class Capybara::Result

def [](*args)
  idx, length = args
  max_idx = case idx
  when Integer
    if idx.negative?
      nil
    else
      length.nil? ? idx : idx + length - 1
    end
  when Range
    # idx.max is broken with beginless ranges
    # idx.end && idx.max # endless range will have end == nil
    max = idx.end
    max = nil if max&.negative?
    max -= 1 if max && idx.exclude_end?
    max
  end
  if max_idx.nil?
    full_results[*args]
  else
    load_up_to(max_idx + 1)
    @result_cache[*args]
  end
end

def add_to_cache(elem)
  elem.allow_reload!(@result_cache.size) if @allow_reload
  @result_cache << elem
end

def allow_reload!
  @allow_reload = true
  self
end

def compare_count
  return 0 unless @query
  count, min, max, between = @query.options.values_at(:count, :minimum, :maximum, :between)
  # Only check filters for as many elements as necessary to determine result
  if count && (count = Integer(count))
    return load_up_to(count + 1) <=> count
  end
  return -1 if min && (min = Integer(min)) && (load_up_to(min) < min)
  return 1 if max && (max = Integer(max)) && (load_up_to(max + 1) > max)
  if between
    min, max = (between.begin && between.min) || 1, between.end
    max -= 1 if max && between.exclude_end?
    size = load_up_to(max ? max + 1 : min)
    return size <=> min unless between.include?(size)
  end
  0
end

def each(&block)
  return enum_for(:each) unless block
  @result_cache.each(&block)
  loop do
    next_result = @results_enum.next
    add_to_cache(next_result)
    yield next_result
  end
  self
end

def empty?
  !any?
end

def failure_message
  message = @query.failure_message
  if count.zero?
    message << ' but there were no matches'
  else
    message << ", found #{count} #{Capybara::Helpers.declension('match', 'matches', count)}: " \
            << full_results.map { |r| r.text.inspect }.join(', ')
  end
  unless rest.empty?
    elements = rest.map { |el| el.text rescue '<<ERROR>>' }.map(&:inspect).join(', ') # rubocop:disable Style/RescueModifier
    message << '. Also found ' << elements << ', which matched the selector but not all filters. '
    message << @filter_errors.join('. ') if (rest.size == 1) && count.zero?
  end
  message
end

def full_results
  loop { @result_cache << @results_enum.next }
  @result_cache
end

def initialize(elements, query)
  @elements = elements
  @result_cache = []
  @filter_errors = []
  @results_enum = lazy_select_elements { |node| query.matches_filters?(node, @filter_errors) }
  @query = query
  @allow_reload = false
end

def lazy_select_elements(&block)
  @elements.select(&block).to_enum # non-lazy evaluation
end

def lazy_select_elements(&block)
  @elements.lazy.select(&block)
end

def load_up_to(num)
  loop do
    break if @result_cache.size >= num
    add_to_cache(@results_enum.next)
  end
  @result_cache.size
end

def matches_count?
  compare_count.zero?
end

def negative_failure_message
  failure_message.sub(/(to find)/, 'not \1')
end

def rest
  @rest ||= @elements - full_results
end

def unfiltered_size
  @elements.length
end