#!/bin/sh

# The MIT License (MIT)
#
# Copyright © 2020-2025 pacman64
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the “Software”), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.


# telltime [port]
#
# Start a TCP server which always replies with the current local date/time as
# a plain-text line.


case "$1" in
    -h|--h|-help|--help)
        awk '/^# +telltime /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
        exit 0
    ;;
esac

# if [ -z "$1" ]; then
#     awk '/^# +telltime /, /^$/ { gsub(/^# ?/, ""); print }' "$0"
#     exit 0
# fi

gawk -v port="$1" '
    BEGIN {
        if (port == "") {
            fmt = "\x1b[31myou forgot the port number\x1b[0m\n"
            printf(fmt) > "/dev/stderr"
            exit 1
        }

        if (port < 1 || port > 65535) {
            fmt = "\x1b[31m%s is an invalid port number\x1b[0m\n"
            printf(fmt, port) > "/dev/stderr"
            exit 1
        }

        server = sprintf("/inet/tcp/%d/0/0", port)
        PROCINFO[server, "READ_TIMEOUT"] = 200

        msg = "current date and time on telnet://localhost:%d\n"
        printf(msg, port) > "/dev/stderr"

        while (1) {
            print strftime("%Y-%m-%d %H:%M:%S") |& server
            close(server)
        }

        exit
    }
'