import inspect
import types
from openai import OpenAI
from .env import Environment

class ApiKeyMissingError(Exception):
    pass

class Explainable:
    API_KEY = None
    PROMPT = """
    Explain the following Python class code. Use these rules:

    - Ignore the Explainable class – it's just an internal utility to add the `.explain()` method.
    It is not relevant to the explanation as it just adds the `.explain()` method to the class.
    Don't even mention it in the explanation. Only mention other inherited classes if they are relevant.
    - Focus on the class that is being explained.
    - Focus only on what the class and its methods do, practically.
    - Do not explain basic Python concepts like `self`, indentation, or decorators.
    - Do not guess the purpose or intent of the class — just describe what the code does.
    - Do not make suggestions for improvement or style.
    - Keep the explanation clear, minimal, and to-the-point.
    - Your audience is a competent Python developer.
    - Use simple language and avoid jargon.
    - Be concise and avoid unnecessary detail.
    - Provide the explanation in a single paragraph or more if needed.
    """
    
    @classmethod
    def use_env(cls, path: str = ".env"):
        env = Environment(env_file_name=path)
        Explainable.API_KEY = env.get("OPENAPI_KEY")

    @classmethod
    def explain(cls) -> str:
        if cls.API_KEY is None:
            raise ApiKeyMissingError("API key is missing. Please set it using `Explainable.use_env()` or by directly assigning `Explainable.API_KEY`.")
        
        try:
            code = inspect.getsource(cls)

            client = OpenAI(api_key=cls.API_KEY)
            response = client.chat.completions.create(
                model="gpt-4",
                messages=[
                    {"role": "system", "content": cls.PROMPT},
                    {"role": "user", "content": code}
                ]
            )
            return response.choices[0].message.content.strip()
        except Exception as e:
            return f"<could not get class source: {e}>"

    def __init_subclass__(cls, **kwargs):
        for name, obj in vars(cls).items():
            if isinstance(obj, types.FunctionType):
                setattr(cls, name, Explainable.wrap_with_explain(obj))
        super().__init_subclass__(**kwargs)

    @staticmethod
    def wrap_with_explain(func):
        def _with_explain(*args, **kwargs):
            return func(*args, **kwargs)

        _with_explain.__name__ = func.__name__
        _with_explain.__doc__ = func.__doc__

        def explain_func():
            if Explainable.API_KEY is None:
                raise ApiKeyMissingError("API key is missing. Please set it using `Explainable.use_env()` or by directly assigning `Explainable.API_KEY`.")
            
            try:
                code = inspect.getsource(func)

                client = OpenAI(api_key=Explainable.API_KEY)
                response = client.chat.completions.create(
                    model="gpt-4",
                    messages=[
                        {"role": "system", "content": Explainable.PROMPT},
                        {"role": "user", "content": code}
                    ]
                )
                return response.choices[0].message.content.strip()
            except Exception as e:
                return f"<could not get function explanation: {e}>"

        _with_explain.explain = explain_func
        return _with_explain