from sage.all import *
from Crypto.Util.number import long_to_bytes
from Crypto.Util.Padding import pad
import gzip, base64, os, string, random

FLAG = os.getenv("FLAG", "dach2026{fake_flag}")
REQUIRED_WINS = 25

p = 0x1337
Fp = GF(p)

I = matrix.random(Fp, 4)

def hash(message: bytes):
    m = pad(message, 25)
    assert len(m) % 25 == 0

    sections = []
    for i in range(0, len(m), 25):
        block = int(m[i:i+25].hex(), 16)

        digits = []
        for _ in range(16):
            digits.append(block % p)
            block //= p

        sections.append(matrix(Fp, [digits[:4], digits[4:8], digits[8:12], digits[12:]]))

    A = I
    for S in sections:
        A *= S

    hashsum = 0
    for el in sum([list(r) for r in A.rows()], [])[::-1]:
        hashsum *= p
        hashsum += int(el)

    return long_to_bytes(hashsum, 25)

def random_hash():
    return hash(os.urandom(25))

def random_message(n):
    return "".join([random.choice(string.ascii_letters) for _ in range(n)])

def main():
    print("Welcome to ZIPPER!")

    wins = 0

    while True:
        target_message = random_message(32)
        target_hash = random_hash() # Make this game impossible ( ͡° ͜ʖ ͡°)

        print(f"I am thinking of a gzip file that decompresses to '{target_message}' and has a hash of '{target_hash.hex()}'.")
        print("What file am I thinking of?")
        user_input = input("> ")

        try:
            file = base64.b64decode(user_input)
            file_hash = hash(file)

            if len(file) == 0:
                continue

            if file_hash != target_hash:
                wins = 0
                print(f"Wrong hash: {file_hash.hex()} != {target_hash.hex()}.")
                continue

            if gzip.decompress(file).decode() != target_message:
                wins = 0
                print("Wrong data!")
                continue

            wins += 1
            print(f"CORRECT! You have {REQUIRED_WINS-wins} wins more to go to get a prize!")

            if wins >= REQUIRED_WINS:
                print("Congratulations, you've outguessed me!")
                print("\n" + FLAG + "\n")
                wins = 0
        except KeyboardInterrupt:
            exit(0)
        except:
            print("Wrong **insert whatever here**!")
            wins = 0

if __name__ == "__main__":
    main()