Improves the Redeeming feedback

Improves fee calculation from the mint

app/src/main/java/com/vitorpamplona/amethyst/service/CashuProcessor.kt

@@ -18,8 +18,6 @@ data class CashuToken(
     val token: String,
     val mint: String,
     val totalAmount: Long,
-    val fees: Int,
-    val redeemInvoiceAmount: Long,
     val proofs: JsonNode
 )
 
@@ -38,10 +36,8 @@ class CashuProcessor {
             for (proof in proofs) {
                 totalAmount += proof.get("amount").asLong()
             }
-            val fees = Math.max(((totalAmount * 0.02).toInt()), 2)
-            val redeemInvoiceAmount = totalAmount - fees
 
-            return GenericLoadable.Loaded(CashuToken(cashuToken, mint, totalAmount, fees, redeemInvoiceAmount, proofs))
+            return GenericLoadable.Loaded(CashuToken(cashuToken, mint, totalAmount, proofs))
         } catch (e: Exception) {
             return GenericLoadable.Error<CashuToken>("Could not parse this cashu token")
         }
@@ -53,10 +49,29 @@ class CashuProcessor {
         runCatching {
             LightningAddressResolver().lnAddressInvoice(
                 lnaddress = lud16,
-                milliSats = token.redeemInvoiceAmount * 1000, // Make invoice and leave room for fees
+                milliSats = token.totalAmount * 1000, // Make invoice and leave room for fees
-                message = "Redeem Cashu",
+                message = "Calculate Fees for Cashu",
-                onSuccess = { invoice ->
+                onSuccess = { baseInvoice ->
-                    meltInvoice(token, invoice, onSuccess, onError, context)
+                    feeCalculator(
+                        token.mint,
+                        baseInvoice,
+                        onSuccess = { fees ->
+                            LightningAddressResolver().lnAddressInvoice(
+                                lnaddress = lud16,
+                                milliSats = (token.totalAmount - fees) * 1000, // Make invoice and leave room for fees
+                                message = "Redeem Cashu",
+                                onSuccess = { invoice ->
+                                    meltInvoice(token, invoice, fees, onSuccess, onError, context)
+                                },
+                                onProgress = {
+                                },
+                                onError = onError,
+                                context = context
+                            )
+                        },
+                        onError = onError,
+                        context
+                    )
                 },
                 onProgress = {
                 },
@@ -66,7 +81,59 @@ class CashuProcessor {
         }
     }
 
-    private fun meltInvoice(token: CashuToken, invoice: String, onSuccess: (String, String) -> Unit, onError: (String, String) -> Unit, context: Context) {
+    fun feeCalculator(
+        mintAddress: String,
+        invoice: String,
+        onSuccess: (Int) -> Unit,
+        onError: (String, String) -> Unit,
+        context: Context
+    ) {
+        checkNotInMainThread()
+
+        try {
+            val client = HttpClient.getHttpClient()
+            val url = "$mintAddress/checkfees" // Melt cashu tokens at Mint
+
+            val factory = Event.mapper.nodeFactory
+
+            val jsonObject = factory.objectNode()
+            jsonObject.put("pr", invoice)
+
+            val mediaType = "application/json; charset=utf-8".toMediaType()
+            val requestBody = jsonObject.toString().toRequestBody(mediaType)
+            val request = Request.Builder()
+                .url(url)
+                .post(requestBody)
+                .build()
+
+            client.newCall(request).execute().use {
+                val body = it.body.string()
+                val tree = jacksonObjectMapper().readTree(body)
+
+                val feeCost = tree?.get("fee")?.asInt()
+
+                if (feeCost != null) {
+                    onSuccess(
+                        feeCost
+                    )
+                } else {
+                    val msg = tree?.get("detail")?.asText()?.split('.')?.getOrNull(0)?.ifBlank { null }
+                    onError(
+                        context.getString(R.string.cashu_failed_redemption),
+                        if (msg != null) {
+                            context.getString(R.string.cashu_failed_redemption_explainer_error_msg, msg)
+                        } else {
+                            context.getString(R.string.cashu_failed_redemption_explainer_error_msg)
+                        }
+                    )
+                }
+            }
+        } catch (e: Exception) {
+            onError(context.getString(R.string.cashu_sucessful_redemption), context.getString(R.string.cashu_failed_redemption_explainer_error_msg, e.message))
+        }
+    }
+
+    private fun meltInvoice(token: CashuToken, invoice: String, fees: Int, onSuccess: (String, String) -> Unit, onError: (String, String) -> Unit, context: Context) {
         try {
             val client = HttpClient.getHttpClient()
             val url = token.mint + "/melt" // Melt cashu tokens at Mint
@@ -93,7 +160,7 @@ class CashuProcessor {
                 if (successful) {
                     onSuccess(
                         context.getString(R.string.cashu_sucessful_redemption),
-                        context.getString(R.string.cashu_sucessful_redemption_explainer, token.totalAmount.toString(), token.fees.toString())
+                        context.getString(R.string.cashu_sucessful_redemption_explainer, token.totalAmount.toString(), fees.toString())
                     )
                 } else {
                     val msg = tree?.get("detail")?.asText()?.split('.')?.getOrNull(0)?.ifBlank { null }

app/src/main/java/com/vitorpamplona/amethyst/ui/components/CashuRedeem.kt

@@ -6,6 +6,7 @@ import androidx.compose.animation.Crossfade
 import androidx.compose.foundation.border
 import androidx.compose.foundation.layout.Column
 import androidx.compose.foundation.layout.Row
+import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.layout.size
@@ -40,15 +41,19 @@ import androidx.core.content.ContextCompat.startActivity
 import com.vitorpamplona.amethyst.R
 import com.vitorpamplona.amethyst.service.CashuProcessor
 import com.vitorpamplona.amethyst.service.CashuToken
+import com.vitorpamplona.amethyst.ui.actions.LoadingAnimation
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
 import com.vitorpamplona.amethyst.ui.theme.QuoteBorder
+import com.vitorpamplona.amethyst.ui.theme.StdHorzSpacer
 import com.vitorpamplona.amethyst.ui.theme.subtleBorder
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 
 @Composable
 fun CashuPreview(cashutoken: String, accountViewModel: AccountViewModel) {
-    var cachuData by remember { mutableStateOf<GenericLoadable<CashuToken>>(GenericLoadable.Loading<CashuToken>()) }
+    var cachuData by remember {
+        mutableStateOf<GenericLoadable<CashuToken>>(GenericLoadable.Loading())
+    }
 
     LaunchedEffect(key1 = cashutoken) {
         launch(Dispatchers.IO) {
@@ -59,7 +64,7 @@ fun CashuPreview(cashutoken: String, accountViewModel: AccountViewModel) {
         }
     }
 
-    Crossfade(targetState = cachuData) {
+    Crossfade(targetState = cachuData, label = "CashuPreview(") {
         when (it) {
             is GenericLoadable.Loaded<CashuToken> -> CashuPreview(it.loaded, accountViewModel)
             is GenericLoadable.Error<CashuToken> -> Text(
@@ -85,14 +90,14 @@ fun CashuPreview(token: CashuToken, accountViewModel: AccountViewModel) {
     Column(
         modifier = Modifier
             .fillMaxWidth()
-            .padding(start = 30.dp, end = 30.dp)
+            .padding(start = 20.dp, end = 20.dp, top = 10.dp, bottom = 10.dp)
             .clip(shape = QuoteBorder)
             .border(1.dp, MaterialTheme.colorScheme.subtleBorder, QuoteBorder)
     ) {
         Column(
             modifier = Modifier
                 .fillMaxWidth()
-                .padding(30.dp)
+                .padding(20.dp)
         ) {
             Row(
                 verticalAlignment = Alignment.CenterVertically,
@@ -117,37 +122,38 @@ fun CashuPreview(token: CashuToken, accountViewModel: AccountViewModel) {
 
             Divider()
 
-            token.totalAmount.let {
+            Text(
-                Text(
+                text = "${token.totalAmount} ${stringResource(id = R.string.sats)}",
-                    text = "$it ${stringResource(id = R.string.sats)}",
+                fontSize = 25.sp,
-                    fontSize = 25.sp,
+                fontWeight = FontWeight.W500,
-                    fontWeight = FontWeight.W500,
-                    modifier = Modifier
-                        .fillMaxWidth()
-                        .padding(vertical = 10.dp)
-                )
-            }
-
-            Row(
-
                 modifier = Modifier
                     .fillMaxWidth()
-                    .padding(bottom = 10.dp)
+                    .padding(vertical = 10.dp)
-            ) {
+            )
-                Button(
 
-                    modifier = Modifier
+            Row(
-                        .padding(vertical = 10.dp).padding(horizontal = 2.dp),
+                modifier = Modifier
+                    .padding(top = 5.dp)
+                    .fillMaxWidth()
+            ) {
+                var isRedeeming by remember {
+                    mutableStateOf(false)
+                }
+
+                Button(
                     onClick = {
                         if (lud16 != null) {
                             scope.launch(Dispatchers.IO) {
+                                isRedeeming = true
                                 CashuProcessor().melt(
                                     token,
                                     lud16,
                                     onSuccess = { title, message ->
+                                        isRedeeming = false
                                         accountViewModel.toast(title, message)
                                     },
                                     onError = { title, message ->
+                                        isRedeeming = false
                                         accountViewModel.toast(title, message)
                                     },
                                     context
@@ -165,15 +171,22 @@ fun CashuPreview(token: CashuToken, accountViewModel: AccountViewModel) {
                         containerColor = MaterialTheme.colorScheme.primary
                     )
                 ) {
+                    if (isRedeeming) {
+                        LoadingAnimation()
+                    }
+
+                    Spacer(modifier = StdHorzSpacer)
+
                     Text(
                         stringResource(R.string.cashu_redeem),
                         color = Color.White,
                         fontSize = 18.sp
                     )
                 }
+
+                Spacer(modifier = StdHorzSpacer)
+
                 Button(
-                    modifier = Modifier
-                        .padding(vertical = 10.dp).padding(horizontal = 1.dp),
                     onClick = {
                         if (useWebService) {
                             // In case we want to use the cashu.me webservice