"""
client.py – Base HTTP client for CoinDesk API.

This module provides the BaseClient class that handles HTTP requests
to the CoinDesk API with proper authentication and error handling.
"""

import requests
import json
from typing import Dict, Any, Optional
from urllib.parse import urljoin, urlencode
import config


class APIError(Exception):
    """Custom exception for API errors."""
    def __init__(self, message: str, status_code: int = None, response: Any = None):
        self.message = message
        self.status_code = status_code
        self.response = response
        super().__init__(self.message)


class BaseClient:
    """
    Base HTTP client for CoinDesk API requests.
    
    Handles authentication, request formatting, and error handling.
    """
    
    def __init__(self, base_url: str = None, headers: Dict[str, str] = None):
        """
        Initialize the base client.
        
        Args:
            base_url: Base URL for the API (defaults to config.BASE_URL)
            headers: Default headers (defaults to config.HEADERS)
        """
        self.base_url = base_url or config.BASE_URL
        self.headers = headers or config.HEADERS.copy()
        self.session = requests.Session()
        self.session.headers.update(self.headers)
    
    def _make_request(self, method: str, endpoint: str, params: Dict[str, Any] = None, 
                     data: Dict[str, Any] = None, **kwargs) -> Dict[str, Any]:
        """
        Make an HTTP request to the API.
        
        Args:
            method: HTTP method (GET, POST, PUT, DELETE)
            endpoint: API endpoint path
            params: URL parameters
            data: Request body data
            **kwargs: Additional arguments for requests
            
        Returns:
            dict: JSON response from the API
            
        Raises:
            APIError: If the request fails or returns an error status
        """
        # Construct full URL
        url = urljoin(self.base_url, endpoint.lstrip('/'))
        
        # Clean up parameters (remove None values)
        if params:
            params = {k: v for k, v in params.items() if v is not None}
        
        try:
            # Make the request
            response = self.session.request(
                method=method,
                url=url,
                params=params,
                json=data,
                **kwargs
            )
            
            # Log the request for debugging
            print(f"[DEBUG] {method} {url}")
            if params:
                print(f"[DEBUG] Params: {params}")
            print(f"[DEBUG] Status: {response.status_code}")
            
            # Check if request was successful
            if response.status_code == 200:
                try:
                    return response.json()
                except json.JSONDecodeError:
                    # If response is not JSON, return the text
                    return {"data": response.text, "status": "success"}
            else:
                # Handle different error status codes
                error_message = f"API request failed with status {response.status_code}"
                
                try:
                    error_data = response.json()
                    if 'error' in error_data:
                        error_message = error_data['error']
                    elif 'message' in error_data:
                        error_message = error_data['message']
                except json.JSONDecodeError:
                    error_message = f"{error_message}: {response.text}"
                
                raise APIError(
                    message=error_message,
                    status_code=response.status_code,
                    response=response
                )
                
        except requests.exceptions.RequestException as e:
            raise APIError(f"Request failed: {str(e)}")
    
    def get(self, endpoint: str, params: Dict[str, Any] = None, **kwargs) -> Dict[str, Any]:
        """
        Make a GET request.
        
        Args:
            endpoint: API endpoint path
            params: URL parameters
            **kwargs: Additional arguments for requests
            
        Returns:
            dict: JSON response from the API
        """
        return self._make_request('GET', endpoint, params=params, **kwargs)
    
    def post(self, endpoint: str, data: Dict[str, Any] = None, 
             params: Dict[str, Any] = None, **kwargs) -> Dict[str, Any]:
        """
        Make a POST request.
        
        Args:
            endpoint: API endpoint path
            data: Request body data
            params: URL parameters
            **kwargs: Additional arguments for requests
            
        Returns:
            dict: JSON response from the API
        """
        return self._make_request('POST', endpoint, params=params, data=data, **kwargs)
    
    def put(self, endpoint: str, data: Dict[str, Any] = None, 
            params: Dict[str, Any] = None, **kwargs) -> Dict[str, Any]:
        """
        Make a PUT request.
        
        Args:
            endpoint: API endpoint path
            data: Request body data
            params: URL parameters
            **kwargs: Additional arguments for requests
            
        Returns:
            dict: JSON response from the API
        """
        return self._make_request('PUT', endpoint, params=params, data=data, **kwargs)
    
    def delete(self, endpoint: str, params: Dict[str, Any] = None, **kwargs) -> Dict[str, Any]:
        """
        Make a DELETE request.
        
        Args:
            endpoint: API endpoint path
            params: URL parameters
            **kwargs: Additional arguments for requests
            
        Returns:
            dict: JSON response from the API
        """
        return self._make_request('DELETE', endpoint, params=params, **kwargs)
    
    def close(self):
        """Close the HTTP session."""
        self.session.close()
    
    def __enter__(self):
        """Context manager entry."""
        return self
    
    def __exit__(self, exc_type, exc_val, exc_tb):
        """Context manager exit."""
        self.close()


# Convenience function to create a client instance
def create_client(base_url: str = None, headers: Dict[str, str] = None) -> BaseClient:
    """
    Create a new BaseClient instance.
    
    Args:
        base_url: Base URL for the API
        headers: Default headers
        
    Returns:
        BaseClient: Configured client instance
    """
    return BaseClient(base_url=base_url, headers=headers)


# Test function to verify the client works
def test_client():
    """Test the base client functionality."""
    try:
        with create_client() as client:
            # Test a simple endpoint (you might need to adjust this based on your API)
            response = client.get("/index/cc/v1/markets")
            print("Client test successful!")
            print(f"Response keys: {list(response.keys()) if isinstance(response, dict) else 'Not a dict'}")
            return True
    except Exception as e:
        print(f"Client test failed: {e}")
        return False


if __name__ == "__main__":
    test_client()