
lock.withLock {
log("onAppTransitionToBackground()")
if (syncState == SyncState.REALTIME) {
realtimeSyncDelegate.shutDownRealtimeSync()
setState(SyncState.FALLBACK)
}
}
}
}
fun getSyncInfo(): SyncInfo {
return lock.withLock {
SyncInfo(
syncState,
)
}
}
/**
* Initiate new sync, if the state allows for new sync to be initiated, according to
* sync algorithm specification
*/
fun startSync() {
lock.withLock {
log("startSync(); state: $syncState")
if (!loginStateDelegate.isUserLoggedIn()) {
log("no logged in user - sync request ignored")
return
}
when (syncState) {
SyncState.IDLE -> {
if (syncPreferencesDelegate.isWaitingForFirstEverSync()) {
startFirstEverSync()
} else {
startFirstSync()
}
}
SyncState.REALTIME -> {
startRealtimeSync()
}
SyncState.FALLBACK -> {
if (isFallbackSyncInProgress) {
log("fallback sync is already in progress - sync request ignored")
} else {
startFallbackSync()
}
}
else -> {
log("sync request ignored")
}
}
}
}
private fun setState(newState: SyncState) {
lock.withLock {
if (syncState == newState) {
return
}
val oldState = syncState
log("setState(); old state: $oldState; new state: $newState")
syncState = newState
if (oldState == SyncState.IDLE) {
registerListeners()
}
if (newState == SyncState.IDLE) {
unregisterListeners()
}
}
}
private fun registerListeners() {
httpSyncDelegate.registerListener(httpListener)
realtimeSyncDelegate.registerListener(realtimeListener)
longSyncDelegate.registerListener(longSyncListener)
appForegroundStateDelegate.registerListener(appForegroundListener)
}
private fun unregisterListeners() {
httpSyncDelegate.unregisterListener(httpListener)
realtimeSyncDelegate.unregisterListener(realtimeListener)
longSyncDelegate.unregisterListener(longSyncListener)
appForegroundStateDelegate.unregisterListener(appForegroundListener)
}
private fun startFirstEverSync() {
lock.withLock {
setState(SyncState.FIRST_EVER_SYNC)
startLongSync(true)
}
}
private fun startFirstSync() {
lock.withLock {
setState(SyncState.FIRST_SYNC)
startHttpSync()
}
}
private fun startFallbackSync() {
lock.withLock {
setState(SyncState.FALLBACK)
isFallbackSyncInProgress = true
startHttpSync()
}
}
private fun startHttpSync() {
httpSyncDelegate.startHttpSync()
}
private fun startLongSync(isFullSync: Boolean) {
longSyncDelegate.startLongSync(isFullSync)
}
private fun startRealtimeSync() {
lock.withLock {
setState(SyncState.REALTIME)
realtimeSyncDelegate.startRealtimeSync()
}
}
private fun onLongSyncCompleted() {
lock.withLock {
log("onLongSyncCompleted()")
if (syncPreferencesDelegate.isWaitingForFirstEverSync()) {
log("first ever sync completed")
syncPreferencesDelegate.setFirstEverSyncCompleted()
}
isFallbackSyncInProgress = false
initRealtimeSyncOrGoToFallback()
}
}
private fun onHttpSyncCompleted() {
lock.withLock {
log("onHttpSyncCompleted()")
if (syncPreferencesDelegate.isWaitingForFirstEverSync()) {
log("first ever sync completed")
syncPreferencesDelegate.setFirstEverSyncCompleted()
}
isFallbackSyncInProgress = false
initRealtimeSyncOrGoToFallback()
}
}
private fun onHttpResponseUnsuccessful() {
lock.withLock {
log("onHttpResponseUnsuccessful()")
isFallbackSyncInProgress = false
startRecoverySync()
}
}
private fun onHttpSyncTimedOut() {
lock.withLock {
log("onHttpSyncTimedOut()")
isFallbackSyncInProgress = false
startPostTimeoutSync()
}
}
private fun startPostTimeoutSync() {
lock.withLock {
setState(SyncState.POST_TIMEOUT_SYNC)
longSyncDelegate.startLongSync(false)
}
}
private fun initRealtimeSyncOrGoToFallback() {
lock.withLock {
log("initRealtimeSyncOrGoToFallback()")
if (syncState == SyncState.REALTIME) {
log("already in REALTIME state - init aborted")
return
}
if (appForegroundStateDelegate.isAppInForeground()) {
log("initializing realtime sync")
realtimeSyncDelegate.initRealtimeSyncForOperation()
} else {
log("app is in background - postponing realtime sync init")
setState(SyncState.FALLBACK)
}
}
}
private fun startRecoverySync() {
lock.withLock {
log("startRecoverySync()")
if (syncState == SyncState.REALTIME) {
realtimeSyncDelegate.shutDownRealtimeSync()
}
setState(SyncState.RECOVERY_SYNC)
longSyncDelegate.startLongSync(true)
}
}
private fun onHttpRecoverySyncEnded() {
lock.withLock {
log("onHttpRecoverySyncEnded")
setState(SyncState.FALLBACK)
}
}
private fun log(message: String) {
loggerDelegate.d(TAG, message)
}
/**
* This method must be called when we clear user's state (e.g. logout)
*/
fun reset() {
lock.withLock {
log("reset()")
setState(SyncState.IDLE)
isFallbackSyncInProgress = false
realtimeSyncDelegate.shutDownRealtimeSync()
}
}
companion object {
private const val TAG = "SyncController"
}
}