From 0be05a1c4c9f9c2838745c3b35f6a5d16f539aae Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Honza=20Rychnovsk=C3=BD?= <rychnovsky.honza@gmail.com>
Date: Mon, 31 Jul 2023 13:34:41 +0200
Subject: [PATCH] [#1108] Getting memo for sent transactions

---
 .../z/ecc/android/sdk/internal/Backend.kt     |  8 ++++++
 .../screen/transactions/view/Transactions.kt  | 14 +++-------
 .../cash/z/ecc/android/sdk/SdkSynchronizer.kt | 27 ++++++++++++-------
 .../cash/z/ecc/android/sdk/Synchronizer.kt    |  8 +++++-
 4 files changed, 36 insertions(+), 21 deletions(-)

diff --git a/backend-lib/src/main/java/cash/z/ecc/android/sdk/internal/Backend.kt b/backend-lib/src/main/java/cash/z/ecc/android/sdk/internal/Backend.kt
index be5ea7c18..295a76f61 100644
--- a/backend-lib/src/main/java/cash/z/ecc/android/sdk/internal/Backend.kt
+++ b/backend-lib/src/main/java/cash/z/ecc/android/sdk/internal/Backend.kt
@@ -75,8 +75,16 @@ interface Backend {
 
     fun getBranchIdForHeight(height: Long): Long
 
+    /**
+     * @throws RuntimeException as a common indicator of the operation failure
+     */
+    @Throws(RuntimeException::class)
     suspend fun getReceivedMemoAsUtf8(idNote: Long): String?
 
+    /**
+     * @throws RuntimeException as a common indicator of the operation failure
+     */
+    @Throws(RuntimeException::class)
     suspend fun getSentMemoAsUtf8(idNote: Long): String?
 
     suspend fun getVerifiedBalance(account: Int): Long
diff --git a/demo-app/src/main/java/cash/z/ecc/android/sdk/demoapp/ui/screen/transactions/view/Transactions.kt b/demo-app/src/main/java/cash/z/ecc/android/sdk/demoapp/ui/screen/transactions/view/Transactions.kt
index aa8a9dee4..82c93b867 100644
--- a/demo-app/src/main/java/cash/z/ecc/android/sdk/demoapp/ui/screen/transactions/view/Transactions.kt
+++ b/demo-app/src/main/java/cash/z/ecc/android/sdk/demoapp/ui/screen/transactions/view/Transactions.kt
@@ -106,18 +106,10 @@ private fun TransactionsMainContent(
                 Button({
                     val memos = synchronizer.getMemos(it)
                     queryScope.launch {
-                        runCatching {
-                            memos.toList().run {
-                                Twig.debug {
-                                    "Transaction memos: count: $size, contains: " +
-                                        joinToString().ifEmpty {
-                                            "-"
-                                        }
-                                }
+                        memos.toList().run {
+                            Twig.debug {
+                                "Transaction memos: count: $size, contains: ${joinToString().ifEmpty { "-" }}"
                             }
-                        }.onFailure {
-                            // https://github.com/zcash/librustzcash/issues/834
-                            Twig.error { "Failed to get memos with: $it" }
                         }
                     }
                 }) {
diff --git a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/SdkSynchronizer.kt b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/SdkSynchronizer.kt
index 4dad23f1e..2adeaa4dc 100644
--- a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/SdkSynchronizer.kt
+++ b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/SdkSynchronizer.kt
@@ -64,7 +64,6 @@ import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.StateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.combine
-import kotlinx.coroutines.flow.filterNotNull
 import kotlinx.coroutines.flow.launchIn
 import kotlinx.coroutines.flow.map
 import kotlinx.coroutines.flow.onEach
@@ -316,15 +315,25 @@ class SdkSynchronizer private constructor(
 
     override fun getMemos(transactionOverview: TransactionOverview): Flow<String> {
         return storage.getNoteIds(transactionOverview.id).map {
-            when (transactionOverview.isSentTransaction) {
-                true -> {
-                    backend.getSentMemoAsUtf8(it)
-                }
-                false -> {
-                    backend.getReceivedMemoAsUtf8(it)
+            runCatching {
+                when (transactionOverview.isSentTransaction) {
+                    true -> {
+                        backend.getSentMemoAsUtf8(it)
+                    }
+                    false -> {
+                        backend.getReceivedMemoAsUtf8(it)
+                    }
                 }
-            }
-        }.filterNotNull()
+            }.onFailure {
+                // https://github.com/zcash/librustzcash/issues/834
+                Twig.error { "Failed to get memo with: $it" }
+            }.onSuccess {
+                Twig.debug { "Transaction memo queried: $it" }
+            }.fold(
+                onSuccess = { it ?: "" },
+                onFailure = { "" }
+            )
+        }
     }
 
     override fun getRecipients(transactionOverview: TransactionOverview): Flow<TransactionRecipient> {
diff --git a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/Synchronizer.kt b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/Synchronizer.kt
index 5a7c0e994..33507f970 100644
--- a/sdk-lib/src/main/java/cash/z/ecc/android/sdk/Synchronizer.kt
+++ b/sdk-lib/src/main/java/cash/z/ecc/android/sdk/Synchronizer.kt
@@ -281,7 +281,13 @@ interface Synchronizer {
     suspend fun quickRewind()
 
     /**
-     * Returns a list of memos for a transaction.
+     * Returns a stream of memos for a transaction. It works for both received and sent transaction.
+     *
+     * Note that this function internally resolves any error which comes, logs it, and then transforms it to an empty
+     * string.
+     *
+     * @param transactionOverview For which the memos will be queried
+     * @return Flow of memo strings
      */
     fun getMemos(transactionOverview: TransactionOverview): Flow<String>