#!/usr/bin/env python3
"""Solve a live The Last Bitbender instance."""

import os
import re
import socket

from decrypt_stage import transform


HOST = os.environ.get("HOST", "34.2.22.80")
PORT = int(os.environ.get("PORT", "30083"))


def recv_until(sock: socket.socket, marker: bytes) -> bytes:
    data = bytearray()
    while marker not in data:
        block = sock.recv(4096)
        if not block:
            break
        data.extend(block)
    return bytes(data)


def main() -> None:
    token = os.environ.get("CTFD_TOKEN")
    if not token:
        raise SystemExit("set CTFD_TOKEN to your COMPFEST CTFd access token")

    with socket.create_connection((HOST, PORT), timeout=10) as sock:
        sock.settimeout(15)
        recv_until(sock, b"CTFd access token: ")
        sock.sendall(token.encode() + b"\n")
        challenge = recv_until(sock, b"response:")
        request = bytes.fromhex(re.search(rb"request: ([0-9a-f]{32})", challenge).group(1).decode())
        response = transform(request).hex().encode()
        sock.sendall(response + b"\n")

        result = bytearray()
        while True:
            try:
                block = sock.recv(4096)
            except TimeoutError:
                break
            if not block:
                break
            result.extend(block)
        print(result.decode().strip())


if __name__ == "__main__":
    main()