"""Instructions to the LLM, to be passed in the prompt."""

from string import Template

from guardrails.utils.templating_utils import get_template_variables

from .base_prompt import BasePrompt


class Instructions(BasePrompt):
    """Instructions class.

    The instructions are passed to the LLM as secondary input. Different
    model may use these differently. For example, chat models may
    receive instructions in the system-prompt.
    """

    def __repr__(self) -> str:
        # Truncate the prompt to 50 characters and add ellipsis if it's longer.
        truncated_instructions = self.source[:50]
        if len(self.source) > 50:
            truncated_instructions += "..."
        return f"Instructions({truncated_instructions})"

    def __eq__(self, __value: object) -> bool:
        return isinstance(__value, Instructions) and self.source == __value.source

    def format(self, **kwargs) -> "Instructions":
        """Format the prompt using the given keyword arguments."""
        # Only use the keyword arguments that are present in the prompt.
        vars = get_template_variables(self.source)
        filtered_kwargs = {k: v for k, v in kwargs.items() if k in vars}

        # Return another instance of the class with the formatted prompt.
        formatted_instructions = Template(self.source).safe_substitute(
            **filtered_kwargs
        )
        return Instructions(formatted_instructions)