MesopGUIMessageVisitor

def process_message(self, message: IOMessage) -> Optional[str]:
    try:
        return self.visit(message)
    except Exception as e:
        logger.warning(f"Failed to render message: {e}")
        self.render_error_message(e, message)
        return None

def render_error_message(
    self,
    e: Exception,
    message: IOMessage,
    *,
    content: Optional[str] = None,
    style: Optional[MesopMessageStyles] = None,
) -> None:
    style = self._styles.message.error or self._styles.message.default
    title = "[Error] " + message.type.replace("_", " ").capitalize()

    with me.box(style=style.box or self._styles.message.default.box):
        self._header(
            message,
            title=title,
            box_style=style.header_box or self._styles.message.default.header_box,
            md_style=style.header_md or self._styles.message.default.header_md,
        )

        content = (
            "Failed to render message:"
            + json.dumps(message.model_dump(), indent=2)
            + f"<br>Error: {e}"
        )

        logger.warning(f"render_error_message: {content=}")
        logger.warning(e, exc_info=True)
        # me.markdown(content, style=style.md or self._styles.message.default.md)
        self._render_content(content, style.md or self._styles.message.default.md)

def visit(self, message: IOMessage) -> Optional[str]:
    method_name = f"visit_{message.type}"
    method = getattr(self, method_name, self.visit_default)
    return method(message)

def visit_default(
    self,
    message: IOMessage,
    *,
    content: Optional[str] = None,
    style: Optional[MesopMessageStyles] = None,
    error: Optional[bool] = False,
    inner_callback: Optional[Callable[..., None]] = None,
    scrollable: Optional[bool] = False,
) -> None:
    # logger.info(f"visit_default: {message=}")
    style = style or self._styles.message.default
    title = message.type.replace("_", " ").capitalize()
    title = "[Error] " + title if error else title
    with me.box(style=style.box or self._styles.message.default.box):
        self._header(
            message,
            title=title,
            box_style=style.header_box,
            md_style=style.header_md,
        )

        content = content or json.dumps(message.model_dump()["content"])

        self._render_content(
            content,
            msg_md_style=style.scrollable_md
            or self._styles.message.default.scrollable_md
            if scrollable
            else style.md or self._styles.message.default.md,
        )

        if inner_callback:
            inner_callback()

def visit_error(self, message: Error) -> None:
    self.visit_default(
        message,
        content=f"### {message.short}\n{message.long}",
        style=self._styles.message.error,
        scrollable=True,
    )

    def visit_function_call_execution(self, message: FunctionCallExecution) -> None:
        content = f"""**function_name**: `{message.function_name}`<br>
**call_id**: `{message.call_id}`<br>
**retval**: {message.retval}"""
        return self.visit_default(
            message,
            content=content,
            style=self._styles.message.function_call_execution,
            scrollable=True,
        )

def visit_multiple_choice(self, message: MultipleChoice) -> str:
    if message.single:
        return self._visit_single_choice(message)
    else:
        return self._visit_many_choices(message)

    def visit_suggested_function_call(self, message: SuggestedFunctionCall) -> None:
        content = f"""**function_name**: `{message.function_name}`<br>
**call_id**: `{message.call_id}`<br>
**arguments**: {json.dumps(message.arguments)}"""
        self.visit_default(
            message,
            content=content,
            style=self._styles.message.suggested_function_call,
            scrollable=True,
        )

    def visit_system_message(self, message: SystemMessage) -> None:
        content = (
            f"""#### **{message.message['heading']}**

{message.message['body']}
"""
            if "heading" in message.message and "body" in message.message
            else json.dumps(message.message)
        )

        self.visit_default(
            message,
            content=content,
            style=self._styles.message.system,
            scrollable=True,
        )

def visit_text_input(self, message: TextInput) -> str:
    def on_input(feedback: str) -> Iterator[None]:
        self._conversation_message.feedback = [feedback]
        self._conversation_message.feedback_completed = True
        yield from self._provide_feedback(feedback)

    def value_if_completed() -> Optional[str]:
        message = self._conversation_message
        return message.feedback[0] if message.feedback_completed else None

    # base_color = "#dff"
    prompt = message.prompt if message.prompt else "Please enter a value"
    if message.suggestions:
        suggestions = ",".join(suggestion for suggestion in message.suggestions)
        prompt += "\n Suggestions: " + suggestions

    self.visit_default(
        message,
        content=prompt,
        style=self._styles.message.text_input,
        inner_callback=lambda: input_text(
            on_input,
            key="prompt",
            disabled=self._readonly or self._has_feedback(),
            value=value_if_completed(),
            style=self._styles.message.text_input_inner,
        ),
    )
    return ""

def visit_text_message(self, message: TextMessage) -> None:
    content = message.body if message.body else ""
    content = content if content.strip() != "" else "*(empty message)*"
    self.visit_default(
        message,
        content=content,
        style=self._styles.message.text,
    )

def visit_workflow_completed(self, message: WorkflowCompleted) -> Optional[str]:
    return self.visit_default(message)