feat(wallet): prefer NIP-44 for NWC and notify non-zap payments

NIP-44 encryption preference: NwcSignerState now fetches each wallet's
kind 13194 info event (via the relay client, injected by Account),
caches whether it advertises `nip44_v2`, and sends pay/RPC requests
with NIP-44 when supported — satisfying NIP-47's "client should always
prefer nip44 if supported by the wallet service". Falls back to NIP-04
(the legacy default) when unknown or unsupported; response decryption
already auto-detects the scheme.

Non-zap payment notifications: NwcPaymentNotificationWatcher keeps a
standing subscription to each connected wallet's NIP-47 notification
stream (kind 23197/23196) on the wallet relay, decrypts payment_received
events, and posts a tray notification on a new Payments Received channel.
Payments carrying a NIP-57 zap request are skipped, since those already
surface through the kind-9735 ZapNotification path — so only plain,
non-zap incoming payments are announced.

Deep-link pairing: the "Connect wallet via app" button now builds its
`nostrnwc://connect` URI through the tested quartz Nip47DeepLink helper
instead of a hardcoded percent-encoded string.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01RDAAS4ktFbWtRnEVXQsjfs

amethyst/src/main/java/com/vitorpamplona/amethyst/AppModules.kt

@@ -71,6 +71,7 @@ import com.vitorpamplona.amethyst.service.images.ThumbnailDiskCache
 import com.vitorpamplona.amethyst.service.location.LocationState
 import com.vitorpamplona.amethyst.service.notifications.AlwaysOnNotificationServiceManager
 import com.vitorpamplona.amethyst.service.notifications.NotificationDispatcher
+import com.vitorpamplona.amethyst.service.notifications.NwcPaymentNotificationWatcher
 import com.vitorpamplona.amethyst.service.notifications.PokeyReceiver
 import com.vitorpamplona.amethyst.service.okhttp.DualHttpClientManager
 import com.vitorpamplona.amethyst.service.okhttp.DualHttpClientManagerForRelays
@@ -882,6 +883,16 @@ class AppModules(
             scope = applicationIOScope,
         )
 
+    // Surfaces non-zap Lightning payments reported by the logged-in account's NWC
+    // wallet(s) as tray notifications (zaps are already shown via ZapNotification).
+    val nwcPaymentNotificationWatcher =
+        NwcPaymentNotificationWatcher(
+            context = appContext,
+            client = client,
+            scope = applicationIOScope,
+            accountFlow = sessionManager.accountContent.map { (it as? AccountState.LoggedIn)?.account },
+        ).also { it.start() }
+
     fun subscribedFlow(
         address: Address,
         account: Account,

amethyst/src/main/java/com/vitorpamplona/amethyst/model/Account.kt

@@ -291,6 +291,7 @@ import com.vitorpamplona.quartz.nip37Drafts.DraftEventCache
 import com.vitorpamplona.quartz.nip37Drafts.DraftWrapEvent
 import com.vitorpamplona.quartz.nip42RelayAuth.RelayAuthEvent
 import com.vitorpamplona.quartz.nip47WalletConnect.Nip47WalletConnect
+import com.vitorpamplona.quartz.nip47WalletConnect.events.NwcInfoEvent
 import com.vitorpamplona.quartz.nip47WalletConnect.rpc.Request
 import com.vitorpamplona.quartz.nip47WalletConnect.rpc.Response
 import com.vitorpamplona.quartz.nip51Lists.bookmarkList.BookmarkListEvent
@@ -470,7 +471,22 @@ class Account(
     // account never surfaces under another (the old cache was a process-wide singleton).
     val relayNotifications = NotifyRequestsCache()
 
-    override val nip47SignerState = NwcSignerState(signer, nwcFilterAssembler, cache, scope, settings)
+    override val nip47SignerState =
+        NwcSignerState(
+            signer,
+            nwcFilterAssembler,
+            cache,
+            scope,
+            settings,
+            fetchInfoEvent = { uri ->
+                // Fetch the wallet's kind 13194 info event so NwcSignerState can prefer
+                // NIP-44 when the wallet advertises it (NIP-47 encryption negotiation).
+                client.fetchFirst(
+                    uri.relayUri,
+                    Filter(kinds = listOf(NwcInfoEvent.KIND), authors = listOf(uri.pubKeyHex), limit = 1),
+                ) as? NwcInfoEvent
+            },
+        )
 
     val nip65RelayList = Nip65RelayListState(signer, cache, scope, settings)
     val localRelayList = LocalRelayListState(signer, cache, scope, settings)

amethyst/src/main/java/com/vitorpamplona/amethyst/model/nip47WalletConnect/NwcSignerState.kt

@@ -37,18 +37,24 @@ import com.vitorpamplona.quartz.nip47WalletConnect.cache.NostrWalletConnectReque
 import com.vitorpamplona.quartz.nip47WalletConnect.cache.NostrWalletConnectResponseCache
 import com.vitorpamplona.quartz.nip47WalletConnect.events.LnZapPaymentRequestEvent
 import com.vitorpamplona.quartz.nip47WalletConnect.events.LnZapPaymentResponseEvent
+import com.vitorpamplona.quartz.nip47WalletConnect.events.NwcInfoEvent
 import com.vitorpamplona.quartz.nip47WalletConnect.rpc.Request
 import com.vitorpamplona.quartz.nip47WalletConnect.rpc.Response
+import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.flow.SharingStarted
 import kotlinx.coroutines.flow.StateFlow
+import kotlinx.coroutines.flow.collectLatest
 import kotlinx.coroutines.flow.combine
+import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.flow.filterNotNull
 import kotlinx.coroutines.flow.flowOn
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.stateIn
 import kotlinx.coroutines.launch
+import java.util.concurrent.ConcurrentHashMap
 
 /**
  * Manages NIP-47 (Nostr Wallet Connect) related signing operations and decryption cache for a given account.
@@ -60,6 +66,12 @@ class NwcSignerState(
     val cache: LocalCache,
     val scope: CoroutineScope,
     val settings: AccountSettings,
+    /**
+     * Fetches a wallet's kind 13194 info event so we can negotiate encryption.
+     * Injected by [com.vitorpamplona.amethyst.model.Account] (which owns the relay
+     * client). Null in tests / when unavailable — requests then fall back to NIP-04.
+     */
+    val fetchInfoEvent: (suspend (Nip47WalletConnect.Nip47URINorm) -> NwcInfoEvent?)? = null,
 ) : INwcSignerState {
     /**
      * Flow of the default wallet's NWC URI, derived from multi-wallet settings.
@@ -105,6 +117,54 @@ class NwcSignerState(
             NostrSignerInternal(KeyPair(it))
         }
 
+    /**
+     * Per-wallet (keyed by wallet service pubkey) cache of whether the wallet
+     * advertises NIP-44 (`nip44_v2`) support in its kind 13194 info event.
+     * NIP-47 says a client "should always prefer nip44 if supported by the wallet
+     * service"; absent/unknown means we keep the NIP-04 legacy default.
+     */
+    private val nip44SupportByWallet = ConcurrentHashMap<HexKey, Boolean>()
+
+    init {
+        // Warm the encryption preference in the background whenever the default
+        // wallet changes so the payment hot path can read it without blocking.
+        scope.launch(Dispatchers.IO) {
+            defaultWalletUri
+                .filterNotNull()
+                .distinctUntilChanged { a, b -> a.pubKeyHex == b.pubKeyHex && a.relayUri == b.relayUri }
+                .collectLatest { warmEncryptionPreference(it) }
+        }
+    }
+
+    /**
+     * Fetches the wallet's info event once and records whether it supports NIP-44.
+     * Best-effort: any failure leaves the wallet on the NIP-04 fallback.
+     */
+    private suspend fun warmEncryptionPreference(uri: Nip47WalletConnect.Nip47URINorm) {
+        val fetch = fetchInfoEvent ?: return
+        if (nip44SupportByWallet.containsKey(uri.pubKeyHex)) return
+
+        val supports =
+            try {
+                fetch(uri)?.encryptionSchemes()?.any { it.equals("nip44_v2", ignoreCase = true) } == true
+            } catch (e: Exception) {
+                if (e is CancellationException) throw e
+                false
+            }
+
+        nip44SupportByWallet[uri.pubKeyHex] = supports
+    }
+
+    /**
+     * Non-blocking read of the negotiated encryption preference for a wallet.
+     * Returns true only once the info event has been fetched and advertised
+     * `nip44_v2`; otherwise NIP-04 (the legacy default).
+     */
+    private fun prefersNip44(uri: Nip47WalletConnect.Nip47URINorm?): Boolean {
+        uri ?: return false
+        return nip44SupportByWallet[uri.pubKeyHex] ?: false
+    }
+
     fun hasWalletConnectSetup(): Boolean = settings.nwcWallets.value.isNotEmpty()
 
     override fun isNIP47Author(pubKey: HexKey?): Boolean = nip47Signer.value.pubKey == pubKey
@@ -138,7 +198,7 @@ class NwcSignerState(
         val walletService = walletUri ?: throw IllegalArgumentException("No NIP47 setup")
         val walletSigner = buildSigner(walletService) ?: signer
 
-        val event = LnZapPaymentRequestEvent.createRequest(request, walletService.pubKeyHex, walletSigner)
+        val event = LnZapPaymentRequestEvent.createRequest(request, walletService.pubKeyHex, walletSigner, useNip44 = prefersNip44(walletService))
 
         val filter =
             NWCPaymentQueryState(
@@ -184,7 +244,7 @@ class NwcSignerState(
     ): Pair<LnZapPaymentRequestEvent, NormalizedRelayUrl> {
         val walletService = defaultWalletUri.value ?: throw IllegalArgumentException("No NIP47 setup")
 
-        val event = LnZapPaymentRequestEvent.create(bolt11, walletService.pubKeyHex, nip47Signer.value)
+        val event = LnZapPaymentRequestEvent.create(bolt11, walletService.pubKeyHex, nip47Signer.value, useNip44 = prefersNip44(walletService))
 
         val filter =
             NWCPaymentQueryState(

amethyst/src/main/java/com/vitorpamplona/amethyst/service/notifications/NotificationCategory.kt

@@ -226,6 +226,19 @@ enum class NotificationCategory(
         group = "com.vitorpamplona.amethyst.CHESS_NOTIFICATION",
         summaryId = 0x30000,
     ),
+    PAYMENT_RECEIVED(
+        channelIdRes = R.string.app_notification_payments_channel_id,
+        channelNameRes = R.string.app_notification_payments_channel_name,
+        channelDescriptionRes = R.string.app_notification_payments_channel_description,
+        summaryTextRes = R.string.app_notification_payments_summary,
+        importance = NotificationManager.IMPORTANCE_DEFAULT,
+        color = 0xFF16B979.toInt(), // lightning green — distinct from the gold zap channel
+        smallIcon = R.drawable.ic_notif_zap,
+        settingsIcon = MaterialSymbols.AccountBalanceWallet,
+        channelGroup = NotifChannelGroup.PAYMENTS,
+        group = "com.vitorpamplona.amethyst.PAYMENT_RECEIVED_NOTIFICATION",
+        summaryId = 0xC0000,
+    ),
     ;
 
     fun channelId(context: Context): String = stringRes(context, channelIdRes)

amethyst/src/main/java/com/vitorpamplona/amethyst/service/notifications/NwcPaymentNotificationWatcher.kt

@@ -0,0 +1,128 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.service.notifications
+
+import android.content.Context
+import com.vitorpamplona.amethyst.commons.model.nip47WalletConnect.NwcWalletEntryNorm
+import com.vitorpamplona.amethyst.model.Account
+import com.vitorpamplona.amethyst.service.notifications.renderers.NwcPaymentNotifier
+import com.vitorpamplona.quartz.nip01Core.core.HexKey
+import com.vitorpamplona.quartz.nip01Core.relay.client.INostrClient
+import com.vitorpamplona.quartz.nip01Core.relay.client.reqs.subscribeAsFlow
+import com.vitorpamplona.quartz.nip01Core.relay.filters.Filter
+import com.vitorpamplona.quartz.nip01Core.signers.NostrSigner
+import com.vitorpamplona.quartz.nip47WalletConnect.events.NwcNotificationEvent
+import com.vitorpamplona.quartz.nip47WalletConnect.rpc.PaymentReceivedNotification
+import com.vitorpamplona.quartz.utils.TimeUtils
+import kotlinx.coroutines.CancellationException
+import kotlinx.coroutines.CoroutineScope
+import kotlinx.coroutines.Dispatchers
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.flow.Flow
+import kotlinx.coroutines.flow.collectLatest
+import kotlinx.coroutines.flow.distinctUntilChanged
+import kotlinx.coroutines.launch
+
+/**
+ * Always-on watcher that turns NIP-47 wallet notifications (kind 23197/23196) into
+ * user-facing tray notifications for the logged-in account.
+ *
+ * For each configured NWC wallet it opens a standing subscription on that wallet's
+ * own relay, filtered to notifications `p`-tagged to our client pubkey. Each event
+ * is decrypted with the per-wallet connection secret and, when it is an incoming
+ * `payment_received`, posted via [NwcPaymentNotifier] — **unless** the transaction
+ * metadata carries a NIP-57 zap request, in which case it is dropped: zaps already
+ * surface through the kind-9735 `ZapNotification` path, so notifying here would
+ * double up.
+ *
+ * Only new notifications (`since` = watch start) are surfaced, so relaunching the
+ * app never replays old payments as fresh alerts; a per-subscription id set
+ * de-duplicates re-delivery across relay reconnects.
+ */
+class NwcPaymentNotificationWatcher(
+    private val context: Context,
+    private val client: INostrClient,
+    private val scope: CoroutineScope,
+    private val accountFlow: Flow<Account?>,
+) {
+    fun start() {
+        scope.launch(Dispatchers.IO) {
+            accountFlow
+                .distinctUntilChanged { a, b -> a?.signer?.pubKey == b?.signer?.pubKey }
+                .collectLatest { account ->
+                    account ?: return@collectLatest
+                    account.settings.nwcWallets.collectLatest { wallets ->
+                        watchWallets(account, wallets)
+                    }
+                }
+        }
+    }
+
+    private suspend fun watchWallets(
+        account: Account,
+        wallets: List<NwcWalletEntryNorm>,
+    ) = coroutineScope {
+        wallets.forEach { wallet ->
+            val signer = account.nip47SignerState.buildSigner(wallet.uri) ?: return@forEach
+
+            val filter =
+                Filter(
+                    kinds = listOf(NwcNotificationEvent.KIND, NwcNotificationEvent.LEGACY_KIND),
+                    authors = listOf(wallet.uri.pubKeyHex),
+                    tags = mapOf("p" to listOf(signer.pubKey)),
+                    since = TimeUtils.now(),
+                )
+
+            launch(Dispatchers.IO) {
+                val seen = HashSet<HexKey>()
+                client.subscribeAsFlow(wallet.uri.relayUri, filter).collect { events ->
+                    events.forEach { event ->
+                        val notification = event as? NwcNotificationEvent ?: return@forEach
+                        if (seen.add(notification.id)) {
+                            handle(account, notification, signer)
+                        }
+                    }
+                }
+            }
+        }
+    }
+
+    private suspend fun handle(
+        account: Account,
+        event: NwcNotificationEvent,
+        signer: NostrSigner,
+    ) {
+        val notification =
+            try {
+                event.decryptNotification(signer)
+            } catch (e: Exception) {
+                if (e is CancellationException) throw e
+                return
+            }
+
+        val tx = (notification as? PaymentReceivedNotification)?.notification ?: return
+
+        // A payment carrying a NIP-57 zap request is already shown by ZapNotification.
+        if (tx.parsedMetadata()?.nostr != null) return
+
+        NwcPaymentNotifier.notify(context, account, tx)
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/service/notifications/renderers/NwcPaymentNotifier.kt

@@ -0,0 +1,78 @@
+/*
+ * Copyright (c) 2025 Vitor Pamplona
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy of
+ * this software and associated documentation files (the "Software"), to deal in
+ * the Software without restriction, including without limitation the rights to use,
+ * copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the
+ * Software, and to permit persons to whom the Software is furnished to do so,
+ * subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+ * FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+ * COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN
+ * AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+ * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+ */
+package com.vitorpamplona.amethyst.service.notifications.renderers
+
+import android.content.Context
+import com.vitorpamplona.amethyst.R
+import com.vitorpamplona.amethyst.model.Account
+import com.vitorpamplona.amethyst.service.notifications.NotificationCategory
+import com.vitorpamplona.amethyst.service.notifications.NotificationRoutes
+import com.vitorpamplona.amethyst.service.notifications.NotificationUtils.postStandard
+import com.vitorpamplona.amethyst.service.notifications.notificationManager
+import com.vitorpamplona.amethyst.ui.note.showAmount
+import com.vitorpamplona.amethyst.ui.stringRes
+import com.vitorpamplona.quartz.nip47WalletConnect.rpc.NwcTransaction
+import com.vitorpamplona.quartz.utils.TimeUtils
+
+/**
+ * Posts a tray notification for an incoming Lightning payment reported by the
+ * connected NWC wallet (NIP-47 `payment_received`). Renders on the green Payments
+ * channel with a wallet icon; the title leads with the amount.
+ *
+ * Zaps are intentionally NOT routed here — a `payment_received` whose transaction
+ * metadata carries a NIP-57 zap request is filtered out upstream by
+ * [com.vitorpamplona.amethyst.service.notifications.NwcPaymentNotificationWatcher],
+ * because those already surface through the kind-9735 [ZapNotification] path.
+ */
+object NwcPaymentNotifier {
+    suspend fun notify(
+        context: Context,
+        account: Account,
+        tx: NwcTransaction,
+    ) {
+        val nm = context.notificationManager()
+        if (!nm.areNotificationsEnabled()) return
+
+        val msats = tx.amount ?: return
+        val amount = showAmount((msats / 1000L).toBigDecimal())
+
+        val id = tx.payment_hash ?: tx.invoice ?: tx.created_at?.toString() ?: return
+        val time = tx.settled_at ?: tx.created_at ?: TimeUtils.now()
+
+        val title = stringRes(context, R.string.app_notification_payments_channel_message, amount)
+        val comment = (tx.parsedMetadata()?.comment ?: tx.description)?.ifBlank { null }
+        val body = comment ?: title
+
+        val accountNpub = NotificationRoutes.accountNpub(account)
+        val uri = NotificationRoutes.notificationsUri(accountNpub, id)
+
+        nm.postStandard(
+            category = NotificationCategory.PAYMENT_RECEIVED,
+            id = id,
+            messageTitle = title,
+            messageBody = body,
+            time = time,
+            pictureUrl = null,
+            uri = uri,
+            applicationContext = context,
+        )
+    }
+}

amethyst/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/wallet/AddNwcWalletScreen.kt

@@ -65,6 +65,7 @@ import com.vitorpamplona.amethyst.ui.stringRes
 import com.vitorpamplona.amethyst.ui.theme.ButtonBorder
 import com.vitorpamplona.amethyst.ui.theme.DoubleHorzSpacer
 import com.vitorpamplona.amethyst.ui.theme.Size24Modifier
+import com.vitorpamplona.quartz.nip47WalletConnect.Nip47DeepLink
 import com.vitorpamplona.quartz.nip47WalletConnect.Nip47WalletConnect
 import kotlinx.coroutines.CancellationException
 import kotlinx.coroutines.launch
@@ -137,7 +138,11 @@ fun AddNwcWalletScreen(
                     onClick = {
                         try {
                             uri.openUri(
-                                "nostrnwc://connect?appname=Amethyst&appicon=https%3A%2F%2Fraw.githubusercontent.com%2Fvitorpamplona%2Famethyst%2Frefs%2Fheads%2Fmain%2Ficon.png&callback=amethyst%2Bwalletconnect%3A%2F%2Fdlnwc",
+                                Nip47DeepLink.buildConnectUri(
+                                    callback = "amethyst+walletconnect://dlnwc",
+                                    appName = "Amethyst",
+                                    appIcon = "https://raw.githubusercontent.com/vitorpamplona/amethyst/refs/heads/main/icon.png",
+                                ),
                             )
                         } catch (_: IllegalArgumentException) {
                             accountViewModel.toastManager.toast(

amethyst/src/main/res/values/strings.xml

@@ -1858,6 +1858,12 @@
     <string name="app_notification_zaps_channel_message_from">From %1$s</string>
     <string name="app_notification_zaps_channel_message_for">for %1$s</string>
 
+    <string name="app_notification_payments_channel_id" translatable="false">PaymentsReceivedID</string>
+    <string name="app_notification_payments_channel_name">Payments Received</string>
+    <string name="app_notification_payments_channel_description">Notifies you when your connected wallet receives a payment that is not a Nostr zap</string>
+    <string name="app_notification_payments_channel_message">Received %1$s sats</string>
+    <string name="app_notification_payments_summary">New payments</string>
+
     <string name="app_notification_reply_label">Reply</string>
     <string name="app_notification_mark_read_label">Mark Read</string>
     <string name="app_notification_me">Me</string>