import requests
import json
import time
import logging
import sys
from requests.adapters import HTTPAdapter
from urllib3.util.retry import Retry

# Configure logger
logger = logging.getLogger(__name__)

class IFindClient:
    """
    iFinD HTTP API Client Base Class.
    Handles authentication and token management.
    """
    def __init__(self, refresh_token: str):
        self.refresh_token = refresh_token
        self.access_token = None
        self.token_expiry = 0
        self.base_url = "https://quantapi.51ifind.com/api/v1"
        
        # Initialize Session with Retry logic
        self.session = requests.Session()
        retries = Retry(
            total=5,
            backoff_factor=1,
            status_forcelist=[500, 502, 503, 504],
            allowed_methods=["POST", "GET"]
        )
        self.session.mount('https://', HTTPAdapter(max_retries=retries))

    def _get_access_token(self):
        """Get or refresh access_token"""
        if self.access_token and time.time() < self.token_expiry:
            return self.access_token

        url = f"{self.base_url}/get_access_token"
        headers = {
            "Content-Type": "application/json",
            "refresh_token": self.refresh_token
        }
        
        try:
            response = self.session.post(url, headers=headers)
            data = response.json()
            if data.get("errorcode") == 0:
                self.access_token = data["data"]["access_token"]
                # Expires in 7 days, refresh every 6 days
                self.token_expiry = time.time() + (6 * 24 * 3600)
                return self.access_token
            else:
                error_msg = f"iFinD access token error: {data.get('errmsg')} (Code: {data.get('errorcode')})"
                if data.get("errorcode") == -1301:
                    logger.critical(f"CRITICAL ERROR: {error_msg}")
                    logger.critical("Please check your IFIND_REFRESH_TOKEN in .env file.")
                    # In backend service, we shouldn't sys.exit() as it kills the server
                    # Just raise exception
                    raise Exception(error_msg)
                raise Exception(error_msg)
        except Exception as e:
            logger.error(f"Error refreshing iFinD access token: {e}")
            return None

    def post(self, endpoint: str, params: dict):
        """Send POST request to API endpoint"""
        token = self._get_access_token()
        if not token:
            return None
        
        url = f"{self.base_url}/{endpoint}"
        headers = {
            "Content-Type": "application/json",
            "access_token": token
        }
        
        try:
            response = self.session.post(url, headers=headers, json=params, timeout=30)
            if response.status_code != 200:
                logger.error(f"iFinD API HTTP Error: {response.status_code} - {response.text}")
                return None
            return response.json()
        except Exception as e:
            logger.error(f"iFinD API Request Error on {endpoint}: {e}")
            return None