#!/usr/bin/env python3
import base64
import sys
from cryptography.hazmat.primitives.ciphers.aead import AESGCM
import traceback

CIPHERTEXT = "Cf7z9+sZxDpNX4XxtVqY3X1NH+s/WlE6hWdpwKgIVRr3SdLls1dmYF7TFS/s2vlUVLxFb47Qd0f5t7GcKacwwvao++I4pA1ZHv8="
NONCE = "1hAHFOm7LXsF7SCj"

def b64decode_str(s: str) -> bytes:
    try:
        return base64.b64decode(s, validate=True)
    except Exception as e:
        raise ValueError(f"Invalid base64 input: {e}")

def decrypt_aes256gcm(key: bytes) -> bytes:
    nonce = b64decode_str(NONCE)
    ciphertext = b64decode_str(CIPHERTEXT)
    if len(key) != 32:
        raise ValueError(f"Invalid key length: {len(key)} bytes (expected 32 bytes for AES-256)")

    aesgcm = AESGCM(key)
    plaintext = aesgcm.decrypt(nonce, ciphertext, None)
    return plaintext

def encrypt_aes256gcm(key: bytes) -> bytes:
    nonce = b64decode_str(NONCE)
    ciphertext = b64decode_str(CIPHERTEXT)
    aesgcm = AESGCM(key)
    test = aesgcm.encrypt(nonce, ciphertext, None)
    return base64.b64encode(test)

def main():
    if len(sys.argv) != 2:
        print("Error: Enter the path to the key binary file as an argument")
        exit(1)
    path = sys.argv[1]
    with open(path, "rb") as f:
        key = f.read()
    try:
        plaintext = decrypt_aes256gcm(key)
    except Exception as e:
        print(f"Decryption failed: {e}", file=sys.stderr)
        traceback.print_exc()
        sys.exit(2)

    print(plaintext)

if __name__ == "__main__":
    main()