import os
from pathlib import Path
from typing import Optional
import warnings


def load_env_file(env_path: str = ".env") -> None:
    """Load environment variables from a .env file if it exists."""
    env_file = Path(env_path)
    if env_file.exists():
        with open(env_file, "r") as f:
            for line in f:
                line = line.strip()
                if line and not line.startswith("#") and "=" in line:
                    key, value = line.split("=", 1)
                    key = key.strip()
                    value = value.strip().strip('"').strip("'")
                    os.environ[key] = value


class Config:
    """Configuration management for API keys and tokens."""

    def __init__(self):
        # Load environment variables from .env file if it exists
        load_env_file()

        # Initialize credentials
        self._openai_api_key = None
        self._hf_token = None
        self._wandb_project = None

    @property
    def openai_api_key(self) -> str:
        """Get OpenAI API key from environment variables."""
        if self._openai_api_key is None:
            self._openai_api_key = os.environ.get("OPENAI_API_KEY")
            if not self._openai_api_key:
                raise ValueError(
                    "OPENAI_API_KEY not found in environment variables. "
                    "Please set it in your .env file or environment."
                )
        return self._openai_api_key

    @property
    def hf_token(self) -> str:
        """Get HuggingFace token from environment variables."""
        if self._hf_token is None:
            self._hf_token = os.environ.get("HF_TOKEN")
            if not self._hf_token:
                raise ValueError(
                    "HF_TOKEN not found in environment variables. "
                    "Please set it in your .env file or environment."
                )
        return self._hf_token

    @property
    def wandb_project(self) -> str:
        """Get Weights & Biases project name."""
        if self._wandb_project is None:
            self._wandb_project = os.environ.get("WANDB_PROJECT", "persona-vectors")
        return self._wandb_project

    def setup_environment(self) -> None:
        """Set up environment variables for the application."""
        # Set OpenAI API key in environment for libraries that expect it
        os.environ["OPENAI_API_KEY"] = self.openai_api_key

        # Set HuggingFace token in environment
        os.environ["HF_TOKEN"] = self.hf_token

        # Set Weights & Biases project
        os.environ["WANDB_PROJECT"] = self.wandb_project

    def validate_credentials(self) -> bool:
        """Validate that all required credentials are available."""
        try:
            _ = self.openai_api_key
            _ = self.hf_token
            return True
        except ValueError as e:
            warnings.warn(f"Credential validation failed: {e}")
            return False


# Global config instance
config = Config()


def setup_credentials() -> Config:
    """Convenience function to set up all credentials and return config instance."""
    config.setup_environment()
    if not config.validate_credentials():
        raise RuntimeError("Failed to validate required credentials")
    return config