import time

class ThredfiClient:
    def __init__(self, partner_uuid, api_key):
        self.partner_uuid = partner_uuid
        self.api_key = api_key
        self.unscoped_token = None
        self.business_tokens = {}  # {business_id: {token, expires_at}}

    def get_unscoped_token(self):
        credentials = f"{self.partner_uuid}:{self.api_key}"
        encoded = base64.b64encode(credentials.encode()).decode()

        response = requests.post(
            "https://dev-backend.thredfi.com/v1/platform/oauth2/token/",
            headers={"Authorization": f"Basic {encoded}"}
        )

        token_data = response.json()
        self.unscoped_token = {
            "token": token_data["access_token"],
            "expires_at": time.time() + token_data["expires_in"] - 300  # 5 min buffer
        }
        return self.unscoped_token["token"]

    def get_business_token(self, business_id):
        # Check if we have a valid cached token
        if business_id in self.business_tokens:
            token_info = self.business_tokens[business_id]
            if time.time() < token_info["expires_at"]:
                return token_info["token"]

        # Get fresh unscoped token if needed
        if not self.unscoped_token or time.time() >= self.unscoped_token["expires_at"]:
            self.get_unscoped_token()

        # Exchange for business token
        response = requests.post(
            f"https://dev-backend.thredfi.com/v1/platform/{business_id}/oauth2/token/",
            headers={"Authorization": f"Bearer {self.unscoped_token['token']}"}
        )

        token_data = response.json()
        self.business_tokens[business_id] = {
            "token": token_data["access_token"],
            "expires_at": time.time() + token_data["expires_in"] - 300
        }

        return self.business_tokens[business_id]["token"]

# Usage
client = ThredfiClient(partner_uuid, api_key)
business_token = client.get_business_token(business_id)