feat: point out unsupported messages

Signed-off-by: Infi <infi@infi.sh>

app/src/main/java/chat/stoat/composables/chat/SystemMessage.kt

@@ -14,7 +14,6 @@ import androidx.compose.material3.LocalContentColor
 import androidx.compose.material3.LocalTextStyle
 import androidx.compose.material3.MaterialShapes
 import androidx.compose.material3.MaterialTheme
-import androidx.compose.material3.Text
 import androidx.compose.material3.toShape
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.CompositionLocalProvider
@@ -58,7 +57,7 @@ fun SystemMessage(message: Message) {
         SystemMessageType.entries.firstOrNull { it.type == message.system.type }
 
     if (systemMessageType == null) {
-        Text(text = message.system.toString())
+        UnsupportedMessage(context = message.system.type)
         return
     }
 

app/src/main/java/chat/stoat/composables/chat/UnsupportedMessage.kt

@@ -0,0 +1,74 @@
+package chat.stoat.composables.chat
+
+import androidx.compose.foundation.background
+import androidx.compose.foundation.layout.Box
+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
+import androidx.compose.foundation.layout.width
+import androidx.compose.material3.ExperimentalMaterial3ExpressiveApi
+import androidx.compose.material3.Icon
+import androidx.compose.material3.LocalContentColor
+import androidx.compose.material3.LocalTextStyle
+import androidx.compose.material3.MaterialShapes
+import androidx.compose.material3.MaterialTheme
+import androidx.compose.material3.Text
+import androidx.compose.material3.toShape
+import androidx.compose.runtime.Composable
+import androidx.compose.runtime.CompositionLocalProvider
+import androidx.compose.ui.Alignment
+import androidx.compose.ui.Modifier
+import androidx.compose.ui.draw.clip
+import androidx.compose.ui.res.painterResource
+import androidx.compose.ui.res.stringResource
+import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.unit.dp
+import chat.stoat.R
+
+@OptIn(ExperimentalMaterial3ExpressiveApi::class)
+@Composable
+fun UnsupportedMessage(modifier: Modifier = Modifier, context: String? = null) {
+    CompositionLocalProvider(
+        LocalContentColor provides MaterialTheme.colorScheme.error.copy(alpha = 0.7f),
+        LocalTextStyle provides LocalTextStyle.current.copy(
+            fontWeight = FontWeight.Medium
+        )
+    ) {
+        Row(
+            verticalAlignment = Alignment.CenterVertically,
+            modifier = Modifier
+                .padding(horizontal = 10.dp, vertical = 16.dp)
+                .fillMaxWidth()
+        ) {
+            Box(
+                contentAlignment = Alignment.Center,
+                modifier = modifier
+                    .clip(MaterialShapes.PixelCircle.toShape())
+                    .background(
+                        color = MaterialTheme.colorScheme.errorContainer,
+                    )
+                    .size(40.dp)
+            ) {
+                CompositionLocalProvider(
+                    LocalContentColor provides MaterialTheme.colorScheme.onErrorContainer,
+                ) {
+                    Icon(
+                        painter = painterResource(R.drawable.icn_error_24dp),
+                        contentDescription = null,
+                        tint = LocalContentColor.current,
+                        modifier = Modifier.size(24.dp)
+                    )
+                }
+            }
+            Spacer(modifier = Modifier.width(10.dp))
+            Text(
+                if (context != null) stringResource(
+                    R.string.message_not_supported_with_context,
+                    context
+                ) else stringResource(R.string.message_not_supported)
+            )
+        }
+    }
+}

app/src/main/java/chat/stoat/screens/chat/views/channel/ChannelScreen.kt

@@ -125,6 +125,7 @@ import chat.stoat.composables.chat.DateDivider
 import chat.stoat.composables.chat.Message
 import chat.stoat.composables.chat.MessageField
 import chat.stoat.composables.chat.SystemMessage
+import chat.stoat.composables.chat.UnsupportedMessage
 import chat.stoat.composables.emoji.EmojiPicker
 import chat.stoat.composables.generic.GroupIcon
 import chat.stoat.composables.generic.PresenceBadge
@@ -726,6 +727,14 @@ fun ChannelScreen(
                                     }
                                     when (val item = viewModel.items[index]) {
                                         is ChannelScreenItem.RegularMessage -> {
+                                            if (item.message.content?.replace("\\s".toRegex(), "")
+                                                    ?.contains(">>>>>>>") == true
+                                            ) {
+                                                // FIXME Dirty hack to prevent a crash caused by malicious messages.
+                                                UnsupportedMessage()
+                                                return@items
+                                            }
+
                                             RegularMessage(
                                                 item.message,
                                                 viewModel.channel,

app/src/main/res/values/strings.xml

@@ -255,6 +255,9 @@
     <string name="message_blocked">Blocked message</string>
     <string name="message_failed_to_send">Failed to send, long press for options</string>
 
+    <string name="message_not_supported">Message cannot be displayed.</string>
+    <string name="message_not_supported_with_context">Message cannot be displayed (%1$s).</string>
+
     <string name="message_embed_special_youtube_switch_alt">Tap to play video from YouTube</string>
 
     <string name="system_message_ownership_changed_alt">Ownership changed</string>