from __future__ import annotations

from dataclasses import dataclass
from pathlib import Path
import logging
import re
from typing import Self

from dotenv import load_dotenv
import os


logger = logging.getLogger(__name__)


@dataclass(slots=True)
class Settings:
    api_key: str | None
    base_url: str | None
    model: str

    @classmethod
    def from_env(cls, env_file: Path | None = None, model_override: str | None = None) -> Self:
        if env_file:
            logger.info("Loading environment variables from %s", env_file)
            load_dotenv(env_file)
        else:
            logger.debug("Loading environment variables using default dotenv lookup")
            load_dotenv()

        settings = cls(
            api_key=os.getenv("GEMINI_API_KEY") or os.getenv("GOOGLE_API_KEY"),
            base_url=os.getenv("GEMINI_BASE_URL") or None,
            model=model_override or os.getenv("GEMINI_MODEL") or "gemini-2.5-flash",
        )
        logger.info(
            "Configuration loaded: model=%s base_url=%s api_key=%s",
            settings.model,
            settings.normalized_base_url() or "<default>",
            "set" if settings.api_key else "missing",
        )
        return settings

    def require_api_key(self) -> None:
        if not self.api_key:
            raise ValueError("Missing GEMINI_API_KEY (or GOOGLE_API_KEY) in the environment.")
        logger.debug("Gemini API key is available")

    def normalized_base_url(self) -> str | None:
        if not self.base_url:
            return None

        base_url = self.base_url.strip().rstrip("/")
        return re.sub(r"/v\d+(?:alpha|beta)?$", "", base_url, flags=re.IGNORECASE)