#!/usr/bin/env python3
# SPDX-License-Identifier: BSD-3-Clause OR Apache-2.0
# encoding: utf-8

"""
A tool to send custom bundles via the MTCP CLA to a specified DTN node.
"""

import argparse
import sys

from pyd3tn.bundle7 import serialize_bundle7, BundleProcFlag
from pyd3tn.bundle6 import serialize_bundle6, RFC5050Flag
from pyd3tn.eid import validate_eid
from pyd3tn.mtcp import MTCPConnection

# The MUST_NOT_BE_FRAGMENTED flag is required if the source EID is dtn:none.
BPV7_FLAGS = BundleProcFlag.MUST_NOT_BE_FRAGMENTED
BPV6_FLAGS = RFC5050Flag.DEFAULT_OUTGOING | RFC5050Flag.MUST_NOT_BE_FRAGMENTED


def _argparse_non_empty_str(value):
    """An argparse type validation function to exclude the empty string."""
    if value is None or value.strip() == "":
        raise argparse.ArgumentTypeError("must not be empty")
    return value


def main():
    parser = argparse.ArgumentParser(
        description="send a bundle via uD3TN's MTCP interface",
    )
    parser.add_argument(
        "dst_eid",
        type=_argparse_non_empty_str,
        help="the destination EID of the created bundle",
    )
    parser.add_argument(
        "PAYLOAD",
        default=None,
        nargs="?",
        help="the payload of the created bundle, (default: read from STDIN)",
    )
    parser.add_argument(
        "-l", "--host",
        default="127.0.0.1",
        help="MTCP host or IP address to connect to (default: 127.0.0.1)",
    )
    parser.add_argument(
        "-p", "--port",
        type=int,
        default=4224,
        help="MTCP port to connect to (default: 4224)",
    )
    parser.add_argument(
        "-s", "--src-eid",
        default="dtn:none",
        help="EID of sender (default: dtn:none)",
    )
    parser.add_argument(
        "-b", "--bundle-version",
        default="7",
        choices=["6", "7"],
        help="Version of the bundle protocol to use (defaults to 7)",
    )
    parser.add_argument(
        "--timeout",
        type=int, default=3000,
        help="TCP timeout in ms (default: 3000)",
    )

    args = parser.parse_args()

    serialize_bundle = {
        "6": serialize_bundle6,
        "7": serialize_bundle7,
    }[args.bundle_version]

    if args.PAYLOAD:
        payload = args.PAYLOAD.encode("utf-8")
    else:
        payload = sys.stdin.buffer.read()
        sys.stdin.buffer.close()

    validate_eid(args.dst_eid)

    with MTCPConnection(args.host, args.port, timeout=args.timeout) as conn:
        conn.send_bundle(serialize_bundle(
            args.src_eid,
            args.dst_eid,
            payload,
            flags=(
                BPV7_FLAGS
                if args.bundle_version == "7"
                else BPV6_FLAGS
            ),
        ))


if __name__ == "__main__":
    main()