import logging
import os
import random
import string

from config import get_settings


class Challenge(object):
    name = __name__
    settings = get_settings()
    port = 0
    # Host the checker connects to. Same machine as the published team ports;
    # override with RECEIVER_HOST if a receiver ever runs off-host.
    host = os.environ.get("RECEIVER_HOST", "127.0.0.1")

    def __init__(self, port, host=None):
        self.port = port
        if host:
            self.host = host
        self.add_logger()

    def url(self, path=""):
        """Absolute URL for the challenge service (see xvi/Challenge.py)."""
        p = "" if path.startswith("/") else "/"
        return f"http://{self.host}:{self.port}{p}{path}"

    def add_logger(self):
        self.logger = logging.getLogger()

    def random_string(self, length):
        charset = string.ascii_uppercase + string.ascii_lowercase + string.digits
        return ''.join(random.choice(charset) for i in range(length))

    def distribute(self, flag):
        raise NotImplementedError

    def check(self):
        raise NotImplementedError

    def credentials(self):
        pwd = os.environ.get(f'PASSWORD_{self.port}')
        if not pwd:
            pwd = getattr(self.settings, f'PASSWORD_{self.port}', '')
        # SSH login user is PER-CHALLENGE, not per-package: the imported XVII
        # Dockerfiles also do `echo root:${PASSWORD} | chpasswd`, so reporting
        # ctfuser here handed participants a login that could never work.
        # gen_receiver_services.py injects SSH_USER_<port> from the registry,
        # which is the single source of truth; the literal is only a fallback.
        user = os.environ.get(f'SSH_USER_{self.port}', 'ctfuser')
        return {
            'username': user,
            'password': pwd,
        }