Fix path message truncation for emoji (double-width) characters

Use UTF-8 byte length instead of character count or display width for message
truncation. This fixes an issue where emoji characters like 😀 (4 UTF-8 bytes,
1 character, 2 display units) caused messages to exceed the RF packet size.

Changes:
- Replace _count_display_width with byte-based length calculation
- Add _count_byte_length and _truncate_to_byte_length helper methods
- Update get_max_message_length to use 127 bytes (channel limit) not 150
- Add type hints to new methods

modules/commands/alternatives/wx_international.py

@@ -1143,35 +1143,8 @@ class GlobalWxCommand(BaseCommand):
             return self.translate('commands.gwx.multiday_error', num_days=num_days)
 
     def _count_display_width(self, text: str) -> int:
-        """Count display width of text, accounting for emojis which may take 2 display units.
-
-        Args:
-            text: Text to measure.
-
-        Returns:
-            int: Estimated display width.
-        """
-        import re
-        # Count regular characters
-        width = len(text)
-        # Emojis typically take 2 display units in terminals/clients
-        # Count emoji characters (basic emoji pattern)
-        emoji_pattern = re.compile(
-            "["
-            "\U0001F600-\U0001F64F"  # emoticons
-            "\U0001F300-\U0001F5FF"  # symbols & pictographs
-            "\U0001F680-\U0001F6FF"  # transport & map symbols
-            "\U0001F1E0-\U0001F1FF"  # flags
-            "\U00002702-\U000027B0"  # dingbats
-            "\U000024C2-\U0001F251"  # enclosed characters
-            "]+",
-            flags=re.UNICODE
-        )
-        emoji_matches = emoji_pattern.findall(text)
-        # Each emoji sequence adds 1 extra width unit (since len() already counts it as 1)
-        # So we add 1 for each emoji sequence to account for display width
-        width += len(emoji_matches)
-        return width
+        """Count UTF-8 byte length of text. Matches RF packet byte limit from get_max_message_length()."""
+        return len(text.encode('utf-8'))
 
     async def _send_multiday_forecast(self, message: MeshMessage, forecast_text: str) -> None:
         """Send multi-day forecast response, splitting into multiple messages if needed.

modules/commands/base_command.py

@@ -584,12 +584,13 @@ class BaseCommand(ABC):
         if not username:
             username = self.bot.config.get('Bot', 'bot_name', fallback='Bot')
 
-        # Calculate max length: 150 - username_length - 2 (for ": ")
-        max_length = 150 - len(str(username)) - 2
+        # 127 bytes are available for channel messages
+        # Calculate max length: 127 - username_length - 2 (for ": ")
+        max_length = 127 - len(str(username).encode('utf-8')) - 2
 
         # Ensure we don't return a negative or unreasonably small value
-        # Minimum of 130 characters to ensure some functionality
-        return max(130, max_length)
+        # Minimum of 110 bytes to ensure some functionality
+        return max(110, max_length)
 
     def check_cooldown(self, user_id: Optional[str] = None) -> tuple[bool, float]:
         """Check if user is on cooldown.

modules/commands/path_command.py

@@ -1629,12 +1629,10 @@ class PathCommand(BaseCommand):
                     # Geographic or graph-based selection
                     name = info.get('name', self.translate('commands.path.unknown_name'))
                     confidence = info.get('confidence', 0.0)
-                    info.get('graph_guess', False)
 
                     # Truncate name if too long
                     truncation = self.translate('commands.path.truncation')
-                    if len(name) > 20:
-                        name = name[:17] + truncation
+                    name = self._truncate_to_byte_length(name, 20, truncation)
 
                     # Add confidence indicator
                     if confidence >= 0.9:
@@ -1650,20 +1648,15 @@ class PathCommand(BaseCommand):
                     # Single repeater found
                     name = info.get('name', self.translate('commands.path.unknown_name'))
 
-                    # Truncate name if too long
                     truncation = self.translate('commands.path.truncation')
-                    if len(name) > 27:
-                        name = name[:24] + truncation
+                    name = self._truncate_to_byte_length(name, 27, truncation)
 
                     line = self.translate('commands.path.node_format', node_id=node_id, name=name)
             else:
                 # Unknown repeater
                 line = self.translate('commands.path.node_unknown', node_id=node_id)
 
-            # Ensure line fits within 130 character limit
-            if len(line) > 130:
-                truncation = self.translate('commands.path.truncation')
-                line = line[:127] + truncation
+            line = self._truncate_to_byte_length(line, 130)
 
             lines.append(line)
 
@@ -1680,7 +1673,7 @@ class PathCommand(BaseCommand):
         # Get dynamic max message length based on message type and bot username
         max_length = self.get_max_message_length(message)
 
-        if len(response) <= max_length:
+        if self._count_byte_length(response) <= max_length:
             # Single message is fine
             await self.send_response(message, response)
         else:
@@ -1691,8 +1684,8 @@ class PathCommand(BaseCommand):
             message_count = 0
 
             for i, line in enumerate(lines):
-                # Check if adding this line would exceed max_length characters
-                if len(current_message) + len(line) + 1 > max_length:  # +1 for newline
+                # Check if adding this line would exceed max_length display width
+                if self._count_byte_length(current_message) + self._count_byte_length(line) + 1 > max_length:  # +1 for newline
                     # Send current message and start new one
                     if current_message:
                         # Add ellipsis on new line to end of continued message (if not the last message)
@@ -1766,6 +1759,24 @@ class PathCommand(BaseCommand):
             self.logger.error(f"Error extracting path from current message: {e}")
             return self.translate('commands.path.error_extracting', error=str(e))
 
+    def _count_byte_length(self, text: str) -> int:
+        """Count UTF-8 byte length of text. This matches the RF packet byte limit."""
+        return len(text.encode('utf-8'))
+
+    def _truncate_to_byte_length(self, text: str, max_bytes: int, ellipsis: str = "...") -> str:
+        """Truncate text to fit within max UTF-8 byte length, never splitting multi-byte chars."""
+        text_bytes: bytes = text.encode('utf-8')
+        if len(text_bytes) <= max_bytes:
+            return text
+
+        ellipsis_bytes: bytes = ellipsis.encode('utf-8')
+        available: int = max_bytes - len(ellipsis_bytes)
+        if available <= 0:
+            return ellipsis
+
+        truncated: str = text_bytes[:available].decode('utf-8', errors='ignore')
+        return truncated + ellipsis
+
     def get_help(self) -> str:
         """Get help text for the path command"""
         return self.translate('commands.path.help')

modules/commands/repeater_command.py

@@ -26,10 +26,6 @@ class RepeaterCommand(BaseCommand):
     category = "management"
     requires_internet = True  # Requires internet access for geocoding (Nominatim)
 
-    # LoRa message size limit (conservative to avoid overload)
-    # DM limit is 150 chars, public channel is 237 chars
-    MAX_LORA_MESSAGE_SIZE = 140  # characters, leaves buffer for protocol overhead
-
     def __init__(self, bot):
         super().__init__(bot)
         self.repeater_enabled = self.get_config_value('Repeater_Command', 'enabled', fallback=True, value_type='bool')
@@ -47,24 +43,6 @@ class RepeaterCommand(BaseCommand):
             return False
         return super().can_execute(message)
 
-    def _truncate_for_lora(self, message: str, max_size: int = None) -> str:
-        """Truncate message to fit within LoRa size limits.
-
-        Args:
-            message: The message to truncate
-            max_size: Maximum size (defaults to MAX_LORA_MESSAGE_SIZE)
-
-        Returns:
-            Truncated message with indicator if truncated
-        """
-        max_size = max_size or self.MAX_LORA_MESSAGE_SIZE
-        if len(message) <= max_size:
-            return message
-
-        truncate_suffix = "...(use web viewer)"
-        available_size = max_size - len(truncate_suffix)
-        return message[:available_size] + truncate_suffix
-
     def _get_deprecation_warning(self, web_viewer_url: str = None) -> str:
         """Get deprecation warning message for commands replaced by web viewer.
 

modules/commands/wx_command.py

@@ -1761,27 +1761,8 @@ class WxCommand(BaseCommand):
         return result
 
     def _count_display_width(self, text: str) -> int:
-        """Count display width of text, accounting for emojis which may take 2 display units"""
-        # Count regular characters
-        width = len(text)
-        # Emojis typically take 2 display units in terminals/clients
-        # Count emoji characters (basic emoji pattern)
-        emoji_pattern = re.compile(
-            "["
-            "\U0001F600-\U0001F64F"  # emoticons
-            "\U0001F300-\U0001F5FF"  # symbols & pictographs
-            "\U0001F680-\U0001F6FF"  # transport & map symbols
-            "\U0001F1E0-\U0001F1FF"  # flags
-            "\U00002702-\U000027B0"  # dingbats
-            "\U000024C2-\U0001F251"  # enclosed characters
-            "]+",
-            flags=re.UNICODE
-        )
-        emoji_matches = emoji_pattern.findall(text)
-        # Each emoji sequence adds 1 extra width unit (since len() already counts it as 1)
-        # So we add 1 for each emoji sequence to account for display width
-        width += len(emoji_matches)
-        return width
+        """Count UTF-8 byte length of text. Matches RF packet byte limit from get_max_message_length()."""
+        return len(text.encode('utf-8'))
 
     async def _send_multiday_forecast(self, message: MeshMessage, forecast_text: str):
         """Send multi-day forecast response, splitting into multiple messages if needed"""