#!/usr/bin/env python3

import argparse
import os
import sys
from lightning import LightningRpc

parser = argparse.ArgumentParser(formatter_class=argparse.ArgumentDefaultsHelpFormatter)
parser.add_argument("bolt11_or_destination_id")
parser.add_argument("amount_in_milli_satoshi", default=None, type=int, nargs="?")
parser.add_argument("payment_hash", nargs="?")
args = parser.parse_args()


def default_configdir():
    home = os.getenv("HOME")
    if home:
        return os.path.join(home, ".lightning")
    return "."


rpc_path = os.path.join(default_configdir(), "lightning-rpc")
ld = LightningRpc(rpc_path)

assert len(args.bolt11_or_destination_id) > 2, "argument bolt11_or_destination_id is invalid"
prefix = args.bolt11_or_destination_id[:2]

if prefix == "ln":
    bolt11 = ld.decodepay(args.bolt11_or_destination_id)
    id_ = bolt11["payee"]
    payment_hash = bolt11["payment_hash"]
    if "msatoshi" in bolt11:
        amount = bolt11["msatoshi"]
    else:
        assert args.amount_in_milli_satoshi, "need argument amount_in_milli_satoshi"
        amount = args.amount_in_milli_satoshi
else:
    assert args.amount_in_milli_satoshi, "need argument amount_in_milli_satoshi"
    assert args.payment_hash, "need argument payment_hash"
    amount = args.amount_in_milli_satoshi
    id_ = args.bolt11_or_destination_id
    payment_hash = args.payment_hash

route = ld.getroute(id_, amount, 1)

fee = route["route"][0]["msatoshi"] - amount

reply = input("Paying fee %s on amount %s (%.3f%%). Send [Y/n]?" % (fee, amount, fee / amount * 100.0))

if reply in ["y", "Y"]:
    ld.sendpay(route["route"], payment_hash)
else:
    print("Not sending.")
    sys.exit(1)