class RuboCop::Cop::StatsD::PositionalArguments

def autocorrect(node)
  -> (corrector) do
    positional_arguments = if node.arguments.last.type == :block_pass
      node.arguments[2...node.arguments.length - 1]
    else
      node.arguments[2...node.arguments.length]
    end
    case positional_arguments[0].type
    when *UNKNOWN_ARGUMENT_TYPES
      # We don't know whether the method returns a hash, in which case it would be interpreted
      # as keyword arguments. In this case, the fix would be to add a keyword splat:
      #
      # `StatsD.instrument('foo', 1, method_call)`
      # => `StatsD.instrument('foo', 1, **method_call)`
      #
      # However, it's also possible this method returns a sample rate, in which case the fix
      # above will not do the right thing.
      #
      # `StatsD.instrument('foo', 1, SAMPLE_RATE_CONSTANT)`
      # => `StatsD.instrument('foo', 1, sample_rate: SAMPLE_RATE_CONSTANT)`
      #
      # Because of this, we will not auto-correct and let the user fix the issue manually.
      return
    when *POSITIONAL_ARGUMENT_TYPES
      value_argument = node.arguments[1]
      from = value_argument.source_range.end_pos
      to = positional_arguments.last.source_range.end_pos
      range = Parser::Source::Range.new(node.source_range.source_buffer, from, to)
      corrector.remove(range)
      keyword_arguments = []
      sample_rate = positional_arguments[0]
      if sample_rate && sample_rate.type != :nil
        keyword_arguments << "sample_rate: #{sample_rate.source}"
      end
      tags = positional_arguments[1]
      if tags && tags.type != :nil
        keyword_arguments << if tags.type == :hash && tags.source[0] != "{"
          "tags: { #{tags.source} }"
        else
          "tags: #{tags.source}"
        end
      end
      unless keyword_arguments.empty?
        corrector.insert_after(value_argument.source_range, ", #{keyword_arguments.join(", ")}")
      end
    end
  end
end

def on_send(node)
  if metric_method?(node) && node.arguments.length >= 3
    case node.arguments[2].type
    when *REFUSED_ARGUMENT_TYPES
      add_offense(node)
    when *ACCEPTED_ARGUMENT_TYPES
      nil
    else
      $stderr.puts "[StatsD/PositionalArguments] Unhandled argument type: #{node.arguments[2].type.inspect}"
    end
  end
end