#!/usr/bin/env ruby
require 'conceal'
require 'optparse'

class Options < Struct.new(:trailing_newline)
end

def main
  opts = Options.new
  opts.trailing_newline = true

  OptionParser.new do |o|
    o.banner = 'Usage: decrypt KEY_FILE'
    o.on('-h', '--help', 'show this message') do
      puts o
      exit(0)
    end
    o.on('-n', "don't print the trailing newline") do
      opts.trailing_newline = false
    end
    o.on('-v', '--version', 'print the version') do
      puts Conceal::VERSION
    end
  end.parse!(ARGV)

  # read the key file
  if ARGV.empty?
    $stderr.puts "Missing KEY_FILE argument"
    exit(1)
  end
  key_file = ARGV.shift
  key = IO.read(key_file)

  # decrypt from stdin
  encrypted_data = $stdin.read
  plaintext = Conceal.decrypt(encrypted_data, key: key)

  $stdout.write(plaintext)
  $stdout.write("\n") if opts.trailing_newline
end

main