import hashlib

# Standard Base58 alphabet
BASE58_ALPHABET = "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz"

def base58_encode(raw_bytes):
    # Convert bytes to an integer
    n = int.from_bytes(raw_bytes, 'big')
    res = ""
    while n \u003e 0:
        n, r = divmod(n, 58)
        res = BASE58_ALPHABET[r] + res
    # Handle leading zeros (which become '1' in Base58)
    pad = 0
    for b in raw_bytes:
        if b == 0: pad += 1
        else: break
    return "1" * pad + res

def decode_p2pkh(script_hex):
    # 1. Check for standard P2PKH pattern
    # 76 (DUP) a9 (HASH160) 14 (PUSH 20) ... 88 (EQUALVERIFY) ac (CHECKSIG)
    if not (script_hex.startswith("76a914") and script_hex.endswith("88ac")):
        print("[ERROR] Not a standard P2PKH script!")
        return

    # 2. Extract the 20-byte hash
    pkh_hex = script_hex[6:-4]
    pkh_bytes = bytes.fromhex(pkh_hex)

    print(f"--- P2PKH Script Audit ---")
    print(f"[*] Raw Script: {script_hex}")
    print(f"[*] Key Hash:   {pkh_hex}")

    # 3. Base58Check Encoding
    # Step A: Prepend Version Byte (0x00 for Mainnet)
    versioned_pkh = b'\\x00' + pkh_bytes

    # Step B: Double SHA256 for checksum
    first_sha = hashlib.sha256(versioned_pkh).digest()
    checksum = hashlib.sha256(first_sha).digest()[:4]

    # Step C: Append Checksum and Encode
    final_payload = versioned_pkh + checksum
    address = base58_encode(final_payload)

    print(f"[*] Final Address: {address}")

# --- Simulation ---

# Case: A real-world legacy address ScriptPubKey
# address: 1A1zP1eP5QGefi2DMPTfTL5SLmv7DivfNa
p2pkh_script = "76a91462e907b15cbf27d5425399ebf6f0fb50ebb88f1888ac"
decode_p2pkh(p2pkh_script)