import http.server
import socket
import socketserver
import ipaddress
import logging
from datetime import datetime

# 日志配置（线程安全），按时间和级别输出到 stdout
logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s %(levelname)s %(message)s",
    datefmt="%Y-%m-%d %H:%M:%S",
)

class TCPServer6(socketserver.TCPServer):
    address_family = socket.AF_INET6
    allow_reuse_address = True

class MyHTTPRequestHandler(http.server.SimpleHTTPRequestHandler):
    def log_response(self, status_code, client_ip, x_forwarded_for):
        # 记录每次响应的日志
        logging.info(
            "method=%s path=%s client_ip=%s x_forwarded_for=%s status=%d",
            self.command,
            self.path,
            client_ip,
            x_forwarded_for if x_forwarded_for is not None else "-",
            status_code,
        )

    def do_GET(self):
        # 获取请求头中的 'X-Forwarded-For' 或 'Remote-Addr'
        x_forwarded_for = self.headers.get('X-Forwarded-For')
        remote_addr = self.client_address[0]

        # 客户端 IP 优先选择 X-Forwarded-For
        client_ip = (x_forwarded_for.split(',')[0].strip() if x_forwarded_for else remote_addr)

        # 将 IPv4-mapped IPv6 地址转换为纯 IPv4（例如 ::ffff:127.0.0.1 -> 127.0.0.1）
        try:
            ip_obj = ipaddress.ip_address(client_ip)
            if isinstance(ip_obj, ipaddress.IPv6Address) and ip_obj.ipv4_mapped:
                client_ip = str(ip_obj.ipv4_mapped)
        except ValueError:
            # 如果解析失败（非标准格式），尝试手工处理以防某些代理返回带方括号或端口
            # 移除 IPv6 方括号及端口（如 [::ffff:127.0.0.1]:8080）
            s = client_ip
            if s.startswith('[') and ']' in s:
                s = s.split(']', 1)[0].lstrip('[')
            if s.count(':') >= 2 and s.startswith('::ffff:'):
                # 处理可能带端口的情况
                s = s.split(':')[-1]
                client_ip = s

        # 发送响应
        status_code = 200
        self.send_response(status_code)
        self.send_header("Content-type", "text/plain")
        self.end_headers()
        self.wfile.write(client_ip.encode())

        # 在响应后记录日志
        try:
            self.log_response(status_code, client_ip, x_forwarded_for)
        except Exception:
            logging.exception("Failed to log response")

if __name__ == "__main__":
    PORT = 8080
    # 对于 AF_INET6 使用四元组绑定所有 IPv6 地址
    server_address = ("::", PORT, 0, 0)
    with TCPServer6(server_address, MyHTTPRequestHandler) as httpd:
        # 可选：在绑定前设置 IPV6_V6ONLY，若需要同时接受 IPv4 映射地址可设为 0
        try:
            httpd.socket.setsockopt(socket.IPPROTO_IPV6, socket.IPV6_V6ONLY, 0)
        except Exception:
            pass
        logging.info("Serving on [::]:%d", PORT)
        httpd.serve_forever()