from itertools import product
import string
import subprocess


def check_pair(script, instr, outstr):
    result = subprocess.run(
        ["/usr/bin/env", "bash", "-c", script],
        input=instr.encode(),
        capture_output=True,
    )
    return result.returncode == 0 and result.stdout == outstr.encode()


def check_pairs(script, pairs):
    for pair in pairs:
        if not check_pair(script, *pair):
            return False
    return True


def find_script(pairs, max_length):
    candidates = []
    chars = len(string.printable)
    total_options = int((chars ** (max_length + 1) - 1) / (chars - 1))
    current_option = 0

    for length in range(max_length + 1):
        for letters in product(string.printable, repeat=length):
            if current_option % 1000 == 0:
                print(f"Progress: {current_option}/{total_options}")

            script = "".join(letters)

            if check_pairs(script, pairs):
                print("> Found candidate:", script)
                candidates.append(script)

            current_option += 1

    print("Candidates:", candidates)


if __name__ == '__main__':
    # Identity
    print("\nSearching for identity")
    find_script((
        ("1", "1"),
        ("2", "2"),
        ("3", "3"),
    ), max_length=2)

    # Successor
    print("\nSearching for successor")
    find_script((
        ("1", "2"),
        ("2", "3"),
        ("3", "4"),
    ), max_length=5)