Fixes UTF-32 Reactions

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

@@ -0,0 +1,23 @@
+package com.vitorpamplona.amethyst.service
+
+fun String.isUTF16Char(pos: Int): Boolean {
+    return Character.charCount(this.codePointAt(pos)) == 2
+}
+
+fun String.firstFullChar(): String {
+    return when (this.length) {
+        0, 1 -> return this
+        2, 3 -> return if (isUTF16Char(0)) this.take(2) else this.take(1)
+        else -> {
+            val first = isUTF16Char(0)
+            val second = isUTF16Char(2)
+            if (first && second) {
+                this.take(4)
+            } else if (first) {
+                this.take(2)
+            } else {
+                this.take(1)
+            }
+        }
+    }
+}

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

@@ -48,6 +48,7 @@ import com.vitorpamplona.amethyst.model.LocalCache
 import com.vitorpamplona.amethyst.model.Note
 import com.vitorpamplona.amethyst.model.User
 import com.vitorpamplona.amethyst.model.UserMetadata
+import com.vitorpamplona.amethyst.service.firstFullChar
 import com.vitorpamplona.amethyst.service.model.LnZapEvent
 import com.vitorpamplona.amethyst.service.model.LnZapRequestEvent
 import com.vitorpamplona.amethyst.ui.actions.ImmutableListOfLists
@@ -180,7 +181,7 @@ fun RenderLikeGallery(
 
     val shortReaction by remember {
         derivedStateOf {
-            reactionType.take(2)
+            reactionType.firstFullChar()
         }
     }
 

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

@@ -65,6 +65,7 @@ import coil.request.CachePolicy
 import coil.request.ImageRequest
 import com.vitorpamplona.amethyst.R
 import com.vitorpamplona.amethyst.model.Note
+import com.vitorpamplona.amethyst.service.firstFullChar
 import com.vitorpamplona.amethyst.ui.actions.NewPostView
 import com.vitorpamplona.amethyst.ui.screen.CombinedZap
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
@@ -677,7 +678,7 @@ fun LikeIcon(
 
     LaunchedEffect(key1 = reactionsState) {
         launch(Dispatchers.Default) {
-            val newReactionType = reactionsState?.note?.isReactedBy(accountViewModel.userProfile())?.take(2)
+            val newReactionType = reactionsState?.note?.isReactedBy(accountViewModel.userProfile())?.firstFullChar()
             if (reactionType != newReactionType) {
                 reactionType = newReactionType
             }

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

@@ -45,6 +45,7 @@ import androidx.lifecycle.ViewModelProvider
 import androidx.lifecycle.viewmodel.compose.viewModel
 import com.vitorpamplona.amethyst.R
 import com.vitorpamplona.amethyst.model.Account
+import com.vitorpamplona.amethyst.service.firstFullChar
 import com.vitorpamplona.amethyst.ui.actions.CloseButton
 import com.vitorpamplona.amethyst.ui.actions.SaveButton
 import com.vitorpamplona.amethyst.ui.screen.loggedIn.AccountViewModel
@@ -64,7 +65,7 @@ class UpdateReactionTypeViewModel(val account: Account) : ViewModel() {
     }
 
     fun addChoice() {
-        val newValue = nextChoice.text.trim().take(2)
+        val newValue = nextChoice.text.trim().firstFullChar()
         reactionSet = reactionSet + newValue
 
         nextChoice = TextFieldValue("")

app/src/test/java/com/vitorpamplona/amethyst/CharsetTest.kt

@@ -0,0 +1,37 @@
+package com.vitorpamplona.amethyst
+
+import com.vitorpamplona.amethyst.service.firstFullChar
+import org.junit.Assert
+import org.junit.Test
+
+class CharsetTest {
+    @Test
+    fun testASCIIChar() {
+        Assert.assertEquals("H", "Hi".firstFullChar())
+    }
+
+    @Test
+    fun testUTF16Char() {
+        Assert.assertEquals("\uD83C\uDF48", "\uD83C\uDF48Hi".firstFullChar())
+    }
+
+    @Test
+    fun testUTF32Char() {
+        Assert.assertEquals("\uD83E\uDDD1\uD83C\uDFFE", "\uD83E\uDDD1\uD83C\uDFFEHi".firstFullChar())
+    }
+
+    @Test
+    fun testAsciiWithUTF32Char() {
+        Assert.assertEquals("H", "Hi\uD83E\uDDD1\uD83C\uDFFEHi".firstFullChar())
+    }
+
+    @Test
+    fun testBlank() {
+        Assert.assertEquals("", "".firstFullChar())
+    }
+
+    @Test
+    fun testSpecialChars() {
+        Assert.assertEquals("=", "=x".firstFullChar())
+    }
+}