#!/usr/bin/env python3.7
#
# Copyright (c) 2013-2024 by Ron Frederick <ronf@timeheart.net> and others.
#
# This program and the accompanying materials are made available under
# the terms of the Eclipse Public License v2.0 which accompanies this
# distribution and is available at:
#
#     http://www.eclipse.org/legal/epl-2.0/
#
# This program may also be made available under the following secondary
# licenses when the conditions for such availability set forth in the
# Eclipse Public License v2.0 are satisfied:
#
#    GNU General Public License, Version 2.0, or any later versions of
#    that license
#
# SPDX-License-Identifier: EPL-2.0 OR GPL-2.0-or-later
#
# Contributors:
#     Ron Frederick - initial implementation, API, and documentation

# To run this program, the file ``ssh_host_key`` must exist with an SSH
# private key in it to use as a server host key. An SSH host certificate
# can optionally be provided in the file ``ssh_host_key-cert.pub``.
#
# The file ``ssh_user_ca`` must exist with a cert-authority entry of
# the certificate authority which can sign valid client certificates.

import asyncio
import sys

import asyncssh


async def handle_client(process: asyncssh.SSHServerProcess) -> None:

    width, height, pixwidth, pixheight = process.term_size

    process.stdout.write(
        f"Terminal type: {process.term_type}, " f"size: {width}x{height}"
    )
    if pixwidth and pixheight:
        process.stdout.write(f" ({pixwidth}x{pixheight} pixels)")
    process.stdout.write("\nTry resizing your window!\n")

    while not process.stdin.at_eof():
        try:
            await process.stdin.read()
        except asyncssh.TerminalSizeChanged as exc:
            process.stdout.write(f"New window size: {exc.width}x{exc.height}")
            if exc.pixwidth and exc.pixheight:
                process.stdout.write(f" ({exc.pixwidth}" f"x{exc.pixheight} pixels)")
            process.stdout.write("\n")


async def start_server() -> None:
    await asyncssh.listen(
        "",
        2230,
        server_host_keys=["ssh_host_key"],
        # authorized_client_keys='ssh_user_ca',
        process_factory=handle_client,
    )


loop = asyncio.new_event_loop()

try:
    loop.run_until_complete(start_server())
except (OSError, asyncssh.Error) as exc:
    sys.exit("Error starting server: " + str(exc))

loop.run_forever()