import os
import requests
import time
from typing import Dict, Any, Optional
from .exceptions import OzonAPIError, OzonAuthError, OzonRateLimitError, OzonBadRequestError

class OzonClient:
    """Base client for interacting with Ozon API."""
    
    BASE_URL = "https://api-seller.ozon.ru"
    
    def __init__(self, client_id: Optional[str] = None, api_key: Optional[str] = None):
        # Fetch from env if not provided
        self.client_id = client_id or os.getenv('OZON_CLIENT_ID')
        self.api_key = api_key or os.getenv('OZON_API_KEY')
        
        if not self.client_id or not self.api_key:
            raise ValueError("OZON_CLIENT_ID and OZON_API_KEY must be provided")
            
        self.session = requests.Session()
        self.session.headers.update({
            "Client-Id": self.client_id,
            "Api-Key": self.api_key,
            "Content-Type": "application/json"
        })

    def request(self, method: str, path: str, data: Optional[Dict[str, Any]] = None, params: Optional[Dict[str, Any]] = None, retries: int = 3) -> Dict[str, Any]:
        """Perform HTTP request to Ozon API with automatic retries."""
        url = f"{self.BASE_URL}{path}"
        
        for attempt in range(retries):
            try:
                response = self.session.request(method, url, json=data, params=params)
                
                # Check rate limiting
                if response.status_code == 429:
                    if attempt < retries - 1:
                        time.sleep(2 ** attempt)  # Exponential backoff
                        continue
                    raise OzonRateLimitError("Rate limit exceeded")

                if response.status_code in (401, 403):
                    raise OzonAuthError(f"Authentication failed: {response.text}")
                    
                if response.status_code == 400:
                    raise OzonBadRequestError(f"Bad Request: {response.text}")
                    
                response.raise_for_status()
                
                # Ozon usually wraps responses in "result" key, but not always.
                # We return the whole JSON parsed response.
                if response.content:
                    return response.json()
                return {}

            except requests.exceptions.RequestException as e:
                if attempt < retries - 1:
                    time.sleep(2 ** attempt)
                    continue
                raise OzonAPIError(f"Request failed: {str(e)}")
                
        raise OzonAPIError("Request failed after max retries")

    def post(self, path: str, data: Optional[Dict[str, Any]] = None) -> Dict[str, Any]:
        return self.request("POST", path, data=data)

    def get(self, path: str, params: Optional[Dict[str, Any]] = None) -> Dict[str, Any]:
        return self.request("GET", path, params=params)