class Parser::Runner::RubyRewrite

def initialize
  super
  @rewriters = []
  @modify    = false
end

def load_and_discover(file)
  load file
  const_name = File.basename(file).
    sub(/\.rb$/, '').
    gsub(/(^|_)([a-z])/) do |m|
      "#{$2.upcase}"
    end
  @rewriters << Object.const_get(const_name)
end

def process(initial_buffer)
  buffer = initial_buffer
  original_name = buffer.name
  @rewriters.each do |rewriter_class|
    @parser.reset
    ast = @parser.parse(buffer)
    rewriter = rewriter_class.new
    new_source = rewriter.rewrite(buffer, ast)
    new_buffer = Source::Buffer.new(initial_buffer.name +
                                '|after ' + rewriter_class.name,
                                source: new_source)
    @parser.reset
    new_ast = @parser.parse(new_buffer)
    if !@modify && ast != new_ast
      $stderr.puts 'ASTs do not match:'
      old = Tempfile.new('old')
      old.write ast.inspect + "\n"; old.flush
      new = Tempfile.new('new')
      new.write new_ast.inspect + "\n"; new.flush
      IO.popen("diff -u #{old.path} #{new.path}") do |io|
        diff = io.read.
          sub(/^---.*/,    "--- #{buffer.name}").
          sub(/^\+\+\+.*/, "+++ #{new_buffer.name}")
        $stderr.write diff
      end
      exit 1
    end
    buffer = new_buffer
  end
  if File.exist?(original_name)
    File.open(original_name, 'w') do |file|
      file.write buffer.source
    end
  else
    if input_size > 1
      puts "Rewritten content of #{buffer.name}:"
    end
    puts buffer.source
  end
end

def runner_name
  'ruby-rewrite'
end

def setup_option_parsing(opts)
  super(opts)
  opts.on '-l file', '--load', 'Load a rewriter' do |file|
    load_and_discover(file)
  end
  opts.on '-m', '--modify', 'Assume rewriters normally modify AST' do
    @modify = true
  end
end