Moves the creation of Draft Notes to the IO Thread

app/src/main/java/com/vitorpamplona/amethyst/ui/note/NoteCompose.kt

@@ -39,7 +39,6 @@ import androidx.compose.runtime.derivedStateOf
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.livedata.observeAsState
 import androidx.compose.runtime.mutableStateOf
-import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
 import androidx.compose.runtime.rememberCoroutineScope
 import androidx.compose.ui.Alignment
@@ -54,6 +53,7 @@ import androidx.compose.ui.unit.dp
 import androidx.lifecycle.distinctUntilChanged
 import androidx.lifecycle.map
 import com.vitorpamplona.amethyst.R
+import com.vitorpamplona.amethyst.commons.compose.produceCachedStateAsync
 import com.vitorpamplona.amethyst.model.Channel
 import com.vitorpamplona.amethyst.model.FeatureSetType
 import com.vitorpamplona.amethyst.model.Note
@@ -724,16 +724,8 @@ fun ObserveDraftEvent(
     val noteState by note.live().metadata.observeAsState()
 
     val noteEvent = noteState?.note?.event as? DraftEvent ?: return
-    val noteAuthor = noteState?.note?.author ?: return
 
-    val innerNote =
-        produceState(initialValue = accountViewModel.createTempCachedDraftNote(noteEvent, noteAuthor), noteEvent.id) {
-            if (value == null || value?.event?.id() != noteEvent.id) {
-                accountViewModel.createTempDraftNote(noteEvent, noteAuthor) {
-                    value = it
-                }
-            }
-        }
+    val innerNote = produceCachedStateAsync(cache = accountViewModel.draftNoteCache, key = noteEvent)
 
     innerNote.value?.let {
         render(it)

app/src/main/java/com/vitorpamplona/amethyst/ui/screen/loggedIn/AccountViewModel.kt

@@ -38,6 +38,7 @@ import coil.request.ImageRequest
 import com.vitorpamplona.amethyst.R
 import com.vitorpamplona.amethyst.ServiceManager
 import com.vitorpamplona.amethyst.commons.compose.GenericBaseCache
+import com.vitorpamplona.amethyst.commons.compose.GenericBaseCacheAsync
 import com.vitorpamplona.amethyst.model.Account
 import com.vitorpamplona.amethyst.model.AccountState
 import com.vitorpamplona.amethyst.model.AddressableNote
@@ -1335,9 +1336,6 @@ class AccountViewModel(val account: Account, val settings: SettingsState) : View
         onReady: (Note) -> Unit,
     ) {
         viewModelScope.launch(Dispatchers.IO) {
-            noteEvent.cachedDraft(account.signer) {
-                onReady(createTempDraftNote(it, author))
-            }
         }
     }
 
@@ -1355,6 +1353,21 @@ class AccountViewModel(val account: Account, val settings: SettingsState) : View
         return note
     }
 
+    val draftNoteCache = CachedDraftNotes(this)
+
+    class CachedDraftNotes(val accountViewModel: AccountViewModel) : GenericBaseCacheAsync<DraftEvent, Note>(20) {
+        override suspend fun compute(
+            key: DraftEvent,
+            onReady: (Note?) -> Unit,
+        ) = withContext(Dispatchers.IO) {
+            key.cachedDraft(accountViewModel.account.signer) {
+                val author = LocalCache.getOrCreateUser(key.pubKey)
+                val note = accountViewModel.createTempDraftNote(it, author)
+                onReady(note)
+            }
+        }
+    }
+
     val bechLinkCache = CachedLoadedBechLink(this)
 
     class CachedLoadedBechLink(val accountViewModel: AccountViewModel) : GenericBaseCache<String, LoadedBechLink>(20) {

commons/src/main/java/com/vitorpamplona/amethyst/commons/compose/AsyncCachedState.kt

@@ -0,0 +1,88 @@
+/**
+ * Copyright (c) 2024 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.commons.compose
+
+import android.util.LruCache
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.State
+import androidx.compose.runtime.produceState
+
+@Composable
+fun <K, V> produceCachedStateAsync(
+    cache: AsyncCachedState<K, V>,
+    key: K,
+): State<V?> {
+    return produceState(initialValue = cache.cached(key), key1 = key) {
+        cache.update(key) {
+            value = it
+        }
+    }
+}
+
+@Composable
+fun <K, V> produceCachedStateAsync(
+    cache: AsyncCachedState<K, V>,
+    key: String,
+    updateValue: K,
+): State<V?> {
+    return produceState(initialValue = cache.cached(updateValue), key1 = key) {
+        cache.update(updateValue) {
+            value = it
+        }
+    }
+}
+
+interface AsyncCachedState<K, V> {
+    fun cached(k: K): V?
+
+    suspend fun update(
+        k: K,
+        onReady: (V?) -> Unit,
+    )
+}
+
+abstract class GenericBaseCacheAsync<K, V>(capacity: Int) : AsyncCachedState<K, V> {
+    private val cache = LruCache<K, V>(capacity)
+
+    override fun cached(k: K): V? {
+        return cache[k]
+    }
+
+    override suspend fun update(
+        k: K,
+        onReady: (V?) -> Unit,
+    ) {
+        cache[k]?.let { onReady(it) }
+
+        compute(k) {
+            if (it != null) {
+                cache.put(k, it)
+            }
+
+            onReady(it)
+        }
+    }
+
+    abstract suspend fun compute(
+        key: K,
+        onReady: (V?) -> Unit,
+    )
+}