import os
from enum import Enum, auto
from dataclasses import dataclass, field


class ProxyType(Enum):
    HTTP = auto()
    HTTPS = auto()
    SOCKS = auto()


@dataclass(frozen=True)
class ProxyInfo:
    ip: str = field(default="", repr=True)
    port: str = field(default="", repr=True)

    def __post_init__(self):
        if (self.ip and not self.port) or (not self.ip and self.port):
            raise ValueError("IP or port cannot be empty")

        if (self.ip and self.port) and (not self.port.isdigit() or not (1 <= int(self.port) <= 65535)):
            raise ValueError("Port must be a digit between 1 and 65535")


class ProxyDetector:
    """仅 Linux：从环境变量读取代理（http_proxy / https_proxy / ftp_proxy）。"""

    def get_proxy_info(self) -> ProxyInfo:
        ip, port = self._get_proxy_info_linux()
        return ProxyInfo(ip, port)

    def is_proxy_enabled(self) -> bool:
        return self._is_proxy_enabled_linux()

    @staticmethod
    def _get_proxy_info_linux() -> tuple[str, str]:
        proxies = {
            "http": os.getenv("http_proxy"),
            "https": os.getenv("https_proxy"),
            "ftp": os.getenv("ftp_proxy"),
        }
        ip = port = ""
        for _proto, proxy in proxies.items():
            if proxy:
                # 支持 http://host:port
                p = proxy.strip()
                if "://" in p:
                    p = p.split("://", 1)[1]
                if "@" in p:
                    p = p.split("@", 1)[1]
                if ":" in p:
                    ip, _, port = p.rpartition(":")
                    port = port.split("/")[0]
                break
        return ip, port

    def _is_proxy_enabled_linux(self) -> bool:
        ip, port = self._get_proxy_info_linux()
        return bool(ip and port)