"""System Prompter - Builds system prompts with optional file context"""

MAX_FILE_CHARS = 4000  # Limit file context to avoid token overflow


class SystemPrompter:
    @staticmethod
    def generate_prompt(file_context: dict | None = None) -> str:
        """Build a system prompt, optionally embedding a file's content.

        Args:
            file_context: dict with keys 'name' and 'content', or None.

        Returns:
            A system prompt string.
        """
        base = (
            "You are an expert code assistant integrated into a lightweight code editor. "
            "Help the user with code suggestions, debugging, explanations, and improvements. "
            "Be concise and precise. Use markdown and fenced code blocks where appropriate."
        )

        if file_context:
            name = file_context.get("name", "unknown")
            content = file_context.get("content", "")
            # Truncate large files to avoid exceeding token limits
            if len(content) > MAX_FILE_CHARS:
                content = content[:MAX_FILE_CHARS] + "\n... [truncated]"
            file_section = (
                f"\n\nThe user currently has the following file open in the editor:\n"
                f"<file name=\"{name}\">\n"
                f"<code>\n{content}\n</code>\n"
                f"</file>\n"
                f"Refer to this file when answering questions about the code."
            )
            return base + file_section

        return base