"""One-time ops bootstrap: encrypt an externally-generated master xprv and
write it to disk, using the exact same scheme generate_master_key.py uses
(Fernet, XPRV_ENCRYPTION_KEY). Use this instead of generate_master_key.py
when you already have an xprv from elsewhere (e.g. generated offline/air-
gapped) and want to bring your own instead of letting the server create one.

This is the single secret the entire custodial wallet derives from (every
user address, the pool address) — treat both the input and the resulting
encrypted file like a root password.

Usage:
    python scripts/encrypt_master_key.py
    python scripts/encrypt_master_key.py --overwrite   # replace an existing key

Requires XPRV_ENCRYPTION_KEY to already be set (.env). Writes to
MASTER_KEY_PATH (.env) — falls back to ./data/keys/master.xprv.enc (the
docker-compose.yml bind-mount location) if that directory exists and .env's
default path doesn't, same fallback as decrypt_master_key.py.
"""

import argparse
import getpass
import os

from embit.bip32 import HDKey

from app.config import settings
from app.wallet.keystore import encrypt_xprv

_DOCKER_COMPOSE_DIR = "./data/keys"


def _resolve_key_path() -> str:
    configured_dir = os.path.dirname(settings.master_key_path) or "."
    if os.path.isdir(configured_dir):
        return settings.master_key_path
    if os.path.isdir(_DOCKER_COMPOSE_DIR):
        path = os.path.join(_DOCKER_COMPOSE_DIR, os.path.basename(settings.master_key_path) or "master.xprv.enc")
        print(f"{configured_dir}/ not found — using {path} instead.")
        return path
    return settings.master_key_path


if __name__ == "__main__":
    parser = argparse.ArgumentParser()
    parser.add_argument("--overwrite", action="store_true", help="replace an existing encrypted key file")
    args = parser.parse_args()

    if not settings.xprv_encryption_key:
        raise SystemExit("XPRV_ENCRYPTION_KEY is not set")

    key_path = _resolve_key_path()
    if os.path.exists(key_path) and not args.overwrite:
        raise SystemExit(f"{key_path} already exists (pass --overwrite to replace it)")

    print("Paste the xprv to encrypt. Input is hidden and not echoed to the terminal.")
    xprv = getpass.getpass("xprv: ").strip()

    try:
        parsed = HDKey.from_base58(xprv)
    except Exception as exc:
        raise SystemExit(f"Not a valid extended key: {exc}") from exc

    # Not checking parsed.version against PLM_MAINNET["xprv"]: PLM reuses Bitcoin
    # mainnet's own xprv/xpub version bytes (see plm_network.py) — a Bitcoin (or
    # any Bitcoin-derived altcoin) xprv passes this check too, so it can't catch
    # "wrong network" mistakes. It only tells us this parses as *some* valid
    # extended key.
    if not parsed.is_private:
        raise SystemExit("This is a public key (xpub), not a private key (xprv) — refusing to encrypt it as one.")

    os.makedirs(os.path.dirname(key_path) or ".", exist_ok=True)
    with open(key_path, "wb") as f:
        f.write(encrypt_xprv(xprv))

    print(f"Master key written (encrypted) to {key_path}")