HackThisSite - Programming Mission 1

#!/usr/bin/env python3
"""Solve HackThisSite Programming Mission 1."""

import html
import os
import re
from pathlib import Path

import requests

BASE = "https://www.hackthissite.org"
LEVEL_URL = f"{BASE}/missions/prog/1/"
WORDLIST = Path(__file__).with_name("wordlist.txt")
USER_AGENT = (
    "Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 "
    "(KHTML, like Gecko) Chrome/131.0.0.0 Safari/537.36"
)


def session():
101 collapsed lines
    cookie = os.environ.get("HTS_COOKIE", "").strip().strip("'\"")
    if not cookie:
        raise SystemExit("HTS_COOKIE is not set")

    client = requests.Session()
    client.headers.update(
        {
            "User-Agent": USER_AGENT,
            "Cookie": cookie,
            "Referer": f"{BASE}/missions/programming/",
            "Accept-Language": "en-US,en;q=0.9",
        }
    )
    return client


def body_text(source):
    source = re.sub(r"<script.*?</script>", "", source, flags=re.S)
    source = re.sub(r"<br\s*/?>", "\n", source)
    source = re.sub(r"</(?:p|div|tr)>", "\n", source)
    source = re.sub(r"<[^>]+>", " ", source)
    source = html.unescape(source)
    source = re.sub(r"[ \t]+", " ", source)
    return re.sub(r"\n\s*\n+", "\n", source)


def load_wordlist(path):
    table = {}
    with path.open("r", encoding="utf-8", errors="replace") as fh:
        for line in fh:
            word = line.strip()
            if word:
                table.setdefault("".join(sorted(word)), word)
    return table


def parse_scrambled(page_text):
    marker = "List of scrambled words:"
    end_marker = "Answer:"
    if marker not in page_text or end_marker not in page_text:
        raise ValueError("could not find the scrambled-word section")
    chunk = page_text.split(marker, 1)[1].split(end_marker, 1)[0]
    return [token for token in re.split(r"[\s,]+", chunk) if token]


def unscramble(words, table):
    result = []
    for word in words:
        key = "".join(sorted(word))
        candidates = [value for value in table.values() if "".join(sorted(value)) == key]
        if not candidates:
            result.append(word)
        else:
            result.append(candidates[0])
    return result


def submit(client, answer):
    response = client.post(
        f"{LEVEL_URL}index.php",
        data={"solution": answer, "submitbutton": "submit"},
        headers={"Referer": LEVEL_URL},
        timeout=30,
    )
    response.raise_for_status()
    text = body_text(response.text).lower()
    success_markers = (
        "congratulation",
        "you have completed",
        "completed this",
        "successfully",
        "correct",
        "well done",
        "mission accomplished",
        "complete!",
    )
    failure_markers = (
        "wrong",
        "incorrect",
        "not correct",
        "try again",
        "failed",
        "too late",
        "time is up",
        "sorry",
    )
    success = any(marker in text for marker in success_markers)
    failure = any(marker in text for marker in failure_markers)
    if success and not failure:
        return True
    if failure and not success:
        return False
    return None


def main():
    client = session()
    response = client.get(LEVEL_URL, timeout=20)
    response.raise_for_status()
    words = parse_scrambled(body_text(response.text))
    table = load_wordlist(WORDLIST)
    answer = ",".join(unscramble(words, table))
    print("scrambled:", words)
    print("answer   :", answer)
    print("verdict  :", submit(client, answer))


if __name__ == "__main__":
    main()