module RuboCop::Cop::UncommunicativeName

def allow_nums
  cop_config['AllowNamesEndingInNumbers']
end

def allowed_names
  cop_config['AllowedNames']
end

def arg_range(arg, length)
  begin_pos = arg.source_range.begin_pos
  Parser::Source::Range.new(processed_source.buffer, begin_pos, begin_pos + length)
end

def case_offense(node, range)
  add_offense(range, message: format(CASE_MSG, name_type: name_type(node)))
end

def check(node, args)
  args.each do |arg|
    # Argument names might be "_" or prefixed with "_" to indicate they
    # are unused. Trim away this prefix and only analyse the basename.
    name_child = arg.children.first
    next if name_child.nil?
    full_name = name_child.to_s
    next if full_name == '_'
    name = full_name.gsub(/\A(_+)/, '')
    next if allowed_names.include?(name)
    length = full_name.size
    length += 1 if arg.restarg_type?
    length += 2 if arg.kwrestarg_type?
    range = arg_range(arg, length)
    issue_offenses(node, range, name)
  end
end

def ends_with_num?(name)
  /\d/.match?(name[-1])
end

def forbidden_names
  cop_config['ForbiddenNames']
end

def forbidden_offense(node, range, name)
  add_offense(range, message: format(FORBIDDEN_MSG, name: name, name_type: name_type(node)))
end

def issue_offenses(node, range, name)
  forbidden_offense(node, range, name) if forbidden_names.include?(name)
  case_offense(node, range) if uppercase?(name)
  length_offense(node, range) unless long_enough?(name)
  return if allow_nums
  num_offense(node, range) if ends_with_num?(name)
end

def length_offense(node, range)
  message = format(LENGTH_MSG, name_type: name_type(node).capitalize, min: min_length)
  add_offense(range, message: message)
end

def long_enough?(name)
  name.size >= min_length
end

def min_length
  cop_config['MinNameLength']
end

def name_type(node)
  @name_type ||= case node.type
                 when :block then 'block parameter'
                 when :def, :defs then 'method parameter'
                 end
end

def num_offense(node, range)
  add_offense(range, message: format(NUM_MSG, name_type: name_type(node)))
end

def uppercase?(name)
  /[[:upper:]]/.match?(name)
end