class Byebug::Runner

def banner
  <<-EOB.gsub(/^ {6}/, '')
    byebug #{Byebug::VERSION}
    Usage: byebug [options] <script.rb> -- <script.rb parameters>
  EOB
end

def debug_program
  error = Byebug.debug_load($PROGRAM_NAME, stop)
  puts "#{error}\n#{error.backtrace}" if error
end

def error_in_script?
  no_script? || non_existing_script? || invalid_script?
end

def help=(text)
  @help ||= text
  interface.puts("#{text}\n")
end

def init_script
  defined?(@init_script) ? @init_script : true
end

def initialize(stop = true, quit = true)
  @stop = stop
  @quit = quit
end

def interface
  @interface ||= LocalInterface.new
end

def invalid_script?
  return false if syntax_valid?(File.read($PROGRAM_NAME))
  print_error('The script has incorrect syntax')
  true
end

def no_script?
  return false unless $ARGV.empty?
  print_error('You must specify a program to debug')
  true
end

def non_existing_script?
  Byebug.mode = :standalone
  program = which($ARGV.shift)
  program = which($ARGV.shift) if program == which('ruby')
  if program
    $PROGRAM_NAME = program
    false
  else
    print_error("The script doesn't exist")
    true
  end
end

def non_script_option?
  version || help || remote
end

def option_parser
  @option_parser ||= OptionParser.new(banner, 25) do |opts|
    opts.banner = banner
    OptionSetter.new(self, opts).setup
  end
end

def print_error(msg)
  interface.errmsg(msg)
  interface.puts(option_parser.help)
end

def remote=(host_and_port)
  @remote ||= Byebug.parse_host_and_port(host_and_port)
  Byebug.start_client(*@remote)
end

def run
  option_parser.order!($ARGV)
  return if non_script_option? || error_in_script?
  Byebug.run_init_script if init_script
  loop do
    debug_program
    break if quit
    ControlProcessor.new.process_commands
  end
end

def version=(number)
  @version ||= number
  interface.puts("\n  Running byebug #{number}\n")
end

def which(cmd)
  return File.expand_path(cmd) if File.exist?(cmd)
  exts = ENV['PATHEXT'] ? ENV['PATHEXT'].split(';') : ['']
  ENV['PATH'].split(File::PATH_SEPARATOR).each do |path|
    exts.each do |ext|
      exe = File.join(path, "#{cmd}#{ext}")
      return exe if File.executable?(exe) && !File.directory?(exe)
    end
  end
  nil
end