import os
import requests
import time
from typing import Dict, Any, Optional
from .exceptions import MegaAPIError, MegaAuthError, MegaRateLimitError, MegaBadRequestError, MegaNotFoundError

class MegaClient:
    """Base client for interacting with MegaMarket API."""
    
    BASE_URL = "https://partner.goodsteam.tech/api/market/v1"
    
    def __init__(self, api_token: Optional[str] = None):
        # Fetch from env if not provided
        self.api_token = api_token or os.getenv('MEGA_API_TOKEN')
        
        if not self.api_token:
            raise ValueError("MEGA_API_TOKEN must be provided")
            
        self.session = requests.Session()
        # Мегамаркет может требовать токен как Bearer, либо внутри тела JSON в "meta".
        # Будем использовать Bearer, как наиболее распространенный стандарт для V1.
        self.session.headers.update({
            "Authorization": f"Bearer {self.api_token}",
            "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 MegaMarket 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 MegaRateLimitError("Rate limit exceeded")

                if response.status_code in (401, 403):
                    raise MegaAuthError(f"Authentication failed: {response.text}")
                    
                if response.status_code == 400:
                    raise MegaBadRequestError(f"Bad Request: {response.text}")

                if response.status_code == 404:
                    raise MegaNotFoundError(f"Not Found: {response.text}")
                    
                response.raise_for_status()
                
                if response.content:
                    return response.json()
                return {}

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

    def post(self, path: str, data: Optional[Dict[str, Any]] = None) -> Dict[str, Any]:
        # Мегамаркет во многих методах требует структуру {"meta": {}, "data": {}}
        # Если data не обернута, обернем ее
        if data and "data" not in data and "meta" not in data:
            payload = {
                "meta": {},
                "data": data
            }
        else:
            payload = data
            
        return self.request("POST", path, data=payload)

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