#!/usr/bin/env ruby

require 'optparse'
require 'portchecker'

# -------------------------------------------------------------------------------- #
# Check port                                                                       #
# -------------------------------------------------------------------------------- #
# This function will take the address and port and check to see if they are open.  #
# -------------------------------------------------------------------------------- #

def check_port(options)
    if Portchecker::Check.port_open?(options[:address], options[:port])
        puts "#{options[:address]} port #{options[:port]} is open"
    else
        puts "#{options[:address]} port #{options[:port]} is closed"
    end
end

# -------------------------------------------------------------------------------- #
# Process Arguments                                                                #
# -------------------------------------------------------------------------------- #
# This function will process the input from the command line and work out what it  #
# is that the user wants to see.                                                   #
#                                                                                  #
# This is the main processing function where all the processing logic is handled.  #
# -------------------------------------------------------------------------------- #

def process_arguments
    options = {}
    # Enforce the presence of
    mandatory = %I[address port]

    optparse = OptionParser.new do |opts|
        opts.banner = "Usage: #{$PROGRAM_NAME}"

        opts.on('-h', '--help', 'Display this screen') do
            puts opts
            exit(1)
        end
        opts.on('-a', '--address string', 'The address to connect to') do |address|
            options[:address] = address
        end

        opts.on('-p', '--port integer', 'The port to connect to') do |port|
            options[:port] = port
        end
    end

    begin
        optparse.parse!
        options[:message] = ARGF.read if !STDIN.tty? # override message parameter if data is piped in
        missing = mandatory.select { |param| options[param].nil? }
        raise OptionParser::MissingArgument.new(missing.join(', ')) unless missing.empty?
    rescue OptionParser::InvalidOption, OptionParser::MissingArgument => e
        puts e.to_s
        puts optparse
        exit
    end

    exit 0 if check_port(options)

    exit 1
end

# -------------------------------------------------------------------------------- #
# Main()                                                                           #
# -------------------------------------------------------------------------------- #
# The main function where all of the heavy lifting and script config is done.      #
# -------------------------------------------------------------------------------- #

def main
    process_arguments
end

main

# -------------------------------------------------------------------------------- #
# End of Script                                                                    #
# -------------------------------------------------------------------------------- #
# This is the end - nothing more to see here.                                      #
# -------------------------------------------------------------------------------- #