class IRB::ExtendCommand::ShowSource

def bold(str)
  Color.colorize(str, [:BOLD])
end

def execute(str = nil)
  unless str.is_a?(String)
    puts "Error: Expected a string but got #{str.inspect}"
    return
  end
  source = self.class.find_source(str, @irb_context)
  if source && File.exist?(source.file)
    show_source(source)
  else
    puts "Error: Couldn't locate a definition for #{str}"
  end
  nil
end

def find_end(file, first_line, irb_context)
  return first_line unless File.exist?(file)
  lex = RubyLex.new(irb_context)
  lines = File.read(file).lines[(first_line - 1)..-1]
  tokens = RubyLex.ripper_lex_without_warning(lines.join)
  prev_tokens = []
  # chunk with line number
  tokens.chunk { |tok| tok.pos[0] }.each do |lnum, chunk|
    code = lines[0..lnum].join
    prev_tokens.concat chunk
    continue = lex.should_continue?(prev_tokens)
    syntax = lex.check_code_syntax(code)
    if !continue && syntax == :valid
      return first_line + lnum
    end
  end
  first_line
end

def find_source(str, irb_context)
  case str
  when /\A[A-Z]\w*(::[A-Z]\w*)*\z/ # Const::Name
    eval(str, irb_context.workspace.binding) # trigger autoload
    base = irb_context.workspace.binding.receiver.yield_self { |r| r.is_a?(Module) ? r : Object }
    file, line = base.const_source_location(str)
  when /\A(?<owner>[A-Z]\w*(::[A-Z]\w*)*)#(?<method>[^ :.]+)\z/ # Class#method
    owner = eval(Regexp.last_match[:owner], irb_context.workspace.binding)
    method = Regexp.last_match[:method]
    if owner.respond_to?(:instance_method)
      methods = owner.instance_methods + owner.private_instance_methods
      file, line = owner.instance_method(method).source_location if methods.include?(method.to_sym)
    end
  when /\A((?<receiver>.+)(\.|::))?(?<method>[^ :.]+)\z/ # method, receiver.method, receiver::method
    receiver = eval(Regexp.last_match[:receiver] || 'self', irb_context.workspace.binding)
    method = Regexp.last_match[:method]
    file, line = receiver.method(method).source_location if receiver.respond_to?(method, true)
  end
  if file && line
    Source.new(file: file, first_line: line, last_line: find_end(file, line, irb_context))
  end
end

def show_source(source)
  puts
  puts "#{bold("From")}: #{source.file}:#{source.first_line}"
  puts
  code = IRB::Color.colorize_code(File.read(source.file))
  puts code.lines[(source.first_line - 1)...source.last_line].join
  puts
end

def transform_args(args)
  # Return a string literal as is for backward compatibility
  if args.empty? || string_literal?(args)
    args
  else # Otherwise, consider the input as a String for convenience
    args.strip.dump
  end
end