#!/usr/bin/env ruby

require "optparse"
require "ffxcodec"

examples = <<-EOF
Examples:

- Encode:
  ffxcodec --alloc=40:24 1234567890 4

- Decode:
  ffxcodec --alloc=40:24 20712612157194244

- Encrypted encode:
  ffxcodec --alloc=40:24 --key=2b7e151628aed2a6abf7158809cf4f3c --tweak=FZNT4F22E5QA5QUM 1234567890 4

- Encrypted decode:
  ffxcodec --alloc=40:24 --key=2b7e151628aed2a6abf7158809cf4f3c --tweak=FZNT4F22E5QA5QUM 5539580373534012574
EOF

options = {}
OptionParser.new do |opts|
  opts.banner = "Usage: ffxcodec [options] [args]"

  opts.on("-aLEFT:RIGHT", "--alloc LEFT:RIGHT", "Bit allocation - must add up to 32/64 (REQUIRED)") do |b|
    left, right = b.split(":").map(&:to_i)
    options[:l_alloc] = left
    options[:r_alloc] = right
  end

  opts.on("-kKEY", "--key KEY", "Hex key to encrypt with (use with --tweak)") do |k|
    options[:key] = k
  end

  opts.on("-tTWEAK", "--tweak TWEAK", "Tweak to encrypt with (use with --key)") do |t|
    options[:tweak] = t
  end

  opts.on("-m", "--maximums", "Show max integers for the given allocation and exit") do
    options[:maximum] = true
  end

  opts.on_tail("-h", "--help", "Show this message") do
    puts opts
    puts ""
    puts examples
    exit
  end
end.parse!

if options[:l_alloc].nil? || options[:r_alloc].nil?
  warn "Must provide left and right bit allocation like: --alloc=40:24"
  exit 2
end

ffx = FFXCodec.new(options[:l_alloc], options[:r_alloc])

if options[:maximum]
  l_max, r_max = ffx.maximums
  puts "Left max: #{l_max}"
  puts "Right max: #{r_max}"
  exit
end

if options[:key] || options[:tweak]
  if [options[:key], options[:tweak]].any?(&:nil?)
    warn "Must use --key with --tweak to enable encryption"
    exit 2
  end
  ffx.setup_encryption(options[:key], options[:tweak])
end

case ARGV.count
when 1
  encoded = ARGV[0].to_i
  a, b = ffx.decode(encoded)
  puts "[#{a}, #{b}]"
when 2
  a = ARGV[0].to_i
  b = ARGV[1].to_i
  encoded = ffx.encode(a, b)
  puts "Encoded: #{encoded}"
else
  warn "Wrong number of values provided to encode or decode."
  exit 2
end