refactor: extract LnurlPayer

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

@@ -19,6 +19,7 @@ import com.bitcointxoko.gudariwallet.ui.clipboard.ClipboardViewModel
 import com.bitcointxoko.gudariwallet.ui.fiat.FiatViewModel
 import com.bitcointxoko.gudariwallet.ui.nfc.NfcViewModel
 import com.bitcointxoko.gudariwallet.ui.receive.ReceiveViewModel
+import com.bitcointxoko.gudariwallet.ui.send.LnurlPayer
 import com.bitcointxoko.gudariwallet.ui.send.LnurlScanner
 import com.bitcointxoko.gudariwallet.ui.send.SendViewModel
 
@@ -31,6 +32,7 @@ class WalletViewModelFactory(private val app: Application) : ViewModelProvider.F
         val repo         = LNbitsWalletRepository(api = api, secrets = secrets)
         val lnurlCache   = LnurlCacheRepository(app)
         val lnurlScanner = LnurlScanner(repo = repo, lnurlCache = lnurlCache)
+        val lnurlPayer = LnurlPayer(repo = repo, scanner = lnurlScanner, cache = lnurlCache)
         val paymentCache = PaymentCacheRepository(app)
         val fiatDataStore = FiatDataStore(app)
         val balancePrefs = BalancePrefsStore(app)
@@ -46,7 +48,8 @@ class WalletViewModelFactory(private val app: Application) : ViewModelProvider.F
             onWithdrawScanned = { raw, lnurl ->
                 receiveVm.handleWithdrawResponse(raw, lnurl)
             },
-            scanner = lnurlScanner
+            scanner = lnurlScanner,
+            payer   = lnurlPayer
         )
 
         val clipboardVm = ClipboardViewModel(

app/src/main/java/com/bitcointxoko/gudariwallet/ui/send/LnurlPayer.kt

@@ -0,0 +1,91 @@
+package com.bitcointxoko.gudariwallet.ui.send
+
+import android.util.Log
+import com.bitcointxoko.gudariwallet.api.LnurlScanResponse
+import com.bitcointxoko.gudariwallet.data.LnurlCacheRepository
+import com.bitcointxoko.gudariwallet.data.WalletRepository
+import com.bitcointxoko.gudariwallet.util.lnurlProtocolError
+
+class LnurlPayer(
+    private val repo    : WalletRepository,
+    private val scanner : LnurlScanner,
+    private val cache   : LnurlCacheRepository,
+) {
+    /**
+     * Attempts payment via direct → proxy. On transient failure, invalidates
+     * the cache, rescans, and retries once. Returns the paymentHash on success.
+     */
+    suspend fun pay(
+        rawRes    : LnurlScanResponse,
+        lnurl     : String,
+        amountMsat: Long,
+        comment   : String?,
+    ): Result<String> {
+        // ── 1. Initial attempt
+        val initial = tryWithFallback(rawRes, lnurl, amountMsat, comment, "INITIAL")
+        if (initial.isSuccess) return initial
+
+        // ── 2. Terminal error — don't retry
+        val initialError = initial.exceptionOrNull() ?: Exception("Payment failed")
+        if (isTerminalPayError(initialError)) {
+            Log.w(TAG, "LNURL [PAY TERMINAL] ${initialError.message}")
+            return Result.failure(initialError)
+        }
+
+        // ── 3. Invalidate cache and rescan
+        Log.w(TAG, "LNURL [PAY RETRY] invalidating cache and rescanning")
+        cache.invalidate(lnurl)
+
+        val rescanResult = scanner.rescan(lnurl)
+        if (rescanResult.isFailure) return Result.failure(
+            rescanResult.exceptionOrNull() ?: Exception("Rescan failed")
+        )
+        val freshRaw = rescanResult.getOrThrow()
+
+        val protocolError = lnurlProtocolError(freshRaw)
+        if (protocolError != null) {
+            Log.w(TAG, "LNURL [RESCAN PROTO] $protocolError")
+            return Result.failure(Exception(protocolError))
+        }
+        cache.put(lnurl, freshRaw)
+
+        // ── 4. Final attempt with fresh metadata
+        val retry = tryWithFallback(freshRaw, lnurl, amountMsat, comment, "RETRY")
+        if (retry.isSuccess) return retry
+
+        Log.e(TAG, "LNURL [PAY FINAL ERR] ${retry.exceptionOrNull()?.message}")
+        return Result.failure(retry.exceptionOrNull() ?: Exception("Payment failed"))
+    }
+
+    private suspend fun tryWithFallback(
+        rawRes    : LnurlScanResponse,
+        lnurl     : String,
+        amountMsat: Long,
+        comment   : String?,
+        label     : String,
+    ): Result<String> {
+        val direct = runCatching { repo.payLnurlDirect(rawRes, amountMsat, comment) }
+        if (direct.isSuccess) {
+            Log.d(TAG, "LNURL [PAY $label DIRECT] success")
+            return Result.success(direct.getOrThrow().paymentHash)
+        }
+        Log.w(TAG, "LNURL [PAY $label DIRECT FAIL] ${direct.exceptionOrNull()?.message} — trying proxy")
+
+        val proxy = runCatching { repo.payLnurl(rawRes, lnurl, amountMsat, comment) }
+        if (proxy.isSuccess) {
+            Log.d(TAG, "LNURL [PAY $label PROXY] success")
+            return Result.success(proxy.getOrThrow().paymentHash)
+        }
+        Log.w(TAG, "LNURL [PAY $label PROXY FAIL] ${proxy.exceptionOrNull()?.message}")
+        return Result.failure(proxy.exceptionOrNull() ?: Exception("Payment failed"))
+    }
+
+    private fun isTerminalPayError(e: Throwable): Boolean {
+        val msg = e.message?.lowercase() ?: return false
+        return msg.contains("insufficient balance") ||
+                msg.contains("unauthorized") ||
+                msg.contains("amount") && msg.contains("bound")
+    }
+
+    companion object { private const val TAG = "LnurlPayer" }
+}

app/src/main/java/com/bitcointxoko/gudariwallet/ui/send/SendViewModel.kt

@@ -55,6 +55,7 @@ class SendViewModel(
     private val balanceVm  : BalanceViewModel,
     private val onWithdrawScanned: (raw: LnurlScanResponse, lnurl: String) -> Unit,
     private val scanner    : LnurlScanner,
+    private val payer      : LnurlPayer,
 ) : ViewModel() {
 
     private val _sendState = MutableStateFlow<SendState>(SendState.Idle)
@@ -201,7 +202,6 @@ class SendViewModel(
         Log.w(TAG, "HOLD INVOICE [POLL TIMEOUT] $paymentHash — leaving in Paying state")
     }
 
-
     fun payLnurl(
         rawRes    : LnurlScanResponse,
         lnurl     : String,
@@ -212,52 +212,21 @@ class SendViewModel(
         viewModelScope.launch {
             _sendState.value = SendState.Paying
 
-            // ── 1. Initial attempt (direct → proxy)
+            val result = payer.pay(rawRes, lnurl, amountMsat, comment)
-            val initial = tryPayLnurlWithFallback(rawRes, lnurl, amountMsat, comment, "INITIAL", strings)
-            if (initial.isSuccess) {
-                recordPaymentSuccess(initial.getOrThrow(), amountMsat, strings = strings)
-                return@launch
-            }
 
-            // ── 2. Both paths failed — check if retrying is worthwhile
+            if (result.isSuccess) {
-            val initialError = initial.exceptionOrNull() ?: Exception(strings.paymentFailed)
+                recordPaymentSuccess(result.getOrThrow(), amountMsat, strings = strings)
-            if (isTerminalPayError(initialError)) {
+            } else {
-                Log.w(TAG, "LNURL [PAY TERMINAL] ${initialError.message} — not retrying")
                 _sendState.value = SendState.Error(
-                    parseApiError(initialError, strings.paymentFailed)         // ← "Payment failed"
+                    parseApiError(
+                        result.exceptionOrNull() ?: Exception(strings.paymentFailed),
+                        strings.paymentFailed
                     )
-                return@launch
-            }
-
-            Log.w(TAG, "LNURL [PAY RETRY  ] — invalidating cache and retrying with fresh scan")
-            lnurlCache.invalidate(lnurl)
-
-            // ── 3. Re-fetch metadata
-            val freshRaw = rescanLnurl(lnurl, strings) ?: return@launch        // error already set
-
-            val scanProtocolError = lnurlProtocolError(freshRaw)
-            if (scanProtocolError != null) {
-                Log.w(TAG, "LNURL [RESCAN PROTO] $scanProtocolError")
-                _sendState.value = SendState.Error(scanProtocolError)
-                return@launch
-            }
-            lnurlCache.put(lnurl, freshRaw)
-
-            // ── 4. Final attempt (direct → proxy) with fresh metadata
-            val retry = tryPayLnurlWithFallback(freshRaw, lnurl, amountMsat, comment, "RETRY", strings)
-            if (retry.isSuccess) {
-                recordPaymentSuccess(retry.getOrThrow(), amountMsat, strings = strings)
-                return@launch
-            }
-
-            // ── 5. Final failure
-            val retryError = retry.exceptionOrNull() ?: Exception(strings.paymentFailed)
-            Log.e(TAG, "LNURL [PAY FINAL ERR] ${retryError.message}")
-            _sendState.value = SendState.Error(
-                parseApiError(retryError, strings.paymentFailed)               // ← "Payment failed"
                 )
             }
         }
+    }
+
 
     fun fetchLnurlInvoice(
         rawRes    : LnurlScanResponse,
@@ -367,7 +336,6 @@ class SendViewModel(
         }
     }
 
-
     /**
      * Biometric gate. Shows prompt if device supports it; calls [pay] directly if not.
      */
@@ -563,55 +531,6 @@ class SendViewModel(
         )
     }
 
-
-    private suspend fun tryPayLnurlWithFallback(
-        rawRes    : LnurlScanResponse,
-        lnurl     : String,
-        amountMsat: Long,
-        comment   : String?,
-        label     : String,
-        strings   : SendStrings,
-    ): Result<String> {
-        val direct = runCatching { repo.payLnurlDirect(rawRes, amountMsat, comment) }
-        if (direct.isSuccess) {
-            Log.d(TAG, "LNURL [PAY $label DIRECT] success")
-            return Result.success(direct.getOrThrow().paymentHash)
-        }
-        Log.w(TAG, "LNURL [PAY $label DIRECT FAIL] ${direct.exceptionOrNull()?.message} — trying proxy")
-
-        val proxy = runCatching { repo.payLnurl(rawRes, lnurl, amountMsat, comment) }
-        if (proxy.isSuccess) {
-            Log.d(TAG, "LNURL [PAY $label PROXY] success")
-            return Result.success(proxy.getOrThrow().paymentHash)
-        }
-        Log.w(TAG, "LNURL [PAY $label PROXY FAIL] ${proxy.exceptionOrNull()?.message}")
-        return Result.failure(
-            proxy.exceptionOrNull() ?: Exception(strings.paymentFailed)        // ← "Payment failed"
-        )
-    }
-
-    private suspend fun rescanLnurl(lnurl: String, strings: SendStrings): LnurlScanResponse? {
-        val result = scanner.rescan(lnurl)
-        if (result.isSuccess) return result.getOrThrow()
-
-        Log.e(TAG, "LNURL [RESCAN ERR] ${result.exceptionOrNull()?.message}")
-        _sendState.value = SendState.Error(
-            parseApiError(
-                result.exceptionOrNull() ?: Exception("Rescan failed"),
-                strings.paymentFailedRescan
-            )
-        )
-        return null
-    }
-
-    private fun isTerminalPayError(e: Throwable?): Boolean {
-        if (e == null) return false
-        val msg = e.message?.lowercase() ?: return false
-        return msg.contains("insufficient balance") ||
-                msg.contains("unauthorized") ||
-                msg.contains("amount") && msg.contains("bound")
-    }
-
     private fun resolveAliasesInBackground(
         payee      : String?,
         routeHints : List<RouteHintHop>,