#!/usr/bin/env ruby

require 'optparse'
require_relative '../lib/sixword'

BaseName = File.basename($0)

def puts_err(message)
  $stderr.puts(BaseName + ': ' + message)
end

def parse_args
  options = {pad: true}
  optparse = OptionParser.new do |opts|
    opts.banner = <<-EOM
usage: #{BaseName} [OPTION]... [FILE]

Six-word encode or decode FILE, or standard input, to standard output.

The data are encoded using the 2048 word dictionary created for S/Key (tm) and
standardized by RFC 2289, RFC 1760, and RFC 1751. It also supports an optional
custom padding scheme to allow for messages that are not a multiple of 8 bytes.

With no FILE, or when FILE is -, read standard input.

#{BaseName} understands a few different styles of hexadecimal input and output.
When encoding, the input will first be decoded to binary data before being
encoded to words. When decoding, the output will be encoded in hex.


Hex styles:

  lower/lowercase:
    Accept a variety of inputs, but don't include whitespace in output.

    Encoding:
      '48:69:20:77:6f:72:6c:64' => 'Hi world' => 'ACRE ADEN INN SLID MAD PAP'
    Decoding:
      'ACRE ADEN INN SLID MAD PAP' => 'Hi world' => '486920776f726c64'

  finger/fingerprint:
    Accept a variety of inputs, and include whitespace in output.
    This is intended to look something like GPG fingerprints.

    Encoding:
      '4869 2077 6F72 6C64' => 'Hi world' => 'ACRE ADEN INN SLID MAP PAP'
    Decoding:
      'ACRE ADEN INN SLID MAP PAP' => 'Hi world' => '4869 2077 6F72 6C64'


Options:
    EOM

    opts.on('-h', '--help', 'Display this message', ' ') do
      $stderr.puts opts, ''
      exit 0
    end

    #

    opts.on('-d', '--decode', 'Decode data') do
      options[:mode] = :decode
    end

    opts.on('-p', '--no-pad', "Don't use custom padding scheme", ' ') do
      options[:pad] = false
    end

    #

    opts.on('-S', '--hex-style STYLE',
            'Treat input (when encoding) or print',
            'output (when decoding) as hex') do |style|
      options[:hex_style] = style
    end

    opts.on('-H', '--hex', 'Short for --hex-style lowercase') do
      options[:hex_style] = 'lowercase'
    end

    opts.on('-f', '--fingerprint', 'Short for --hex-style fingerprint') do
      options[:hex_style] = 'fingerprint'
    end
  end

  optparse.parse!

  case ARGV.length
  when 0
    filename = '-'
  when 1
    filename = ARGV.fetch(0)
  else
    $stderr.puts optparse, ''
    puts_err "extra operand #{ARGV.fetch(1).inspect}"
    exit 1
  end

  begin
    runner = Sixword::CLI.new(filename, options)
    runner.run!
  rescue Sixword::CLI::CLIError => err
    puts_err err.message
    exit 2
  rescue Sixword::InvalidParity => err
    puts_err err.message
    exit 3
  rescue Sixword::UnknownWord => err
    puts_err err.message
    exit 4
  rescue Sixword::InvalidWord => err
    puts_err err.message
    exit 5
  rescue Sixword::InputError => err
    puts_err err.message
    exit 10
  rescue Interrupt
    $stderr.puts
    exit 130 # not actually the same as signalled exit, but oh well
  end
end

parse_args