feat: nwc caching

app/src/main/java/com/bitcointxoko/gudariwallet/data/NwcCacheRepository.kt

@@ -0,0 +1,137 @@
+package com.bitcointxoko.gudariwallet.data
+
+import android.app.Application
+import com.bitcointxoko.gudariwallet.api.NwcBudget
+import com.bitcointxoko.gudariwallet.api.NwcGetResponse
+import com.bitcointxoko.gudariwallet.api.NwcKey
+import com.bitcointxoko.gudariwallet.data.db.AppDatabase
+import com.bitcointxoko.gudariwallet.data.db.NwcBudgetEntity
+import com.bitcointxoko.gudariwallet.data.db.NwcKeyDao
+import com.bitcointxoko.gudariwallet.data.db.NwcKeyEntity
+import kotlinx.coroutines.flow.Flow
+
+class NwcCacheRepository(app: Application) {
+    private val dao: NwcKeyDao = AppDatabase.getInstance(app).nwcKeyDao()
+
+    // ── Observe (for ViewModels to collect) ───────────────────────────
+
+    fun observeKeys(): Flow<List<NwcKeyEntity>> = dao.observeAll()
+
+    fun observeKey(pubkey: String): Flow<NwcKeyEntity?> = dao.observeKey(pubkey)
+
+    fun observeBudgets(pubkey: String): Flow<List<NwcBudgetEntity>> =
+        dao.observeBudgets(pubkey)
+
+    // ── Sync (called after network fetches) ───────────────────────────
+    // One-shot synchronous read — for startup population only
+    suspend fun getKeysOnce(): List<NwcGetResponse> =
+        dao.getAllKeys().map { it.toDomain().toGetResponse() }
+
+    /**
+     * Smart sync for the full key list.
+     *
+     * - New keys (not yet cached) → full insert
+     * - Existing keys → update last_used only (all other fields are immutable)
+     * - Keys present in cache but absent from server response → evict
+     *
+     * Never overwrites immutable fields on existing rows.
+     */
+    suspend fun syncKeys(responses: List<NwcGetResponse>) {
+        val incoming = responses.associateBy { it.data.pubkey }
+        val cached   = dao.getAllPubkeys().toSet()
+
+        dao.syncTransaction {
+            val newPubkeys = incoming.keys - cached
+            newPubkeys.forEach { pubkey ->
+                val response = incoming.getValue(pubkey)
+                dao.insertKey(response.data.toEntity())
+                dao.insertBudgets(response.budgets.map { it.toEntity() })
+            }
+
+            val existingPubkeys = incoming.keys intersect cached
+            existingPubkeys.forEach { pubkey ->
+                dao.updateLastUsed(pubkey, incoming.getValue(pubkey).data.last_used)
+            }
+
+            val removedPubkeys = cached - incoming.keys
+            if (removedPubkeys.isNotEmpty()) {
+                dao.deleteKeys(removedPubkeys)
+            }
+        }
+    }
+
+    /**
+     * Write a single key response into the cache.
+     * Used after registerNwcKey() — inserts the new key exactly once.
+     * IGNORE conflict strategy on the DAO ensures this is a no-op if
+     * somehow called twice for the same pubkey.
+     */
+    suspend fun saveKey(response: NwcGetResponse) {
+        dao.insertKey(response.data.toEntity())
+        dao.insertBudgets(response.budgets.map { it.toEntity() })
+    }
+
+    /**
+     * Update only last_used for a single key.
+     * Called after getNwcKey(refreshLastUsed = true) on the detail screen.
+     */
+    suspend fun refreshLastUsed(pubkey: String, lastUsed: Long) {
+        dao.updateLastUsed(pubkey, lastUsed)
+    }
+
+    /**
+     * Evict a key from the cache.
+     * Called after a successful deleteNwcKey() network call.
+     * CASCADE on the FK removes associated budgets automatically.
+     */
+    suspend fun deleteKey(pubkey: String) {
+        dao.deleteKey(pubkey)
+    }
+}
+
+// ── Mappers ───────────────────────────────────────────────────────────
+// Kept in this file — they exist solely to serve NwcCacheRepository.
+// If mappers grow (e.g. reverse domain→entity direction is needed),
+// extract to NwcEntityMappers.kt.
+
+private fun NwcKey.toEntity(): NwcKeyEntity = NwcKeyEntity(
+    pubkey      = pubkey,
+    wallet      = wallet,
+    description = description,
+    expiresAt   = expires_at,
+    permissions = permissions,
+    createdAt   = created_at,
+    lastUsed    = last_used,
+    cachedAt    = System.currentTimeMillis() / 1000L
+)
+
+private fun NwcBudget.toEntity(): NwcBudgetEntity = NwcBudgetEntity(
+    id               = id,
+    pubkey           = pubkey,
+    budgetMsats      = budget_msats,
+    refreshWindow    = refresh_window,
+    createdAt        = created_at,
+    usedBudgetMsats  = used_budget_msats
+)
+
+fun NwcKeyEntity.toDomain(): NwcKey = NwcKey(
+    pubkey      = pubkey,
+    wallet      = wallet,
+    description = description,
+    expires_at  = expiresAt,
+    permissions = permissions,
+    created_at  = createdAt,
+    last_used   = lastUsed
+)
+
+fun NwcBudgetEntity.toDomain(): NwcBudget = NwcBudget(
+    id               = id,
+    pubkey           = pubkey,
+    budget_msats     = budgetMsats,
+    refresh_window   = refreshWindow,
+    created_at       = createdAt,
+    used_budget_msats = usedBudgetMsats
+)
+
+fun NwcKey.toGetResponse() = NwcGetResponse(data = this, budgets = emptyList())
+

app/src/main/java/com/bitcointxoko/gudariwallet/data/db/AppDatabase.kt

@@ -13,8 +13,10 @@ import androidx.sqlite.db.SupportSQLiteDatabase
         PaymentRecordEntity::class,
         LnurlCacheEntity::class,
         NodeAliasCacheEntity::class,
+        NwcKeyEntity::class,
+        NwcBudgetEntity::class
     ],
-    version = 6,
+    version = 7,
     exportSchema = false
 )
 @TypeConverters(PaymentConverters::class)
@@ -23,6 +25,7 @@ abstract class AppDatabase : RoomDatabase() {
     abstract fun paymentDao(): PaymentDao
     abstract fun lnurlCacheDao(): LnurlCacheDao
     abstract fun nodeAliasCacheDao(): NodeAliasCacheDao
+    abstract fun nwcKeyDao(): NwcKeyDao
 
     companion object {
         @Volatile private var INSTANCE: AppDatabase? = null
@@ -86,6 +89,41 @@ abstract class AppDatabase : RoomDatabase() {
             }
         }
 
+        val MIGRATION_6_7 = object : Migration(6, 7) {
+            override fun migrate(db: SupportSQLiteDatabase) {
+                db.execSQL("""
+                CREATE TABLE IF NOT EXISTS nwc_keys (
+                    pubkey       TEXT    NOT NULL PRIMARY KEY,
+                    wallet       TEXT    NOT NULL,
+                    description  TEXT    NOT NULL,
+                    expires_at   INTEGER NOT NULL,
+                    permissions  TEXT    NOT NULL,
+                    created_at   INTEGER NOT NULL,
+                    last_used    INTEGER NOT NULL,
+                    cached_at    INTEGER NOT NULL
+                )
+            """.trimIndent())
+
+                db.execSQL("""
+                CREATE TABLE IF NOT EXISTS nwc_budgets (
+                    id                 INTEGER NOT NULL PRIMARY KEY,
+                    pubkey             TEXT    NOT NULL,
+                    budget_msats       INTEGER NOT NULL,
+                    refresh_window     INTEGER NOT NULL,
+                    created_at         INTEGER NOT NULL,
+                    used_budget_msats  INTEGER NOT NULL,
+                    FOREIGN KEY(pubkey) REFERENCES nwc_keys(pubkey)
+                        ON DELETE CASCADE
+                )
+            """.trimIndent())
+
+                db.execSQL("""
+                CREATE INDEX IF NOT EXISTS index_nwc_budgets_pubkey
+                ON nwc_budgets(pubkey)
+            """.trimIndent())
+            }
+        }
+
         fun getInstance(context: Context): AppDatabase =
             INSTANCE ?: synchronized(this) {
                 INSTANCE ?: Room.databaseBuilder(
@@ -93,7 +131,14 @@ abstract class AppDatabase : RoomDatabase() {
                     AppDatabase::class.java,
                     "gudari_wallet.db"
                 )
-                    .addMigrations(MIGRATION_1_2, MIGRATION_2_3, MIGRATION_3_4, MIGRATION_4_5, MIGRATION_5_6)
+                    .addMigrations(
+                        MIGRATION_1_2,
+                        MIGRATION_2_3,
+                        MIGRATION_3_4,
+                        MIGRATION_4_5,
+                        MIGRATION_5_6,
+                        MIGRATION_6_7
+                    )
                     .build()
                     .also { INSTANCE = it }
             }

app/src/main/java/com/bitcointxoko/gudariwallet/data/db/NwcBudgetEntity.kt

@@ -0,0 +1,33 @@
+package com.bitcointxoko.gudariwallet.data.db
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.ForeignKey
+import androidx.room.Index
+import androidx.room.PrimaryKey
+
+@Entity(
+    tableName = "nwc_budgets",
+    foreignKeys = [ForeignKey(
+        entity = NwcKeyEntity::class,
+        parentColumns = ["pubkey"],
+        childColumns = ["pubkey"],
+        onDelete = ForeignKey.CASCADE    // auto-cleans budgets when key is deleted
+    )],
+    indices = [Index("pubkey")]
+)
+data class NwcBudgetEntity(
+    @PrimaryKey
+    @ColumnInfo(name = "id")
+    val id: Int,
+    @ColumnInfo(name = "pubkey")
+    val pubkey: String,
+    @ColumnInfo(name = "budget_msats")
+    val budgetMsats: Long,
+    @ColumnInfo(name = "refresh_window")
+    val refreshWindow: Int,
+    @ColumnInfo(name = "created_at")
+    val createdAt: Long,
+    @ColumnInfo(name = "used_budget_msats")
+    val usedBudgetMsats: Long
+)

app/src/main/java/com/bitcointxoko/gudariwallet/data/db/NwcKeyDao.kt

@@ -0,0 +1,97 @@
+package com.bitcointxoko.gudariwallet.data.db
+
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.OnConflictStrategy
+import androidx.room.Query
+import androidx.room.Transaction
+import kotlinx.coroutines.flow.Flow
+
+@Dao
+interface NwcKeyDao {
+
+    // ── Observe (UI layer subscriptions) ──────────────────────────────
+
+    /**
+     * Live stream of all cached keys, newest first.
+     * Room re-emits automatically on any write — this is the only
+     * channel the list screen needs to collect.
+     */
+    @Query("SELECT * FROM nwc_keys ORDER BY created_at DESC")
+    fun observeAll(): Flow<List<NwcKeyEntity>>
+
+    /**
+     * Live stream of a single key — for the detail screen.
+     * Emits null if the key has been evicted (e.g. after a delete).
+     */
+    @Query("SELECT * FROM nwc_keys WHERE pubkey = :pubkey")
+    fun observeKey(pubkey: String): Flow<NwcKeyEntity?>
+
+    /**
+     * Live stream of budgets for a given key — for the detail screen.
+     * CASCADE delete on the parent ensures this automatically becomes
+     * empty when the parent key is deleted.
+     */
+    @Query("SELECT * FROM nwc_budgets WHERE pubkey = :pubkey")
+    fun observeBudgets(pubkey: String): Flow<List<NwcBudgetEntity>>
+
+    // ── One-shot reads (sync logic, not UI) ───────────────────────────
+
+    /**
+     * Lightweight membership check used by syncKeys() to determine
+     * which incoming keys are new vs. already cached.
+     * Returns only pubkeys — avoids loading full rows unnecessarily.
+     */
+    @Query("SELECT pubkey FROM nwc_keys")
+    suspend fun getAllPubkeys(): List<String>
+
+    /**
+     * One-shot full read of all cached keys — used for instant startup
+     * population before the Flow subscription is active.
+     * Same query as observeAll() but returns a plain list instead of Flow.
+     */
+    @Query("SELECT * FROM nwc_keys ORDER BY created_at DESC")
+    suspend fun getAllKeys(): List<NwcKeyEntity>
+
+    // ── Writes ────────────────────────────────────────────────────────
+
+    /**
+     * Insert a brand-new key. IGNORE on conflict means an existing row
+     * is never overwritten by this path — all immutable fields are safe.
+     * Used exclusively when a key is first seen (creation or first sync).
+     */
+    @Insert(onConflict = OnConflictStrategy.IGNORE)
+    suspend fun insertKey(key: NwcKeyEntity)
+
+    @Transaction
+    suspend fun syncTransaction(block: suspend () -> Unit) = block()
+
+    /**
+     * Insert budgets for a new key. Also IGNORE on conflict —
+     * budget fields are immutable post-creation.
+     */
+    @Insert(onConflict = OnConflictStrategy.IGNORE)
+    suspend fun insertBudgets(budgets: List<NwcBudgetEntity>)
+
+    /**
+     * Update ONLY last_used — the single mutable field on a key.
+     * This is the only update path that should ever run post-creation.
+     */
+    @Query("UPDATE nwc_keys SET last_used = :lastUsed WHERE pubkey = :pubkey")
+    suspend fun updateLastUsed(pubkey: String, lastUsed: Long)
+
+    /**
+     * Evict a key by pubkey. The CASCADE foreign key on nwc_budgets
+     * automatically deletes all associated budget rows — no manual
+     * budget cleanup needed.
+     */
+    @Query("DELETE FROM nwc_keys WHERE pubkey = :pubkey")
+    suspend fun deleteKey(pubkey: String)
+
+    /**
+     * Evict a set of keys in one statement — used by syncKeys() to
+     * remove server-deleted keys without issuing N individual deletes.
+     */
+    @Query("DELETE FROM nwc_keys WHERE pubkey IN (:pubkeys)")
+    suspend fun deleteKeys(pubkeys: Collection<String>)
+}

app/src/main/java/com/bitcointxoko/gudariwallet/data/db/NwcKeyEntity.kt

@@ -0,0 +1,26 @@
+package com.bitcointxoko.gudariwallet.data.db
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+
+@Entity(tableName = "nwc_keys")
+data class NwcKeyEntity(
+    @PrimaryKey
+    @ColumnInfo(name = "pubkey")
+    val pubkey: String,
+    @ColumnInfo(name = "wallet")
+    val wallet: String,
+    @ColumnInfo(name = "description")
+    val description: String,
+    @ColumnInfo(name = "expires_at")
+    val expiresAt: Long,
+    @ColumnInfo(name = "permissions")
+    val permissions: String,   // stored as comma-separated string
+    @ColumnInfo(name = "created_at")
+    val createdAt: Long,
+    @ColumnInfo(name = "last_used")
+    val lastUsed: Long,
+    @ColumnInfo(name = "cached_at")
+    val cachedAt: Long         // epoch-seconds, used for staleness check if desired
+)

app/src/main/java/com/bitcointxoko/gudariwallet/ui/WalletScreen.kt

@@ -127,7 +127,7 @@ fun WalletScreen(
     }
     val historyVm: HistoryViewModel = viewModel(factory = historyFactory)
     val nwcVm: NwcViewModel = viewModel(
-        factory = NwcViewModel.Factory(repo = vm.repo)  // same pattern as historyVm
+        factory = NwcViewModel.Factory(repo = vm.repo, cache = vm.nwcCache)  // same pattern as historyVm
     )
 
     val navBackStackEntry by navController.currentBackStackEntryAsState()

app/src/main/java/com/bitcointxoko/gudariwallet/ui/WalletViewModel.kt

@@ -12,6 +12,7 @@ import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.launch
 import com.bitcointxoko.gudariwallet.data.BalancePrefsStore
 import com.bitcointxoko.gudariwallet.data.LightningAddressStore
+import com.bitcointxoko.gudariwallet.data.NwcCacheRepository
 import com.bitcointxoko.gudariwallet.ui.balance.BalanceViewModel
 import com.bitcointxoko.gudariwallet.ui.clipboard.ClipboardViewModel
 import com.bitcointxoko.gudariwallet.ui.fiat.FiatViewModel
@@ -28,6 +29,7 @@ class WalletViewModel(
     val         repo      : WalletRepository,
     val         aliasRepo : NodeAliasRepository,
     val         paymentCache: PaymentCacheRepository,
+    val         nwcCache     : NwcCacheRepository,
     private val balancePrefs: BalancePrefsStore,
     private val lnAddressStore     : LightningAddressStore,
     val         balanceVm    : BalanceViewModel,

app/src/main/java/com/bitcointxoko/gudariwallet/ui/WalletViewModelFactory.kt

@@ -11,7 +11,9 @@ import com.bitcointxoko.gudariwallet.data.NodeAliasServiceRepository
 import com.bitcointxoko.gudariwallet.data.LNbitsWalletRepository
 import com.bitcointxoko.gudariwallet.data.LightningAddressStore
 import com.bitcointxoko.gudariwallet.data.LnurlCacheRepository
+import com.bitcointxoko.gudariwallet.data.NwcCacheRepository
 import com.bitcointxoko.gudariwallet.data.PaymentCacheRepository
+import com.bitcointxoko.gudariwallet.data.db.AppDatabase
 import com.bitcointxoko.gudariwallet.security.EncryptedSecretStore
 import com.bitcointxoko.gudariwallet.service.NodeAliasService
 import com.bitcointxoko.gudariwallet.ui.balance.BalanceViewModel
@@ -35,6 +37,7 @@ class WalletViewModelFactory(private val app: Application) : ViewModelProvider.F
         val lnurlPayer = LnurlPayer(repo = repo, scanner = lnurlScanner, cache = lnurlCache)
         val poller     = PaymentPoller(repo)
         val paymentCache = PaymentCacheRepository(app)
+        val nwcCache     = NwcCacheRepository(app)
         val fiatDataStore = FiatDataStore(app)
         val balancePrefs = BalancePrefsStore(app)
         val lnAddressStore = LightningAddressStore(app)
@@ -62,6 +65,7 @@ class WalletViewModelFactory(private val app: Application) : ViewModelProvider.F
             repo,
             aliasRepo = aliasRepo,
             paymentCache = paymentCache,
+            nwcCache       = nwcCache,
             balancePrefs = balancePrefs,
             balanceVm = balanceVm,
             fiatVm = fiatVm,

app/src/main/java/com/bitcointxoko/gudariwallet/ui/nwc/NwcScreen.kt

@@ -58,7 +58,8 @@ fun NwcScreen(
         snackbarHost = { SnackbarHost(snackbarHostState) }
     ) { innerPadding ->
 
-        val isRefreshing = uiState is NwcUiState.Loading
+        val isRefreshing = uiState is NwcUiState.Loading ||
+                (uiState as? NwcUiState.Success)?.isRefreshingLastUsed == true
 
         PullToRefreshBox(
             isRefreshing = isRefreshing,

app/src/main/java/com/bitcointxoko/gudariwallet/ui/nwc/NwcViewModel.kt

@@ -6,12 +6,21 @@ import androidx.lifecycle.viewModelScope
 import com.bitcointxoko.gudariwallet.api.NwcGetResponse
 import com.bitcointxoko.gudariwallet.api.NwcNewBudget
 import com.bitcointxoko.gudariwallet.api.NwcRegistrationRequest
+import com.bitcointxoko.gudariwallet.data.NwcCacheRepository
 import com.bitcointxoko.gudariwallet.data.WalletRepository
+import com.bitcointxoko.gudariwallet.data.db.toDomain
+import com.bitcointxoko.gudariwallet.data.toDomain
+import com.bitcointxoko.gudariwallet.data.toGetResponse
 import com.bitcointxoko.gudariwallet.util.NwcKeyGenerator
 import com.bitcointxoko.gudariwallet.util.NwcKeypair
+import kotlinx.coroutines.Job
 import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.drop
+import kotlinx.coroutines.flow.launchIn
+import kotlinx.coroutines.flow.onEach
 import kotlinx.coroutines.launch
 import timber.log.Timber
 
@@ -21,7 +30,10 @@ private const val TAG = "NwcViewModel"
 
 sealed interface NwcUiState {
     data object Loading : NwcUiState
-    data class  Success(val connections: List<NwcGetResponse>) : NwcUiState
+    data class  Success(
+        val connections: List<NwcGetResponse>,
+        val isRefreshingLastUsed: Boolean = false   // true only while network sync is in-flight
+    ) : NwcUiState
     data class  Error(val message: String) : NwcUiState
 }
 
@@ -37,7 +49,8 @@ sealed interface ConnectionDetailState {
 // ── ViewModel ─────────────────────────────────────────────────────────────────
 
 class NwcViewModel(
-    private val repo: WalletRepository
+    private val repo: WalletRepository,
+    private val cache: NwcCacheRepository
 ) : ViewModel() {
 
     private val _uiState = MutableStateFlow<NwcUiState>(NwcUiState.Loading)
@@ -64,8 +77,11 @@ class NwcViewModel(
         MutableStateFlow<ConnectionDetailState>(ConnectionDetailState.Loading)
     val connectionDetailState: StateFlow<ConnectionDetailState> =
         _connectionDetailState.asStateFlow()
+    private var detailObserverJob: Job? = null
+    private var cacheObserverJob: Job? = null
 
     // ── Sheet / dialog UI state (survives config change) ────────────────────────
+    private var isSyncing = false
 
     private val _showAddSheet        = MutableStateFlow(false)
     val showAddSheet: StateFlow<Boolean> = _showAddSheet.asStateFlow()
@@ -85,25 +101,64 @@ class NwcViewModel(
     }
 
     init {
-        loadConnections()
+        loadConnections(includeExpired = true)
     }
 
     // ── Load ──────────────────────────────────────────────────────────────────
 
     fun loadConnections(includeExpired: Boolean = false) {
         Timber.d("[$TAG] loadConnections(includeExpired=$includeExpired)")
-        _uiState.value = NwcUiState.Loading
+        isSyncing = true
+
+        // 1. Subscribe to cache — emits immediately if rows exist, stays alive
+        //    for the ViewModel lifetime. Every cache write re-emits automatically.
+        if (cacheObserverJob == null) {
+            // Fast path: one-shot read populates UI before the Flow cold-starts
+            viewModelScope.launch {
+                val snapshot = cache.getKeysOnce()
+                if (snapshot.isNotEmpty() && _uiState.value !is NwcUiState.Success) {
+                    Timber.d("[$TAG] cache snapshot: ${snapshot.size} connection(s)")
+                    _uiState.value = NwcUiState.Success(
+                        connections          = snapshot,
+                        isRefreshingLastUsed = true
+                    )
+                }
+            }
+            cacheObserverJob = cache.observeKeys()
+                .drop(1)   // skip first emission — snapshot already handled it
+                .onEach { cached ->
+                    if (cached.isNotEmpty()) {
+                        Timber.d("[$TAG] cache hit: ${cached.size} connection(s)")
+                        _uiState.value = NwcUiState.Success(
+                            connections          = cached.map { it.toDomain().toGetResponse() },
+                            isRefreshingLastUsed = isSyncing   // ← reflects current sync state, not always true
+                        )
+                    } else if (_uiState.value !is NwcUiState.Success) {
+                        _uiState.value = NwcUiState.Loading
+                    }
+                }
+                .launchIn(viewModelScope)
+        }
+
+        // 2. Fetch from network; result is written to cache which re-emits above
         viewModelScope.launch {
             runCatching { repo.getNwcKeys(includeExpired) }
                 .onSuccess { keys ->
-                    Timber.i("[$TAG] loaded ${keys.size} NWC connection(s)")
-                    _uiState.value = NwcUiState.Success(keys)
+                    Timber.i("[$TAG] network: ${keys.size} NWC connection(s)")
+                    isSyncing = false
+                    cache.syncKeys(keys)           // Room write → Flow re-emits
                 }
                 .onFailure { e ->
                     Timber.e(e, "[$TAG] failed to load NWC connections")
-                    _uiState.value = NwcUiState.Error(
-                        e.message ?: "Failed to load connections"
-                    )
+                    // Only show error if we have nothing cached to show
+                    isSyncing = false
+                    if (_uiState.value !is NwcUiState.Success) {
+                        _uiState.value = NwcUiState.Error(
+                            e.message ?: "Failed to load connections"
+                        )
+                    } else {
+                        Timber.w("[$TAG] network failed but cache is showing — non-fatal")
+                    }
                 }
         }
     }
@@ -135,7 +190,7 @@ class NwcViewModel(
                     Timber.d("[$TAG] generated keypair pubkey=${keypair.pubKeyHex.take(16)}… (${keypair.pubKeyHex.length} chars)")
                     Timber.d("[$TAG] REGISTERING pubkey=${keypair.pubKeyHex}")
 
-                    repo.registerNwcKey(
+                    val registered = repo.registerNwcKey(
                         pubkey  = keypair.pubKeyHex,
                         request = NwcRegistrationRequest(
                             description = description,
@@ -145,7 +200,8 @@ class NwcViewModel(
                         )
                     )
                     Timber.i("[$TAG] registered key ✓")
-
+                    cache.saveKey(registered)
+                    Timber.d("[$TAG] new key cached ✓")
                     val url = repo.getNwcPairingUrl(keypair.privKeyHex)
                     Timber.i("[$TAG] pairing URL fetched ✓")
                     Timber.d("[$TAG] URI=$url")
@@ -186,6 +242,7 @@ class NwcViewModel(
                 runCatching { repo.deleteNwcKey(pubkey) }
                     .onSuccess {
                         Timber.i("[$TAG] deleted connection pubkey=${pubkey.take(16)}… ✓")
+                        cache.deleteKey(pubkey)
                         val current = _uiState.value
                         if (current is NwcUiState.Success) {
                             _uiState.value = NwcUiState.Success(
@@ -209,27 +266,48 @@ class NwcViewModel(
 
     fun loadConnectionDetail(pubkey: String) {
         Timber.d("[$TAG] loadConnectionDetail pubkey=${pubkey.take(16)}…")
+
+        // Cancel any subscription from a previous key — prevents stale Flow
+        // from a previously viewed key overwriting the current detail state
+        detailObserverJob?.cancel()
         _connectionDetailState.value = ConnectionDetailState.Loading
+
+        detailObserverJob = combine(
+            cache.observeKey(pubkey),
+            cache.observeBudgets(pubkey)
+        ) { keyEntity, budgetEntities ->
+            Pair(keyEntity, budgetEntities)
+        }
+            .onEach { (keyEntity, budgetEntities) ->
+                if (keyEntity != null) {
+                    Timber.d("[$TAG] detail cache hit for ${pubkey.take(16)}…")
+                    _connectionDetailState.value = ConnectionDetailState.Success(
+                        connection = keyEntity.toDomain().toConnectionData(),
+                        budgets    = budgetEntities.map { it.toDomain().toBudgetData() }
+                    )
+                } else if (_connectionDetailState.value !is ConnectionDetailState.Success) {
+                    _connectionDetailState.value = ConnectionDetailState.Loading
+                }
+            }
+            .launchIn(viewModelScope)   // ← now tracked and cancellable
+
         viewModelScope.launch {
             runCatching {
-                repo.getNwcKey(
-                    pubkey          = pubkey,
-                    includeExpired  = true,   // show detail even for expired keys
-                    refreshLastUsed = false
-                )
+                repo.getNwcKey(pubkey = pubkey, includeExpired = true, refreshLastUsed = false)
             }
                 .onSuccess { response ->
                     Timber.i("[$TAG] loaded connection detail ✓")
-                    _connectionDetailState.value = ConnectionDetailState.Success(
-                        connection = response.data.toConnectionData(),
-                        budgets    = response.budgets.map { it.toBudgetData() }
-                    )
+                    cache.refreshLastUsed(pubkey, response.data.last_used)
                 }
                 .onFailure { e ->
                     Timber.e(e, "[$TAG] failed to load connection detail")
-                    _connectionDetailState.value = ConnectionDetailState.Error(
-                        e.message ?: "Failed to load connection"
-                    )
+                    if (_connectionDetailState.value !is ConnectionDetailState.Success) {
+                        _connectionDetailState.value = ConnectionDetailState.Error(
+                            e.message ?: "Failed to load connection"
+                        )
+                    } else {
+                        Timber.w("[$TAG] detail network refresh failed — cache showing (non-fatal)")
+                    }
                 }
         }
     }
@@ -237,6 +315,8 @@ class NwcViewModel(
     /** Reset to Loading so the next open always shows a fresh load. */
     fun clearConnectionDetail() {
         Timber.d("[$TAG] clearConnectionDetail")
+        detailObserverJob?.cancel()      // ← stop the old key's Flow immediately
+        detailObserverJob = null
         _connectionDetailState.value = ConnectionDetailState.Loading
     }
 
@@ -253,7 +333,7 @@ class NwcViewModel(
             runCatching { repo.getNwcKeys(includeExpired) }
                 .onSuccess { keys ->
                     Timber.d("[$TAG] silentRefresh: ${keys.size} connection(s)")
-                    _uiState.value = NwcUiState.Success(keys)
+                    cache.syncKeys(keys)   // Room write → cache Flow re-emits to UI
                 }
                 .onFailure { e ->
                     Timber.w(e, "[$TAG] silentRefresh failed (non-fatal)")
@@ -264,10 +344,12 @@ class NwcViewModel(
 
     // ── Factory ───────────────────────────────────────────────────────────────
 
-    class Factory(private val repo: WalletRepository) :
-        ViewModelProvider.Factory {
+    class Factory(
+        private val repo: WalletRepository,
+        private val cache: NwcCacheRepository
+    ) : ViewModelProvider.Factory {
         @Suppress("UNCHECKED_CAST")
         override fun <T : ViewModel> create(modelClass: Class<T>): T =
-            NwcViewModel(repo) as T
+            NwcViewModel(repo, cache) as T
     }
 }