import hashlib

# Standard Base58 Alphabet
ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"

def decode_base58(s):
    """Converts a Base58 string back into raw bytes."""
    num = 0
    for char in s:
        num = num * 58 + ALPHABET.index(char)

    # Convert to 25 bytes (1 version + 20 hash + 4 checksum)
    return num.to_bytes(25, byteorder='big')

def audit_address(address_str):
    print(f"--- Bitcoin Address (Base58) Audit ---")
    print(f"[*] Address: {address_str}")

    # 1. Decode to raw bytes
    try:
        decoded = decode_base58(address_str)
    except Exception as e:
        print("[ERROR] Invalid characters in address.")
        return

    # 2. Split components
    version = decoded[0]
    payload = decoded[1:21]
    checksum_received = decoded[21:]

    print(f"[*] Version Byte: {hex(version)}")
    print(f"[*] PKH (20 bytes): {payload.hex()}")
    print(f"[*] Checksum: {checksum_received.hex()}")

    # 3. Verify Checksum (Double SHA256)
    # Hash the (version + payload)
    hash1 = hashlib.sha256(decoded[:21]).digest()
    hash2 = hashlib.sha256(hash1).digest()
    checksum_calculated = hash2[:4]

    # 4. Final Comparison
    if checksum_received == checksum_calculated:
        print("[SUCCESS] Checksum is VALID.")
        if version == 0x00:
            print("[TYPE] Legacy P2PKH (starts with 1)")
        elif version == 0x05:
            print("[TYPE] Legacy P2SH (starts with 3)")
    else:
        print("[ERROR] INVALID CHECKSUM! This address has a typo.")

# --- Simulation ---

# Case: A valid legacy address
valid_addr = "1BvBMSEYstWetqTFn5Au4m4GFg7xJaNVN2"
audit_address(valid_addr)

# Case: An address with a typo (changed the last '2' to '3')
print("\n--- Testing Typo ---")
typo_addr = "1BvBMSEYstWetqTFn5Au4m4GFg7xJaNVN3"
audit_address(typo_addr)