class RuboCop::Cop::Metrics::Utils::CodeLengthCalculator

def build_foldable_checks(types)
  types.map do |type|
    case type
    when :array
      ->(node) { node.array_type? }
    when :hash
      ->(node) { node.hash_type? }
    when :heredoc
      ->(node) { heredoc_node?(node) }
    else
      raise ArgumentError, "Unknown foldable type: #{type.inspect}. "\
                           "Valid foldable types are: #{FOLDABLE_TYPES.join(', ')}."
    end
  end
end

def calculate
  length = code_length(@node)
  return length if @foldable_types.empty?
  each_top_level_descendant(@node, @foldable_types) do |descendant|
    next unless foldable_node?(descendant)
    descendant_length = code_length(descendant)
    length = length - descendant_length + 1
    # Subtract 2 length of opening and closing brace if method argument omits hash braces.
    length -= 2 if descendant.hash_type? && !descendant.braces?
  end
  length
end

def classlike_code_length(node)
  return 0 if namespace_module?(node)
  body_line_numbers = line_range(node).to_a[1...-1]
  target_line_numbers = body_line_numbers -
                        line_numbers_of_inner_nodes(node, :module, :class)
  target_line_numbers.reduce(0) do |length, line_number|
    source_line = @processed_source[line_number]
    next length if irrelevant_line?(source_line)
    length + 1
  end
end

def classlike_node?(node)
  CLASSLIKE_TYPES.include?(node&.type)
end

def code_length(node)
  if classlike_node?(node)
    classlike_code_length(node)
  elsif heredoc_node?(node)
    heredoc_length(node)
  else
    body = extract_body(node)
    return 0 unless body
    body.source.each_line.count { |line| !irrelevant_line?(line) }
  end
end

def count_comments?
  @count_comments
end

def each_top_level_descendant(node, types, &block)
  node.each_child_node do |child|
    next if classlike_node?(child)
    if types.include?(child.type)
      yield child
    else
      each_top_level_descendant(child, types, &block)
    end
  end
end

def extract_body(node)
  case node.type
  when :class, :module, :block, :def, :defs
    node.body
  when :casgn
    _scope, _name, value = *node
    extract_body(value)
  else
    node
  end
end

def foldable_node?(node)
  @foldable_checks.any? { |check| check.call(node) }
end

def heredoc_length(node)
  lines = node.loc.heredoc_body.source.lines
  lines.count { |line| !irrelevant_line?(line) } + 2
end

def heredoc_node?(node)
  node.respond_to?(:heredoc?) && node.heredoc?
end

def initialize(node, processed_source, count_comments: false, foldable_types: [])
  @node = node
  @processed_source = processed_source
  @count_comments = count_comments
  @foldable_checks = build_foldable_checks(foldable_types)
  @foldable_types = normalize_foldable_types(foldable_types)
end

def irrelevant_line?(source_line)
  source_line.blank? || !count_comments? && comment_line?(source_line)
end

def line_numbers_of_inner_nodes(node, *types)
  line_numbers = Set.new
  node.each_descendant(*types) do |inner_node|
    line_range = line_range(inner_node)
    line_numbers.merge(line_range)
  end
  line_numbers.to_a
end

def namespace_module?(node)
  classlike_node?(node.body)
end

def normalize_foldable_types(types)
  types.concat(%i[str dstr]) if types.delete(:heredoc)
  types
end