module Regexp::Expression::Shared

def self.included(mod)
  mod.class_eval do
    extend Shared::ClassMethods
    attr_accessor :type, :token, :text, :ts, :te,
                  :level, :set_level, :conditional_level,
                  :options, :parent,
                  :custom_to_s_handling, :pre_quantifier_decorations
    attr_reader   :nesting_level, :quantifier
  end
end

def ==(other)
  self.class   == other.class &&
    text       == other.text &&
    quantifier == other.quantifier &&
    options    == other.options &&
    (terminal? || expressions == other.expressions)
end

def base_length
  to_s(:base).length
end

def coded_offset
  '@%d+%d' % offset
end

def ends_at(include_quantifier = true)
  ts + (include_quantifier ? full_length : base_length)
end

def full_length
  to_s(:original).length
end

def human_name
  [token, type].compact.join(' ').tr('_', ' ')
end

def init_from_token_and_options(token, options = {})
  self.type              = token.type
  self.token             = token.token
  self.text              = token.text
  self.ts                = token.ts
  self.te                = token.te
  self.level             = token.level
  self.set_level         = token.set_level
  self.conditional_level = token.conditional_level
  self.nesting_level     = 0
  self.options           = options || {}
end

def initialize_copy(orig)
  self.text       = orig.text.dup         if orig.text
  self.options    = orig.options.dup      if orig.options
  self.quantifier = orig.quantifier.clone if orig.quantifier
  self.parent     = nil # updated by Subexpression#initialize_copy
  if orig.pre_quantifier_decorations
    self.pre_quantifier_decorations = orig.pre_quantifier_decorations.map(&:dup)
  end
  super
end

def inspect
  [
    "#<#{self.class}",
    pretty_print_instance_variables.map { |v| " #{v}=#{instance_variable_get(v).inspect}" },
    ">"
  ].join
end

def intersperse(expressions, separator)
  expressions.flat_map { |exp| [exp, separator] }.slice(0...-1)
end

def is?(test_token, test_type = nil)
  return true if test_token === :*
  token == test_token and (test_type ? type?(test_type) : true)
end

def negated?
  negative?
end

def negative?
  false
end

def nesting_level=(lvl)
  @nesting_level = lvl
  quantifier && quantifier.nesting_level = lvl
  terminal? || each { |subexp| subexp.nesting_level = lvl + 1 }
end

def offset
  [starts_at, full_length]
end

def one_of?(scope, top = true)
  case scope
  when Array
    scope.include?(:*) || scope.include?(token)
  when Hash
    if scope.has_key?(:*)
      test_type = scope.has_key?(type) ? type : :*
      one_of?(scope[test_type], false)
    else
      scope.has_key?(type) && one_of?(scope[type], false)
    end
  when Symbol
    scope.equal?(:*) || (top ? type?(scope) : is?(scope))
  else
    raise ArgumentError,
          "Array, Hash, or Symbol expected, #{scope.class.name} given"
  end
end

def optional?
  quantified? && quantifier.min == 0
end

def parts
  [text.dup]
end

def pre_quantifier_decoration(expression_format = :original)
  pre_quantifier_decorations.to_a.join if expression_format == :original
end

def pretty_print(q)
  q.pp_object(self)
end

def pretty_print_instance_variables
  [
    (:@text unless text.to_s.empty?),
    (:@quantifier if quantified?),
    (:@options unless options.empty?),
    (:@expressions unless terminal?),
  ].compact
end

def quantified?
  !quantifier.nil?
end

def quantifier=(qtf)
  @quantifier = qtf
  @repetitions = nil # clear memoized value
end

def quantifier_affix(expression_format = :full)
  quantifier.to_s if quantified? && expression_format != :base
end

def starts_at
  ts
end

def to_s(format = :full)
  base = parts.each_with_object(''.dup) do |part, buff|
    if part.instance_of?(String)
      buff << part
    elsif !part.custom_to_s_handling
      buff << part.to_s(:original)
    end
  end
  "#{base}#{pre_quantifier_decoration(format)}#{quantifier_affix(format)}"
end

def token_class
  self.class.token_class
end

def type?(test_type)
  test_types = Array(test_type).map(&:to_sym)
  test_types.include?(:*) || test_types.include?(type)
end