from __future__ import annotations

import time
from dataclasses import dataclass

import aiohttp


@dataclass
class OAuth2Token:
    access_token: str
    refresh_token: str
    expires_at: float
    token_type: str = "Bearer"

    @property
    def is_expired(self) -> bool:
        return time.time() > self.expires_at - 60


class EmailOAuth2Manager:
    MICROSOFT_TOKEN_URL = "https://login.microsoftonline.com/common/oauth2/v2.0/token"
    GOOGLE_TOKEN_URL = "https://oauth2.googleapis.com/token"

    def __init__(self, provider: str, client_id: str, client_secret: str):
        self._provider = provider
        self._client_id = client_id
        self._client_secret = client_secret
        self._token: OAuth2Token | None = None

    def _token_url(self) -> str:
        if self._provider in ("outlook", "office365", "hotmail", "live"):
            return self.MICROSOFT_TOKEN_URL
        return self.GOOGLE_TOKEN_URL

    async def get_access_token(self, refresh_token: str) -> str:
        if self._token and not self._token.is_expired:
            return self._token.access_token

        data = {
            "client_id": self._client_id,
            "client_secret": self._client_secret,
            "refresh_token": refresh_token,
            "grant_type": "refresh_token",
        }
        async with aiohttp.ClientSession() as session:
            async with session.post(
                self._token_url(), data=data, timeout=aiohttp.ClientTimeout(total=15)
            ) as resp:
                if resp.status != 200:
                    raise RuntimeError(f"OAuth2 token refresh failed: {await resp.text()}")
                token_data = await resp.json()
                self._token = OAuth2Token(
                    access_token=token_data["access_token"],
                    refresh_token=token_data.get("refresh_token", refresh_token),
                    expires_at=time.time() + token_data.get("expires_in", 3600),
                )
                return self._token.access_token

    def build_xoauth2_string(self, username: str, access_token: str) -> str:
        return f"user={username}\x01auth=Bearer {access_token}\x01\x01"