import requests
import os
from typing import IO, Optional

from . import Result

def auth_header() -> dict:
    token = os.getenv("CSST_DFS_TOKEN", None)
    if not token:
        raise ValueError("env CSST_DFS_TOKEN is not set.")
    return {
        "Authorization": f"Bearer {token}"
    }

def get_request_url(endpoint: str) -> str:
    base_url = os.getenv("CSST_DFS_GATEWAY", None)
    if not base_url:
        raise ValueError("env CSST_DFS_GATEWAY is not set.")
    if not endpoint.startswith("http://"):
        base_url = "http://" + base_url
    return f"{base_url}{endpoint}"

def request_error_handler_decorator(func):
    def wrapper(*args, **kwargs):
        try:
            result = func(*args, **kwargs)
            if 'content-type' in result.headers and result.headers['content-type'] == "application/octet-stream":
                return result
            return Result.from_response(result)
        except requests.exceptions.ConnectionError as e:
            return Result.error(code=502, message= f"Bad Gateway: {e}")
        except Exception as e:
            return Result.error(message = str(e))
    return wrapper

@request_error_handler_decorator
def get(endpoint: str, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", 300)) -> requests.Response:
    return requests.get(
        url = get_request_url(endpoint),
        headers = auth_header(),
        timeout = timeout
    )  

@request_error_handler_decorator
def post(endpoint: str, data: dict, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", 300)) -> requests.Response:
    return requests.post(
        url = get_request_url(endpoint),
        headers = auth_header(),
        json = data,
        timeout = timeout
    )

@request_error_handler_decorator
def put(endpoint: str, data: Optional[dict] = None, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", 300)) -> requests.Response:
    return requests.put(
        url = get_request_url(endpoint),
        headers = auth_header(),
        json = data,
        timeout = timeout
    )

@request_error_handler_decorator
def delete(endpoint: str, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", 300)) -> requests.Response:
    return requests.delete(
        url = get_request_url(endpoint),
        headers = auth_header(),
        timeout = timeout
    )

def post_file(endpoint: str, file_path: str, data: dict) -> requests.Response:
    with open(file_path, "rb") as bytesio:
        return post_bytesio(endpoint, bytesio, data)

@request_error_handler_decorator
def post_bytesio(endpoint: str, file_bytes: IO, data: dict, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", 300)) -> requests.Response:
    return requests.post(
        url = get_request_url(endpoint),
        headers = auth_header(),
        files = {
            "file": file_bytes
        },
        data = data, timeout = timeout
    )

def download_file(endpoint: str, timeout = os.getenv("CSST_DFS_REQUEST_TIMEOUT", 300)) -> requests.Response:
    """
    下载指定endpoint对应的文件。
    
    Args:
        endpoint (str): 文件对应的endpoint。
    
    Returns:
        requests.Response: 发送HTTP GET请求后返回的响应对象。
    
    """
    return requests.get(
        url = get_request_url(endpoint),
        headers = auth_header(), timeout = timeout
    )