feat: add transfer from savings button on empty spending screen

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Show loading state on Spending tab when node is not running #875
 
 ### Added
+- Transfer from Savings button on empty Spending screen when savings balance exists #882
 - Connection issues overlay with connectivity fixes across Send, Receive, and Transfer flows #878
 - Lightning Connections empty state with onboarding screen #857
 - Unified PIN management screen (enable/disable/change in one place) #857

app/src/main/java/to/bitkit/ui/ContentView.kt

@@ -815,6 +815,7 @@ private fun NavGraphBuilder.home(
     }
     composableWithDefaultTransitions<Routes.Spending> {
         val hasSeenSavingsIntro by settingsViewModel.hasSeenSavingsIntro.collectAsStateWithLifecycle()
+        val hasSeenSpendingIntro by settingsViewModel.hasSeenSpendingIntro.collectAsStateWithLifecycle()
         val lightningState by walletViewModel.lightningState.collectAsStateWithLifecycle()
         val lightningActivities by activityListViewModel.lightningActivities.collectAsStateWithLifecycle()
 
@@ -831,6 +832,13 @@ private fun NavGraphBuilder.home(
                     navController.navigateToTransferSavingsAvailability()
                 }
             },
+            onTransferFromSavingsClick = {
+                if (!hasSeenSpendingIntro) {
+                    navController.navigateToTransferSpendingIntro()
+                } else {
+                    navController.navigateToTransferSpendingAmount()
+                }
+            },
             onBackClick = { navController.popBackStack() },
         )
     }

app/src/main/java/to/bitkit/ui/screens/wallets/SpendingWalletScreen.kt

@@ -56,6 +56,7 @@ fun SpendingWalletScreen(
     onActivityItemClick: (String) -> Unit,
     onEmptyActivityRowClick: () -> Unit,
     onTransferToSavingsClick: () -> Unit,
+    onTransferFromSavingsClick: () -> Unit,
     onBackClick: () -> Unit,
     balances: BalanceState = LocalBalances.current,
 ) {
@@ -69,6 +70,9 @@ fun SpendingWalletScreen(
         val hasChannels = channels.isNotEmpty()
         mutableStateOf(hasLnBalance && hasChannels)
     }
+    val canTransferFromSavings by remember(showEmptyState, balances.totalOnchainSats) {
+        mutableStateOf(showEmptyState && balances.totalOnchainSats > 0uL)
+    }
 
     Box(
         modifier = Modifier
@@ -112,6 +116,23 @@ fun SpendingWalletScreen(
                     )
                 }
 
+                if (canTransferFromSavings) {
+                    VerticalSpacer(32.dp)
+
+                    SecondaryButton(
+                        onClick = onTransferFromSavingsClick,
+                        text = stringResource(R.string.lightning__funding__button1),
+                        icon = {
+                            Icon(
+                                painter = painterResource(R.drawable.ic_transfer),
+                                contentDescription = null,
+                                modifier = Modifier.size(16.dp)
+                            )
+                        },
+                        modifier = Modifier.testTag("TransferFromSavings")
+                    )
+                }
+
                 if (!showEmptyState) {
                     Spacer(modifier = Modifier.height(32.dp))
 
@@ -163,6 +184,7 @@ private fun Preview() {
                 onActivityItemClick = {},
                 onEmptyActivityRowClick = {},
                 onTransferToSavingsClick = {},
+                onTransferFromSavingsClick = {},
                 onBackClick = {},
                 balances = BalanceState(totalLightningSats = 50_000u),
             )
@@ -183,6 +205,7 @@ private fun PreviewTransfer() {
                 onActivityItemClick = {},
                 onEmptyActivityRowClick = {},
                 onTransferToSavingsClick = {},
+                onTransferFromSavingsClick = {},
                 onBackClick = {},
                 balances = BalanceState(
                     totalLightningSats = 50_000u,
@@ -206,6 +229,7 @@ private fun PreviewNoActivity() {
                 onActivityItemClick = {},
                 onEmptyActivityRowClick = {},
                 onTransferToSavingsClick = {},
+                onTransferFromSavingsClick = {},
                 onBackClick = {},
                 balances = BalanceState(totalLightningSats = 50_000u),
             )
@@ -226,7 +250,29 @@ private fun PreviewEmpty() {
                 onActivityItemClick = {},
                 onEmptyActivityRowClick = {},
                 onTransferToSavingsClick = {},
+                onTransferFromSavingsClick = {},
+                onBackClick = {},
+            )
+            TabBar()
+        }
+    }
+}
+
+@Preview(showSystemUi = true)
+@Composable
+private fun PreviewEmptyWithSavings() {
+    AppThemeSurface {
+        Box {
+            SpendingWalletScreen(
+                channels = persistentListOf(),
+                lightningActivities = persistentListOf(),
+                onAllActivityButtonClick = {},
+                onActivityItemClick = {},
+                onEmptyActivityRowClick = {},
+                onTransferToSavingsClick = {},
+                onTransferFromSavingsClick = {},
                 onBackClick = {},
+                balances = BalanceState(totalOnchainSats = 100_000u),
             )
             TabBar()
         }