SyncStateManager

Manages subscription sync state for resuming after app restarts.

Purpose:

• Persist last processed transaction ID per address

• Enable subscription resumption (don't replay all history on restart)

• Track sync progress

Storage:

• Uses DataStore (shared preferences alternative)

• Key format: "last_tx_id_{address}"

• Value: Last processed transaction ID (Int)

Resume Flow:

1. App starts

2. Get last processed ID: getLastProcessedTransactionId(address)

3. Subscribe from that ID: subscribeToUnshieldedTransactions(address, lastId)

4. Process updates

5. Save progress: saveLastProcessedTransactionId(address, newId)

Example:

// On app start
val lastId = syncStateManager.getLastProcessedTransactionId(address)
// lastId = 42 (from previous session)

// Subscribe from last ID (skip already processed txs)
indexerClient.subscribeToUnshieldedTransactions(address, fromTransactionId = lastId)
    .collect { update ->
        utxoManager.processUpdate(update)

        if (update is Progress) {
            syncStateManager.saveLastProcessedTransactionId(address, update.highestTransactionId)
        }
    }