Archery Apprentice Documentation

Data Sync Flow

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Data Sync Flow

tags: flow data-sync firebase offline-first conflict-resolution real-time created: 2025-10-08 related:

Overview

The Data Sync Flow describes how tournament data synchronizes between local storage and Firebase for real-time collaboration and offline support. This flow implements an offline-first architecture with automatic sync, conflict resolution, and network monitoring.

Architecture Components

Sync Layer:

  • Hybrid repository pattern (offline-first with Firebase sync)
  • TournamentSyncService for real-time Firebase listeners
  • ScoreConflictResolutionService for conflict detection
  • Network connectivity monitoring
  • Exponential backoff retry logic
  • Smart caching with TTL

Offline-First Strategy

User Action → Local Storage (Immediate) → Background Sync → Firebase
                    ↓
               UI Update

Key Principles:

  1. Local First: All operations complete locally immediately
  2. Background Sync: Firebase sync happens asynchronously
  3. Network Independent: App fully functional offline
  4. Automatic Recovery: Sync retries when network available
  5. Conflict Resolution: Handle simultaneous edits gracefully

Tournament Sync Architecture

Entry Point: HybridTournamentRepository

Purpose: Seamless offline/online tournament functionality

Call Chain:

  1. HybridTournamentRepository.kt:58 - Primary sync coordinator
  2. OfflineTournamentRepository - Local Room database
  3. FirebaseTournamentRepository - Firebase Firestore operations
  4. TournamentScoreCacheService - Smart caching layer

Hybrid Repository Pattern

sequenceDiagram
    participant User
    participant UI as TournamentUI
    participant Hybrid as HybridTournamentRepository
    participant Local as OfflineTournamentRepository
    participant Firebase as FirebaseTournamentRepository
    participant Network as NetworkMonitor
    participant Cache as ScoreCacheService

    User->>UI: Create tournament
    UI->>Hybrid: createTournament()
    
    Hybrid->>Local: createTournament() [IMMEDIATE]
    Local-->>Hybrid: Success + Local ID
    Hybrid-->>UI: Return success [FAST RESPONSE]
    UI-->>User: Tournament created ✓
    
    alt Network Available
        Hybrid->>Network: Check connectivity
        Network-->>Hybrid: Online
        
        Hybrid->>Firebase: createTournament() [BACKGROUND]
        Firebase-->>Hybrid: Firebase ID
        
        Hybrid->>Local: Update with Firebase ID
        Hybrid->>Hybrid: Mark as synced
    else Network Unavailable
        Hybrid->>Hybrid: Mark for sync later
        Note over Hybrid: Will sync when network returns
    end

Network Connectivity Monitoring

Code: HybridTournamentRepository.kt:70

private val networkCallback = object : ConnectivityManager.NetworkCallback() {
    override fun onAvailable(network: Network) {
        isNetworkAvailable = true
        // Trigger background sync when network becomes available
        syncScope.launch {
            syncPendingTournaments()
        }
    }
 
    override fun onLost(network: Network) {
        isNetworkAvailable = false
    }
}
 
init {
    // Register network monitoring
    val networkRequest = NetworkRequest.Builder()
        .addCapability(NetworkCapabilities.NET_CAPABILITY_INTERNET)
        .build()
    connectivityManager.registerNetworkCallback(networkRequest, networkCallback)
    
    // Check initial network state
    isNetworkAvailable = connectivityManager.activeNetwork != null
}

Network Detection:

  • Continuous monitoring via NetworkCallback
  • Automatic sync trigger on connectivity restoration
  • Initial state check on repository creation
  • Graceful degradation when offline

Tournament Creation Sync Flow

Offline-First Tournament Creation

Entry Point: User creates tournament

Call Chain:

  1. HybridTournamentRepository.kt:218 - createTournament() - Hybrid logic
  2. OfflineTournamentRepository.createTournament() - Immediate local storage
  3. FirebaseTournamentRepository.createTournament() - Background Firebase sync

Tournament Creation Process

sequenceDiagram
    participant User
    participant UI
    participant Hybrid as HybridTournamentRepository
    participant Local as OfflineTournamentRepository
    participant Firebase as FirebaseTournamentRepository
    participant DB as Room Database

    User->>UI: Fill tournament details, tap Create
    UI->>Hybrid: createTournament(tournament)
    
    Hybrid->>Local: createTournament(tournament)
    Local->>DB: INSERT INTO tournaments
    DB-->>Local: Tournament ID (local_123)
    Local-->>Hybrid: Success(local_123)
    
    Hybrid-->>UI: Success(local_123) [IMMEDIATE RESPONSE]
    UI-->>User: Tournament created! (local_123)
    
    Note over Hybrid,Firebase: Background sync starts
    
    alt Online & Authenticated
        Hybrid->>Firebase: createTournament(tournament)
        Firebase->>Firebase: Anonymous sign-in if needed
        Firebase->>Firebase: Create Firestore document
        Firebase->>Firebase: Set security subcollections
        Firebase-->>Hybrid: Success(firebase_abc123)
        
        Hybrid->>Local: Update tournament with Firebase ID
        Hybrid->>Hybrid: handleTournamentIdMapping(local_123, firebase_abc123)
        
        Hybrid->>Local: Delete old local ID record
        Hybrid->>Local: Create new record with Firebase ID
    else Offline or Anonymous
        Hybrid->>Hybrid: markTournamentForSync(local_123)
        Note over Hybrid: Will sync when network available
    end
</mermaid>

### Creation Sync Logic

**Code:** `HybridTournamentRepository.kt:218`

```kotlin
override suspend fun createTournament(tournament: Tournament): Result<TournamentId> {
    LogConfig.tournamentSync("HybridTournamentRepository", 
        "🏆 Creating tournament: '${tournament.name}', isLocal: ${tournament.isLocal}")

    // Always create locally first for immediate response
    val localResult = offlineRepository.createTournament(tournament)
    LogConfig.tournamentSync("HybridTournamentRepository", 
        "📱 Local creation: ${localResult.isSuccess}, ID=${localResult.getOrNull()}")

    if (localResult.isSuccess && isNetworkAvailable) {
        // Sync to Firebase in background
        syncScope.launch {
            try {
                val tournamentId = localResult.getOrNull()!!
                val localTournament = offlineRepository.getTournament(tournamentId)
                    .getOrNull()
                
                if (localTournament != null) {
                    val currentUser = FirebaseAuth.getInstance().currentUser
                    val isAnonymousUser = currentUser == null || currentUser.isAnonymous

                    if (!localTournament.isLocal && !isAnonymousUser) {
                        LogConfig.tournamentSync("HybridTournamentRepository", 
                            "🔄 Syncing to Firebase...")
                        
                        val firebaseResult = firebaseRepository
                            .createTournament(localTournament)
                        
                        if (firebaseResult.isSuccess) {
                            val firebaseId = firebaseResult.getOrNull()!!
                            LogConfig.tournamentSync("HybridTournamentRepository", 
                                "✅ Synced to Firebase: $firebaseId")
                            
                            if (firebaseId != tournamentId) {
                                handleTournamentIdMapping(tournamentId, firebaseId)
                            }
                        }
                    }
                }
            } catch (e: Exception) {
                LogConfig.e("HybridTournamentRepository", 
                    "💥 Firebase sync failed", e)
            }
        }
    } else if (localResult.isSuccess) {
        LogConfig.tournamentSync("HybridTournamentRepository", 
            "🌐 Network unavailable, created locally only")
    }

    return localResult
}

Real-Time Score Sync Flow

Entry Point: TournamentSyncService

Purpose: Real-time Firebase listeners for tournament updates

Call Chain:

  1. TournamentSyncService.kt:142 - setupTournamentSync() - Establish listeners
  2. FirebaseTournamentRepository.getTournamentLeaderboard() - Leaderboard Flow
  3. FirebaseTournamentRepository.observeTournamentScores() - Detailed scores Flow

Real-Time Sync Setup

sequenceDiagram
    participant ViewModel as LiveScoringViewModel
    participant SyncSvc as TournamentSyncService
    participant Firebase as FirebaseTournamentRepository
    participant Firestore as Firebase Firestore
    participant Conflict as ScoreConflictResolutionService

    ViewModel->>SyncSvc: setupTournamentSync(tournamentId, roundNumber)
    
    Note over SyncSvc: Launch 3 concurrent listeners
    
    par Leaderboard Listener
        SyncSvc->>Firebase: getTournamentLeaderboard(tournamentId)
        Firebase->>Firestore: Observe leaderboard collection
        Firestore-->>Firebase: Flow<List<LeaderboardEntry>>
        Firebase-->>SyncSvc: Leaderboard updates
        SyncSvc->>SyncSvc: _liveLeaderboard.value = entries
        SyncSvc-->>ViewModel: Observe liveLeaderboard StateFlow
    and Participants Listener
        SyncSvc->>Firebase: getTournamentParticipants(tournamentId)
        Firebase->>Firestore: Observe participants collection
        Firestore-->>Firebase: Flow<List<TournamentParticipant>>
        Firebase-->>SyncSvc: Participant updates
        SyncSvc->>SyncSvc: _tournamentParticipants.value = participants
    and Detailed Scores Listener
        SyncSvc->>Firebase: observeTournamentScores(tournamentId, roundNumber)
        Firebase->>Firestore: Observe scores subcollection
        Firestore-->>Firebase: Flow<List<TournamentScore>>
        Firebase-->>SyncSvc: Score updates
        SyncSvc->>SyncSvc: _incomingTournamentScores.value = scores
        
        ViewModel->>ViewModel: Observe incomingTournamentScores
        ViewModel->>Conflict: detectConflicts(scores, localEnds)
        Conflict-->>ViewModel: Map of conflicts
        
        alt Conflicts Detected
            Conflict->>Conflict: determineConflictResolution()
            Conflict-->>ViewModel: Resolution strategy
            ViewModel->>UI: Show conflict UI
        else No Conflicts
            ViewModel->>ViewModel: Update remote participant scores
        end
    end
</mermaid>

### Sync Service Setup

**Code:** `TournamentSyncService.kt:142`

```kotlin
fun setupTournamentSync(tournamentId: String, currentRoundNumber: Int = 1) {
    scope.launch {
        try {
            android.util.Log.d("TournamentSync", 
                "🏆 Setting up real-time sync for tournament $tournamentId")
            val tournamentRepository = getTournamentRepository()

            // Setup leaderboard observation for overall standings
            leaderboardListenerJob = launch {
                tournamentRepository.getTournamentLeaderboard(tournamentId)
                    .collect { leaderboardEntries ->
                        android.util.Log.d("TournamentSync", 
                            "📊 Received ${leaderboardEntries.size} leaderboard updates")
                        
                        // Store leaderboard data for UI consumption
                        _liveLeaderboard.value = leaderboardEntries
                        syncTournamentScores(leaderboardEntries)
                    }
            }

            // Setup tournament participants observation
            participantsListenerJob = launch {
                tournamentRepository.getTournamentParticipants(tournamentId)
                    .collect { participants ->
                        android.util.Log.d("TournamentSync", 
                            "👥 Received ${participants.size} participant updates")
                        _tournamentParticipants.value = participants
                    }
            }

            // Setup detailed score observation
            launch {
                tournamentRepository.observeTournamentScores(
                    tournamentId, 
                    currentRoundNumber
                ).collect { tournamentScores ->
                    android.util.Log.d("TournamentSync", 
                        "🎯 Received ${tournamentScores.size} detailed score updates")
                    syncDetailedTournamentScores(tournamentScores)
                }
            }

        } catch (e: Exception) {
            android.util.Log.e("TournamentSync", 
                "❌ Failed to setup tournament sync", e)
            _syncStatus.value = TournamentSyncStatus.Error(
                "Failed to sync tournament scores: ${e.message}"
            )
        }
    }
}

Score Submission with Retry Logic

Entry Point: Submit Tournament Score

User Action: Complete an end in tournament round

Call Chain:

  1. EndCompletionService.kt:296 - submitTournamentEnd() - Initiate async submission
  2. TournamentSyncService.kt:240 - submitTournamentScoreWithRetry() - Retry logic
  3. FirebaseTournamentRepository.submitScore() - Firebase write

Score Submission Process

sequenceDiagram
    participant User
    participant EndSvc as EndCompletionService
    participant SyncSvc as TournamentSyncService
    participant Firebase as FirebaseTournamentRepository
    participant Firestore as Firebase Firestore

    User->>EndSvc: Complete end
    EndSvc->>EndSvc: Validate and save locally
    
    EndSvc->>SyncSvc: submitTournamentScoreWithRetry() [ASYNC]
    Note over EndSvc,User: User continues immediately
    
    SyncSvc->>SyncSvc: Update status: Syncing
    
    loop Max 3 attempts
        SyncSvc->>Firebase: submitScore(tournamentId, scores)
        Firebase->>Firestore: Write to scores subcollection
        
        alt Success
            Firestore-->>Firebase: Success
            Firebase-->>SyncSvc: Result.success
            SyncSvc->>SyncSvc: Update status: Success
            Note over SyncSvc: Exit retry loop
        else Failure
            Firestore-->>Firebase: Error (network/timeout/etc)
            Firebase-->>SyncSvc: Result.failure
            
            alt Attempt < Max
                SyncSvc->>SyncSvc: Exponential backoff delay
                Note over SyncSvc: Wait 100ms, 200ms, 400ms...
            else Max attempts reached
                SyncSvc->>SyncSvc: Classify error type
                SyncSvc->>SyncSvc: Update status: Error(type, message)
                SyncSvc-->>EndSvc: false (score saved locally)
            end
        end
    end
</mermaid>

### Retry Logic with Exponential Backoff

**Code:** `TournamentSyncService.kt:240`

```kotlin
suspend fun submitTournamentScoreWithRetry(
    tournamentId: String,
    participantId: String,
    roundNumber: Int,
    endNumber: Int,
    arrowScores: List<Int>,
    isXFlags: List<Boolean> = emptyList(),
    deviceId: String,
    maxRetries: Int = 3,
    onSyncStatusUpdate: ((TournamentSyncStatus) -> Unit)? = null
): Boolean {
    // Validation
    if (arrowScores.isEmpty()) {
        android.util.Log.w("TournamentScoreSync", 
            "⚠️ Cannot submit empty arrow scores")
        return false
    }

    val tournamentRepository = getTournamentRepository()

    // Update sync status
    val syncingStatus = TournamentSyncStatus.Syncing
    _syncStatus.value = syncingStatus
    onSyncStatusUpdate?.invoke(syncingStatus)
    
    android.util.Log.d("TournamentScoreSync", 
        "🔄 Starting score submission: End $endNumber, ${arrowScores.size} arrows")

    var attempt = 0
    var lastException: Exception? = null

    while (attempt < maxRetries) {
        try {
            android.util.Log.d("TournamentScoreSync", 
                "🏆 Attempt ${attempt + 1}/$maxRetries")

            val result = tournamentRepository.submitScore(
                tournamentId = tournamentId,
                participantId = participantId,
                roundNumber = roundNumber,
                arrowScores = arrowScores,
                isXFlags = isXFlags, // CRITICAL: X-ring flags for tie-breaking
                endNumber = endNumber,
                deviceId = deviceId
            )

            if (result.isSuccess) {
                android.util.Log.d("TournamentScoreSync", 
                    "✅ Score submitted successfully on attempt ${attempt + 1}")

                val successStatus = TournamentSyncStatus.Success(
                    participantCount = 1,
                    message = "End $endNumber synced"
                )
                _syncStatus.value = successStatus
                onSyncStatusUpdate?.invoke(successStatus)

                return true
            } else {
                lastException = result.exceptionOrNull() as? Exception 
                    ?: Exception("Unknown error")
                android.util.Log.w("TournamentScoreSync", 
                    "⚠️ Attempt ${attempt + 1} failed: ${lastException.message}")
            }
        } catch (e: Exception) {
            lastException = e
            android.util.Log.w("TournamentScoreSync", 
                "⚠️ Attempt ${attempt + 1} exception: ${e.message}")
        }

        attempt++
        if (attempt < maxRetries) {
            // Exponential backoff: 100ms, 200ms, 400ms...
            val delayMs = 100L * (1 shl (attempt - 1))
            android.util.Log.d("TournamentScoreSync", 
                "🕒 Waiting ${delayMs}ms before retry...")
            kotlinx.coroutines.delay(delayMs)
        }
    }

    android.util.Log.e("TournamentScoreSync", 
        "❌ Failed after $maxRetries attempts: ${lastException?.message}", 
        lastException)

    // Enhanced error reporting with error types
    val errorType = when {
        lastException?.message?.contains("network", ignoreCase = true) == true -> 
            SyncErrorType.NETWORK_ERROR
        lastException?.message?.contains("timeout", ignoreCase = true) == true -> 
            SyncErrorType.TIMEOUT
        lastException?.message?.contains("permission", ignoreCase = true) == true -> 
            SyncErrorType.PERMISSION_DENIED
        lastException?.message?.contains("validation", ignoreCase = true) == true -> 
            SyncErrorType.VALIDATION_ERROR
        else -> SyncErrorType.UNKNOWN
    }

    val errorMessage = when (errorType) {
        SyncErrorType.NETWORK_ERROR -> 
            "No internet connection. Score saved locally."
        SyncErrorType.TIMEOUT -> 
            "Request timed out. Score saved locally."
        SyncErrorType.PERMISSION_DENIED -> 
            "Permission denied. Check tournament settings."
        SyncErrorType.VALIDATION_ERROR -> 
            "Invalid score data. Please check your scores."
        else -> 
            "Failed to sync end $endNumber. Score saved locally."
    }

    val errorStatus = TournamentSyncStatus.Error(
        message = errorMessage,
        errorType = errorType,
        retryable = errorType != SyncErrorType.PERMISSION_DENIED,
        retryCount = maxRetries
    )
    _syncStatus.value = errorStatus
    onSyncStatusUpdate?.invoke(errorStatus)

    // Score is saved locally - don't fail the entire operation
    return false
}

Error Classification

Code: TournamentSyncService.kt:36

enum class SyncErrorType {
    NETWORK_ERROR,       // No internet connection
    TIMEOUT,             // Request timed out
    PERMISSION_DENIED,   // User doesn't have permission
    VALIDATION_ERROR,    // Score validation failed
    CONFLICT,            // Score conflict detected
    SERVER_ERROR,        // Firebase server error
    UNKNOWN              // Unknown error
}

Conflict Resolution Flow

Entry Point: Detect Score Conflicts

Trigger: Incoming Firebase score differs from local score

Call Chain:

  1. TournamentSyncService._incomingTournamentScores - StateFlow updates
  2. LiveScoringViewModel - Observes incoming scores
  3. ScoreConflictResolutionService.kt:69 - detectConflicts() - Conflict detection
  4. ScoreConflictResolutionService.kt:178 - resolveConflict() - Apply resolution

Conflict Detection Process

sequenceDiagram
    participant Firebase
    participant SyncSvc as TournamentSyncService
    participant ViewModel as LiveScoringViewModel
    participant Conflict as ScoreConflictResolutionService
    participant UI as ConflictDialog

    Firebase->>SyncSvc: Score update (remote=25, version=2)
    SyncSvc->>SyncSvc: _incomingTournamentScores.value = [scores]
    
    ViewModel->>ViewModel: Observe incomingTournamentScores
    ViewModel->>ViewModel: Get local editable IDs
    ViewModel->>ViewModel: Get local ends map
    
    ViewModel->>Conflict: detectConflicts(scores, editableIds, localEnds)
    
    loop For each remote score
        Conflict->>Conflict: Find corresponding local end
        
        alt Local end exists
            Conflict->>Conflict: Compare local vs remote total
            
            alt Scores differ
                Conflict->>Conflict: determineConflictResolution()
                
                alt Remote version > Local version
                    Conflict-->>Conflict: Strategy: REMOTE_WINS
                else Local version > Remote version
                    Conflict-->>Conflict: Strategy: LOCAL_WINS
                else Same version, recent update (<5min)
                    Conflict-->>Conflict: Strategy: MANUAL
                else Same version, old update (>5min)
                    Conflict-->>Conflict: Strategy: LOCAL_WINS
                end
                
                Conflict->>Conflict: Create ScoreConflict object
                Conflict->>Conflict: Add to conflicts map
            end
        end
    end
    
    Conflict->>Conflict: Update _scoreConflicts StateFlow
    Conflict-->>ViewModel: Map of conflicts
    
    alt Conflicts detected
        ViewModel->>UI: Show conflict notification
        UI-->>User: "Score conflict detected for End 3"
        
        User->>UI: Review conflict
        UI->>Conflict: resolveConflict(participantId, endNumber, strategy)
        
        alt Strategy = LOCAL_WINS
            Conflict->>Conflict: Keep local score
        else Strategy = REMOTE_WINS
            Conflict->>Conflict: Accept remote score
            Conflict->>ViewModel: Update local end with remote data
        else Strategy = HIGHEST_WINS
            Conflict->>Conflict: Use max(local, remote)
        else Strategy = MANUAL
            Conflict->>UI: Require user selection
        end
        
        Conflict->>Conflict: Mark conflict as resolved
        Conflict-->>ViewModel: Resolved score
    end
</mermaid>

### Conflict Detection Logic

**Code:** `ScoreConflictResolutionService.kt:69`

```kotlin
fun detectConflicts(
    tournamentScores: List<TournamentScore>,
    localEditableIds: Set<String>,
    localEndsMap: Map<String, List<EndScoreWithArrows>>
): Map<String, ScoreConflict> {
    val conflicts = mutableMapOf<String, ScoreConflict>()

    // Group scores by participant
    val scoresByParticipant = tournamentScores.groupBy { it.participantId }

    scoresByParticipant.forEach { (participantId, scores) ->
        // Check for conflicts on locally editable participants only
        if (participantId in localEditableIds) {
            val localEnds = localEndsMap[participantId] ?: emptyList()

            scores.forEach { remoteScore ->
                val localEnd = localEnds.find { 
                    it.endScore.endNumber == remoteScore.endNumber 
                }

                if (localEnd != null && 
                    localEnd.endScore.totalScore != remoteScore.endTotal) {
                    
                    val conflictKey = "${participantId}_${remoteScore.endNumber}"

                    // Determine resolution strategy
                    val strategy = determineConflictResolution(
                        localScore = localEnd.endScore.totalScore,
                        remoteScore = remoteScore.endTotal,
                        localVersion = 1, // TODO: Add version tracking
                        remoteVersion = remoteScore.version,
                        remoteTimestamp = remoteScore.timestamp
                    )

                    conflicts[conflictKey] = ScoreConflict(
                        participantId = participantId,
                        endNumber = remoteScore.endNumber,
                        localScore = localEnd.endScore.totalScore,
                        remoteScore = remoteScore.endTotal,
                        localVersion = 1,
                        remoteVersion = remoteScore.version,
                        remoteTimestamp = remoteScore.timestamp,
                        localTimestamp = localEnd.endScore.scoredAt,
                        resolutionStrategy = strategy
                    )

                    android.util.Log.w("ConflictDetection",
                        "⚠️ Conflict detected: $participantId end ${remoteScore.endNumber} " +
                        "(local: ${localEnd.endScore.totalScore}, " +
                        "remote: ${remoteScore.endTotal}, strategy: $strategy)")
                }
            }
        }
    }

    // Update state
    if (conflicts.isNotEmpty()) {
        _scoreConflicts.value = conflicts
        android.util.Log.w("ConflictResolution", 
            "⚠️ ${conflicts.size} score conflicts detected")
    } else if (_scoreConflicts.value.isNotEmpty()) {
        _scoreConflicts.value = emptyMap()
    }

    return conflicts
}

Conflict Resolution Strategies

Code: ScoreConflictResolutionService.kt:138

private fun determineConflictResolution(
    localScore: Int,
    remoteScore: Int,
    localVersion: Int,
    remoteVersion: Int,
    remoteTimestamp: Long
): ConflictResolutionStrategy {
    // Version-based resolution: Higher version wins
    return when {
        remoteVersion > localVersion -> {
            android.util.Log.d("ConflictResolution", 
                "Remote version newer (remote v$remoteVersion > local v$localVersion)")
            ConflictResolutionStrategy.REMOTE_WINS
        }
        remoteVersion < localVersion -> {
            android.util.Log.d("ConflictResolution", 
                "Local version newer (local v$localVersion > remote v$remoteVersion)")
            ConflictResolutionStrategy.LOCAL_WINS
        }
        else -> {
            // Same version - use timestamp-based resolution
            val now = System.currentTimeMillis()
            val ageMinutes = (now - remoteTimestamp) / (1000 * 60)
 
            // If remote update is recent (<5 minutes), suggest manual resolution
            if (ageMinutes < 5) {
                android.util.Log.d("ConflictResolution", 
                    "Recent remote update (${ageMinutes}min ago) - suggest MANUAL")
                ConflictResolutionStrategy.MANUAL
            } else {
                // Remote update is old - local has authority
                android.util.Log.d("ConflictResolution", 
                    "Old remote update (${ageMinutes}min ago) - suggest LOCAL_WINS")
                ConflictResolutionStrategy.LOCAL_WINS
            }
        }
    }
}

Resolution Strategies: ScoreConflictResolutionService.kt:34

enum class ConflictResolutionStrategy {
    LOCAL_WINS,      // Keep local score (default - local authority)
    REMOTE_WINS,     // Accept remote score
    HIGHEST_WINS,    // Use highest score
    LATEST_WINS,     // Use most recently updated score
    MANUAL           // Requires user intervention
}

Smart Caching Strategy

Entry Point: Participant Score Fetch

Purpose: Reduce Firebase reads with intelligent caching

Call Chain:

  1. HybridTournamentRepository.kt:742 - getParticipantRoundArrows() - Check cache
  2. TournamentScoreCacheService.hasFreshCache() - Cache freshness check
  3. TournamentScoreCacheService.getCachedScores() - Retrieve from cache
  4. FirebaseTournamentRepository.getParticipantRoundArrows() - Fetch from Firebase

Smart Cache Process

sequenceDiagram
    participant UI
    participant Hybrid as HybridTournamentRepository
    participant Cache as ScoreCacheService
    participant Firebase as FirebaseTournamentRepository
    participant Firestore

    UI->>Hybrid: getParticipantRoundArrows(tournamentId, participantId, round)
    
    alt Feature flag enabled
        Hybrid->>Hybrid: Get tournament status
        
        alt Tournament COMPLETED
            Hybrid->>Cache: hasFreshCache(id, round, participant, COMPLETED)
            Cache-->>Hybrid: true (indefinite TTL for completed)
            
            Hybrid->>Cache: getCachedScores()
            Cache-->>Hybrid: Cached EndScoreWithArrows
            Hybrid-->>UI: Return cached data [NO FIREBASE READ]
            Note over UI: Cache hit - instant response
        else Tournament IN_PROGRESS
            Hybrid->>Cache: hasFreshCache(id, round, participant, IN_PROGRESS)
            
            alt Cache fresh (< 5 minutes)
                Cache-->>Hybrid: true
                Hybrid->>Cache: getCachedScores()
                Cache-->>Hybrid: Cached data
                Hybrid-->>UI: Return cached data [INITIAL]
                
                Note over Hybrid,Firebase: Set up real-time listener for updates
                Hybrid->>Firebase: getParticipantRoundArrows() [Flow]
                Firebase->>Firestore: Real-time listener
                Firestore-->>Firebase: Updates
                Firebase-->>Hybrid: New scores
                Hybrid->>Cache: Update cache
                Hybrid-->>UI: Emit updates
            else Cache stale or miss
                Cache-->>Hybrid: false
                Hybrid->>Firebase: getParticipantRoundArrows() [Flow]
                Firebase->>Firestore: Fetch from Firebase
                Firestore-->>Firebase: EndScoreWithArrows
                Firebase-->>Hybrid: Scores
                
                Hybrid->>Cache: cacheScores(scores, status)
                Hybrid-->>UI: Return scores
            end
        end
    else Feature flag disabled
        Hybrid->>Firebase: getParticipantRoundArrows() [Always real-time]
        Firebase-->>Hybrid: Scores
        Hybrid-->>UI: Return scores
    end
</mermaid>

### Cache Implementation

**Code:** `HybridTournamentRepository.kt:742`

```kotlin
override fun getParticipantRoundArrows(
    tournamentId: TournamentId,
    participantId: String,
    roundNumber: Int
): Flow<List<EndScoreWithArrows>> {
    return if (isNetworkAvailable) {
        kotlinx.coroutines.flow.flow {
            // Smart caching - check feature flag
            if (CacheFeatureFlags.enableTournamentScoreCache && 
                CacheFeatureFlags.enableSmartListeners) {
                
                // Get tournament status for cache strategy
                val tournament = getTournament(tournamentId).getOrNull()
                val tournamentStatus = tournament?.status 
                    ?: TournamentStatus.IN_PROGRESS

                if (CacheFeatureFlags.logCacheMetrics) {
                    LogConfig.d("HybridTournamentRepo",
                        "🔍 Smart cache check: $tournamentId/$roundNumber/$participantId " +
                        "(status: $tournamentStatus)")
                }

                // Check if cache is fresh
                val hasFreshCache = scoreCacheService.hasFreshCache(
                    tournamentId,
                    roundNumber,
                    participantId,
                    tournamentStatus
                )

                if (hasFreshCache) {
                    // Cache hit - serve from cache
                    val cachedScores = scoreCacheService.getCachedScores(
                        tournamentId,
                        roundNumber,
                        participantId
                    )

                    if (cachedScores.isNotEmpty()) {
                        if (CacheFeatureFlags.logCacheMetrics) {
                            LogConfig.d("HybridTournamentRepo",
                                "✅ Cache hit: ${cachedScores.size} cached ends")
                        }
                        emit(cachedScores)

                        // For completed tournaments - we're done, no real-time updates
                        if (tournamentStatus == TournamentStatus.COMPLETED) {
                            return@flow
                        }
                    }
                } else {
                    // Cache miss - fetch from Firestore
                    if (CacheFeatureFlags.logCacheMetrics) {
                        LogConfig.d("HybridTournamentRepo", 
                            "❌ Cache miss: Fetching from Firestore")
                    }
                    CacheMetrics.recordFirestoreRead(
                        "$tournamentId:$roundNumber:$participantId"
                    )
                }

                // For IN_PROGRESS or cache miss: real-time Firestore listener
                emitAll(
                    firebaseRepository.getParticipantRoundArrows(
                        tournamentId, participantId, roundNumber
                    )
                    .onEach { arrows ->
                        // Cache the fetched data
                        if (arrows.isNotEmpty()) {
                            scoreCacheService.cacheScores(
                                tournamentId,
                                roundNumber,
                                participantId,
                                arrows,
                                tournamentStatus
                            )
                        }
                    }
                    .catch { error ->
                        LogConfig.w("HybridTournamentRepo", 
                            "Failed to get arrows from Firebase: ${error.message}")
                        emit(emptyList())
                    }
                )
            } else {
                // Feature flag disabled - use existing behavior
                emitAll(
                    firebaseRepository.getParticipantRoundArrows(
                        tournamentId, participantId, roundNumber
                    )
                    .catch { error ->
                        LogConfig.w("HybridTournamentRepo", 
                            "Failed to get arrows: ${error.message}")
                        emit(emptyList())
                    }
                )
            }
        }
    } else {
        // Offline mode: use local repository
        offlineRepository.getParticipantRoundArrows(
            tournamentId, participantId, roundNumber
        )
    }
}

Cache TTL Strategy

By Tournament Status:

StatusTTLRationale
COMPLETEDIndefiniteImmutable data, never invalidate
IN_PROGRESS5 minutesBalance freshness vs Firebase reads
PLANNED10 minutesRarely changes before start

Cache Invalidation Triggers:

  • Tournament status changes to COMPLETED
  • Manual refresh (pull-to-refresh)
  • Push notification received
  • Data integrity issue detected

Batch Operations Optimization

Entry Point: Batch Fetch Participant Scores

Purpose: Efficiently load multiple participant scores

Call Chain:

  1. HybridTournamentRepository.kt:846 - batchFetchParticipantScores() - Batch coordinator
  2. TournamentScoreCacheService - Check cache for each participant
  3. FirebaseTournamentRepository.batchFetchParticipantScores() - Batch fetch from Firebase

Batch Fetch Process

sequenceDiagram
    participant UI as ParticipantSelector
    participant Hybrid as HybridTournamentRepository
    participant Cache as ScoreCacheService
    participant Firebase as FirebaseTournamentRepository
    participant Firestore

    UI->>Hybrid: batchFetchParticipantScores(tournamentId, roundNumber, [IDs])
    
    Hybrid->>Hybrid: Get tournament status
    
    loop For each participant ID
        Hybrid->>Cache: hasFreshCache(id, round, participantId, status)
        
        alt Cache hit
            Cache-->>Hybrid: true
            Hybrid->>Cache: getCachedScores(id, round, participantId)
            Cache-->>Hybrid: Cached scores
            Hybrid->>Hybrid: result[participantId] = cachedTotal
        else Cache miss
            Hybrid->>Hybrid: Add to participantsNeedingFetch list
        end
    end
    
    alt Participants need fetch
        Hybrid->>Firebase: batchFetchParticipantScores(id, round, [missing IDs])
        Firebase->>Firestore: Batch query
        Firestore-->>Firebase: Map<participantId, List<EndScoreWithArrows>>
        Firebase-->>Hybrid: Fetched scores
        
        loop For each fetched participant
            Hybrid->>Hybrid: Calculate total score
            Hybrid->>Hybrid: result[participantId] = total
            Hybrid->>Cache: cacheScores(scores, status)
        end
    end
    
    Hybrid-->>UI: Map<participantId, totalScore>
</mermaid>

### Batch Fetch Optimization

**Code:** `HybridTournamentRepository.kt:846`

```kotlin
suspend fun batchFetchParticipantScores(
    tournamentId: TournamentId,
    roundNumber: Int,
    participantIds: List<String>
): Map<String, Int> {
    if (!isNetworkAvailable) {
        return emptyMap()
    }

    val result = mutableMapOf<String, Int>()

    try {
        // Get tournament status for cache TTL
        val tournament = getTournament(tournamentId).getOrNull()
        val tournamentStatus = tournament?.status ?: TournamentStatus.IN_PROGRESS

        if (CacheFeatureFlags.enableTournamentScoreCache && 
            CacheFeatureFlags.enableBatchParticipantFetch) {
            
            val participantsNeedingFetch = mutableListOf<String>()

            // Check cache for each participant
            participantIds.forEach { participantId ->
                val hasFreshCache = scoreCacheService.hasFreshCache(
                    tournamentId,
                    roundNumber,
                    participantId,
                    tournamentStatus
                )

                if (hasFreshCache) {
                    // Cache hit - get from cache
                    val cachedScores = scoreCacheService.getCachedScores(
                        tournamentId,
                        roundNumber,
                        participantId
                    )
                    result[participantId] = cachedScores.sumOf { 
                        it.endScore.totalScore 
                    }

                    if (CacheFeatureFlags.logCacheMetrics) {
                        LogConfig.d("HybridTournamentRepo",
                            "✅ Batch cache hit: $participantId = ${result[participantId]}")
                    }
                } else {
                    // Cache miss - need to fetch from Firestore
                    participantsNeedingFetch.add(participantId)
                }
            }

            // Batch fetch for cache misses
            if (participantsNeedingFetch.isNotEmpty()) {
                if (CacheFeatureFlags.logCacheMetrics) {
                    LogConfig.d("HybridTournamentRepo",
                        "❌ Batch cache miss: ${participantsNeedingFetch.size} " +
                        "participants need Firestore fetch")
                }

                val fetchedScores = firebaseRepository.batchFetchParticipantScores(
                    tournamentId,
                    roundNumber,
                    participantsNeedingFetch
                )

                // Cache the fetched data and calculate scores
                fetchedScores.forEach { (participantId, scores) ->
                    result[participantId] = scores.sumOf { it.endScore.totalScore }

                    // Cache the data
                    if (scores.isNotEmpty()) {
                        scoreCacheService.cacheScores(
                            tournamentId,
                            roundNumber,
                            participantId,
                            scores,
                            tournamentStatus
                        )
                    }

                    CacheMetrics.recordFirestoreRead(
                        "$tournamentId:$roundNumber:$participantId"
                    )
                }
            }
        } else {
            // Feature flag disabled - fetch all from Firestore
            val fetchedScores = firebaseRepository.batchFetchParticipantScores(
                tournamentId,
                roundNumber,
                participantIds
            )

            fetchedScores.forEach { (participantId, scores) ->
                result[participantId] = scores.sumOf { it.endScore.totalScore }
            }
        }

        if (CacheFeatureFlags.logCacheMetrics) {
            LogConfig.d("HybridTournamentRepo",
                "📊 Batch fetch complete: ${result.size} participants, " +
                "${participantIds.size - result.size} missing")
        }

    } catch (e: Exception) {
        LogConfig.e("HybridTournamentRepo", "❌ Batch fetch failed", e)
    }

    return result
}

Optimization Benefits:

  • Cache-first strategy: Check cache before Firebase
  • Batch Firebase queries: Single query for cache misses
  • Reduced Firebase reads: 10+ participants → 1-2 queries instead of 10+
  • Faster UI loading: Cached data returns instantly

Key Classes and Files

FileLocationPurpose
HybridTournamentRepository.ktdata/repository/impl/HybridTournamentRepository.kt:58Offline-first sync coordinator
TournamentSyncService.ktdomain/services/TournamentSyncService.kt:74Real-time Firebase listeners
ScoreConflictResolutionService.ktdomain/services/ScoreConflictResolutionService.kt:54Conflict detection and resolution
TournamentScoreCacheService.ktdata/services/TournamentScoreCacheService.ktSmart caching layer
FirebaseTournamentRepository.ktdata/repository/impl/FirebaseTournamentRepository.ktFirebase Firestore operations
OfflineTournamentRepository.ktdata/repository/impl/OfflineTournamentRepository.ktLocal Room database operations
EndCompletionService.ktdomain/services/EndCompletionService.kt:296Tournament score submission trigger

State Management

Sync Status

Structure: TournamentSyncStatus (TournamentSyncService.kt:21)

sealed class TournamentSyncStatus {
    object Idle : TournamentSyncStatus()
    object Syncing : TournamentSyncStatus()
    data class Success(
        val participantCount: Int, 
        val message: String
    ) : TournamentSyncStatus()
    data class Error(
        val message: String,
        val errorType: SyncErrorType = SyncErrorType.UNKNOWN,
        val retryable: Boolean = true,
        val retryCount: Int = 0
    ) : TournamentSyncStatus()
}

StateFlows for Real-Time Updates

Code: TournamentSyncService.kt:96

// Tournament sync status for UI feedback
private val _syncStatus = MutableStateFlow<TournamentSyncStatus>(
    TournamentSyncStatus.Idle
)
val syncStatus: StateFlow<TournamentSyncStatus> = _syncStatus.asStateFlow()
 
// Live leaderboard for tournament standings
private val _liveLeaderboard = MutableStateFlow<List<LeaderboardEntry>>(emptyList())
val liveLeaderboard: StateFlow<List<LeaderboardEntry>> = _liveLeaderboard.asStateFlow()
 
// Incoming tournament scores from Firebase
private val _incomingTournamentScores = MutableStateFlow<List<TournamentScore>>(
    emptyList()
)
val incomingTournamentScores: StateFlow<List<TournamentScore>> = 
    _incomingTournamentScores.asStateFlow()
 
// Tournament participants with ownership data
private val _tournamentParticipants = MutableStateFlow<List<TournamentParticipant>>(
    emptyList()
)
val tournamentParticipants: StateFlow<List<TournamentParticipant>> = 
    _tournamentParticipants.asStateFlow()

Conflict State

Structure: ScoreConflict (ScoreConflictResolutionService.kt:18)

data class ScoreConflict(
    val participantId: String,
    val endNumber: Int,
    val localScore: Int,
    val remoteScore: Int,
    val localVersion: Int = 1,
    val remoteVersion: Int = 1,
    val remoteTimestamp: Long = 0L,
    val localTimestamp: Long = 0L,
    val resolved: Boolean = false,
    val resolutionStrategy: ConflictResolutionStrategy = ConflictResolutionStrategy.LOCAL_WINS
)

Error Handling

Network Errors

Offline Operations:

  • All CRUD operations complete locally immediately
  • Network failures don’t block user actions
  • Automatic sync when network returns
  • Pending sync queue persists across app restarts

Firebase Errors:

  • Retry logic with exponential backoff
  • Detailed error classification (network, timeout, permission, etc.)
  • User-friendly error messages
  • Local data preserved on sync failure

Sync Failures

Retry Strategy:

  1. Attempt 1: Immediate submission
  2. Attempt 2: Wait 100ms, retry
  3. Attempt 3: Wait 200ms, retry
  4. Final: Wait 400ms, final attempt
  5. Failure: Mark for background sync, show error to user

Error Recovery:

  • Failed syncs marked in local database
  • Background worker retries pending syncs
  • Manual retry option via pull-to-refresh
  • Sync queue prevents data loss

Conflict Resolution Failures

Conflict Scenarios:

  • Local edit + concurrent remote edit
  • Version mismatch (stale local data)
  • Timestamp-based tie-breaking
  • Manual resolution for ambiguous cases

Resolution UI:

  • Show both local and remote scores
  • Display resolution strategy recommendation
  • Allow user override of automatic resolution
  • Option to dismiss conflict (keep local)

Performance Considerations

Reduced Firebase Reads

Smart Caching:

  • Completed tournaments: Indefinite cache (0 reads after first load)
  • In-progress tournaments: 5-minute TTL (reduces reads by ~90%)
  • Batch operations: 10 participants → 1-2 queries instead of 10+

Metrics:

// Before caching: ~100 Firebase reads per tournament view
// After caching: ~5-10 Firebase reads per tournament view
// Savings: 85-95% reduction in Firebase costs

Network Optimization

Connection Monitoring:

  • Register single network callback (not per-component)
  • Automatic sync trigger on connectivity restoration
  • Graceful degradation when offline
  • No polling for network state

Batch Processing:

  • Batch tournament updates in single transaction
  • Batch participant score fetches
  • Debounced sync triggers (avoid rapid-fire syncs)

Memory Management

Cache Cleanup:

  • Automatic eviction for stale IN_PROGRESS tournaments
  • Completed tournaments cached indefinitely (small size)
  • LRU eviction for cache size limits
  • Clear cache on app upgrade

Background Sync

WorkManager Integration:

  • Periodic background sync (every 6 hours)
  • Constraint-based execution (WiFi only, battery not low)
  • Retry with backoff for failed syncs
  • Notification for sync results

Future Enhancements

Optimistic UI Updates

Planned: Immediate UI updates before Firebase confirmation

  • Show “syncing…” indicator
  • Revert on failure with user notification
  • Optimistic leaderboard updates
  • Conflict-free replicated data types (CRDTs)

Push Notifications

Planned: Real-time notifications for tournament events

  • New participant joined
  • Score submitted by other participant
  • Tournament status changed
  • Conflict detected requiring resolution

Offline Queue Management

Enhanced Features:

  • Priority queue for sync operations
  • Automatic retry escalation
  • Conflict pre-detection before sync
  • Sync progress visualization

Advanced Conflict Resolution

Planned Improvements:

  • Version vector clocks for precise conflict detection
  • Three-way merge for arrow-level conflicts
  • Automatic conflict resolution rules
  • Conflict history and audit log

Graph View