from typing import Union

from pydantic import BaseModel


class Prompt(BaseModel):
    file_path: str
    cached: Union[str, None] = None
    hot_reload: bool = True

    def render(self, **kwargs) -> str:
        if (self.cached is None) or (self.hot_reload):
            with open(self.file_path, "r") as f:
                self.cached = f.read()
        return self.cached.format(**kwargs)


class PromptMgr:
    def __init__(self, hot_reload: bool = True, src_dir: str = "resources/prompts"):
        """Creates a prompt manager.

        Args:
            hot_reload: If true, reloads the prompt every time it is called.
            src_dir: The directory where the prompts are stored.

        """
        self.hot_reload = hot_reload
        self.src_dir = src_dir

    def bind(self, prompt_id: str) -> Prompt:
        return Prompt(
            file_path=f"{self.src_dir}/{prompt_id}.txt", hot_reload=self.hot_reload
        )